XFA: Upgrade libpng to 1.6.20.

R=tsepez@chromium.org

Review URL: https://codereview.chromium.org/1591483003 .

1 files changed, 0 insertions, 3022 deletions

diff --git a/third_party/lpng_v163/pngwutil.c b/third_party/lpng_v163/pngwutil.c
deleted file mode 100644
index dd5d659f3c..0000000000
--- a/third_party/lpng_v163/pngwutil.c
+++ /dev/null
@@ -1,3022 +0,0 @@
-

-/* pngwutil.c - utilities to write a PNG file

- *

- * Last changed in libpng 1.6.2 [April 25, 2013]

- * Copyright (c) 1998-2013 Glenn Randers-Pehrson

- * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)

- * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)

- *

- * This code is released under the libpng license.

- * For conditions of distribution and use, see the disclaimer

- * and license in png.h

- */

-#include "pngpriv.h"

-

-#ifdef PNG_WRITE_SUPPORTED

-

-#ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED

-/* Place a 32-bit number into a buffer in PNG byte order.  We work

- * with unsigned numbers for convenience, although one supported

- * ancillary chunk uses signed (two's complement) numbers.

- */

-void PNGAPI

-png_save_uint_32(png_bytep buf, png_uint_32 i)

-{

-   buf[0] = (png_byte)((i >> 24) & 0xff);

-   buf[1] = (png_byte)((i >> 16) & 0xff);

-   buf[2] = (png_byte)((i >> 8) & 0xff);

-   buf[3] = (png_byte)(i & 0xff);

-}

-

-/* Place a 16-bit number into a buffer in PNG byte order.

- * The parameter is declared unsigned int, not png_uint_16,

- * just to avoid potential problems on pre-ANSI C compilers.

- */

-void PNGAPI

-png_save_uint_16(png_bytep buf, unsigned int i)

-{

-   buf[0] = (png_byte)((i >> 8) & 0xff);

-   buf[1] = (png_byte)(i & 0xff);

-}

-#endif

-

-/* Simple function to write the signature.  If we have already written

- * the magic bytes of the signature, or more likely, the PNG stream is

- * being embedded into another stream and doesn't need its own signature,

- * we should call png_set_sig_bytes() to tell libpng how many of the

- * bytes have already been written.

- */

-void PNGAPI

-png_write_sig(png_structrp png_ptr)

-{

-   png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};

-

-#ifdef PNG_IO_STATE_SUPPORTED

-   /* Inform the I/O callback that the signature is being written */

-   png_ptr->io_state = PNG_IO_WRITING | PNG_IO_SIGNATURE;

-#endif

-

-   /* Write the rest of the 8 byte signature */

-   png_write_data(png_ptr, &png_signature[png_ptr->sig_bytes],

-      (png_size_t)(8 - png_ptr->sig_bytes));

-

-   if (png_ptr->sig_bytes < 3)

-      png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;

-}

-

-/* Write the start of a PNG chunk.  The type is the chunk type.

- * The total_length is the sum of the lengths of all the data you will be

- * passing in png_write_chunk_data().

- */

-static void

-png_write_chunk_header(png_structrp png_ptr, png_uint_32 chunk_name,

-    png_uint_32 length)

-{

-   png_byte buf[8];

-

-#if defined(PNG_DEBUG) && (PNG_DEBUG > 0)

-   PNG_CSTRING_FROM_CHUNK(buf, chunk_name);

-   png_debug2(0, "Writing %s chunk, length = %lu", buf, (unsigned long)length);

-#endif

-

-   if (png_ptr == NULL)

-      return;

-

-#ifdef PNG_IO_STATE_SUPPORTED

-   /* Inform the I/O callback that the chunk header is being written.

-    * PNG_IO_CHUNK_HDR requires a single I/O call.

-    */

-   png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_HDR;

-#endif

-

-   /* Write the length and the chunk name */

-   png_save_uint_32(buf, length);

-   png_save_uint_32(buf + 4, chunk_name);

-   png_write_data(png_ptr, buf, 8);

-

-   /* Put the chunk name into png_ptr->chunk_name */

-   png_ptr->chunk_name = chunk_name;

-

-   /* Reset the crc and run it over the chunk name */

-   png_reset_crc(png_ptr);

-

-   png_calculate_crc(png_ptr, buf + 4, 4);

-

-#ifdef PNG_IO_STATE_SUPPORTED

-   /* Inform the I/O callback that chunk data will (possibly) be written.

-    * PNG_IO_CHUNK_DATA does NOT require a specific number of I/O calls.

-    */

-   png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_DATA;

-#endif

-}

-

-void PNGAPI

-png_write_chunk_start(png_structrp png_ptr, png_const_bytep chunk_string,

-    png_uint_32 length)

-{

-   png_write_chunk_header(png_ptr, PNG_CHUNK_FROM_STRING(chunk_string), length);

-}

-

-/* Write the data of a PNG chunk started with png_write_chunk_header().

- * Note that multiple calls to this function are allowed, and that the

- * sum of the lengths from these calls *must* add up to the total_length

- * given to png_write_chunk_header().

- */

-void PNGAPI

-png_write_chunk_data(png_structrp png_ptr, png_const_bytep data,

-    png_size_t length)

-{

-   /* Write the data, and run the CRC over it */

-   if (png_ptr == NULL)

-      return;

-

-   if (data != NULL && length > 0)

-   {

-      png_write_data(png_ptr, data, length);

-

-      /* Update the CRC after writing the data,

-       * in case that the user I/O routine alters it.

-       */

-      png_calculate_crc(png_ptr, data, length);

-   }

-}

-

-/* Finish a chunk started with png_write_chunk_header(). */

-void PNGAPI

-png_write_chunk_end(png_structrp png_ptr)

-{

-   png_byte buf[4];

-

-   if (png_ptr == NULL) return;

-

-#ifdef PNG_IO_STATE_SUPPORTED

-   /* Inform the I/O callback that the chunk CRC is being written.

-    * PNG_IO_CHUNK_CRC requires a single I/O function call.

-    */

-   png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_CRC;

-#endif

-

-   /* Write the crc in a single operation */

-   png_save_uint_32(buf, png_ptr->crc);

-

-   png_write_data(png_ptr, buf, (png_size_t)4);

-}

-

-/* Write a PNG chunk all at once.  The type is an array of ASCII characters

- * representing the chunk name.  The array must be at least 4 bytes in

- * length, and does not need to be null terminated.  To be safe, pass the

- * pre-defined chunk names here, and if you need a new one, define it

- * where the others are defined.  The length is the length of the data.

- * All the data must be present.  If that is not possible, use the

- * png_write_chunk_start(), png_write_chunk_data(), and png_write_chunk_end()

- * functions instead.

- */

-static void

-png_write_complete_chunk(png_structrp png_ptr, png_uint_32 chunk_name,

-   png_const_bytep data, png_size_t length)

-{

-   if (png_ptr == NULL)

-      return;

-

-   /* On 64 bit architectures 'length' may not fit in a png_uint_32. */

-   if (length > PNG_UINT_31_MAX)

-      png_error(png_ptr, "length exceeds PNG maxima");

-

-   png_write_chunk_header(png_ptr, chunk_name, (png_uint_32)length);

-   png_write_chunk_data(png_ptr, data, length);

-   png_write_chunk_end(png_ptr);

-}

-

-/* This is the API that calls the internal function above. */

-void PNGAPI

-png_write_chunk(png_structrp png_ptr, png_const_bytep chunk_string,

-   png_const_bytep data, png_size_t length)

-{

-   png_write_complete_chunk(png_ptr, PNG_CHUNK_FROM_STRING(chunk_string), data,

-      length);

-}

-

-/* This is used below to find the size of an image to pass to png_deflate_claim,

- * so it only needs to be accurate if the size is less than 16384 bytes (the

- * point at which a lower LZ window size can be used.)

- */

-static png_alloc_size_t

-png_image_size(png_structrp png_ptr)

-{

-   /* Only return sizes up to the maximum of a png_uint_32, do this by limiting

-    * the width and height used to 15 bits.

-    */

-   png_uint_32 h = png_ptr->height;

-

-   if (png_ptr->rowbytes < 32768 && h < 32768)

-   {

-      if (png_ptr->interlaced)

-      {

-         /* Interlacing makes the image larger because of the replication of

-          * both the filter byte and the padding to a byte boundary.

-          */

-         png_uint_32 w = png_ptr->width;

-         unsigned int pd = png_ptr->pixel_depth;

-         png_alloc_size_t cb_base;

-         int pass;

-

-         for (cb_base=0, pass=0; pass<=6; ++pass)

-         {

-            png_uint_32 pw = PNG_PASS_COLS(w, pass);

-

-            if (pw > 0)

-               cb_base += (PNG_ROWBYTES(pd, pw)+1) * PNG_PASS_ROWS(h, pass);

-         }

-

-         return cb_base;

-      }

-

-      else

-         return (png_ptr->rowbytes+1) * h;

-   }

-

-   else

-      return 0xffffffffU;

-}

-

-#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED

-   /* This is the code to hack the first two bytes of the deflate stream (the

-    * deflate header) to correct the windowBits value to match the actual data

-    * size.  Note that the second argument is the *uncompressed* size but the

-    * first argument is the *compressed* data (and it must be deflate

-    * compressed.)

-    */

-static void

-optimize_cmf(png_bytep data, png_alloc_size_t data_size)

-{

-   /* Optimize the CMF field in the zlib stream.  The resultant zlib stream is

-    * still compliant to the stream specification.

-    */

-   if (data_size <= 16384) /* else windowBits must be 15 */

-   {

-      unsigned int z_cmf = data[0];  /* zlib compression method and flags */

-

-      if ((z_cmf & 0x0f) == 8 && (z_cmf & 0xf0) <= 0x70)

-      {

-         unsigned int z_cinfo;

-         unsigned int half_z_window_size;

-

-         z_cinfo = z_cmf >> 4;

-         half_z_window_size = 1U << (z_cinfo + 7);

-

-         if (data_size <= half_z_window_size) /* else no change */

-         {

-            unsigned int tmp;

-

-            do

-            {

-               half_z_window_size >>= 1;

-               --z_cinfo;

-            }

-            while (z_cinfo > 0 && data_size <= half_z_window_size);

-

-            z_cmf = (z_cmf & 0x0f) | (z_cinfo << 4);

-

-            data[0] = (png_byte)z_cmf;

-            tmp = data[1] & 0xe0;

-            tmp += 0x1f - ((z_cmf << 8) + tmp) % 0x1f;

-            data[1] = (png_byte)tmp;

-         }

-      }

-   }

-}

-#else

-#  define optimize_cmf(dp,dl) ((void)0)

-#endif /* PNG_WRITE_OPTIMIZE_CMF_SUPPORTED */

-

-/* Initialize the compressor for the appropriate type of compression. */

-static int

-png_deflate_claim(png_structrp png_ptr, png_uint_32 owner,

-   png_alloc_size_t data_size)

-{

-   if (png_ptr->zowner != 0)

-   {

-      char msg[64];

-

-      PNG_STRING_FROM_CHUNK(msg, owner);

-      msg[4] = ':';

-      msg[5] = ' ';

-      PNG_STRING_FROM_CHUNK(msg+6, png_ptr->zowner);

-      /* So the message that results is "<chunk> using zstream"; this is an

-       * internal error, but is very useful for debugging.  i18n requirements

-       * are minimal.

-       */

-      (void)png_safecat(msg, (sizeof msg), 10, " using zstream");

-#     if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC

-         png_warning(png_ptr, msg);

-

-         /* Attempt sane error recovery */

-         if (png_ptr->zowner == png_IDAT) /* don't steal from IDAT */

-         {

-            png_ptr->zstream.msg = PNGZ_MSG_CAST("in use by IDAT");

-            return Z_STREAM_ERROR;

-         }

-

-         png_ptr->zowner = 0;

-#     else

-         png_error(png_ptr, msg);

-#     endif

-   }

-

-   {

-      int level = png_ptr->zlib_level;

-      int method = png_ptr->zlib_method;

-      int windowBits = png_ptr->zlib_window_bits;

-      int memLevel = png_ptr->zlib_mem_level;

-      int strategy; /* set below */

-      int ret; /* zlib return code */

-

-      if (owner == png_IDAT)

-      {

-         if (png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY)

-            strategy = png_ptr->zlib_strategy;

-

-         else if (png_ptr->do_filter != PNG_FILTER_NONE)

-            strategy = PNG_Z_DEFAULT_STRATEGY;

-

-         else

-            strategy = PNG_Z_DEFAULT_NOFILTER_STRATEGY;

-      }

-

-      else

-      {

-#        ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED

-            level = png_ptr->zlib_text_level;

-            method = png_ptr->zlib_text_method;

-            windowBits = png_ptr->zlib_text_window_bits;

-            memLevel = png_ptr->zlib_text_mem_level;

-            strategy = png_ptr->zlib_text_strategy;

-#        else

-            /* If customization is not supported the values all come from the

-             * IDAT values except for the strategy, which is fixed to the

-             * default.  (This is the pre-1.6.0 behavior too, although it was

-             * implemented in a very different way.)

-             */

-            strategy = Z_DEFAULT_STRATEGY;

-#        endif

-      }

-

-      /* Adjust 'windowBits' down if larger than 'data_size'; to stop this

-       * happening just pass 32768 as the data_size parameter.  Notice that zlib

-       * requires an extra 262 bytes in the window in addition to the data to be

-       * able to see the whole of the data, so if data_size+262 takes us to the

-       * next windowBits size we need to fix up the value later.  (Because even

-       * though deflate needs the extra window, inflate does not!)

-       */

-      if (data_size <= 16384)

-      {

-         /* IMPLEMENTATION NOTE: this 'half_window_size' stuff is only here to

-          * work round a Microsoft Visual C misbehavior which, contrary to C-90,

-          * widens the result of the following shift to 64-bits if (and,

-          * apparently, only if) it is used in a test.

-          */

-         unsigned int half_window_size = 1U << (windowBits-1);

-

-         while (data_size + 262 <= half_window_size)

-         {

-            half_window_size >>= 1;

-            --windowBits;

-         }

-      }

-

-      /* Check against the previous initialized values, if any. */

-      if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) &&

-         (png_ptr->zlib_set_level != level ||

-         png_ptr->zlib_set_method != method ||

-         png_ptr->zlib_set_window_bits != windowBits ||

-         png_ptr->zlib_set_mem_level != memLevel ||

-         png_ptr->zlib_set_strategy != strategy))

-      {

-         if (deflateEnd(&png_ptr->zstream) != Z_OK)

-            png_warning(png_ptr, "deflateEnd failed (ignored)");

-

-         png_ptr->flags &= ~PNG_FLAG_ZSTREAM_INITIALIZED;

-      }

-

-      /* For safety clear out the input and output pointers (currently zlib

-       * doesn't use them on Init, but it might in the future).

-       */

-      png_ptr->zstream.next_in = NULL;

-      png_ptr->zstream.avail_in = 0;

-      png_ptr->zstream.next_out = NULL;

-      png_ptr->zstream.avail_out = 0;

-

-      /* Now initialize if required, setting the new parameters, otherwise just

-       * to a simple reset to the previous parameters.

-       */

-      if (png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED)

-         ret = deflateReset(&png_ptr->zstream);

-

-      else

-      {

-         ret = deflateInit2(&png_ptr->zstream, level, method, windowBits,

-            memLevel, strategy);

-

-         if (ret == Z_OK)

-            png_ptr->flags |= PNG_FLAG_ZSTREAM_INITIALIZED;

-      }

-

-      /* The return code is from either deflateReset or deflateInit2; they have

-       * pretty much the same set of error codes.

-       */

-      if (ret == Z_OK)

-         png_ptr->zowner = owner;

-

-      else

-         png_zstream_error(png_ptr, ret);

-

-      return ret;

-   }

-}

-

-/* Clean up (or trim) a linked list of compression buffers. */

-void /* PRIVATE */

-png_free_buffer_list(png_structrp png_ptr, png_compression_bufferp *listp)

-{

-   png_compression_bufferp list = *listp;

-

-   if (list != NULL)

-   {

-      *listp = NULL;

-

-      do

-      {

-         png_compression_bufferp next = list->next;

-

-         png_free(png_ptr, list);

-         list = next;

-      }

-      while (list != NULL);

-   }

-}

-

-#ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED

-/* This pair of functions encapsulates the operation of (a) compressing a

- * text string, and (b) issuing it later as a series of chunk data writes.

- * The compression_state structure is shared context for these functions

- * set up by the caller to allow access to the relevant local variables.

- *

- * compression_buffer (new in 1.6.0) is just a linked list of zbuffer_size

- * temporary buffers.  From 1.6.0 it is retained in png_struct so that it will

- * be correctly freed in the event of a write error (previous implementations

- * just leaked memory.)

- */

-typedef struct

-{

-   png_const_bytep      input;        /* The uncompressed input data */

-   png_alloc_size_t     input_len;    /* Its length */

-   png_uint_32          output_len;   /* Final compressed length */

-   png_byte             output[1024]; /* First block of output */

-} compression_state;

-

-static void

-png_text_compress_init(compression_state *comp, png_const_bytep input,

-   png_alloc_size_t input_len)

-{

-   comp->input = input;

-   comp->input_len = input_len;

-   comp->output_len = 0;

-}

-

-/* Compress the data in the compression state input */

-static int

-png_text_compress(png_structrp png_ptr, png_uint_32 chunk_name,

-   compression_state *comp, png_uint_32 prefix_len)

-{

-   int ret;

-

-   /* To find the length of the output it is necessary to first compress the

-    * input, the result is buffered rather than using the two-pass algorithm

-    * that is used on the inflate side; deflate is assumed to be slower and a

-    * PNG writer is assumed to have more memory available than a PNG reader.

-    *

-    * IMPLEMENTATION NOTE: the zlib API deflateBound() can be used to find an

-    * upper limit on the output size, but it is always bigger than the input

-    * size so it is likely to be more efficient to use this linked-list

-    * approach.

-    */

-   ret = png_deflate_claim(png_ptr, chunk_name, comp->input_len);

-

-   if (ret != Z_OK)

-      return ret;

-

-   /* Set up the compression buffers, we need a loop here to avoid overflowing a

-    * uInt.  Use ZLIB_IO_MAX to limit the input.  The output is always limited

-    * by the output buffer size, so there is no need to check that.  Since this

-    * is ANSI-C we know that an 'int', hence a uInt, is always at least 16 bits

-    * in size.

-    */

-   {

-      png_compression_bufferp *end = &png_ptr->zbuffer_list;

-      png_alloc_size_t input_len = comp->input_len; /* may be zero! */

-      png_uint_32 output_len;

-

-      /* zlib updates these for us: */

-      png_ptr->zstream.next_in = PNGZ_INPUT_CAST(comp->input);

-      png_ptr->zstream.avail_in = 0; /* Set below */

-      png_ptr->zstream.next_out = comp->output;

-      png_ptr->zstream.avail_out = (sizeof comp->output);

-

-      output_len = png_ptr->zstream.avail_out;

-

-      do

-      {

-         uInt avail_in = ZLIB_IO_MAX;

-

-         if (avail_in > input_len)

-            avail_in = (uInt)input_len;

-

-         input_len -= avail_in;

-

-         png_ptr->zstream.avail_in = avail_in;

-

-         if (png_ptr->zstream.avail_out == 0)

-         {

-            png_compression_buffer *next;

-

-            /* Chunk data is limited to 2^31 bytes in length, so the prefix

-             * length must be counted here.

-             */

-            if (output_len + prefix_len > PNG_UINT_31_MAX)

-            {

-               ret = Z_MEM_ERROR;

-               break;

-            }

-

-            /* Need a new (malloc'ed) buffer, but there may be one present

-             * already.

-             */

-            next = *end;

-            if (next == NULL)

-            {

-               next = png_voidcast(png_compression_bufferp, png_malloc_base

-                  (png_ptr, PNG_COMPRESSION_BUFFER_SIZE(png_ptr)));

-

-               if (next == NULL)

-               {

-                  ret = Z_MEM_ERROR;

-                  break;

-               }

-

-               /* Link in this buffer (so that it will be freed later) */

-               next->next = NULL;

-               *end = next;

-            }

-

-            png_ptr->zstream.next_out = next->output;

-            png_ptr->zstream.avail_out = png_ptr->zbuffer_size;

-            output_len += png_ptr->zstream.avail_out;

-

-            /* Move 'end' to the next buffer pointer. */

-            end = &next->next;

-         }

-

-         /* Compress the data */

-         ret = deflate(&png_ptr->zstream,

-            input_len > 0 ? Z_NO_FLUSH : Z_FINISH);

-

-         /* Claw back input data that was not consumed (because avail_in is

-          * reset above every time round the loop).

-          */

-         input_len += png_ptr->zstream.avail_in;

-         png_ptr->zstream.avail_in = 0; /* safety */

-      }

-      while (ret == Z_OK);

-

-      /* There may be some space left in the last output buffer, this needs to

-       * be subtracted from output_len.

-       */

-      output_len -= png_ptr->zstream.avail_out;

-      png_ptr->zstream.avail_out = 0; /* safety */

-      comp->output_len = output_len;

-

-      /* Now double check the output length, put in a custom message if it is

-       * too long.  Otherwise ensure the z_stream::msg pointer is set to

-       * something.

-       */

-      if (output_len + prefix_len >= PNG_UINT_31_MAX)

-      {

-         png_ptr->zstream.msg = PNGZ_MSG_CAST("compressed data too long");

-         ret = Z_MEM_ERROR;

-      }

-

-      else

-         png_zstream_error(png_ptr, ret);

-

-      /* Reset zlib for another zTXt/iTXt or image data */

-      png_ptr->zowner = 0;

-

-      /* The only success case is Z_STREAM_END, input_len must be 0, if not this

-       * is an internal error.

-       */

-      if (ret == Z_STREAM_END && input_len == 0)

-      {

-         /* Fix up the deflate header, if required */

-         optimize_cmf(comp->output, comp->input_len);

-

-         /* But Z_OK is returned, not Z_STREAM_END; this allows the claim

-          * function above to return Z_STREAM_END on an error (though it never

-          * does in the current versions of zlib.)

-          */

-         return Z_OK;

-      }

-

-      else

-         return ret;

-   }

-}

-

-/* Ship the compressed text out via chunk writes */

-static void

-png_write_compressed_data_out(png_structrp png_ptr, compression_state *comp)

-{

-   png_uint_32 output_len = comp->output_len;

-   png_const_bytep output = comp->output;

-   png_uint_32 avail = (sizeof comp->output);

-   png_compression_buffer *next = png_ptr->zbuffer_list;

-

-   for (;;)

-   {

-      if (avail > output_len)

-         avail = output_len;

-

-      png_write_chunk_data(png_ptr, output, avail);

-

-      output_len -= avail;

-

-      if (output_len == 0 || next == NULL)

-         break;

-

-      avail = png_ptr->zbuffer_size;

-      output = next->output;

-      next = next->next;

-   }

-

-   /* This is an internal error; 'next' must have been NULL! */

-   if (output_len > 0)

-      png_error(png_ptr, "error writing ancillary chunked compressed data");

-}

-#endif /* PNG_WRITE_COMPRESSED_TEXT_SUPPORTED */

-

-#if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_pCAL_SUPPORTED) || \

-    defined(PNG_WRITE_iCCP_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)

-/* Check that the tEXt or zTXt keyword is valid per PNG 1.0 specification,

- * and if invalid, correct the keyword rather than discarding the entire

- * chunk.  The PNG 1.0 specification requires keywords 1-79 characters in

- * length, forbids leading or trailing whitespace, multiple internal spaces,

- * and the non-break space (0x80) from ISO 8859-1.  Returns keyword length.

- *

- * The 'new_key' buffer must be 80 characters in size (for the keyword plus a

- * trailing '\0').  If this routine returns 0 then there was no keyword, or a

- * valid one could not be generated, and the caller must png_error.

- */

-static png_uint_32

-png_check_keyword(png_structrp png_ptr, png_const_charp key, png_bytep new_key)

-{

-   png_const_charp orig_key = key;

-   png_uint_32 key_len = 0;

-   int bad_character = 0;

-   int space = 1;

-

-   png_debug(1, "in png_check_keyword");

-

-   if (key == NULL)

-   {

-      *new_key = 0;

-      return 0;

-   }

-

-   while (*key && key_len < 79)

-   {

-      png_byte ch = (png_byte)(0xff & *key++);

-

-      if ((ch > 32 && ch <= 126) || (ch >= 161 /*&& ch <= 255*/))

-         *new_key++ = ch, ++key_len, space = 0;

-

-      else if (!space)

-      {

-         /* A space or an invalid character when one wasn't seen immediately

-          * before; output just a space.

-          */

-         *new_key++ = 32, ++key_len, space = 1;

-

-         /* If the character was not a space then it is invalid. */

-         if (ch != 32)

-            bad_character = ch;

-      }

-

-      else if (!bad_character)

-         bad_character = ch; /* just skip it, record the first error */

-   }

-

-   if (key_len > 0 && space) /* trailing space */

-   {

-      --key_len, --new_key;

-      if (!bad_character)

-         bad_character = 32;

-   }

-

-   /* Terminate the keyword */

-   *new_key = 0;

-

-   if (key_len == 0)

-      return 0;

-

-   /* Try to only output one warning per keyword: */

-   if (*key) /* keyword too long */

-      png_warning(png_ptr, "keyword truncated");

-

-   else if (bad_character)

-   {

-      PNG_WARNING_PARAMETERS(p)

-

-      png_warning_parameter(p, 1, orig_key);

-      png_warning_parameter_signed(p, 2, PNG_NUMBER_FORMAT_02x, bad_character);

-

-      png_formatted_warning(png_ptr, p, "keyword \"@1\": bad character '0x@2'");

-   }

-

-   return key_len;

-}

-#endif

-

-/* Write the IHDR chunk, and update the png_struct with the necessary

- * information.  Note that the rest of this code depends upon this

- * information being correct.

- */

-void /* PRIVATE */

-png_write_IHDR(png_structrp png_ptr, png_uint_32 width, png_uint_32 height,

-    int bit_depth, int color_type, int compression_type, int filter_type,

-    int interlace_type)

-{

-   png_byte buf[13]; /* Buffer to store the IHDR info */

-

-   png_debug(1, "in png_write_IHDR");

-

-   /* Check that we have valid input data from the application info */

-   switch (color_type)

-   {

-      case PNG_COLOR_TYPE_GRAY:

-         switch (bit_depth)

-         {

-            case 1:

-            case 2:

-            case 4:

-            case 8:

-#ifdef PNG_WRITE_16BIT_SUPPORTED

-            case 16:

-#endif

-               png_ptr->channels = 1; break;

-

-            default:

-               png_error(png_ptr,

-                   "Invalid bit depth for grayscale image");

-         }

-         break;

-

-      case PNG_COLOR_TYPE_RGB:

-#ifdef PNG_WRITE_16BIT_SUPPORTED

-         if (bit_depth != 8 && bit_depth != 16)

-#else

-         if (bit_depth != 8)

-#endif

-            png_error(png_ptr, "Invalid bit depth for RGB image");

-

-         png_ptr->channels = 3;

-         break;

-

-      case PNG_COLOR_TYPE_PALETTE:

-         switch (bit_depth)

-         {

-            case 1:

-            case 2:

-            case 4:

-            case 8:

-               png_ptr->channels = 1;

-               break;

-

-            default:

-               png_error(png_ptr, "Invalid bit depth for paletted image");

-         }

-         break;

-

-      case PNG_COLOR_TYPE_GRAY_ALPHA:

-         if (bit_depth != 8 && bit_depth != 16)

-            png_error(png_ptr, "Invalid bit depth for grayscale+alpha image");

-

-         png_ptr->channels = 2;

-         break;

-

-      case PNG_COLOR_TYPE_RGB_ALPHA:

-#ifdef PNG_WRITE_16BIT_SUPPORTED

-         if (bit_depth != 8 && bit_depth != 16)

-#else

-         if (bit_depth != 8)

-#endif

-            png_error(png_ptr, "Invalid bit depth for RGBA image");

-

-         png_ptr->channels = 4;

-         break;

-

-      default:

-         png_error(png_ptr, "Invalid image color type specified");

-   }

-

-   if (compression_type != PNG_COMPRESSION_TYPE_BASE)

-   {

-      png_warning(png_ptr, "Invalid compression type specified");

-      compression_type = PNG_COMPRESSION_TYPE_BASE;

-   }

-

-   /* Write filter_method 64 (intrapixel differencing) only if

-    * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and

-    * 2. Libpng did not write a PNG signature (this filter_method is only

-    *    used in PNG datastreams that are embedded in MNG datastreams) and

-    * 3. The application called png_permit_mng_features with a mask that

-    *    included PNG_FLAG_MNG_FILTER_64 and

-    * 4. The filter_method is 64 and

-    * 5. The color_type is RGB or RGBA

-    */

-   if (

-#ifdef PNG_MNG_FEATURES_SUPPORTED

-       !((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&

-       ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE) == 0) &&

-       (color_type == PNG_COLOR_TYPE_RGB ||

-        color_type == PNG_COLOR_TYPE_RGB_ALPHA) &&

-       (filter_type == PNG_INTRAPIXEL_DIFFERENCING)) &&

-#endif

-       filter_type != PNG_FILTER_TYPE_BASE)

-   {

-      png_warning(png_ptr, "Invalid filter type specified");

-      filter_type = PNG_FILTER_TYPE_BASE;

-   }

-

-#ifdef PNG_WRITE_INTERLACING_SUPPORTED

-   if (interlace_type != PNG_INTERLACE_NONE &&

-       interlace_type != PNG_INTERLACE_ADAM7)

-   {

-      png_warning(png_ptr, "Invalid interlace type specified");

-      interlace_type = PNG_INTERLACE_ADAM7;

-   }

-#else

-   interlace_type=PNG_INTERLACE_NONE;

-#endif

-

-   /* Save the relevent information */

-   png_ptr->bit_depth = (png_byte)bit_depth;

-   png_ptr->color_type = (png_byte)color_type;

-   png_ptr->interlaced = (png_byte)interlace_type;

-#ifdef PNG_MNG_FEATURES_SUPPORTED

-   png_ptr->filter_type = (png_byte)filter_type;

-#endif

-   png_ptr->compression_type = (png_byte)compression_type;

-   png_ptr->width = width;

-   png_ptr->height = height;

-

-   png_ptr->pixel_depth = (png_byte)(bit_depth * png_ptr->channels);

-   png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, width);

-   /* Set the usr info, so any transformations can modify it */

-   png_ptr->usr_width = png_ptr->width;

-   png_ptr->usr_bit_depth = png_ptr->bit_depth;

-   png_ptr->usr_channels = png_ptr->channels;

-

-   /* Pack the header information into the buffer */

-   png_save_uint_32(buf, width);

-   png_save_uint_32(buf + 4, height);

-   buf[8] = (png_byte)bit_depth;

-   buf[9] = (png_byte)color_type;

-   buf[10] = (png_byte)compression_type;

-   buf[11] = (png_byte)filter_type;

-   buf[12] = (png_byte)interlace_type;

-

-   /* Write the chunk */

-   png_write_complete_chunk(png_ptr, png_IHDR, buf, (png_size_t)13);

-

-   if (!(png_ptr->do_filter))

-   {

-      if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE ||

-          png_ptr->bit_depth < 8)

-         png_ptr->do_filter = PNG_FILTER_NONE;

-

-      else

-         png_ptr->do_filter = PNG_ALL_FILTERS;

-   }

-

-   png_ptr->mode = PNG_HAVE_IHDR; /* not READY_FOR_ZTXT */

-}

-

-/* Write the palette.  We are careful not to trust png_color to be in the

- * correct order for PNG, so people can redefine it to any convenient

- * structure.

- */

-void /* PRIVATE */

-png_write_PLTE(png_structrp png_ptr, png_const_colorp palette,

-    png_uint_32 num_pal)

-{

-   png_uint_32 i;

-   png_const_colorp pal_ptr;

-   png_byte buf[3];

-

-   png_debug(1, "in png_write_PLTE");

-

-   if ((

-#ifdef PNG_MNG_FEATURES_SUPPORTED

-       !(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) &&

-#endif

-       num_pal == 0) || num_pal > 256)

-   {

-      if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)

-      {

-         png_error(png_ptr, "Invalid number of colors in palette");

-      }

-

-      else

-      {

-         png_warning(png_ptr, "Invalid number of colors in palette");

-         return;

-      }

-   }

-

-   if (!(png_ptr->color_type&PNG_COLOR_MASK_COLOR))

-   {

-      png_warning(png_ptr,

-          "Ignoring request to write a PLTE chunk in grayscale PNG");

-

-      return;

-   }

-

-   png_ptr->num_palette = (png_uint_16)num_pal;

-   png_debug1(3, "num_palette = %d", png_ptr->num_palette);

-

-   png_write_chunk_header(png_ptr, png_PLTE, (png_uint_32)(num_pal * 3));

-#ifdef PNG_POINTER_INDEXING_SUPPORTED

-

-   for (i = 0, pal_ptr = palette; i < num_pal; i++, pal_ptr++)

-   {

-      buf[0] = pal_ptr->red;

-      buf[1] = pal_ptr->green;

-      buf[2] = pal_ptr->blue;

-      png_write_chunk_data(png_ptr, buf, (png_size_t)3);

-   }

-

-#else

-   /* This is a little slower but some buggy compilers need to do this

-    * instead

-    */

-   pal_ptr=palette;

-

-   for (i = 0; i < num_pal; i++)

-   {

-      buf[0] = pal_ptr[i].red;

-      buf[1] = pal_ptr[i].green;

-      buf[2] = pal_ptr[i].blue;

-      png_write_chunk_data(png_ptr, buf, (png_size_t)3);

-   }

-

-#endif

-   png_write_chunk_end(png_ptr);

-   png_ptr->mode |= PNG_HAVE_PLTE;

-}

-

-/* This is similar to png_text_compress, above, except that it does not require

- * all of the data at once and, instead of buffering the compressed result,

- * writes it as IDAT chunks.  Unlike png_text_compress it *can* png_error out

- * because it calls the write interface.  As a result it does its own error

- * reporting and does not return an error code.  In the event of error it will

- * just call png_error.  The input data length may exceed 32-bits.  The 'flush'

- * parameter is exactly the same as that to deflate, with the following

- * meanings:

- *

- * Z_NO_FLUSH: normal incremental output of compressed data

- * Z_SYNC_FLUSH: do a SYNC_FLUSH, used by png_write_flush

- * Z_FINISH: this is the end of the input, do a Z_FINISH and clean up

- *

- * The routine manages the acquire and release of the png_ptr->zstream by

- * checking and (at the end) clearing png_ptr->zowner, it does some sanity

- * checks on the 'mode' flags while doing this.

- */

-void /* PRIVATE */

-png_compress_IDAT(png_structrp png_ptr, png_const_bytep input,

-   png_alloc_size_t input_len, int flush)

-{

-   if (png_ptr->zowner != png_IDAT)

-   {

-      /* First time.   Ensure we have a temporary buffer for compression and

-       * trim the buffer list if it has more than one entry to free memory.

-       * If 'WRITE_COMPRESSED_TEXT' is not set the list will never have been

-       * created at this point, but the check here is quick and safe.

-       */

-      if (png_ptr->zbuffer_list == NULL)

-      {

-         png_ptr->zbuffer_list = png_voidcast(png_compression_bufferp,

-            png_malloc(png_ptr, PNG_COMPRESSION_BUFFER_SIZE(png_ptr)));

-         png_ptr->zbuffer_list->next = NULL;

-      }

-

-      else

-         png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list->next);

-

-      /* It is a terminal error if we can't claim the zstream. */

-      if (png_deflate_claim(png_ptr, png_IDAT, png_image_size(png_ptr)) != Z_OK)

-         png_error(png_ptr, png_ptr->zstream.msg);

-

-      /* The output state is maintained in png_ptr->zstream, so it must be

-       * initialized here after the claim.

-       */

-      png_ptr->zstream.next_out = png_ptr->zbuffer_list->output;

-      png_ptr->zstream.avail_out = png_ptr->zbuffer_size;

-   }

-

-   /* Now loop reading and writing until all the input is consumed or an error

-    * terminates the operation.  The _out values are maintained across calls to

-    * this function, but the input must be reset each time.

-    */

-   png_ptr->zstream.next_in = PNGZ_INPUT_CAST(input);

-   png_ptr->zstream.avail_in = 0; /* set below */

-   for (;;)

-   {

-      int ret;

-

-      /* INPUT: from the row data */

-      uInt avail = ZLIB_IO_MAX;

-

-      if (avail > input_len)

-         avail = (uInt)input_len; /* safe because of the check */

-

-      png_ptr->zstream.avail_in = avail;

-      input_len -= avail;

-

-      ret = deflate(&png_ptr->zstream, input_len > 0 ? Z_NO_FLUSH : flush);

-

-      /* Include as-yet unconsumed input */

-      input_len += png_ptr->zstream.avail_in;

-      png_ptr->zstream.avail_in = 0;

-

-      /* OUTPUT: write complete IDAT chunks when avail_out drops to zero, note

-       * that these two zstream fields are preserved across the calls, therefore

-       * there is no need to set these up on entry to the loop.

-       */

-      if (png_ptr->zstream.avail_out == 0)

-      {

-         png_bytep data = png_ptr->zbuffer_list->output;

-         uInt size = png_ptr->zbuffer_size;

-

-         /* Write an IDAT containing the data then reset the buffer.  The

-          * first IDAT may need deflate header optimization.

-          */

-#        ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED

-            if (!(png_ptr->mode & PNG_HAVE_IDAT) &&

-               png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)

-               optimize_cmf(data, png_image_size(png_ptr));

-#        endif

-

-         png_write_complete_chunk(png_ptr, png_IDAT, data, size);

-         png_ptr->mode |= PNG_HAVE_IDAT;

-

-         png_ptr->zstream.next_out = data;

-         png_ptr->zstream.avail_out = size;

-

-         /* For SYNC_FLUSH or FINISH it is essential to keep calling zlib with

-          * the same flush parameter until it has finished output, for NO_FLUSH

-          * it doesn't matter.

-          */

-         if (ret == Z_OK && flush != Z_NO_FLUSH)

-            continue;

-      }

-

-      /* The order of these checks doesn't matter much; it just effect which

-       * possible error might be detected if multiple things go wrong at once.

-       */

-      if (ret == Z_OK) /* most likely return code! */

-      {

-         /* If all the input has been consumed then just return.  If Z_FINISH

-          * was used as the flush parameter something has gone wrong if we get

-          * here.

-          */

-         if (input_len == 0)

-         {

-            if (flush == Z_FINISH)

-               png_error(png_ptr, "Z_OK on Z_FINISH with output space");

-

-            return;

-         }

-      }

-

-      else if (ret == Z_STREAM_END && flush == Z_FINISH)

-      {

-         /* This is the end of the IDAT data; any pending output must be

-          * flushed.  For small PNG files we may still be at the beginning.

-          */

-         png_bytep data = png_ptr->zbuffer_list->output;

-         uInt size = png_ptr->zbuffer_size - png_ptr->zstream.avail_out;

-

-#        ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED

-            if (!(png_ptr->mode & PNG_HAVE_IDAT) &&

-               png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)

-               optimize_cmf(data, png_image_size(png_ptr));

-#        endif

-

-         png_write_complete_chunk(png_ptr, png_IDAT, data, size);

-         png_ptr->zstream.avail_out = 0;

-         png_ptr->zstream.next_out = NULL;

-         png_ptr->mode |= PNG_HAVE_IDAT | PNG_AFTER_IDAT;

-

-         png_ptr->zowner = 0; /* Release the stream */

-         return;

-      }

-

-      else

-      {

-         /* This is an error condition. */

-         png_zstream_error(png_ptr, ret);

-         png_error(png_ptr, png_ptr->zstream.msg);

-      }

-   }

-}

-

-/* Write an IEND chunk */

-void /* PRIVATE */

-png_write_IEND(png_structrp png_ptr)

-{

-   png_debug(1, "in png_write_IEND");

-

-   png_write_complete_chunk(png_ptr, png_IEND, NULL, (png_size_t)0);

-   png_ptr->mode |= PNG_HAVE_IEND;

-}

-

-#ifdef PNG_WRITE_gAMA_SUPPORTED

-/* Write a gAMA chunk */

-void /* PRIVATE */

-png_write_gAMA_fixed(png_structrp png_ptr, png_fixed_point file_gamma)

-{

-   png_byte buf[4];

-

-   png_debug(1, "in png_write_gAMA");

-

-   /* file_gamma is saved in 1/100,000ths */

-   png_save_uint_32(buf, (png_uint_32)file_gamma);

-   png_write_complete_chunk(png_ptr, png_gAMA, buf, (png_size_t)4);

-}

-#endif

-

-#ifdef PNG_WRITE_sRGB_SUPPORTED

-/* Write a sRGB chunk */

-void /* PRIVATE */

-png_write_sRGB(png_structrp png_ptr, int srgb_intent)

-{

-   png_byte buf[1];

-

-   png_debug(1, "in png_write_sRGB");

-

-   if (srgb_intent >= PNG_sRGB_INTENT_LAST)

-      png_warning(png_ptr,

-          "Invalid sRGB rendering intent specified");

-

-   buf[0]=(png_byte)srgb_intent;

-   png_write_complete_chunk(png_ptr, png_sRGB, buf, (png_size_t)1);

-}

-#endif

-

-#ifdef PNG_WRITE_iCCP_SUPPORTED

-/* Write an iCCP chunk */

-void /* PRIVATE */

-png_write_iCCP(png_structrp png_ptr, png_const_charp name,

-    png_const_bytep profile)

-{

-   png_uint_32 name_len;

-   png_uint_32 profile_len;

-   png_byte new_name[81]; /* 1 byte for the compression byte */

-   compression_state comp;

-

-   png_debug(1, "in png_write_iCCP");

-

-   /* These are all internal problems: the profile should have been checked

-    * before when it was stored.

-    */

-   if (profile == NULL)

-      png_error(png_ptr, "No profile for iCCP chunk"); /* internal error */

-

-   profile_len = png_get_uint_32(profile);

-

-   if (profile_len < 132)

-      png_error(png_ptr, "ICC profile too short");

-

-   if (profile_len & 0x03)

-      png_error(png_ptr, "ICC profile length invalid (not a multiple of 4)");

-

-   {

-      png_uint_32 embedded_profile_len = png_get_uint_32(profile);

-

-      if (profile_len != embedded_profile_len)

-         png_error(png_ptr, "Profile length does not match profile");

-   }

-

-   name_len = png_check_keyword(png_ptr, name, new_name);

-

-   if (name_len == 0)

-      png_error(png_ptr, "iCCP: invalid keyword");

-

-   new_name[++name_len] = PNG_COMPRESSION_TYPE_BASE;

-

-   /* Make sure we include the NULL after the name and the compression type */

-   ++name_len;

-

-   png_text_compress_init(&comp, profile, profile_len);

-

-   /* Allow for keyword terminator and compression byte */

-   if (png_text_compress(png_ptr, png_iCCP, &comp, name_len) != Z_OK)

-      png_error(png_ptr, png_ptr->zstream.msg);

-

-   png_write_chunk_header(png_ptr, png_iCCP, name_len + comp.output_len);

-

-   png_write_chunk_data(png_ptr, new_name, name_len);

-

-   png_write_compressed_data_out(png_ptr, &comp);

-

-   png_write_chunk_end(png_ptr);

-}

-#endif

-

-#ifdef PNG_WRITE_sPLT_SUPPORTED

-/* Write a sPLT chunk */

-void /* PRIVATE */

-png_write_sPLT(png_structrp png_ptr, png_const_sPLT_tp spalette)

-{

-   png_uint_32 name_len;

-   png_byte new_name[80];

-   png_byte entrybuf[10];

-   png_size_t entry_size = (spalette->depth == 8 ? 6 : 10);

-   png_size_t palette_size = entry_size * spalette->nentries;

-   png_sPLT_entryp ep;

-#ifndef PNG_POINTER_INDEXING_SUPPORTED

-   int i;

-#endif

-

-   png_debug(1, "in png_write_sPLT");

-

-   name_len = png_check_keyword(png_ptr, spalette->name, new_name);

-

-   if (name_len == 0)

-      png_error(png_ptr, "sPLT: invalid keyword");

-

-   /* Make sure we include the NULL after the name */

-   png_write_chunk_header(png_ptr, png_sPLT,

-       (png_uint_32)(name_len + 2 + palette_size));

-

-   png_write_chunk_data(png_ptr, (png_bytep)new_name,

-       (png_size_t)(name_len + 1));

-

-   png_write_chunk_data(png_ptr, &spalette->depth, (png_size_t)1);

-

-   /* Loop through each palette entry, writing appropriately */

-#ifdef PNG_POINTER_INDEXING_SUPPORTED

-   for (ep = spalette->entries; ep<spalette->entries + spalette->nentries; ep++)

-   {

-      if (spalette->depth == 8)

-      {

-         entrybuf[0] = (png_byte)ep->red;

-         entrybuf[1] = (png_byte)ep->green;

-         entrybuf[2] = (png_byte)ep->blue;

-         entrybuf[3] = (png_byte)ep->alpha;

-         png_save_uint_16(entrybuf + 4, ep->frequency);

-      }

-

-      else

-      {

-         png_save_uint_16(entrybuf + 0, ep->red);

-         png_save_uint_16(entrybuf + 2, ep->green);

-         png_save_uint_16(entrybuf + 4, ep->blue);

-         png_save_uint_16(entrybuf + 6, ep->alpha);

-         png_save_uint_16(entrybuf + 8, ep->frequency);

-      }

-

-      png_write_chunk_data(png_ptr, entrybuf, entry_size);

-   }

-#else

-   ep=spalette->entries;

-   for (i = 0; i>spalette->nentries; i++)

-   {

-      if (spalette->depth == 8)

-      {

-         entrybuf[0] = (png_byte)ep[i].red;

-         entrybuf[1] = (png_byte)ep[i].green;

-         entrybuf[2] = (png_byte)ep[i].blue;

-         entrybuf[3] = (png_byte)ep[i].alpha;

-         png_save_uint_16(entrybuf + 4, ep[i].frequency);

-      }

-

-      else

-      {

-         png_save_uint_16(entrybuf + 0, ep[i].red);

-         png_save_uint_16(entrybuf + 2, ep[i].green);

-         png_save_uint_16(entrybuf + 4, ep[i].blue);

-         png_save_uint_16(entrybuf + 6, ep[i].alpha);

-         png_save_uint_16(entrybuf + 8, ep[i].frequency);

-      }

-

-      png_write_chunk_data(png_ptr, entrybuf, entry_size);

-   }

-#endif

-

-   png_write_chunk_end(png_ptr);

-}

-#endif

-

-#ifdef PNG_WRITE_sBIT_SUPPORTED

-/* Write the sBIT chunk */

-void /* PRIVATE */

-png_write_sBIT(png_structrp png_ptr, png_const_color_8p sbit, int color_type)

-{

-   png_byte buf[4];

-   png_size_t size;

-

-   png_debug(1, "in png_write_sBIT");

-

-   /* Make sure we don't depend upon the order of PNG_COLOR_8 */

-   if (color_type & PNG_COLOR_MASK_COLOR)

-   {

-      png_byte maxbits;

-

-      maxbits = (png_byte)(color_type==PNG_COLOR_TYPE_PALETTE ? 8 :

-          png_ptr->usr_bit_depth);

-

-      if (sbit->red == 0 || sbit->red > maxbits ||

-          sbit->green == 0 || sbit->green > maxbits ||

-          sbit->blue == 0 || sbit->blue > maxbits)

-      {

-         png_warning(png_ptr, "Invalid sBIT depth specified");

-         return;

-      }

-

-      buf[0] = sbit->red;

-      buf[1] = sbit->green;

-      buf[2] = sbit->blue;

-      size = 3;

-   }

-

-   else

-   {

-      if (sbit->gray == 0 || sbit->gray > png_ptr->usr_bit_depth)

-      {

-         png_warning(png_ptr, "Invalid sBIT depth specified");

-         return;

-      }

-

-      buf[0] = sbit->gray;

-      size = 1;

-   }

-

-   if (color_type & PNG_COLOR_MASK_ALPHA)

-   {

-      if (sbit->alpha == 0 || sbit->alpha > png_ptr->usr_bit_depth)

-      {

-         png_warning(png_ptr, "Invalid sBIT depth specified");

-         return;

-      }

-

-      buf[size++] = sbit->alpha;

-   }

-

-   png_write_complete_chunk(png_ptr, png_sBIT, buf, size);

-}

-#endif

-

-#ifdef PNG_WRITE_cHRM_SUPPORTED

-/* Write the cHRM chunk */

-void /* PRIVATE */

-png_write_cHRM_fixed(png_structrp png_ptr, const png_xy *xy)

-{

-   png_byte buf[32];

-

-   png_debug(1, "in png_write_cHRM");

-

-   /* Each value is saved in 1/100,000ths */

-   png_save_int_32(buf,      xy->whitex);

-   png_save_int_32(buf +  4, xy->whitey);

-

-   png_save_int_32(buf +  8, xy->redx);

-   png_save_int_32(buf + 12, xy->redy);

-

-   png_save_int_32(buf + 16, xy->greenx);

-   png_save_int_32(buf + 20, xy->greeny);

-

-   png_save_int_32(buf + 24, xy->bluex);

-   png_save_int_32(buf + 28, xy->bluey);

-

-   png_write_complete_chunk(png_ptr, png_cHRM, buf, 32);

-}

-#endif

-

-#ifdef PNG_WRITE_tRNS_SUPPORTED

-/* Write the tRNS chunk */

-void /* PRIVATE */

-png_write_tRNS(png_structrp png_ptr, png_const_bytep trans_alpha,

-    png_const_color_16p tran, int num_trans, int color_type)

-{

-   png_byte buf[6];

-

-   png_debug(1, "in png_write_tRNS");

-

-   if (color_type == PNG_COLOR_TYPE_PALETTE)

-   {

-      if (num_trans <= 0 || num_trans > (int)png_ptr->num_palette)

-      {

-         png_app_warning(png_ptr,

-             "Invalid number of transparent colors specified");

-         return;

-      }

-

-      /* Write the chunk out as it is */

-      png_write_complete_chunk(png_ptr, png_tRNS, trans_alpha,

-         (png_size_t)num_trans);

-   }

-

-   else if (color_type == PNG_COLOR_TYPE_GRAY)

-   {

-      /* One 16 bit value */

-      if (tran->gray >= (1 << png_ptr->bit_depth))

-      {

-         png_app_warning(png_ptr,

-             "Ignoring attempt to write tRNS chunk out-of-range for bit_depth");

-

-         return;

-      }

-

-      png_save_uint_16(buf, tran->gray);

-      png_write_complete_chunk(png_ptr, png_tRNS, buf, (png_size_t)2);

-   }

-

-   else if (color_type == PNG_COLOR_TYPE_RGB)

-   {

-      /* Three 16 bit values */

-      png_save_uint_16(buf, tran->red);

-      png_save_uint_16(buf + 2, tran->green);

-      png_save_uint_16(buf + 4, tran->blue);

-#ifdef PNG_WRITE_16BIT_SUPPORTED

-      if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]))

-#else

-      if (buf[0] | buf[2] | buf[4])

-#endif

-      {

-         png_app_warning(png_ptr,

-           "Ignoring attempt to write 16-bit tRNS chunk when bit_depth is 8");

-         return;

-      }

-

-      png_write_complete_chunk(png_ptr, png_tRNS, buf, (png_size_t)6);

-   }

-

-   else

-   {

-      png_app_warning(png_ptr, "Can't write tRNS with an alpha channel");

-   }

-}

-#endif

-

-#ifdef PNG_WRITE_bKGD_SUPPORTED

-/* Write the background chunk */

-void /* PRIVATE */

-png_write_bKGD(png_structrp png_ptr, png_const_color_16p back, int color_type)

-{

-   png_byte buf[6];

-

-   png_debug(1, "in png_write_bKGD");

-

-   if (color_type == PNG_COLOR_TYPE_PALETTE)

-   {

-      if (

-#ifdef PNG_MNG_FEATURES_SUPPORTED

-          (png_ptr->num_palette ||

-          (!(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE))) &&

-#endif

-         back->index >= png_ptr->num_palette)

-      {

-         png_warning(png_ptr, "Invalid background palette index");

-         return;

-      }

-

-      buf[0] = back->index;

-      png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)1);

-   }

-

-   else if (color_type & PNG_COLOR_MASK_COLOR)

-   {

-      png_save_uint_16(buf, back->red);

-      png_save_uint_16(buf + 2, back->green);

-      png_save_uint_16(buf + 4, back->blue);

-#ifdef PNG_WRITE_16BIT_SUPPORTED

-      if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]))

-#else

-      if (buf[0] | buf[2] | buf[4])

-#endif

-      {

-         png_warning(png_ptr,

-             "Ignoring attempt to write 16-bit bKGD chunk when bit_depth is 8");

-

-         return;

-      }

-

-      png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)6);

-   }

-

-   else

-   {

-      if (back->gray >= (1 << png_ptr->bit_depth))

-      {

-         png_warning(png_ptr,

-             "Ignoring attempt to write bKGD chunk out-of-range for bit_depth");

-

-         return;

-      }

-

-      png_save_uint_16(buf, back->gray);

-      png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)2);

-   }

-}

-#endif

-

-#ifdef PNG_WRITE_hIST_SUPPORTED

-/* Write the histogram */

-void /* PRIVATE */

-png_write_hIST(png_structrp png_ptr, png_const_uint_16p hist, int num_hist)

-{

-   int i;

-   png_byte buf[3];

-

-   png_debug(1, "in png_write_hIST");

-

-   if (num_hist > (int)png_ptr->num_palette)

-   {

-      png_debug2(3, "num_hist = %d, num_palette = %d", num_hist,

-          png_ptr->num_palette);

-

-      png_warning(png_ptr, "Invalid number of histogram entries specified");

-      return;

-   }

-

-   png_write_chunk_header(png_ptr, png_hIST, (png_uint_32)(num_hist * 2));

-

-   for (i = 0; i < num_hist; i++)

-   {

-      png_save_uint_16(buf, hist[i]);

-      png_write_chunk_data(png_ptr, buf, (png_size_t)2);

-   }

-

-   png_write_chunk_end(png_ptr);

-}

-#endif

-

-#ifdef PNG_WRITE_tEXt_SUPPORTED

-/* Write a tEXt chunk */

-void /* PRIVATE */

-png_write_tEXt(png_structrp png_ptr, png_const_charp key, png_const_charp text,

-    png_size_t text_len)

-{

-   png_uint_32 key_len;

-   png_byte new_key[80];

-

-   png_debug(1, "in png_write_tEXt");

-

-   key_len = png_check_keyword(png_ptr, key, new_key);

-

-   if (key_len == 0)

-      png_error(png_ptr, "tEXt: invalid keyword");

-

-   if (text == NULL || *text == '\0')

-      text_len = 0;

-

-   else

-      text_len = strlen(text);

-

-   if (text_len > PNG_UINT_31_MAX - (key_len+1))

-      png_error(png_ptr, "tEXt: text too long");

-

-   /* Make sure we include the 0 after the key */

-   png_write_chunk_header(png_ptr, png_tEXt,

-       (png_uint_32)/*checked above*/(key_len + text_len + 1));

-   /*

-    * We leave it to the application to meet PNG-1.0 requirements on the

-    * contents of the text.  PNG-1.0 through PNG-1.2 discourage the use of

-    * any non-Latin-1 characters except for NEWLINE.  ISO PNG will forbid them.

-    * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.

-    */

-   png_write_chunk_data(png_ptr, new_key, key_len + 1);

-

-   if (text_len)

-      png_write_chunk_data(png_ptr, (png_const_bytep)text, text_len);

-

-   png_write_chunk_end(png_ptr);

-}

-#endif

-

-#ifdef PNG_WRITE_zTXt_SUPPORTED

-/* Write a compressed text chunk */

-void /* PRIVATE */

-png_write_zTXt(png_structrp png_ptr, png_const_charp key, png_const_charp text,

-    png_size_t text_len, int compression)

-{

-   png_uint_32 key_len;

-   png_byte new_key[81];

-   compression_state comp;

-

-   png_debug(1, "in png_write_zTXt");

-   PNG_UNUSED(text_len) /* Always use strlen */

-

-   if (compression == PNG_TEXT_COMPRESSION_NONE)

-   {

-      png_write_tEXt(png_ptr, key, text, 0);

-      return;

-   }

-

-   if (compression != PNG_TEXT_COMPRESSION_zTXt)

-      png_error(png_ptr, "zTXt: invalid compression type");

-

-   key_len = png_check_keyword(png_ptr, key, new_key);

-

-   if (key_len == 0)

-      png_error(png_ptr, "zTXt: invalid keyword");

-

-   /* Add the compression method and 1 for the keyword separator. */

-   new_key[++key_len] = PNG_COMPRESSION_TYPE_BASE;

-   ++key_len;

-

-   /* Compute the compressed data; do it now for the length */

-   png_text_compress_init(&comp, (png_const_bytep)text,

-      text == NULL ? 0 : strlen(text));

-

-   if (png_text_compress(png_ptr, png_zTXt, &comp, key_len) != Z_OK)

-      png_error(png_ptr, png_ptr->zstream.msg);

-

-   /* Write start of chunk */

-   png_write_chunk_header(png_ptr, png_zTXt, key_len + comp.output_len);

-

-   /* Write key */

-   png_write_chunk_data(png_ptr, new_key, key_len);

-

-   /* Write the compressed data */

-   png_write_compressed_data_out(png_ptr, &comp);

-

-   /* Close the chunk */

-   png_write_chunk_end(png_ptr);

-}

-#endif

-

-#ifdef PNG_WRITE_iTXt_SUPPORTED

-/* Write an iTXt chunk */

-void /* PRIVATE */

-png_write_iTXt(png_structrp png_ptr, int compression, png_const_charp key,

-    png_const_charp lang, png_const_charp lang_key, png_const_charp text)

-{

-   png_uint_32 key_len, prefix_len;

-   png_size_t lang_len, lang_key_len;

-   png_byte new_key[82];

-   compression_state comp;

-

-   png_debug(1, "in png_write_iTXt");

-

-   key_len = png_check_keyword(png_ptr, key, new_key);

-

-   if (key_len == 0)

-      png_error(png_ptr, "iTXt: invalid keyword");

-

-   /* Set the compression flag */

-   switch (compression)

-   {

-      case PNG_ITXT_COMPRESSION_NONE:

-      case PNG_TEXT_COMPRESSION_NONE:

-         compression = new_key[++key_len] = 0; /* no compression */

-         break;

-

-      case PNG_TEXT_COMPRESSION_zTXt:

-      case PNG_ITXT_COMPRESSION_zTXt:

-         compression = new_key[++key_len] = 1; /* compressed */

-         break;

-

-      default:

-         png_error(png_ptr, "iTXt: invalid compression");

-   }

-

-   new_key[++key_len] = PNG_COMPRESSION_TYPE_BASE;

-   ++key_len; /* for the keywod separator */

-

-   /* We leave it to the application to meet PNG-1.0 requirements on the

-    * contents of the text.  PNG-1.0 through PNG-1.2 discourage the use of

-    * any non-Latin-1 characters except for NEWLINE.  ISO PNG, however,

-    * specifies that the text is UTF-8 and this really doesn't require any

-    * checking.

-    *

-    * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.

-    *

-    * TODO: validate the language tag correctly (see the spec.)

-    */

-   if (lang == NULL) lang = ""; /* empty language is valid */

-   lang_len = strlen(lang)+1;

-   if (lang_key == NULL) lang_key = ""; /* may be empty */

-   lang_key_len = strlen(lang_key)+1;

-   if (text == NULL) text = ""; /* may be empty */

-

-   prefix_len = key_len;

-   if (lang_len > PNG_UINT_31_MAX-prefix_len)

-      prefix_len = PNG_UINT_31_MAX;

-   else

-      prefix_len = (png_uint_32)(prefix_len + lang_len);

-

-   if (lang_key_len > PNG_UINT_31_MAX-prefix_len)

-      prefix_len = PNG_UINT_31_MAX;

-   else

-      prefix_len = (png_uint_32)(prefix_len + lang_key_len);

-

-   png_text_compress_init(&comp, (png_const_bytep)text, strlen(text));

-

-   if (compression)

-   {

-      if (png_text_compress(png_ptr, png_iTXt, &comp, prefix_len) != Z_OK)

-         png_error(png_ptr, png_ptr->zstream.msg);

-   }

-

-   else

-   {

-      if (comp.input_len > PNG_UINT_31_MAX-prefix_len)

-         png_error(png_ptr, "iTXt: uncompressed text too long");

-

-      /* So the string will fit in a chunk: */

-      comp.output_len = (png_uint_32)/*SAFE*/comp.input_len;

-   }

-

-   png_write_chunk_header(png_ptr, png_iTXt, comp.output_len + prefix_len);

-

-   png_write_chunk_data(png_ptr, new_key, key_len);

-

-   png_write_chunk_data(png_ptr, (png_const_bytep)lang, lang_len);

-

-   png_write_chunk_data(png_ptr, (png_const_bytep)lang_key, lang_key_len);

-

-   if (compression)

-      png_write_compressed_data_out(png_ptr, &comp);

-

-   else

-      png_write_chunk_data(png_ptr, (png_const_bytep)text, comp.input_len);

-

-   png_write_chunk_end(png_ptr);

-}

-#endif

-

-#ifdef PNG_WRITE_oFFs_SUPPORTED

-/* Write the oFFs chunk */

-void /* PRIVATE */

-png_write_oFFs(png_structrp png_ptr, png_int_32 x_offset, png_int_32 y_offset,

-    int unit_type)

-{

-   png_byte buf[9];

-

-   png_debug(1, "in png_write_oFFs");

-

-   if (unit_type >= PNG_OFFSET_LAST)

-      png_warning(png_ptr, "Unrecognized unit type for oFFs chunk");

-

-   png_save_int_32(buf, x_offset);

-   png_save_int_32(buf + 4, y_offset);

-   buf[8] = (png_byte)unit_type;

-

-   png_write_complete_chunk(png_ptr, png_oFFs, buf, (png_size_t)9);

-}

-#endif

-#ifdef PNG_WRITE_pCAL_SUPPORTED

-/* Write the pCAL chunk (described in the PNG extensions document) */

-void /* PRIVATE */

-png_write_pCAL(png_structrp png_ptr, png_charp purpose, png_int_32 X0,

-    png_int_32 X1, int type, int nparams, png_const_charp units,

-    png_charpp params)

-{

-   png_uint_32 purpose_len;

-   png_size_t units_len, total_len;

-   png_size_tp params_len;

-   png_byte buf[10];

-   png_byte new_purpose[80];

-   int i;

-

-   png_debug1(1, "in png_write_pCAL (%d parameters)", nparams);

-

-   if (type >= PNG_EQUATION_LAST)

-      png_error(png_ptr, "Unrecognized equation type for pCAL chunk");

-

-   purpose_len = png_check_keyword(png_ptr, purpose, new_purpose);

-

-   if (purpose_len == 0)

-      png_error(png_ptr, "pCAL: invalid keyword");

-

-   ++purpose_len; /* terminator */

-

-   png_debug1(3, "pCAL purpose length = %d", (int)purpose_len);

-   units_len = strlen(units) + (nparams == 0 ? 0 : 1);

-   png_debug1(3, "pCAL units length = %d", (int)units_len);

-   total_len = purpose_len + units_len + 10;

-

-   params_len = (png_size_tp)png_malloc(png_ptr,

-       (png_alloc_size_t)(nparams * (sizeof (png_size_t))));

-

-   /* Find the length of each parameter, making sure we don't count the

-    * null terminator for the last parameter.

-    */

-   for (i = 0; i < nparams; i++)

-   {

-      params_len[i] = strlen(params[i]) + (i == nparams - 1 ? 0 : 1);

-      png_debug2(3, "pCAL parameter %d length = %lu", i,

-          (unsigned long)params_len[i]);

-      total_len += params_len[i];

-   }

-

-   png_debug1(3, "pCAL total length = %d", (int)total_len);

-   png_write_chunk_header(png_ptr, png_pCAL, (png_uint_32)total_len);

-   png_write_chunk_data(png_ptr, new_purpose, purpose_len);

-   png_save_int_32(buf, X0);

-   png_save_int_32(buf + 4, X1);

-   buf[8] = (png_byte)type;

-   buf[9] = (png_byte)nparams;

-   png_write_chunk_data(png_ptr, buf, (png_size_t)10);

-   png_write_chunk_data(png_ptr, (png_const_bytep)units, (png_size_t)units_len);

-

-   for (i = 0; i < nparams; i++)

-   {

-      png_write_chunk_data(png_ptr, (png_const_bytep)params[i], params_len[i]);

-   }

-

-   png_free(png_ptr, params_len);

-   png_write_chunk_end(png_ptr);

-}

-#endif

-

-#ifdef PNG_WRITE_sCAL_SUPPORTED

-/* Write the sCAL chunk */

-void /* PRIVATE */

-png_write_sCAL_s(png_structrp png_ptr, int unit, png_const_charp width,

-    png_const_charp height)

-{

-   png_byte buf[64];

-   png_size_t wlen, hlen, total_len;

-

-   png_debug(1, "in png_write_sCAL_s");

-

-   wlen = strlen(width);

-   hlen = strlen(height);

-   total_len = wlen + hlen + 2;

-

-   if (total_len > 64)

-   {

-      png_warning(png_ptr, "Can't write sCAL (buffer too small)");

-      return;

-   }

-

-   buf[0] = (png_byte)unit;

-   memcpy(buf + 1, width, wlen + 1);      /* Append the '\0' here */

-   memcpy(buf + wlen + 2, height, hlen);  /* Do NOT append the '\0' here */

-

-   png_debug1(3, "sCAL total length = %u", (unsigned int)total_len);

-   png_write_complete_chunk(png_ptr, png_sCAL, buf, total_len);

-}

-#endif

-

-#ifdef PNG_WRITE_pHYs_SUPPORTED

-/* Write the pHYs chunk */

-void /* PRIVATE */

-png_write_pHYs(png_structrp png_ptr, png_uint_32 x_pixels_per_unit,

-    png_uint_32 y_pixels_per_unit,

-    int unit_type)

-{

-   png_byte buf[9];

-

-   png_debug(1, "in png_write_pHYs");

-

-   if (unit_type >= PNG_RESOLUTION_LAST)

-      png_warning(png_ptr, "Unrecognized unit type for pHYs chunk");

-

-   png_save_uint_32(buf, x_pixels_per_unit);

-   png_save_uint_32(buf + 4, y_pixels_per_unit);

-   buf[8] = (png_byte)unit_type;

-

-   png_write_complete_chunk(png_ptr, png_pHYs, buf, (png_size_t)9);

-}

-#endif

-

-#ifdef PNG_WRITE_tIME_SUPPORTED

-/* Write the tIME chunk.  Use either png_convert_from_struct_tm()

- * or png_convert_from_time_t(), or fill in the structure yourself.

- */

-void /* PRIVATE */

-png_write_tIME(png_structrp png_ptr, png_const_timep mod_time)

-{

-   png_byte buf[7];

-

-   png_debug(1, "in png_write_tIME");

-

-   if (mod_time->month  > 12 || mod_time->month  < 1 ||

-       mod_time->day    > 31 || mod_time->day    < 1 ||

-       mod_time->hour   > 23 || mod_time->second > 60)

-   {

-      png_warning(png_ptr, "Invalid time specified for tIME chunk");

-      return;

-   }

-

-   png_save_uint_16(buf, mod_time->year);

-   buf[2] = mod_time->month;

-   buf[3] = mod_time->day;

-   buf[4] = mod_time->hour;

-   buf[5] = mod_time->minute;

-   buf[6] = mod_time->second;

-

-   png_write_complete_chunk(png_ptr, png_tIME, buf, (png_size_t)7);

-}

-#endif

-

-/* Initializes the row writing capability of libpng */

-void /* PRIVATE */

-png_write_start_row(png_structrp png_ptr)

-{

-#ifdef PNG_WRITE_INTERLACING_SUPPORTED

-   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */

-

-   /* Start of interlace block */

-   static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};

-

-   /* Offset to next interlace block */

-   static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};

-

-   /* Start of interlace block in the y direction */

-   static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};

-

-   /* Offset to next interlace block in the y direction */

-   static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};

-#endif

-

-   png_alloc_size_t buf_size;

-   int usr_pixel_depth;

-

-   png_debug(1, "in png_write_start_row");

-

-   usr_pixel_depth = png_ptr->usr_channels * png_ptr->usr_bit_depth;

-   buf_size = PNG_ROWBYTES(usr_pixel_depth, png_ptr->width) + 1;

-

-   /* 1.5.6: added to allow checking in the row write code. */

-   png_ptr->transformed_pixel_depth = png_ptr->pixel_depth;

-   png_ptr->maximum_pixel_depth = (png_byte)usr_pixel_depth;

-

-   /* Set up row buffer */

-   png_ptr->row_buf = (png_bytep)png_malloc(png_ptr, buf_size);

-

-   png_ptr->row_buf[0] = PNG_FILTER_VALUE_NONE;

-

-#ifdef PNG_WRITE_FILTER_SUPPORTED

-   /* Set up filtering buffer, if using this filter */

-   if (png_ptr->do_filter & PNG_FILTER_SUB)

-   {

-      png_ptr->sub_row = (png_bytep)png_malloc(png_ptr, png_ptr->rowbytes + 1);

-

-      png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB;

-   }

-

-   /* We only need to keep the previous row if we are using one of these. */

-   if (png_ptr->do_filter & (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH))

-   {

-      /* Set up previous row buffer */

-      png_ptr->prev_row = (png_bytep)png_calloc(png_ptr, buf_size);

-

-      if (png_ptr->do_filter & PNG_FILTER_UP)

-      {

-         png_ptr->up_row = (png_bytep)png_malloc(png_ptr,

-            png_ptr->rowbytes + 1);

-

-         png_ptr->up_row[0] = PNG_FILTER_VALUE_UP;

-      }

-

-      if (png_ptr->do_filter & PNG_FILTER_AVG)

-      {

-         png_ptr->avg_row = (png_bytep)png_malloc(png_ptr,

-             png_ptr->rowbytes + 1);

-

-         png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG;

-      }

-

-      if (png_ptr->do_filter & PNG_FILTER_PAETH)

-      {

-         png_ptr->paeth_row = (png_bytep)png_malloc(png_ptr,

-             png_ptr->rowbytes + 1);

-

-         png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH;

-      }

-   }

-#endif /* PNG_WRITE_FILTER_SUPPORTED */

-

-#ifdef PNG_WRITE_INTERLACING_SUPPORTED

-   /* If interlaced, we need to set up width and height of pass */

-   if (png_ptr->interlaced)

-   {

-      if (!(png_ptr->transformations & PNG_INTERLACE))

-      {

-         png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -

-             png_pass_ystart[0]) / png_pass_yinc[0];

-

-         png_ptr->usr_width = (png_ptr->width + png_pass_inc[0] - 1 -

-             png_pass_start[0]) / png_pass_inc[0];

-      }

-

-      else

-      {

-         png_ptr->num_rows = png_ptr->height;

-         png_ptr->usr_width = png_ptr->width;

-      }

-   }

-

-   else

-#endif

-   {

-      png_ptr->num_rows = png_ptr->height;

-      png_ptr->usr_width = png_ptr->width;

-   }

-}

-

-/* Internal use only.  Called when finished processing a row of data. */

-void /* PRIVATE */

-png_write_finish_row(png_structrp png_ptr)

-{

-#ifdef PNG_WRITE_INTERLACING_SUPPORTED

-   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */

-

-   /* Start of interlace block */

-   static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};

-

-   /* Offset to next interlace block */

-   static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};

-

-   /* Start of interlace block in the y direction */

-   static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};

-

-   /* Offset to next interlace block in the y direction */

-   static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};

-#endif

-

-   png_debug(1, "in png_write_finish_row");

-

-   /* Next row */

-   png_ptr->row_number++;

-

-   /* See if we are done */

-   if (png_ptr->row_number < png_ptr->num_rows)

-      return;

-

-#ifdef PNG_WRITE_INTERLACING_SUPPORTED

-   /* If interlaced, go to next pass */

-   if (png_ptr->interlaced)

-   {

-      png_ptr->row_number = 0;

-      if (png_ptr->transformations & PNG_INTERLACE)

-      {

-         png_ptr->pass++;

-      }

-

-      else

-      {

-         /* Loop until we find a non-zero width or height pass */

-         do

-         {

-            png_ptr->pass++;

-

-            if (png_ptr->pass >= 7)

-               break;

-

-            png_ptr->usr_width = (png_ptr->width +

-                png_pass_inc[png_ptr->pass] - 1 -

-                png_pass_start[png_ptr->pass]) /

-                png_pass_inc[png_ptr->pass];

-

-            png_ptr->num_rows = (png_ptr->height +

-                png_pass_yinc[png_ptr->pass] - 1 -

-                png_pass_ystart[png_ptr->pass]) /

-                png_pass_yinc[png_ptr->pass];

-

-            if (png_ptr->transformations & PNG_INTERLACE)

-               break;

-

-         } while (png_ptr->usr_width == 0 || png_ptr->num_rows == 0);

-

-      }

-

-      /* Reset the row above the image for the next pass */

-      if (png_ptr->pass < 7)

-      {

-         if (png_ptr->prev_row != NULL)

-            memset(png_ptr->prev_row, 0,

-                (png_size_t)(PNG_ROWBYTES(png_ptr->usr_channels*

-                png_ptr->usr_bit_depth, png_ptr->width)) + 1);

-

-         return;

-      }

-   }

-#endif

-

-   /* If we get here, we've just written the last row, so we need

-      to flush the compressor */

-   png_compress_IDAT(png_ptr, NULL, 0, Z_FINISH);

-}

-

-#ifdef PNG_WRITE_INTERLACING_SUPPORTED

-/* Pick out the correct pixels for the interlace pass.

- * The basic idea here is to go through the row with a source

- * pointer and a destination pointer (sp and dp), and copy the

- * correct pixels for the pass.  As the row gets compacted,

- * sp will always be >= dp, so we should never overwrite anything.

- * See the default: case for the easiest code to understand.

- */

-void /* PRIVATE */

-png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)

-{

-   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */

-

-   /* Start of interlace block */

-   static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};

-

-   /* Offset to next interlace block */

-   static PNG_CONST png_byte  png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};

-

-   png_debug(1, "in png_do_write_interlace");

-

-   /* We don't have to do anything on the last pass (6) */

-   if (pass < 6)

-   {

-      /* Each pixel depth is handled separately */

-      switch (row_info->pixel_depth)

-      {

-         case 1:

-         {

-            png_bytep sp;

-            png_bytep dp;

-            int shift;

-            int d;

-            int value;

-            png_uint_32 i;

-            png_uint_32 row_width = row_info->width;

-

-            dp = row;

-            d = 0;

-            shift = 7;

-

-            for (i = png_pass_start[pass]; i < row_width;

-               i += png_pass_inc[pass])

-            {

-               sp = row + (png_size_t)(i >> 3);

-               value = (int)(*sp >> (7 - (int)(i & 0x07))) & 0x01;

-               d |= (value << shift);

-

-               if (shift == 0)

-               {

-                  shift = 7;

-                  *dp++ = (png_byte)d;

-                  d = 0;

-               }

-

-               else

-                  shift--;

-

-            }

-            if (shift != 7)

-               *dp = (png_byte)d;

-

-            break;

-         }

-

-         case 2:

-         {

-            png_bytep sp;

-            png_bytep dp;

-            int shift;

-            int d;

-            int value;

-            png_uint_32 i;

-            png_uint_32 row_width = row_info->width;

-

-            dp = row;

-            shift = 6;

-            d = 0;

-

-            for (i = png_pass_start[pass]; i < row_width;

-               i += png_pass_inc[pass])

-            {

-               sp = row + (png_size_t)(i >> 2);

-               value = (*sp >> ((3 - (int)(i & 0x03)) << 1)) & 0x03;

-               d |= (value << shift);

-

-               if (shift == 0)

-               {

-                  shift = 6;

-                  *dp++ = (png_byte)d;

-                  d = 0;

-               }

-

-               else

-                  shift -= 2;

-            }

-            if (shift != 6)

-               *dp = (png_byte)d;

-

-            break;

-         }

-

-         case 4:

-         {

-            png_bytep sp;

-            png_bytep dp;

-            int shift;

-            int d;

-            int value;

-            png_uint_32 i;

-            png_uint_32 row_width = row_info->width;

-

-            dp = row;

-            shift = 4;

-            d = 0;

-            for (i = png_pass_start[pass]; i < row_width;

-                i += png_pass_inc[pass])

-            {

-               sp = row + (png_size_t)(i >> 1);

-               value = (*sp >> ((1 - (int)(i & 0x01)) << 2)) & 0x0f;

-               d |= (value << shift);

-

-               if (shift == 0)

-               {

-                  shift = 4;

-                  *dp++ = (png_byte)d;

-                  d = 0;

-               }

-

-               else

-                  shift -= 4;

-            }

-            if (shift != 4)

-               *dp = (png_byte)d;

-

-            break;

-         }

-

-         default:

-         {

-            png_bytep sp;

-            png_bytep dp;

-            png_uint_32 i;

-            png_uint_32 row_width = row_info->width;

-            png_size_t pixel_bytes;

-

-            /* Start at the beginning */

-            dp = row;

-

-            /* Find out how many bytes each pixel takes up */

-            pixel_bytes = (row_info->pixel_depth >> 3);

-

-            /* Loop through the row, only looking at the pixels that matter */

-            for (i = png_pass_start[pass]; i < row_width;

-               i += png_pass_inc[pass])

-            {

-               /* Find out where the original pixel is */

-               sp = row + (png_size_t)i * pixel_bytes;

-

-               /* Move the pixel */

-               if (dp != sp)

-                  memcpy(dp, sp, pixel_bytes);

-

-               /* Next pixel */

-               dp += pixel_bytes;

-            }

-            break;

-         }

-      }

-      /* Set new row width */

-      row_info->width = (row_info->width +

-          png_pass_inc[pass] - 1 -

-          png_pass_start[pass]) /

-          png_pass_inc[pass];

-

-      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,

-          row_info->width);

-   }

-}

-#endif

-

-/* This filters the row, chooses which filter to use, if it has not already

- * been specified by the application, and then writes the row out with the

- * chosen filter.

- */

-static void png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row,

-   png_size_t row_bytes);

-

-#define PNG_MAXSUM (((png_uint_32)(-1)) >> 1)

-#define PNG_HISHIFT 10

-#define PNG_LOMASK ((png_uint_32)0xffffL)

-#define PNG_HIMASK ((png_uint_32)(~PNG_LOMASK >> PNG_HISHIFT))

-void /* PRIVATE */

-png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)

-{

-   png_bytep best_row;

-#ifdef PNG_WRITE_FILTER_SUPPORTED

-   png_bytep prev_row, row_buf;

-   png_uint_32 mins, bpp;

-   png_byte filter_to_do = png_ptr->do_filter;

-   png_size_t row_bytes = row_info->rowbytes;

-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED

-   int num_p_filters = png_ptr->num_prev_filters;

-#endif

-

-   png_debug(1, "in png_write_find_filter");

-

-#ifndef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED

-  if (png_ptr->row_number == 0 && filter_to_do == PNG_ALL_FILTERS)

-  {

-     /* These will never be selected so we need not test them. */

-     filter_to_do &= ~(PNG_FILTER_UP | PNG_FILTER_PAETH);

-  }

-#endif

-

-   /* Find out how many bytes offset each pixel is */

-   bpp = (row_info->pixel_depth + 7) >> 3;

-

-   prev_row = png_ptr->prev_row;

-#endif

-   best_row = png_ptr->row_buf;

-#ifdef PNG_WRITE_FILTER_SUPPORTED

-   row_buf = best_row;

-   mins = PNG_MAXSUM;

-

-   /* The prediction method we use is to find which method provides the

-    * smallest value when summing the absolute values of the distances

-    * from zero, using anything >= 128 as negative numbers.  This is known

-    * as the "minimum sum of absolute differences" heuristic.  Other

-    * heuristics are the "weighted minimum sum of absolute differences"

-    * (experimental and can in theory improve compression), and the "zlib

-    * predictive" method (not implemented yet), which does test compressions

-    * of lines using different filter methods, and then chooses the

-    * (series of) filter(s) that give minimum compressed data size (VERY

-    * computationally expensive).

-    *

-    * GRR 980525:  consider also

-    *

-    *   (1) minimum sum of absolute differences from running average (i.e.,

-    *       keep running sum of non-absolute differences & count of bytes)

-    *       [track dispersion, too?  restart average if dispersion too large?]

-    *

-    *  (1b) minimum sum of absolute differences from sliding average, probably

-    *       with window size <= deflate window (usually 32K)

-    *

-    *   (2) minimum sum of squared differences from zero or running average

-    *       (i.e., ~ root-mean-square approach)

-    */

-

-

-   /* We don't need to test the 'no filter' case if this is the only filter

-    * that has been chosen, as it doesn't actually do anything to the data.

-    */

-   if ((filter_to_do & PNG_FILTER_NONE) && filter_to_do != PNG_FILTER_NONE)

-   {

-      png_bytep rp;

-      png_uint_32 sum = 0;

-      png_size_t i;

-      int v;

-

-      for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++)

-      {

-         v = *rp;

-         sum += (v < 128) ? v : 256 - v;

-      }

-

-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED

-      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)

-      {

-         png_uint_32 sumhi, sumlo;

-         int j;

-         sumlo = sum & PNG_LOMASK;

-         sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; /* Gives us some footroom */

-

-         /* Reduce the sum if we match any of the previous rows */

-         for (j = 0; j < num_p_filters; j++)

-         {

-            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)

-            {

-               sumlo = (sumlo * png_ptr->filter_weights[j]) >>

-                   PNG_WEIGHT_SHIFT;

-

-               sumhi = (sumhi * png_ptr->filter_weights[j]) >>

-                   PNG_WEIGHT_SHIFT;

-            }

-         }

-

-         /* Factor in the cost of this filter (this is here for completeness,

-          * but it makes no sense to have a "cost" for the NONE filter, as

-          * it has the minimum possible computational cost - none).

-          */

-         sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >>

-             PNG_COST_SHIFT;

-

-         sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >>

-             PNG_COST_SHIFT;

-

-         if (sumhi > PNG_HIMASK)

-            sum = PNG_MAXSUM;

-

-         else

-            sum = (sumhi << PNG_HISHIFT) + sumlo;

-      }

-#endif

-      mins = sum;

-   }

-

-   /* Sub filter */

-   if (filter_to_do == PNG_FILTER_SUB)

-   /* It's the only filter so no testing is needed */

-   {

-      png_bytep rp, lp, dp;

-      png_size_t i;

-

-      for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;

-           i++, rp++, dp++)

-      {

-         *dp = *rp;

-      }

-

-      for (lp = row_buf + 1; i < row_bytes;

-         i++, rp++, lp++, dp++)

-      {

-         *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);

-      }

-

-      best_row = png_ptr->sub_row;

-   }

-

-   else if (filter_to_do & PNG_FILTER_SUB)

-   {

-      png_bytep rp, dp, lp;

-      png_uint_32 sum = 0, lmins = mins;

-      png_size_t i;

-      int v;

-

-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED

-      /* We temporarily increase the "minimum sum" by the factor we

-       * would reduce the sum of this filter, so that we can do the

-       * early exit comparison without scaling the sum each time.

-       */

-      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)

-      {

-         int j;

-         png_uint_32 lmhi, lmlo;

-         lmlo = lmins & PNG_LOMASK;

-         lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;

-

-         for (j = 0; j < num_p_filters; j++)

-         {

-            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB)

-            {

-               lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>

-                   PNG_WEIGHT_SHIFT;

-

-               lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>

-                   PNG_WEIGHT_SHIFT;

-            }

-         }

-

-         lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>

-             PNG_COST_SHIFT;

-

-         lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>

-             PNG_COST_SHIFT;

-

-         if (lmhi > PNG_HIMASK)

-            lmins = PNG_MAXSUM;

-

-         else

-            lmins = (lmhi << PNG_HISHIFT) + lmlo;

-      }

-#endif

-

-      for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;

-           i++, rp++, dp++)

-      {

-         v = *dp = *rp;

-

-         sum += (v < 128) ? v : 256 - v;

-      }

-

-      for (lp = row_buf + 1; i < row_bytes;

-         i++, rp++, lp++, dp++)

-      {

-         v = *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);

-

-         sum += (v < 128) ? v : 256 - v;

-

-         if (sum > lmins)  /* We are already worse, don't continue. */

-            break;

-      }

-

-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED

-      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)

-      {

-         int j;

-         png_uint_32 sumhi, sumlo;

-         sumlo = sum & PNG_LOMASK;

-         sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;

-

-         for (j = 0; j < num_p_filters; j++)

-         {

-            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB)

-            {

-               sumlo = (sumlo * png_ptr->inv_filter_weights[j]) >>

-                   PNG_WEIGHT_SHIFT;

-

-               sumhi = (sumhi * png_ptr->inv_filter_weights[j]) >>

-                   PNG_WEIGHT_SHIFT;

-            }

-         }

-

-         sumlo = (sumlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>

-             PNG_COST_SHIFT;

-

-         sumhi = (sumhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>

-             PNG_COST_SHIFT;

-

-         if (sumhi > PNG_HIMASK)

-            sum = PNG_MAXSUM;

-

-         else

-            sum = (sumhi << PNG_HISHIFT) + sumlo;

-      }

-#endif

-

-      if (sum < mins)

-      {

-         mins = sum;

-         best_row = png_ptr->sub_row;

-      }

-   }

-

-   /* Up filter */

-   if (filter_to_do == PNG_FILTER_UP)

-   {

-      png_bytep rp, dp, pp;

-      png_size_t i;

-

-      for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,

-          pp = prev_row + 1; i < row_bytes;

-          i++, rp++, pp++, dp++)

-      {

-         *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);

-      }

-

-      best_row = png_ptr->up_row;

-   }

-

-   else if (filter_to_do & PNG_FILTER_UP)

-   {

-      png_bytep rp, dp, pp;

-      png_uint_32 sum = 0, lmins = mins;

-      png_size_t i;

-      int v;

-

-

-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED

-      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)

-      {

-         int j;

-         png_uint_32 lmhi, lmlo;

-         lmlo = lmins & PNG_LOMASK;

-         lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;

-

-         for (j = 0; j < num_p_filters; j++)

-         {

-            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)

-            {

-               lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>

-                   PNG_WEIGHT_SHIFT;

-

-               lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>

-                   PNG_WEIGHT_SHIFT;

-            }

-         }

-

-         lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >>

-             PNG_COST_SHIFT;

-

-         lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >>

-             PNG_COST_SHIFT;

-

-         if (lmhi > PNG_HIMASK)

-            lmins = PNG_MAXSUM;

-

-         else

-            lmins = (lmhi << PNG_HISHIFT) + lmlo;

-      }

-#endif

-

-      for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,

-          pp = prev_row + 1; i < row_bytes; i++)

-      {

-         v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);

-

-         sum += (v < 128) ? v : 256 - v;

-

-         if (sum > lmins)  /* We are already worse, don't continue. */

-            break;

-      }

-

-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED

-      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)

-      {

-         int j;

-         png_uint_32 sumhi, sumlo;

-         sumlo = sum & PNG_LOMASK;

-         sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;

-

-         for (j = 0; j < num_p_filters; j++)

-         {

-            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)

-            {

-               sumlo = (sumlo * png_ptr->filter_weights[j]) >>

-                   PNG_WEIGHT_SHIFT;

-

-               sumhi = (sumhi * png_ptr->filter_weights[j]) >>

-                   PNG_WEIGHT_SHIFT;

-            }

-         }

-

-         sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >>

-             PNG_COST_SHIFT;

-

-         sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >>

-             PNG_COST_SHIFT;

-

-         if (sumhi > PNG_HIMASK)

-            sum = PNG_MAXSUM;

-

-         else

-            sum = (sumhi << PNG_HISHIFT) + sumlo;

-      }

-#endif

-

-      if (sum < mins)

-      {

-         mins = sum;

-         best_row = png_ptr->up_row;

-      }

-   }

-

-   /* Avg filter */

-   if (filter_to_do == PNG_FILTER_AVG)

-   {

-      png_bytep rp, dp, pp, lp;

-      png_uint_32 i;

-

-      for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,

-           pp = prev_row + 1; i < bpp; i++)

-      {

-         *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);

-      }

-

-      for (lp = row_buf + 1; i < row_bytes; i++)

-      {

-         *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2))

-                 & 0xff);

-      }

-      best_row = png_ptr->avg_row;

-   }

-

-   else if (filter_to_do & PNG_FILTER_AVG)

-   {

-      png_bytep rp, dp, pp, lp;

-      png_uint_32 sum = 0, lmins = mins;

-      png_size_t i;

-      int v;

-

-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED

-      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)

-      {

-         int j;

-         png_uint_32 lmhi, lmlo;

-         lmlo = lmins & PNG_LOMASK;

-         lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;

-

-         for (j = 0; j < num_p_filters; j++)

-         {

-            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_AVG)

-            {

-               lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>

-                   PNG_WEIGHT_SHIFT;

-

-               lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>

-                   PNG_WEIGHT_SHIFT;

-            }

-         }

-

-         lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >>

-             PNG_COST_SHIFT;

-

-         lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >>

-             PNG_COST_SHIFT;

-

-         if (lmhi > PNG_HIMASK)

-            lmins = PNG_MAXSUM;

-

-         else

-            lmins = (lmhi << PNG_HISHIFT) + lmlo;

-      }

-#endif

-

-      for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,

-           pp = prev_row + 1; i < bpp; i++)

-      {

-         v = *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);

-

-         sum += (v < 128) ? v : 256 - v;

-      }

-

-      for (lp = row_buf + 1; i < row_bytes; i++)

-      {

-         v = *dp++ =

-             (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2)) & 0xff);

-

-         sum += (v < 128) ? v : 256 - v;

-

-         if (sum > lmins)  /* We are already worse, don't continue. */

-            break;

-      }

-

-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED

-      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)

-      {

-         int j;

-         png_uint_32 sumhi, sumlo;

-         sumlo = sum & PNG_LOMASK;

-         sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;

-

-         for (j = 0; j < num_p_filters; j++)

-         {

-            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)

-            {

-               sumlo = (sumlo * png_ptr->filter_weights[j]) >>

-                   PNG_WEIGHT_SHIFT;

-

-               sumhi = (sumhi * png_ptr->filter_weights[j]) >>

-                   PNG_WEIGHT_SHIFT;

-            }

-         }

-

-         sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >>

-             PNG_COST_SHIFT;

-

-         sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >>

-             PNG_COST_SHIFT;

-

-         if (sumhi > PNG_HIMASK)

-            sum = PNG_MAXSUM;

-

-         else

-            sum = (sumhi << PNG_HISHIFT) + sumlo;

-      }

-#endif

-

-      if (sum < mins)

-      {

-         mins = sum;

-         best_row = png_ptr->avg_row;

-      }

-   }

-

-   /* Paeth filter */

-   if (filter_to_do == PNG_FILTER_PAETH)

-   {

-      png_bytep rp, dp, pp, cp, lp;

-      png_size_t i;

-

-      for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,

-          pp = prev_row + 1; i < bpp; i++)

-      {

-         *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);

-      }

-

-      for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)

-      {

-         int a, b, c, pa, pb, pc, p;

-

-         b = *pp++;

-         c = *cp++;

-         a = *lp++;

-

-         p = b - c;

-         pc = a - c;

-

-#ifdef PNG_USE_ABS

-         pa = abs(p);

-         pb = abs(pc);

-         pc = abs(p + pc);

-#else

-         pa = p < 0 ? -p : p;

-         pb = pc < 0 ? -pc : pc;

-         pc = (p + pc) < 0 ? -(p + pc) : p + pc;

-#endif

-

-         p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;

-

-         *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);

-      }

-      best_row = png_ptr->paeth_row;

-   }

-

-   else if (filter_to_do & PNG_FILTER_PAETH)

-   {

-      png_bytep rp, dp, pp, cp, lp;

-      png_uint_32 sum = 0, lmins = mins;

-      png_size_t i;

-      int v;

-

-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED

-      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)

-      {

-         int j;

-         png_uint_32 lmhi, lmlo;

-         lmlo = lmins & PNG_LOMASK;

-         lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;

-

-         for (j = 0; j < num_p_filters; j++)

-         {

-            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH)

-            {

-               lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>

-                   PNG_WEIGHT_SHIFT;

-

-               lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>

-                   PNG_WEIGHT_SHIFT;

-            }

-         }

-

-         lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >>

-             PNG_COST_SHIFT;

-

-         lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >>

-             PNG_COST_SHIFT;

-

-         if (lmhi > PNG_HIMASK)

-            lmins = PNG_MAXSUM;

-

-         else

-            lmins = (lmhi << PNG_HISHIFT) + lmlo;

-      }

-#endif

-

-      for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,

-          pp = prev_row + 1; i < bpp; i++)

-      {

-         v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);

-

-         sum += (v < 128) ? v : 256 - v;

-      }

-

-      for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)

-      {

-         int a, b, c, pa, pb, pc, p;

-

-         b = *pp++;

-         c = *cp++;

-         a = *lp++;

-

-#ifndef PNG_SLOW_PAETH

-         p = b - c;

-         pc = a - c;

-#ifdef PNG_USE_ABS

-         pa = abs(p);

-         pb = abs(pc);

-         pc = abs(p + pc);

-#else

-         pa = p < 0 ? -p : p;

-         pb = pc < 0 ? -pc : pc;

-         pc = (p + pc) < 0 ? -(p + pc) : p + pc;

-#endif

-         p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;

-#else /* PNG_SLOW_PAETH */

-         p = a + b - c;

-         pa = abs(p - a);

-         pb = abs(p - b);

-         pc = abs(p - c);

-

-         if (pa <= pb && pa <= pc)

-            p = a;

-

-         else if (pb <= pc)

-            p = b;

-

-         else

-            p = c;

-#endif /* PNG_SLOW_PAETH */

-

-         v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);

-

-         sum += (v < 128) ? v : 256 - v;

-

-         if (sum > lmins)  /* We are already worse, don't continue. */

-            break;

-      }

-

-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED

-      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)

-      {

-         int j;

-         png_uint_32 sumhi, sumlo;

-         sumlo = sum & PNG_LOMASK;

-         sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;

-

-         for (j = 0; j < num_p_filters; j++)

-         {

-            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH)

-            {

-               sumlo = (sumlo * png_ptr->filter_weights[j]) >>

-                   PNG_WEIGHT_SHIFT;

-

-               sumhi = (sumhi * png_ptr->filter_weights[j]) >>

-                   PNG_WEIGHT_SHIFT;

-            }

-         }

-

-         sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >>

-             PNG_COST_SHIFT;

-

-         sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >>

-             PNG_COST_SHIFT;

-

-         if (sumhi > PNG_HIMASK)

-            sum = PNG_MAXSUM;

-

-         else

-            sum = (sumhi << PNG_HISHIFT) + sumlo;

-      }

-#endif

-

-      if (sum < mins)

-      {

-         best_row = png_ptr->paeth_row;

-      }

-   }

-#endif /* PNG_WRITE_FILTER_SUPPORTED */

-

-   /* Do the actual writing of the filtered row data from the chosen filter. */

-   png_write_filtered_row(png_ptr, best_row, row_info->rowbytes+1);

-

-#ifdef PNG_WRITE_FILTER_SUPPORTED

-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED

-   /* Save the type of filter we picked this time for future calculations */

-   if (png_ptr->num_prev_filters > 0)

-   {

-      int j;

-

-      for (j = 1; j < num_p_filters; j++)

-      {

-         png_ptr->prev_filters[j] = png_ptr->prev_filters[j - 1];

-      }

-

-      png_ptr->prev_filters[j] = best_row[0];

-   }

-#endif

-#endif /* PNG_WRITE_FILTER_SUPPORTED */

-}

-

-

-/* Do the actual writing of a previously filtered row. */

-static void

-png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row,

-   png_size_t full_row_length/*includes filter byte*/)

-{

-   png_debug(1, "in png_write_filtered_row");

-

-   png_debug1(2, "filter = %d", filtered_row[0]);

-

-   png_compress_IDAT(png_ptr, filtered_row, full_row_length, Z_NO_FLUSH);

-

-   /* Swap the current and previous rows */

-   if (png_ptr->prev_row != NULL)

-   {

-      png_bytep tptr;

-

-      tptr = png_ptr->prev_row;

-      png_ptr->prev_row = png_ptr->row_buf;

-      png_ptr->row_buf = tptr;

-   }

-

-   /* Finish row - updates counters and flushes zlib if last row */

-   png_write_finish_row(png_ptr);

-

-#ifdef PNG_WRITE_FLUSH_SUPPORTED

-   png_ptr->flush_rows++;

-

-   if (png_ptr->flush_dist > 0 &&

-       png_ptr->flush_rows >= png_ptr->flush_dist)

-   {

-      png_write_flush(png_ptr);

-   }

-#endif

-}

-#endif /* PNG_WRITE_SUPPORTED */