Backport PNG output format to origin/master branch.

The pdfium library itself does not support the format, but the test utility
can convert to this output format.

GN build can't be tested standalone, so push this out to the next CL.

R=jam@chromium.org

Review URL: https://codereview.chromium.org/950113002

1 files changed, 163 insertions, 0 deletions

diff --git a/samples/fx_lpng/lpng_v163/fx_pngwio.c b/samples/fx_lpng/lpng_v163/fx_pngwio.c
new file mode 100644
index 0000000000..9268c163b0
--- /dev/null
+++ b/samples/fx_lpng/lpng_v163/fx_pngwio.c
@@ -0,0 +1,163 @@
+

+/* pngwio.c - functions for data output

+ *

+ * Last changed in libpng 1.6.0 [February 14, 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

+ *

+ * This file provides a location for all output.  Users who need

+ * special handling are expected to write functions that have the same

+ * arguments as these and perform similar functions, but that possibly

+ * use different output methods.  Note that you shouldn't change these

+ * functions, but rather write replacement functions and then change

+ * them at run time with png_set_write_fn(...).

+ */

+#include "pngpriv.h"

+

+#ifdef PNG_WRITE_SUPPORTED

+

+/* Write the data to whatever output you are using.  The default routine

+ * writes to a file pointer.  Note that this routine sometimes gets called

+ * with very small lengths, so you should implement some kind of simple

+ * buffering if you are using unbuffered writes.  This should never be asked

+ * to write more than 64K on a 16 bit machine.

+ */

+

+void /* PRIVATE */

+png_write_data(png_structrp png_ptr, png_const_bytep data, png_size_t length)

+{

+   /* NOTE: write_data_fn must not change the buffer! */

+   if (png_ptr->write_data_fn != NULL )

+      (*(png_ptr->write_data_fn))(png_ptr, png_constcast(png_bytep,data),

+         length);

+

+   else

+      png_error(png_ptr, "Call to NULL write function");

+}

+

+#ifdef PNG_STDIO_SUPPORTED

+/* This is the function that does the actual writing of data.  If you are

+ * not writing to a standard C stream, you should create a replacement

+ * write_data function and use it at run time with png_set_write_fn(), rather

+ * than changing the library.

+ */

+void PNGCBAPI

+png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length)

+{

+   png_size_t check;

+

+   if (png_ptr == NULL)

+      return;

+

+   check = fwrite(data, 1, length, (png_FILE_p)(png_ptr->io_ptr));

+

+   if (check != length)

+      png_error(png_ptr, "Write Error");

+}

+#endif

+

+/* This function is called to output any data pending writing (normally

+ * to disk).  After png_flush is called, there should be no data pending

+ * writing in any buffers.

+ */

+#ifdef PNG_WRITE_FLUSH_SUPPORTED

+void /* PRIVATE */

+png_flush(png_structrp png_ptr)

+{

+   if (png_ptr->output_flush_fn != NULL)

+      (*(png_ptr->output_flush_fn))(png_ptr);

+}

+

+#  ifdef PNG_STDIO_SUPPORTED

+void PNGCBAPI

+png_default_flush(png_structp png_ptr)

+{

+   png_FILE_p io_ptr;

+

+   if (png_ptr == NULL)

+      return;

+

+   io_ptr = png_voidcast(png_FILE_p, (png_ptr->io_ptr));

+   fflush(io_ptr);

+}

+#  endif

+#endif

+

+/* This function allows the application to supply new output functions for

+ * libpng if standard C streams aren't being used.

+ *

+ * This function takes as its arguments:

+ * png_ptr       - pointer to a png output data structure

+ * io_ptr        - pointer to user supplied structure containing info about

+ *                 the output functions.  May be NULL.

+ * write_data_fn - pointer to a new output function that takes as its

+ *                 arguments a pointer to a png_struct, a pointer to

+ *                 data to be written, and a 32-bit unsigned int that is

+ *                 the number of bytes to be written.  The new write

+ *                 function should call png_error(png_ptr, "Error msg")

+ *                 to exit and output any fatal error messages.  May be

+ *                 NULL, in which case libpng's default function will

+ *                 be used.

+ * flush_data_fn - pointer to a new flush function that takes as its

+ *                 arguments a pointer to a png_struct.  After a call to

+ *                 the flush function, there should be no data in any buffers

+ *                 or pending transmission.  If the output method doesn't do

+ *                 any buffering of output, a function prototype must still be

+ *                 supplied although it doesn't have to do anything.  If

+ *                 PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile

+ *                 time, output_flush_fn will be ignored, although it must be

+ *                 supplied for compatibility.  May be NULL, in which case

+ *                 libpng's default function will be used, if

+ *                 PNG_WRITE_FLUSH_SUPPORTED is defined.  This is not

+ *                 a good idea if io_ptr does not point to a standard

+ *                 *FILE structure.

+ */

+void PNGAPI

+png_set_write_fn(png_structrp png_ptr, png_voidp io_ptr,

+    png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn)

+{

+   if (png_ptr == NULL)

+      return;

+

+   png_ptr->io_ptr = io_ptr;

+

+#ifdef PNG_STDIO_SUPPORTED

+   if (write_data_fn != NULL)

+      png_ptr->write_data_fn = write_data_fn;

+

+   else

+      png_ptr->write_data_fn = png_default_write_data;

+#else

+   png_ptr->write_data_fn = write_data_fn;

+#endif

+

+#ifdef PNG_WRITE_FLUSH_SUPPORTED

+#  ifdef PNG_STDIO_SUPPORTED

+

+   if (output_flush_fn != NULL)

+      png_ptr->output_flush_fn = output_flush_fn;

+

+   else

+      png_ptr->output_flush_fn = png_default_flush;

+

+#  else

+   png_ptr->output_flush_fn = output_flush_fn;

+#  endif

+#endif /* PNG_WRITE_FLUSH_SUPPORTED */

+

+   /* It is an error to read while writing a png file */

+   if (png_ptr->read_data_fn != NULL)

+   {

+      png_ptr->read_data_fn = NULL;

+

+      png_warning(png_ptr,

+          "Can't set both read_data_fn and write_data_fn in the"

+          " same structure");

+   }

+}

+#endif /* PNG_WRITE_SUPPORTED */