Revert "Update libpng from 1.6.22 -> 1.6.34"chromium/3543

This reverts commit 6b2e2f0ec7c5f629c5270d14c2339197af7392d8.

Reason for revert: Broke Chromium integration.

Original change's description:
> Update libpng from 1.6.22 -> 1.6.34
> 
> Updates third_party/libpng16 to Chromium's third_party/libpng @
> e87a02987101e2dbe319a4aba6b52470f7624b4a and applies PDFium specific
> patches.
> 
> BUG=chromium:880322
> 
> Change-Id: I6724f55099c70a79da6d6e4863b9c6c9157ec571
> Reviewed-on: https://pdfium-review.googlesource.com/41910
> Reviewed-by: Lei Zhang <thestig@chromium.org>
> Commit-Queue: Ryan Harrison <rharrison@chromium.org>

TBR=thestig@chromium.org,rharrison@chromium.org

Change-Id: I2fd1f78e5d07ca983b2430bf078544185292ee1d
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:880322
Reviewed-on: https://pdfium-review.googlesource.com/41970
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>

1 files changed, 98 insertions, 154 deletions

diff --git a/third_party/libpng16/pngset.c b/third_party/libpng16/pngset.c
index 6f3a1ee11e..1c51270cc5 100644
--- a/third_party/libpng16/pngset.c
+++ b/third_party/libpng16/pngset.c
@@ -1,8 +1,8 @@
 
 /* pngset.c - storage of image information into info struct
  *
- * Last changed in libpng 1.6.32 [August 24, 2017]
- * Copyright (c) 1998-2017 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.21 [January 15, 2016]
+ * Copyright (c) 1998-2015 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.)
  *
@@ -104,14 +104,14 @@ png_set_cHRM(png_const_structrp png_ptr, png_inforp info_ptr,
     double green_x, double green_y, double blue_x, double blue_y)
 {
    png_set_cHRM_fixed(png_ptr, info_ptr,
-       png_fixed(png_ptr, white_x, "cHRM White X"),
-       png_fixed(png_ptr, white_y, "cHRM White Y"),
-       png_fixed(png_ptr, red_x, "cHRM Red X"),
-       png_fixed(png_ptr, red_y, "cHRM Red Y"),
-       png_fixed(png_ptr, green_x, "cHRM Green X"),
-       png_fixed(png_ptr, green_y, "cHRM Green Y"),
-       png_fixed(png_ptr, blue_x, "cHRM Blue X"),
-       png_fixed(png_ptr, blue_y, "cHRM Blue Y"));
+      png_fixed(png_ptr, white_x, "cHRM White X"),
+      png_fixed(png_ptr, white_y, "cHRM White Y"),
+      png_fixed(png_ptr, red_x, "cHRM Red X"),
+      png_fixed(png_ptr, red_y, "cHRM Red Y"),
+      png_fixed(png_ptr, green_x, "cHRM Green X"),
+      png_fixed(png_ptr, green_y, "cHRM Green Y"),
+      png_fixed(png_ptr, blue_x, "cHRM Blue X"),
+      png_fixed(png_ptr, blue_y, "cHRM Blue Y"));
 }
 
 void PNGAPI
@@ -120,67 +120,20 @@ png_set_cHRM_XYZ(png_const_structrp png_ptr, png_inforp info_ptr, double red_X,
     double blue_X, double blue_Y, double blue_Z)
 {
    png_set_cHRM_XYZ_fixed(png_ptr, info_ptr,
-       png_fixed(png_ptr, red_X, "cHRM Red X"),
-       png_fixed(png_ptr, red_Y, "cHRM Red Y"),
-       png_fixed(png_ptr, red_Z, "cHRM Red Z"),
-       png_fixed(png_ptr, green_X, "cHRM Green X"),
-       png_fixed(png_ptr, green_Y, "cHRM Green Y"),
-       png_fixed(png_ptr, green_Z, "cHRM Green Z"),
-       png_fixed(png_ptr, blue_X, "cHRM Blue X"),
-       png_fixed(png_ptr, blue_Y, "cHRM Blue Y"),
-       png_fixed(png_ptr, blue_Z, "cHRM Blue Z"));
+      png_fixed(png_ptr, red_X, "cHRM Red X"),
+      png_fixed(png_ptr, red_Y, "cHRM Red Y"),
+      png_fixed(png_ptr, red_Z, "cHRM Red Z"),
+      png_fixed(png_ptr, green_X, "cHRM Green X"),
+      png_fixed(png_ptr, green_Y, "cHRM Green Y"),
+      png_fixed(png_ptr, green_Z, "cHRM Green Z"),
+      png_fixed(png_ptr, blue_X, "cHRM Blue X"),
+      png_fixed(png_ptr, blue_Y, "cHRM Blue Y"),
+      png_fixed(png_ptr, blue_Z, "cHRM Blue Z"));
 }
 #  endif /* FLOATING_POINT */
 
 #endif /* cHRM */
 
-#ifdef PNG_eXIf_SUPPORTED
-void PNGAPI
-png_set_eXIf(png_const_structrp png_ptr, png_inforp info_ptr,
-    const png_bytep eXIf_buf)
-{
-  png_warning(png_ptr, "png_set_eXIf does not work; use png_set_eXIf_1");
-  PNG_UNUSED(info_ptr)
-  PNG_UNUSED(eXIf_buf)
-}
-
-void PNGAPI
-png_set_eXIf_1(png_const_structrp png_ptr, png_inforp info_ptr,
-    const png_uint_32 num_exif, const png_bytep eXIf_buf)
-{
-   int i;
-
-   png_debug1(1, "in %s storage function", "eXIf");
-
-   if (png_ptr == NULL || info_ptr == NULL)
-      return;
-
-   if (info_ptr->exif)
-   {
-      png_free(png_ptr, info_ptr->exif);
-      info_ptr->exif = NULL;
-   }
-
-   info_ptr->num_exif = num_exif;
-
-   info_ptr->exif = png_voidcast(png_bytep, png_malloc_warn(png_ptr,
-       info_ptr->num_exif));
-
-   if (info_ptr->exif == NULL)
-   {
-      png_warning(png_ptr, "Insufficient memory for eXIf chunk data");
-      return;
-   }
-
-   info_ptr->free_me |= PNG_FREE_EXIF;
-
-   for (i = 0; i < (int) info_ptr->num_exif; i++)
-      info_ptr->exif[i] = eXIf_buf[i];
-
-   info_ptr->valid |= PNG_INFO_eXIf;
-}
-#endif /* eXIf */
-
 #ifdef PNG_gAMA_SUPPORTED
 void PNGFAPI
 png_set_gAMA_fixed(png_const_structrp png_ptr, png_inforp info_ptr,
@@ -375,10 +328,10 @@ png_set_pCAL(png_const_structrp png_ptr, png_inforp info_ptr,
 
    length = strlen(units) + 1;
    png_debug1(3, "allocating units for info (%lu bytes)",
-       (unsigned long)length);
+     (unsigned long)length);
 
    info_ptr->pcal_units = png_voidcast(png_charp,
-       png_malloc_warn(png_ptr, length));
+      png_malloc_warn(png_ptr, length));
 
    if (info_ptr->pcal_units == NULL)
    {
@@ -390,7 +343,7 @@ png_set_pCAL(png_const_structrp png_ptr, png_inforp info_ptr,
    memcpy(info_ptr->pcal_units, units, length);
 
    info_ptr->pcal_params = png_voidcast(png_charpp, png_malloc_warn(png_ptr,
-       (png_size_t)(((unsigned int)nparams + 1) * (sizeof (png_charp)))));
+       (png_size_t)((nparams + 1) * (sizeof (png_charp)))));
 
    if (info_ptr->pcal_params == NULL)
    {
@@ -399,8 +352,7 @@ png_set_pCAL(png_const_structrp png_ptr, png_inforp info_ptr,
       return;
    }
 
-   memset(info_ptr->pcal_params, 0, ((unsigned int)nparams + 1) *
-       (sizeof (png_charp)));
+   memset(info_ptr->pcal_params, 0, (nparams + 1) * (sizeof (png_charp)));
 
    for (i = 0; i < nparams; i++)
    {
@@ -458,7 +410,7 @@ png_set_sCAL_s(png_const_structrp png_ptr, png_inforp info_ptr,
    png_debug1(3, "allocating unit for info (%u bytes)", (unsigned int)lengthw);
 
    info_ptr->scal_s_width = png_voidcast(png_charp,
-       png_malloc_warn(png_ptr, lengthw));
+      png_malloc_warn(png_ptr, lengthw));
 
    if (info_ptr->scal_s_width == NULL)
    {
@@ -474,7 +426,7 @@ png_set_sCAL_s(png_const_structrp png_ptr, png_inforp info_ptr,
    png_debug1(3, "allocating unit for info (%u bytes)", (unsigned int)lengthh);
 
    info_ptr->scal_s_height = png_voidcast(png_charp,
-       png_malloc_warn(png_ptr, lengthh));
+      png_malloc_warn(png_ptr, lengthh));
 
    if (info_ptr->scal_s_height == NULL)
    {
@@ -513,9 +465,9 @@ png_set_sCAL(png_const_structrp png_ptr, png_inforp info_ptr, int unit,
       char sheight[PNG_sCAL_MAX_DIGITS+1];
 
       png_ascii_from_fp(png_ptr, swidth, (sizeof swidth), width,
-          PNG_sCAL_PRECISION);
+         PNG_sCAL_PRECISION);
       png_ascii_from_fp(png_ptr, sheight, (sizeof sheight), height,
-          PNG_sCAL_PRECISION);
+         PNG_sCAL_PRECISION);
 
       png_set_sCAL_s(png_ptr, info_ptr, unit, swidth, sheight);
    }
@@ -623,8 +575,7 @@ png_set_PLTE(png_structrp png_ptr, png_inforp info_ptr,
        PNG_MAX_PALETTE_LENGTH * (sizeof (png_color))));
 
    if (num_palette > 0)
-      memcpy(png_ptr->palette, palette, (unsigned int)num_palette *
-          (sizeof (png_color)));
+      memcpy(png_ptr->palette, palette, num_palette * (sizeof (png_color)));
    info_ptr->palette = png_ptr->palette;
    info_ptr->num_palette = png_ptr->num_palette = (png_uint_16)num_palette;
 
@@ -709,7 +660,7 @@ png_set_iCCP(png_const_structrp png_ptr, png_inforp info_ptr,
     */
    {
       int result = png_colorspace_set_ICC(png_ptr, &info_ptr->colorspace, name,
-          proflen, profile, info_ptr->color_type);
+         proflen, profile, info_ptr->color_type);
 
       png_colorspace_sync_info(png_ptr, info_ptr);
 
@@ -734,7 +685,7 @@ png_set_iCCP(png_const_structrp png_ptr, png_inforp info_ptr,
 
    memcpy(new_iccp_name, name, length);
    new_iccp_profile = png_voidcast(png_bytep,
-       png_malloc_warn(png_ptr, proflen));
+      png_malloc_warn(png_ptr, proflen));
 
    if (new_iccp_profile == NULL)
    {
@@ -809,14 +760,14 @@ png_set_text_2(png_const_structrp png_ptr, png_inforp info_ptr,
           * the overflow checks.
           */
          new_text = png_voidcast(png_textp,png_realloc_array(png_ptr,
-             info_ptr->text, old_num_text, max_text-old_num_text,
-             sizeof *new_text));
+            info_ptr->text, old_num_text, max_text-old_num_text,
+            sizeof *new_text));
       }
 
       if (new_text == NULL)
       {
          png_chunk_report(png_ptr, "too many text chunks",
-             PNG_CHUNK_WRITE_ERROR);
+            PNG_CHUNK_WRITE_ERROR);
 
          return 1;
       }
@@ -844,7 +795,7 @@ png_set_text_2(png_const_structrp png_ptr, png_inforp info_ptr,
           text_ptr[i].compression >= PNG_TEXT_COMPRESSION_LAST)
       {
          png_chunk_report(png_ptr, "text compression mode is out of range",
-             PNG_CHUNK_WRITE_ERROR);
+            PNG_CHUNK_WRITE_ERROR);
          continue;
       }
 
@@ -876,7 +827,7 @@ png_set_text_2(png_const_structrp png_ptr, png_inforp info_ptr,
 #  else /* iTXt */
       {
          png_chunk_report(png_ptr, "iTXt chunk not supported",
-             PNG_CHUNK_WRITE_ERROR);
+            PNG_CHUNK_WRITE_ERROR);
          continue;
       }
 #  endif
@@ -905,7 +856,7 @@ png_set_text_2(png_const_structrp png_ptr, png_inforp info_ptr,
       if (textp->key == NULL)
       {
          png_chunk_report(png_ptr, "text chunk: out of memory",
-             PNG_CHUNK_WRITE_ERROR);
+               PNG_CHUNK_WRITE_ERROR);
 
          return 1;
       }
@@ -1017,7 +968,8 @@ png_set_tRNS(png_structrp png_ptr, png_inforp info_ptr,
        {
          /* Changed from num_trans to PNG_MAX_PALETTE_LENGTH in version 1.2.1 */
           info_ptr->trans_alpha = png_voidcast(png_bytep,
-              png_malloc(png_ptr, PNG_MAX_PALETTE_LENGTH));
+             png_malloc(png_ptr, PNG_MAX_PALETTE_LENGTH));
+
           memcpy(info_ptr->trans_alpha, trans_alpha, (png_size_t)num_trans);
        }
        png_ptr->trans_alpha = info_ptr->trans_alpha;
@@ -1037,7 +989,7 @@ png_set_tRNS(png_structrp png_ptr, png_inforp info_ptr,
              trans_color->green > sample_max ||
              trans_color->blue > sample_max)))
             png_warning(png_ptr,
-                "tRNS chunk has out-of-range samples for bit_depth");
+               "tRNS chunk has out-of-range samples for bit_depth");
       }
 #endif
 
@@ -1079,8 +1031,8 @@ png_set_sPLT(png_const_structrp png_ptr,
     * overflows.  Notice that the parameters are (int) and (size_t)
     */
    np = png_voidcast(png_sPLT_tp,png_realloc_array(png_ptr,
-       info_ptr->splt_palettes, info_ptr->splt_palettes_num, nentries,
-       sizeof *np));
+      info_ptr->splt_palettes, info_ptr->splt_palettes_num, nentries,
+      sizeof *np));
 
    if (np == NULL)
    {
@@ -1141,7 +1093,7 @@ png_set_sPLT(png_const_structrp png_ptr,
        * checked it when doing the allocation.
        */
       memcpy(np->entries, entries->entries,
-          (unsigned int)entries->nentries * sizeof (png_sPLT_entry));
+         entries->nentries * sizeof (png_sPLT_entry));
 
       /* Note that 'continue' skips the advance of the out pointer and out
        * count, so an invalid entry is not added.
@@ -1149,9 +1101,8 @@ png_set_sPLT(png_const_structrp png_ptr,
       info_ptr->valid |= PNG_INFO_sPLT;
       ++(info_ptr->splt_palettes_num);
       ++np;
-      ++entries;
    }
-   while (--nentries);
+   while (++entries, --nentries);
 
    if (nentries > 0)
       png_chunk_report(png_ptr, "sPLT out of memory", PNG_CHUNK_WRITE_ERROR);
@@ -1172,10 +1123,10 @@ check_location(png_const_structrp png_ptr, int location)
    {
       /* Write struct, so unknown chunks come from the app */
       png_app_warning(png_ptr,
-          "png_set_unknown_chunks now expects a valid location");
+         "png_set_unknown_chunks now expects a valid location");
       /* Use the old behavior */
       location = (png_byte)(png_ptr->mode &
-          (PNG_HAVE_IHDR|PNG_HAVE_PLTE|PNG_AFTER_IDAT));
+         (PNG_HAVE_IHDR|PNG_HAVE_PLTE|PNG_AFTER_IDAT));
    }
 
    /* This need not be an internal error - if the app calls
@@ -1198,7 +1149,7 @@ check_location(png_const_structrp png_ptr, int location)
 
 void PNGAPI
 png_set_unknown_chunks(png_const_structrp png_ptr,
-    png_inforp info_ptr, png_const_unknown_chunkp unknowns, int num_unknowns)
+   png_inforp info_ptr, png_const_unknown_chunkp unknowns, int num_unknowns)
 {
    png_unknown_chunkp np;
 
@@ -1237,13 +1188,13 @@ png_set_unknown_chunks(png_const_structrp png_ptr,
     * appropriate to read or write.
     */
    np = png_voidcast(png_unknown_chunkp, png_realloc_array(png_ptr,
-       info_ptr->unknown_chunks, info_ptr->unknown_chunks_num, num_unknowns,
-       sizeof *np));
+         info_ptr->unknown_chunks, info_ptr->unknown_chunks_num, num_unknowns,
+         sizeof *np));
 
    if (np == NULL)
    {
       png_chunk_report(png_ptr, "too many unknown chunks",
-          PNG_CHUNK_WRITE_ERROR);
+         PNG_CHUNK_WRITE_ERROR);
 
       return;
    }
@@ -1272,12 +1223,12 @@ png_set_unknown_chunks(png_const_structrp png_ptr,
       else
       {
          np->data = png_voidcast(png_bytep,
-             png_malloc_base(png_ptr, unknowns->size));
+            png_malloc_base(png_ptr, unknowns->size));
 
          if (np->data == NULL)
          {
             png_chunk_report(png_ptr, "unknown chunk: out of memory",
-                PNG_CHUNK_WRITE_ERROR);
+               PNG_CHUNK_WRITE_ERROR);
             /* But just skip storing the unknown chunk */
             continue;
          }
@@ -1311,7 +1262,7 @@ png_set_unknown_chunk_location(png_const_structrp png_ptr, png_inforp info_ptr,
       {
          png_app_error(png_ptr, "invalid unknown chunk location");
          /* Fake out the pre 1.6.0 behavior: */
-         if (((unsigned int)location & PNG_HAVE_IDAT) != 0) /* undocumented! */
+         if ((location & PNG_HAVE_IDAT) != 0) /* undocumented! */
             location = PNG_AFTER_IDAT;
 
          else
@@ -1402,7 +1353,6 @@ png_set_keep_unknown_chunks(png_structrp png_ptr, int keep,
       static PNG_CONST png_byte chunks_to_ignore[] = {
          98,  75,  71,  68, '\0',  /* bKGD */
          99,  72,  82,  77, '\0',  /* cHRM */
-        101,  88,  73, 102, '\0',  /* eXIf */
         103,  65,  77,  65, '\0',  /* gAMA */
         104,  73,  83,  84, '\0',  /* hIST */
         105,  67,  67,  80, '\0',  /* iCCP */
@@ -1436,7 +1386,7 @@ png_set_keep_unknown_chunks(png_structrp png_ptr, int keep,
          return;
       }
 
-      num_chunks = (unsigned int)num_chunks_in;
+      num_chunks = num_chunks_in;
    }
 
    old_num_chunks = png_ptr->num_chunk_list;
@@ -1485,7 +1435,7 @@ png_set_keep_unknown_chunks(png_structrp png_ptr, int keep,
       for (i=0; i<num_chunks; ++i)
       {
          old_num_chunks = add_one_chunk(new_list, old_num_chunks,
-             chunk_list+5*i, keep);
+            chunk_list+5*i, keep);
       }
 
       /* Now remove any spurious 'default' entries. */
@@ -1565,60 +1515,60 @@ png_set_rows(png_const_structrp png_ptr, png_inforp info_ptr,
 void PNGAPI
 png_set_compression_buffer_size(png_structrp png_ptr, png_size_t size)
 {
-   if (png_ptr == NULL)
-      return;
+    if (png_ptr == NULL)
+       return;
 
-   if (size == 0 || size > PNG_UINT_31_MAX)
-      png_error(png_ptr, "invalid compression buffer size");
+    if (size == 0 || size > PNG_UINT_31_MAX)
+       png_error(png_ptr, "invalid compression buffer size");
 
 #  ifdef PNG_SEQUENTIAL_READ_SUPPORTED
-   if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
-   {
-      png_ptr->IDAT_read_size = (png_uint_32)size; /* checked above */
-      return;
-   }
+      if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
+      {
+         png_ptr->IDAT_read_size = (png_uint_32)size; /* checked above */
+         return;
+      }
 #  endif
 
 #  ifdef PNG_WRITE_SUPPORTED
-   if ((png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
-   {
-      if (png_ptr->zowner != 0)
+      if ((png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
       {
-         png_warning(png_ptr,
-             "Compression buffer size cannot be changed because it is in use");
+         if (png_ptr->zowner != 0)
+         {
+            png_warning(png_ptr,
+              "Compression buffer size cannot be changed because it is in use");
 
-         return;
-      }
+            return;
+         }
 
 #ifndef __COVERITY__
-      /* Some compilers complain that this is always false.  However, it
-       * can be true when integer overflow happens.
-       */
-      if (size > ZLIB_IO_MAX)
-      {
-         png_warning(png_ptr,
-             "Compression buffer size limited to system maximum");
-         size = ZLIB_IO_MAX; /* must fit */
-      }
+         /* Some compilers complain that this is always false.  However, it
+          * can be true when integer overflow happens.
+          */
+         if (size > ZLIB_IO_MAX)
+         {
+            png_warning(png_ptr,
+               "Compression buffer size limited to system maximum");
+            size = ZLIB_IO_MAX; /* must fit */
+         }
 #endif
 
-      if (size < 6)
-      {
-         /* Deflate will potentially go into an infinite loop on a SYNC_FLUSH
-          * if this is permitted.
-          */
-         png_warning(png_ptr,
-             "Compression buffer size cannot be reduced below 6");
+         if (size < 6)
+         {
+            /* Deflate will potentially go into an infinite loop on a SYNC_FLUSH
+             * if this is permitted.
+             */
+            png_warning(png_ptr,
+               "Compression buffer size cannot be reduced below 6");
 
-         return;
-      }
+            return;
+         }
 
-      if (png_ptr->zbuffer_size != size)
-      {
-         png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list);
-         png_ptr->zbuffer_size = (uInt)size;
+         if (png_ptr->zbuffer_size != size)
+         {
+            png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list);
+            png_ptr->zbuffer_size = (uInt)size;
+         }
       }
-   }
 #  endif
 }
 
@@ -1626,7 +1576,7 @@ void PNGAPI
 png_set_invalid(png_const_structrp png_ptr, png_inforp info_ptr, int mask)
 {
    if (png_ptr != NULL && info_ptr != NULL)
-      info_ptr->valid &= (unsigned int)(~mask);
+      info_ptr->valid &= ~mask;
 }
 
 
@@ -1725,9 +1675,7 @@ png_set_check_for_invalid_index(png_structrp png_ptr, int allowed)
 png_uint_32 /* PRIVATE */
 png_check_keyword(png_structrp png_ptr, png_const_charp key, png_bytep new_key)
 {
-#ifdef PNG_WARNINGS_SUPPORTED
    png_const_charp orig_key = key;
-#endif
    png_uint_32 key_len = 0;
    int bad_character = 0;
    int space = 1;
@@ -1745,16 +1693,14 @@ png_check_keyword(png_structrp png_ptr, png_const_charp key, png_bytep new_key)
       png_byte ch = (png_byte)*key++;
 
       if ((ch > 32 && ch <= 126) || (ch >= 161 /*&& ch <= 255*/))
-      {
-         *new_key++ = ch; ++key_len; space = 0;
-      }
+         *new_key++ = ch, ++key_len, space = 0;
 
       else if (space == 0)
       {
          /* A space or an invalid character when one wasn't seen immediately
           * before; output just a space.
           */
-         *new_key++ = 32; ++key_len; space = 1;
+         *new_key++ = 32, ++key_len, space = 1;
 
          /* If the character was not a space then it is invalid. */
          if (ch != 32)
@@ -1767,7 +1713,7 @@ png_check_keyword(png_structrp png_ptr, png_const_charp key, png_bytep new_key)
 
    if (key_len > 0 && space != 0) /* trailing space */
    {
-      --key_len; --new_key;
+      --key_len, --new_key;
       if (bad_character == 0)
          bad_character = 32;
    }
@@ -1792,9 +1738,7 @@ png_check_keyword(png_structrp png_ptr, png_const_charp key, png_bytep new_key)
 
       png_formatted_warning(png_ptr, p, "keyword \"@1\": bad character '0x@2'");
    }
-#else /* !WARNINGS */
-   PNG_UNUSED(png_ptr)
-#endif /* !WARNINGS */
+#endif /* WARNINGS */
 
    return key_len;
 }