libpng: update to 1.2.43

I unpacked libpng 1.2.43 and did:
 cd third_party/libpng
 for x in $(ls -1) ; do cp /tmp/libpng-1.2.43/$x .; done

The diffs appear to all be safe. The Chromium specific config is in pngusr.h
and isn't touched by this change.

1.2.43 fixes http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2010-0205

c7013d773eb45b8ed6a864e419e544106a0dd95d  /tmp/libpng-1.2.43.tar.xz

BUG=38512
TEST=none

http://codereview.chromium.org/1118002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@41972 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 340 insertions, 227 deletions

diff --git a/third_party/libpng/pngrutil.c b/third_party/libpng/pngrutil.c
index ae1e3f7..9fd48be 100644
--- a/third_party/libpng/pngrutil.c
+++ b/third_party/libpng/pngrutil.c
@@ -1,28 +1,33 @@
 
 /* pngrutil.c - utilities to read a PNG file
  *
- * Last changed in libpng 1.2.37 [June 4, 2009]
- * For conditions of distribution and use, see copyright notice in png.h
+ * Last changed in libpng 1.2.43 [February 25, 2010]
  * Copyright (c) 1998-2009 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 contains routines that are only called from within
  * libpng itself during the course of reading an image.
  */
 
 #define PNG_INTERNAL
+#define PNG_NO_PEDANTIC_WARNINGS
 #include "png.h"
-#if defined(PNG_READ_SUPPORTED)
+#ifdef PNG_READ_SUPPORTED
 
 #if defined(_WIN32_WCE) && (_WIN32_WCE<0x500)
 #  define WIN32_WCE_OLD
 #endif
 
 #ifdef PNG_FLOATING_POINT_SUPPORTED
-#  if defined(WIN32_WCE_OLD)
+#  ifdef WIN32_WCE_OLD
 /* The strtod() function is not supported on WindowsCE */
-__inline double png_strtod(png_structp png_ptr, PNG_CONST char *nptr, char **endptr)
+__inline double png_strtod(png_structp png_ptr, PNG_CONST char *nptr,
+    char **endptr)
 {
    double result = 0;
    int len;
@@ -213,180 +218,205 @@ png_crc_error(png_structp png_ptr)
 
 #if defined(PNG_READ_zTXt_SUPPORTED) || defined(PNG_READ_iTXt_SUPPORTED) || \
     defined(PNG_READ_iCCP_SUPPORTED)
-/*
- * Decompress trailing data in a chunk.  The assumption is that chunkdata
- * points at an allocated area holding the contents of a chunk with a
- * trailing compressed part.  What we get back is an allocated area
- * holding the original prefix part and an uncompressed version of the
- * trailing part (the malloc area passed in is freed).
- */
-void /* PRIVATE */
-png_decompress_chunk(png_structp png_ptr, int comp_type,
-                              png_size_t chunklength,
-                              png_size_t prefix_size, png_size_t *newlength)
+static png_size_t
+png_inflate(png_structp png_ptr, const png_byte *data, png_size_t size,
+	png_bytep output, png_size_t output_size)
 {
-   static PNG_CONST char msg[] = "Error decoding compressed text";
-   png_charp text;
-   png_size_t text_size;
+   png_size_t count = 0;
+
+   png_ptr->zstream.next_in = (png_bytep)data; /* const_cast: VALID */
+   png_ptr->zstream.avail_in = size;
 
-   if (comp_type == PNG_COMPRESSION_TYPE_BASE)
+   while (1)
    {
-      int ret = Z_OK;
-      png_ptr->zstream.next_in = (png_bytep)(png_ptr->chunkdata + prefix_size);
-      png_ptr->zstream.avail_in = (uInt)(chunklength - prefix_size);
+      int ret, avail;
+
+      /* Reset the output buffer each time round - we empty it
+       * after every inflate call.
+       */
       png_ptr->zstream.next_out = png_ptr->zbuf;
-      png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
+      png_ptr->zstream.avail_out = png_ptr->zbuf_size;
 
-      text_size = 0;
-      text = NULL;
+      ret = inflate(&png_ptr->zstream, Z_NO_FLUSH);
+      avail = png_ptr->zbuf_size - png_ptr->zstream.avail_out;
 
-      while (png_ptr->zstream.avail_in)
+      /* First copy/count any new output - but only if we didn't
+       * get an error code.
+       */
+      if ((ret == Z_OK || ret == Z_STREAM_END) && avail > 0)
       {
-         ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
-         if (ret != Z_OK && ret != Z_STREAM_END)
-         {
-            if (png_ptr->zstream.msg != NULL)
-               png_warning(png_ptr, png_ptr->zstream.msg);
-            else
-               png_warning(png_ptr, msg);
-            inflateReset(&png_ptr->zstream);
-            png_ptr->zstream.avail_in = 0;
+         if (output != 0 && output_size > count)
+	 {
+	    int copy = output_size - count;
+	    if (avail < copy) copy = avail;
+	    png_memcpy(output + count, png_ptr->zbuf, copy);
+	 }
+         count += avail;
+      }
 
-            if (text ==  NULL)
-            {
-               text_size = prefix_size + png_sizeof(msg) + 1;
-               text = (png_charp)png_malloc_warn(png_ptr, text_size);
-               if (text ==  NULL)
-                 {
-                    png_free(png_ptr, png_ptr->chunkdata);
-                    png_ptr->chunkdata = NULL;
-                    png_error(png_ptr, "Not enough memory to decompress chunk");
-                 }
-               png_memcpy(text, png_ptr->chunkdata, prefix_size);
-            }
+      if (ret == Z_OK)
+         continue;
 
-            text[text_size - 1] = 0x00;
+      /* Termination conditions - always reset the zstream, it
+       * must be left in inflateInit state.
+       */
+      png_ptr->zstream.avail_in = 0;
+      inflateReset(&png_ptr->zstream);
 
-            /* Copy what we can of the error message into the text chunk */
-            text_size = (png_size_t)(chunklength -
-              (text - png_ptr->chunkdata) - 1);
-            if (text_size > png_sizeof(msg))
-               text_size = png_sizeof(msg);
-            png_memcpy(text + prefix_size, msg, text_size);
-            break;
-         }
-         if (!png_ptr->zstream.avail_out || ret == Z_STREAM_END)
-         {
-            if (text == NULL)
-            {
-               text_size = prefix_size +
-                   png_ptr->zbuf_size - png_ptr->zstream.avail_out;
-               text = (png_charp)png_malloc_warn(png_ptr, text_size + 1);
-               if (text ==  NULL)
-               {
-                  png_free(png_ptr, png_ptr->chunkdata);
-                  png_ptr->chunkdata = NULL;
-                  png_error(png_ptr,
-                    "Not enough memory to decompress chunk.");
-               }
-               png_memcpy(text + prefix_size, png_ptr->zbuf,
-                    text_size - prefix_size);
-               png_memcpy(text, png_ptr->chunkdata, prefix_size);
-               *(text + text_size) = 0x00;
-            }
-            else
-            {
-               png_charp tmp;
+      if (ret == Z_STREAM_END)
+         return count; /* NOTE: may be zero. */
 
-               tmp = text;
-               text = (png_charp)png_malloc_warn(png_ptr,
-                  (png_uint_32)(text_size +
-                  png_ptr->zbuf_size - png_ptr->zstream.avail_out + 1));
-               if (text == NULL)
-               {
-                  png_free(png_ptr, tmp);
-                  png_free(png_ptr, png_ptr->chunkdata);
-                  png_ptr->chunkdata = NULL;
-                  png_error(png_ptr,
-                    "Not enough memory to decompress chunk..");
-               }
-               png_memcpy(text, tmp, text_size);
-               png_free(png_ptr, tmp);
-               png_memcpy(text + text_size, png_ptr->zbuf,
-                  (png_ptr->zbuf_size - png_ptr->zstream.avail_out));
-               text_size += png_ptr->zbuf_size - png_ptr->zstream.avail_out;
-               *(text + text_size) = 0x00;
-            }
-            if (ret == Z_STREAM_END)
-               break;
-            else
-            {
-               png_ptr->zstream.next_out = png_ptr->zbuf;
-               png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
-            }
-         }
-      }
-      if (ret != Z_STREAM_END)
+      /* Now handle the error codes - the API always returns 0
+       * and the error message is dumped into the uncompressed
+       * buffer if available.
+       */
       {
-#if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
-         char umsg[52];
+         char *msg, umsg[52];
+	 if (png_ptr->zstream.msg != 0)
+	    msg = png_ptr->zstream.msg;
+	 else
+	 {
+#if defined(PNG_STDIO_SUPPORTED) && !defined(_WIN32_WCE)
+	    switch (ret)
+	    {
+	 case Z_BUF_ERROR:
+	    msg = "Buffer error in compressed datastream in %s chunk";
+	    break;
+	 case Z_DATA_ERROR:
+	    msg = "Data error in compressed datastream in %s chunk";
+	    break;
+	 default:
+	    msg = "Incomplete compressed datastream in %s chunk";
+	    break;
+	    }
+
+	    png_snprintf(umsg, sizeof umsg, msg, png_ptr->chunk_name);
+	    msg = umsg;
+#else
+	    msg = "Damaged compressed datastream in chunk other than IDAT";
+#endif
+	 }
 
-         if (ret == Z_BUF_ERROR)
-            png_snprintf(umsg, 52,
-                "Buffer error in compressed datastream in %s chunk",
-                png_ptr->chunk_name);
+         png_warning(png_ptr, msg);
+      }
 
-         else if (ret == Z_DATA_ERROR)
-            png_snprintf(umsg, 52,
-                "Data error in compressed datastream in %s chunk",
-                png_ptr->chunk_name);
+      /* 0 means an error - notice that this code simple ignores
+       * zero length compressed chunks as a result.
+       */
+      return 0;
+   }
+}
 
-         else
-            png_snprintf(umsg, 52,
-                "Incomplete compressed datastream in %s chunk",
-                png_ptr->chunk_name);
+/*
+ * Decompress trailing data in a chunk.  The assumption is that chunkdata
+ * points at an allocated area holding the contents of a chunk with a
+ * trailing compressed part.  What we get back is an allocated area
+ * holding the original prefix part and an uncompressed version of the
+ * trailing part (the malloc area passed in is freed).
+ */
+void /* PRIVATE */
+png_decompress_chunk(png_structp png_ptr, int comp_type,
+    png_size_t chunklength,
+    png_size_t prefix_size, png_size_t *newlength)
+{
+   /* The caller should guarantee this */
+   if (prefix_size > chunklength)
+   {
+      /* The recovery is to delete the chunk. */
+      png_warning(png_ptr, "invalid chunklength");
+      prefix_size = 0; /* To delete everything */
+   }
 
-         png_warning(png_ptr, umsg);
+   else if (comp_type == PNG_COMPRESSION_TYPE_BASE)
+   {
+      png_size_t expanded_size = png_inflate(png_ptr,
+		(png_bytep)(png_ptr->chunkdata + prefix_size),
+                chunklength - prefix_size,
+		0/*output*/, 0/*output size*/);
+
+      /* Now check the limits on this chunk - if the limit fails the
+       * compressed data will be removed, the prefix will remain.
+       */
+#ifdef PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED
+      if (png_ptr->user_chunk_malloc_max &&
+          (prefix_size + expanded_size >= png_ptr->user_chunk_malloc_max - 1))
 #else
-         png_warning(png_ptr,
-            "Incomplete compressed datastream in chunk other than IDAT");
+      if ((PNG_USER_CHUNK_MALLOC_MAX > 0) &&
+          prefix_size + expanded_size >= PNG_USER_CHUNK_MALLOC_MAX - 1)
 #endif
-         text_size = prefix_size;
-         if (text ==  NULL)
-         {
-            text = (png_charp)png_malloc_warn(png_ptr, text_size+1);
-            if (text == NULL)
-              {
-                png_free(png_ptr, png_ptr->chunkdata);
-                png_ptr->chunkdata = NULL;
-                png_error(png_ptr, "Not enough memory for text.");
-              }
-            png_memcpy(text, png_ptr->chunkdata, prefix_size);
-         }
-         *(text + text_size) = 0x00;
-      }
+         png_warning(png_ptr, "Exceeded size limit while expanding chunk");
 
-      inflateReset(&png_ptr->zstream);
-      png_ptr->zstream.avail_in = 0;
+      /* If the size is zero either there was an error and a message
+       * has already been output (warning) or the size really is zero
+       * and we have nothing to do - the code will exit through the
+       * error case below.
+       */
+      else if (expanded_size > 0)
+      {
+         /* Success (maybe) - really uncompress the chunk. */
+	 png_size_t new_size = 0;
+	 png_charp text = png_malloc_warn(png_ptr,
+			prefix_size + expanded_size + 1);
 
-      png_free(png_ptr, png_ptr->chunkdata);
-      png_ptr->chunkdata = text;
-      *newlength=text_size;
+         if (text != NULL)
+         {
+	    png_memcpy(text, png_ptr->chunkdata, prefix_size);
+	    new_size = png_inflate(png_ptr,
+                (png_bytep)(png_ptr->chunkdata + prefix_size),
+		chunklength - prefix_size,
+                (png_bytep)(text + prefix_size), expanded_size);
+	    text[prefix_size + expanded_size] = 0; /* just in case */
+
+	    if (new_size == expanded_size)
+	    {
+	       png_free(png_ptr, png_ptr->chunkdata);
+	       png_ptr->chunkdata = text;
+	       *newlength = prefix_size + expanded_size;
+	       return; /* The success return! */
+	    }
+      
+	    png_warning(png_ptr, "png_inflate logic error");
+	    png_free(png_ptr, text);
+	 }
+	 else
+          png_warning(png_ptr, "Not enough memory to decompress chunk.");
+      }
    }
+
    else /* if (comp_type != PNG_COMPRESSION_TYPE_BASE) */
    {
-#if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
       char umsg[50];
 
-      png_snprintf(umsg, 50, "Unknown zTXt compression type %d", comp_type);
+#if defined(PNG_STDIO_SUPPORTED) && !defined(_WIN32_WCE)
+      png_snprintf(umsg, sizeof umsg, "Unknown zTXt compression type %d", comp_type);
       png_warning(png_ptr, umsg);
 #else
       png_warning(png_ptr, "Unknown zTXt compression type");
 #endif
 
-      *(png_ptr->chunkdata + prefix_size) = 0x00;
-      *newlength = prefix_size;
+      /* The recovery is to simply drop the data. */
    }
+
+   /* Generic error return - leave the prefix, delete the compressed
+    * data, reallocate the chunkdata to remove the potentially large
+    * amount of compressed data.
+    */
+   {
+      png_charp text = png_malloc_warn(png_ptr, prefix_size + 1);
+      if (text != NULL)
+      {
+	 if (prefix_size > 0)
+            png_memcpy(text, png_ptr->chunkdata, prefix_size);
+	 png_free(png_ptr, png_ptr->chunkdata);
+	 png_ptr->chunkdata = text;
+
+	 /* This is an extra zero in the 'uncompressed' part. */
+	 *(png_ptr->chunkdata + prefix_size) = 0x00;
+      }
+      /* Ignore a malloc error here - it is safe. */
+   }
+
+   *newlength = prefix_size;
 }
 #endif
 
@@ -427,7 +457,7 @@ png_handle_IHDR(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
    png_ptr->bit_depth = (png_byte)bit_depth;
    png_ptr->interlaced = (png_byte)interlace_type;
    png_ptr->color_type = (png_byte)color_type;
-#if defined(PNG_MNG_FEATURES_SUPPORTED)
+#ifdef PNG_MNG_FEATURES_SUPPORTED
    png_ptr->filter_type = (png_byte)filter_type;
 #endif
    png_ptr->compression_type = (png_byte)compression_type;
@@ -470,7 +500,7 @@ png_handle_PLTE(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 {
    png_color palette[PNG_MAX_PALETTE_LENGTH];
    int num, i;
-#ifndef PNG_NO_POINTER_INDEXING
+#ifdef PNG_POINTER_INDEXING_SUPPORTED
    png_colorp pal_ptr;
 #endif
 
@@ -498,7 +528,7 @@ png_handle_PLTE(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
       png_crc_finish(png_ptr, length);
       return;
    }
-#if !defined(PNG_READ_OPT_PLTE_SUPPORTED)
+#ifndef PNG_READ_OPT_PLTE_SUPPORTED
    if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
    {
       png_crc_finish(png_ptr, length);
@@ -523,7 +553,7 @@ png_handle_PLTE(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 
    num = (int)length / 3;
 
-#ifndef PNG_NO_POINTER_INDEXING
+#ifdef PNG_POINTER_INDEXING_SUPPORTED
    for (i = 0, pal_ptr = palette; i < num; i++, pal_ptr++)
    {
       png_byte buf[3];
@@ -551,13 +581,13 @@ png_handle_PLTE(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
     * have an RGB image, the PLTE can be considered ancillary, so
     * we will act as though it is.
     */
-#if !defined(PNG_READ_OPT_PLTE_SUPPORTED)
+#ifndef PNG_READ_OPT_PLTE_SUPPORTED
    if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
 #endif
    {
       png_crc_finish(png_ptr, 0);
    }
-#if !defined(PNG_READ_OPT_PLTE_SUPPORTED)
+#ifndef PNG_READ_OPT_PLTE_SUPPORTED
    else if (png_crc_error(png_ptr))  /* Only if we have a CRC error */
    {
       /* If we don't want to use the data from an ancillary chunk,
@@ -586,7 +616,7 @@ png_handle_PLTE(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 
    png_set_PLTE(png_ptr, info_ptr, palette, num);
 
-#if defined(PNG_READ_tRNS_SUPPORTED)
+#ifdef PNG_READ_tRNS_SUPPORTED
    if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
    {
       if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS))
@@ -628,7 +658,7 @@ png_handle_IEND(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
    info_ptr = info_ptr; /* Quiet compiler warnings about unused info_ptr */
 }
 
-#if defined(PNG_READ_gAMA_SUPPORTED)
+#ifdef PNG_READ_gAMA_SUPPORTED
 void /* PRIVATE */
 png_handle_gAMA(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 {
@@ -653,7 +683,7 @@ png_handle_gAMA(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
       png_warning(png_ptr, "Out of place gAMA chunk");
 
    if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_gAMA)
-#if defined(PNG_READ_sRGB_SUPPORTED)
+#ifdef PNG_READ_sRGB_SUPPORTED
       && !(info_ptr->valid & PNG_INFO_sRGB)
 #endif
       )
@@ -683,13 +713,13 @@ png_handle_gAMA(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
          return;
       }
 
-#if defined(PNG_READ_sRGB_SUPPORTED)
+#ifdef PNG_READ_sRGB_SUPPORTED
    if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sRGB))
       if (PNG_OUT_OF_RANGE(igamma, 45500L, 500))
       {
          png_warning(png_ptr,
            "Ignoring incorrect gAMA value when sRGB is also present");
-#ifndef PNG_NO_CONSOLE_IO
+#ifdef PNG_CONSOLE_IO_SUPPORTED
          fprintf(stderr, "gamma = (%d/100000)", (int)igamma);
 #endif
          return;
@@ -709,7 +739,7 @@ png_handle_gAMA(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 }
 #endif
 
-#if defined(PNG_READ_sBIT_SUPPORTED)
+#ifdef PNG_READ_sBIT_SUPPORTED
 void /* PRIVATE */
 png_handle_sBIT(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 {
@@ -775,7 +805,7 @@ png_handle_sBIT(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 }
 #endif
 
-#if defined(PNG_READ_cHRM_SUPPORTED)
+#ifdef PNG_READ_cHRM_SUPPORTED
 void /* PRIVATE */
 png_handle_cHRM(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 {
@@ -803,7 +833,7 @@ png_handle_cHRM(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
       png_warning(png_ptr, "Missing PLTE before cHRM");
 
    if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_cHRM)
-#if defined(PNG_READ_sRGB_SUPPORTED)
+#ifdef PNG_READ_sRGB_SUPPORTED
       && !(info_ptr->valid & PNG_INFO_sRGB)
 #endif
       )
@@ -855,7 +885,7 @@ png_handle_cHRM(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
    blue_y  = (float)int_y_blue  / (float)100000.0;
 #endif
 
-#if defined(PNG_READ_sRGB_SUPPORTED)
+#ifdef PNG_READ_sRGB_SUPPORTED
    if ((info_ptr != NULL) && (info_ptr->valid & PNG_INFO_sRGB))
       {
       if (PNG_OUT_OF_RANGE(int_x_white, 31270,  1000) ||
@@ -869,7 +899,7 @@ png_handle_cHRM(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
          {
             png_warning(png_ptr,
               "Ignoring incorrect cHRM value when sRGB is also present");
-#ifndef PNG_NO_CONSOLE_IO
+#ifdef PNG_CONSOLE_IO_SUPPORTED
 #ifdef PNG_FLOATING_POINT_SUPPORTED
             fprintf(stderr, "wx=%f, wy=%f, rx=%f, ry=%f\n",
                white_x, white_y, red_x, red_y);
@@ -881,7 +911,7 @@ png_handle_cHRM(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
             fprintf(stderr, "gx=%ld, gy=%ld, bx=%ld, by=%ld\n",
                int_x_green, int_y_green, int_x_blue, int_y_blue);
 #endif
-#endif /* PNG_NO_CONSOLE_IO */
+#endif /* PNG_CONSOLE_IO_SUPPORTED */
          }
          return;
       }
@@ -899,7 +929,7 @@ png_handle_cHRM(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 }
 #endif
 
-#if defined(PNG_READ_sRGB_SUPPORTED)
+#ifdef PNG_READ_sRGB_SUPPORTED
 void /* PRIVATE */
 png_handle_sRGB(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 {
@@ -961,7 +991,7 @@ png_handle_sRGB(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
       {
          png_warning(png_ptr,
            "Ignoring incorrect gAMA value when sRGB is also present");
-#ifndef PNG_NO_CONSOLE_IO
+#ifdef PNG_CONSOLE_IO_SUPPORTED
 #  ifdef PNG_FIXED_POINT_SUPPORTED
          fprintf(stderr, "incorrect gamma=(%d/100000)\n",
             (int)png_ptr->int_gamma);
@@ -997,7 +1027,7 @@ png_handle_sRGB(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 }
 #endif /* PNG_READ_sRGB_SUPPORTED */
 
-#if defined(PNG_READ_iCCP_SUPPORTED)
+#ifdef PNG_READ_iCCP_SUPPORTED
 void /* PRIVATE */
 png_handle_iCCP(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 /* Note: this does not properly handle chunks that are > 64K under DOS */
@@ -1117,14 +1147,14 @@ png_handle_iCCP(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 }
 #endif /* PNG_READ_iCCP_SUPPORTED */
 
-#if defined(PNG_READ_sPLT_SUPPORTED)
+#ifdef PNG_READ_sPLT_SUPPORTED
 void /* PRIVATE */
 png_handle_sPLT(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 /* Note: this does not properly handle chunks that are > 64K under DOS */
 {
    png_bytep entry_start;
    png_sPLT_t new_palette;
-#ifdef PNG_NO_POINTER_INDEXING
+#ifdef PNG_POINTER_INDEXING_SUPPORTED
    png_sPLT_entryp pp;
 #endif
    int data_length, entry_size, i;
@@ -1133,6 +1163,23 @@ png_handle_sPLT(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 
    png_debug(1, "in png_handle_sPLT");
 
+#ifdef PNG_USER_LIMITS_SUPPORTED
+
+   if (png_ptr->user_chunk_cache_max != 0)
+   {
+      if (png_ptr->user_chunk_cache_max == 1)
+      {
+         png_crc_finish(png_ptr, length);
+         return;
+      }
+      if (--png_ptr->user_chunk_cache_max == 1)
+      {
+         png_warning(png_ptr, "No space in chunk cache for sPLT");
+         png_crc_finish(png_ptr, length);
+         return;
+      }
+   }
+#endif
 
    if (!(png_ptr->mode & PNG_HAVE_IHDR))
       png_error(png_ptr, "Missing IHDR before sPLT");
@@ -1166,7 +1213,8 @@ png_handle_sPLT(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 
    png_ptr->chunkdata[slength] = 0x00;
 
-   for (entry_start = (png_bytep)png_ptr->chunkdata; *entry_start; entry_start++)
+   for (entry_start = (png_bytep)png_ptr->chunkdata; *entry_start;
+       entry_start++)
       /* Empty loop to find end of name */ ;
    ++entry_start;
 
@@ -1207,10 +1255,10 @@ png_handle_sPLT(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
        return;
    }
 
-#ifndef PNG_NO_POINTER_INDEXING
+#ifdef PNG_POINTER_INDEXING_SUPPORTED
    for (i = 0; i < new_palette.nentries; i++)
    {
-      png_sPLT_entryp pp = new_palette.entries + i;
+      pp = new_palette.entries + i;
 
       if (new_palette.depth == 8)
       {
@@ -1262,7 +1310,7 @@ png_handle_sPLT(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 }
 #endif /* PNG_READ_sPLT_SUPPORTED */
 
-#if defined(PNG_READ_tRNS_SUPPORTED)
+#ifdef PNG_READ_tRNS_SUPPORTED
 void /* PRIVATE */
 png_handle_tRNS(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 {
@@ -1357,7 +1405,7 @@ png_handle_tRNS(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 }
 #endif
 
-#if defined(PNG_READ_bKGD_SUPPORTED)
+#ifdef PNG_READ_bKGD_SUPPORTED
 void /* PRIVATE */
 png_handle_bKGD(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 {
@@ -1446,7 +1494,7 @@ png_handle_bKGD(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 }
 #endif
 
-#if defined(PNG_READ_hIST_SUPPORTED)
+#ifdef PNG_READ_hIST_SUPPORTED
 void /* PRIVATE */
 png_handle_hIST(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 {
@@ -1500,7 +1548,7 @@ png_handle_hIST(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 }
 #endif
 
-#if defined(PNG_READ_pHYs_SUPPORTED)
+#ifdef PNG_READ_pHYs_SUPPORTED
 void /* PRIVATE */
 png_handle_pHYs(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 {
@@ -1543,7 +1591,7 @@ png_handle_pHYs(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 }
 #endif
 
-#if defined(PNG_READ_oFFs_SUPPORTED)
+#ifdef PNG_READ_oFFs_SUPPORTED
 void /* PRIVATE */
 png_handle_oFFs(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 {
@@ -1586,7 +1634,7 @@ png_handle_oFFs(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 }
 #endif
 
-#if defined(PNG_READ_pCAL_SUPPORTED)
+#ifdef PNG_READ_pCAL_SUPPORTED
 /* Read the pCAL chunk (described in the PNG Extensions document) */
 void /* PRIVATE */
 png_handle_pCAL(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
@@ -1720,7 +1768,7 @@ png_handle_pCAL(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 }
 #endif
 
-#if defined(PNG_READ_sCAL_SUPPORTED)
+#ifdef PNG_READ_sCAL_SUPPORTED
 /* Read the sCAL chunk */
 void /* PRIVATE */
 png_handle_sCAL(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
@@ -1863,7 +1911,7 @@ png_handle_sCAL(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 }
 #endif
 
-#if defined(PNG_READ_tIME_SUPPORTED)
+#ifdef PNG_READ_tIME_SUPPORTED
 void /* PRIVATE */
 png_handle_tIME(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 {
@@ -1906,7 +1954,7 @@ png_handle_tIME(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 }
 #endif
 
-#if defined(PNG_READ_tEXt_SUPPORTED)
+#ifdef PNG_READ_tEXt_SUPPORTED
 /* Note: this does not properly handle chunks that are > 64K under DOS */
 void /* PRIVATE */
 png_handle_tEXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
@@ -1920,6 +1968,22 @@ png_handle_tEXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 
    png_debug(1, "in png_handle_tEXt");
 
+#ifdef PNG_USER_LIMITS_SUPPORTED
+   if (png_ptr->user_chunk_cache_max != 0)
+   {
+      if (png_ptr->user_chunk_cache_max == 1)
+      {
+         png_crc_finish(png_ptr, length);
+         return;
+      }
+      if (--png_ptr->user_chunk_cache_max == 1)
+      {
+         png_warning(png_ptr, "No space in chunk cache for tEXt");
+         png_crc_finish(png_ptr, length);
+         return;
+      }
+   }
+#endif
 
    if (!(png_ptr->mode & PNG_HAVE_IHDR))
       png_error(png_ptr, "Missing IHDR before tEXt");
@@ -1993,7 +2057,7 @@ png_handle_tEXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 }
 #endif
 
-#if defined(PNG_READ_zTXt_SUPPORTED)
+#ifdef PNG_READ_zTXt_SUPPORTED
 /* Note: this does not correctly handle chunks that are > 64K under DOS */
 void /* PRIVATE */
 png_handle_zTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
@@ -2006,6 +2070,22 @@ png_handle_zTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 
    png_debug(1, "in png_handle_zTXt");
 
+#ifdef PNG_USER_LIMITS_SUPPORTED
+   if (png_ptr->user_chunk_cache_max != 0)
+   {
+      if (png_ptr->user_chunk_cache_max == 1)
+      {
+         png_crc_finish(png_ptr, length);
+         return;
+      }
+      if (--png_ptr->user_chunk_cache_max == 1)
+      {
+         png_warning(png_ptr, "No space in chunk cache for zTXt");
+         png_crc_finish(png_ptr, length);
+         return;
+      }
+   }
+#endif
 
    if (!(png_ptr->mode & PNG_HAVE_IHDR))
       png_error(png_ptr, "Missing IHDR before zTXt");
@@ -2097,7 +2177,7 @@ png_handle_zTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 }
 #endif
 
-#if defined(PNG_READ_iTXt_SUPPORTED)
+#ifdef PNG_READ_iTXt_SUPPORTED
 /* Note: this does not correctly handle chunks that are > 64K under DOS */
 void /* PRIVATE */
 png_handle_iTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
@@ -2111,6 +2191,22 @@ png_handle_iTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 
    png_debug(1, "in png_handle_iTXt");
 
+#ifdef PNG_USER_LIMITS_SUPPORTED
+   if (png_ptr->user_chunk_cache_max != 0)
+   {
+      if (png_ptr->user_chunk_cache_max == 1)
+      {
+         png_crc_finish(png_ptr, length);
+         return;
+      }
+      if (--png_ptr->user_chunk_cache_max == 1)
+      {
+         png_warning(png_ptr, "No space in chunk cache for iTXt");
+         png_crc_finish(png_ptr, length);
+         return;
+      }
+   }
+#endif
 
    if (!(png_ptr->mode & PNG_HAVE_IHDR))
       png_error(png_ptr, "Missing IHDR before iTXt");
@@ -2239,6 +2335,22 @@ png_handle_unknown(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 
    png_debug(1, "in png_handle_unknown");
 
+#ifdef PNG_USER_LIMITS_SUPPORTED
+   if (png_ptr->user_chunk_cache_max != 0)
+   {
+      if (png_ptr->user_chunk_cache_max == 1)
+      {
+         png_crc_finish(png_ptr, length);
+         return;
+      }
+      if (--png_ptr->user_chunk_cache_max == 1)
+      {
+         png_warning(png_ptr, "No space in chunk cache for unknown chunk");
+         png_crc_finish(png_ptr, length);
+         return;
+      }
+   }
+#endif
 
    if (png_ptr->mode & PNG_HAVE_IDAT)
    {
@@ -2251,10 +2363,10 @@ png_handle_unknown(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 
    if (!(png_ptr->chunk_name[0] & 0x20))
    {
-#if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
       if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
            PNG_HANDLE_CHUNK_ALWAYS
-#if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
+#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
            && png_ptr->read_user_chunk_fn == NULL
 #endif
         )
@@ -2262,9 +2374,12 @@ png_handle_unknown(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
           png_chunk_error(png_ptr, "unknown critical chunk");
    }
 
-#if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
-   if ((png_ptr->flags & PNG_FLAG_KEEP_UNKNOWN_CHUNKS) ||
-       (png_ptr->read_user_chunk_fn != NULL))
+#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
+   if ((png_ptr->flags & PNG_FLAG_KEEP_UNKNOWN_CHUNKS)
+#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
+       || (png_ptr->read_user_chunk_fn != NULL)
+#endif
+        )
    {
 #ifdef PNG_MAX_MALLOC_64K
        if (length > (png_uint_32)65535L)
@@ -2275,9 +2390,10 @@ png_handle_unknown(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
        }
 #endif
        png_memcpy((png_charp)png_ptr->unknown_chunk.name,
-                  (png_charp)png_ptr->chunk_name, 
+                  (png_charp)png_ptr->chunk_name,
                   png_sizeof(png_ptr->unknown_chunk.name));
-       png_ptr->unknown_chunk.name[png_sizeof(png_ptr->unknown_chunk.name)-1] = '\0';
+       png_ptr->unknown_chunk.name[png_sizeof(png_ptr->unknown_chunk.name)-1]
+           = '\0';
        png_ptr->unknown_chunk.size = (png_size_t)length;
        if (length == 0)
          png_ptr->unknown_chunk.data = NULL;
@@ -2286,7 +2402,7 @@ png_handle_unknown(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
          png_ptr->unknown_chunk.data = (png_bytep)png_malloc(png_ptr, length);
          png_crc_read(png_ptr, (png_bytep)png_ptr->unknown_chunk.data, length);
        }
-#if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
+#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
        if (png_ptr->read_user_chunk_fn != NULL)
        {
           /* Callback to user unknown chunk handler */
@@ -2298,8 +2414,10 @@ png_handle_unknown(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
           if (ret == 0)
           {
              if (!(png_ptr->chunk_name[0] & 0x20))
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
                 if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
                      PNG_HANDLE_CHUNK_ALWAYS)
+#endif
                    png_chunk_error(png_ptr, "unknown critical chunk");
              png_set_unknown_chunks(png_ptr, info_ptr,
                &png_ptr->unknown_chunk, 1);
@@ -2317,7 +2435,7 @@ png_handle_unknown(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 
    png_crc_finish(png_ptr, skip);
 
-#if !defined(PNG_READ_USER_CHUNKS_SUPPORTED)
+#ifndef PNG_READ_USER_CHUNKS_SUPPORTED
    info_ptr = info_ptr; /* Quiet compiler warnings about unused info_ptr */
 #endif
 }
@@ -2375,7 +2493,7 @@ png_combine_row(png_structp png_ptr, png_bytep row, int mask)
             png_uint_32 i;
             png_uint_32 row_width = png_ptr->width;
 
-#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+#ifdef PNG_READ_PACKSWAP_SUPPORTED
             if (png_ptr->transformations & PNG_PACKSWAP)
             {
                 s_start = 0;
@@ -2430,7 +2548,7 @@ png_combine_row(png_structp png_ptr, png_bytep row, int mask)
             png_uint_32 row_width = png_ptr->width;
             int value;
 
-#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+#ifdef PNG_READ_PACKSWAP_SUPPORTED
             if (png_ptr->transformations & PNG_PACKSWAP)
             {
                s_start = 0;
@@ -2482,7 +2600,7 @@ png_combine_row(png_structp png_ptr, png_bytep row, int mask)
             png_uint_32 row_width = png_ptr->width;
             int value;
 
-#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+#ifdef PNG_READ_PACKSWAP_SUPPORTED
             if (png_ptr->transformations & PNG_PACKSWAP)
             {
                s_start = 0;
@@ -2565,11 +2683,9 @@ png_do_read_interlace(png_structp png_ptr)
    png_bytep row = png_ptr->row_buf + 1;
    int pass = png_ptr->pass;
    png_uint_32 transformations = png_ptr->transformations;
-#ifdef PNG_USE_LOCAL_ARRAYS
    /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
    /* Offset to next interlace block */
    PNG_CONST int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
-#endif
 
    png_debug(1, "in png_do_read_interlace");
    if (row != NULL && row_info != NULL)
@@ -2591,7 +2707,7 @@ png_do_read_interlace(png_structp png_ptr)
             png_uint_32 i;
             int j;
 
-#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+#ifdef PNG_READ_PACKSWAP_SUPPORTED
             if (transformations & PNG_PACKSWAP)
             {
                 sshift = (int)((row_info->width + 7) & 0x07);
@@ -2644,7 +2760,7 @@ png_do_read_interlace(png_structp png_ptr)
             int jstop = png_pass_inc[pass];
             png_uint_32 i;
 
-#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+#ifdef PNG_READ_PACKSWAP_SUPPORTED
             if (transformations & PNG_PACKSWAP)
             {
                sshift = (int)(((row_info->width + 3) & 0x03) << 1);
@@ -2700,7 +2816,7 @@ png_do_read_interlace(png_structp png_ptr)
             png_uint_32 i;
             int jstop = png_pass_inc[pass];
 
-#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+#ifdef PNG_READ_PACKSWAP_SUPPORTED
             if (transformations & PNG_PACKSWAP)
             {
                sshift = (int)(((row_info->width + 1) & 0x01) << 2);
@@ -2749,7 +2865,8 @@ png_do_read_interlace(png_structp png_ptr)
          default:
          {
             png_size_t pixel_bytes = (row_info->pixel_depth >> 3);
-            png_bytep sp = row + (png_size_t)(row_info->width - 1) * pixel_bytes;
+            png_bytep sp = row + (png_size_t)(row_info->width - 1)
+                * pixel_bytes;
             png_bytep dp = row + (png_size_t)(final_width - 1) * pixel_bytes;
 
             int jstop = png_pass_inc[pass];
@@ -2774,7 +2891,7 @@ png_do_read_interlace(png_structp png_ptr)
       row_info->width = final_width;
       row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, final_width);
    }
-#if !defined(PNG_READ_PACKSWAP_SUPPORTED)
+#ifndef PNG_READ_PACKSWAP_SUPPORTED
    transformations = transformations; /* Silence compiler warning */
 #endif
 }
@@ -2903,11 +3020,10 @@ png_read_filter_row(png_structp png_ptr, png_row_infop row_info, png_bytep row,
    }
 }
 
-#ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
 void /* PRIVATE */
 png_read_finish_row(png_structp png_ptr)
 {
-#ifdef PNG_USE_LOCAL_ARRAYS
 #ifdef PNG_READ_INTERLACING_SUPPORTED
    /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
 
@@ -2923,7 +3039,6 @@ png_read_finish_row(png_structp png_ptr)
    /* Offset to next interlace block in the y direction */
    PNG_CONST int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
 #endif /* PNG_READ_INTERLACING_SUPPORTED */
-#endif
 
    png_debug(1, "in png_read_finish_row");
    png_ptr->row_number++;
@@ -2946,9 +3061,6 @@ png_read_finish_row(png_structp png_ptr)
             png_pass_start[png_ptr->pass]) /
             png_pass_inc[png_ptr->pass];
 
-         png_ptr->irowbytes = PNG_ROWBYTES(png_ptr->pixel_depth,
-            png_ptr->iwidth) + 1;
-
          if (!(png_ptr->transformations & PNG_INTERLACE))
          {
             png_ptr->num_rows = (png_ptr->height +
@@ -3007,7 +3119,7 @@ png_read_finish_row(png_structp png_ptr)
          {
             if (!(png_ptr->zstream.avail_out) || png_ptr->zstream.avail_in ||
                png_ptr->idat_size)
-               png_warning(png_ptr, "Extra compressed data");
+               png_warning(png_ptr, "Extra compressed data.");
             png_ptr->mode |= PNG_AFTER_IDAT;
             png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
             break;
@@ -3029,18 +3141,17 @@ png_read_finish_row(png_structp png_ptr)
    }
 
    if (png_ptr->idat_size || png_ptr->zstream.avail_in)
-      png_warning(png_ptr, "Extra compression data");
+      png_warning(png_ptr, "Extra compression data.");
 
    inflateReset(&png_ptr->zstream);
 
    png_ptr->mode |= PNG_AFTER_IDAT;
 }
-#endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
+#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
 
 void /* PRIVATE */
 png_read_start_row(png_structp png_ptr)
 {
-#ifdef PNG_USE_LOCAL_ARRAYS
 #ifdef PNG_READ_INTERLACING_SUPPORTED
    /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
 
@@ -3056,7 +3167,6 @@ png_read_start_row(png_structp png_ptr)
    /* Offset to next interlace block in the y direction */
    PNG_CONST int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
 #endif
-#endif
 
    int max_pixel_depth;
    png_size_t row_bytes;
@@ -3077,25 +3187,21 @@ png_read_start_row(png_structp png_ptr)
          png_pass_inc[png_ptr->pass] - 1 -
          png_pass_start[png_ptr->pass]) /
          png_pass_inc[png_ptr->pass];
-
-         png_ptr->irowbytes =
-            PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->iwidth) + 1;
    }
    else
 #endif /* PNG_READ_INTERLACING_SUPPORTED */
    {
       png_ptr->num_rows = png_ptr->height;
       png_ptr->iwidth = png_ptr->width;
-      png_ptr->irowbytes = png_ptr->rowbytes + 1;
    }
    max_pixel_depth = png_ptr->pixel_depth;
 
-#if defined(PNG_READ_PACK_SUPPORTED)
+#ifdef PNG_READ_PACK_SUPPORTED
    if ((png_ptr->transformations & PNG_PACK) && png_ptr->bit_depth < 8)
       max_pixel_depth = 8;
 #endif
 
-#if defined(PNG_READ_EXPAND_SUPPORTED)
+#ifdef PNG_READ_EXPAND_SUPPORTED
    if (png_ptr->transformations & PNG_EXPAND)
    {
       if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
@@ -3123,7 +3229,7 @@ png_read_start_row(png_structp png_ptr)
    }
 #endif
 
-#if defined(PNG_READ_FILLER_SUPPORTED)
+#ifdef PNG_READ_FILLER_SUPPORTED
    if (png_ptr->transformations & (PNG_FILLER))
    {
       if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
@@ -3145,14 +3251,14 @@ png_read_start_row(png_structp png_ptr)
    }
 #endif
 
-#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
    if (png_ptr->transformations & PNG_GRAY_TO_RGB)
    {
       if (
-#if defined(PNG_READ_EXPAND_SUPPORTED)
+#ifdef PNG_READ_EXPAND_SUPPORTED
         (png_ptr->num_trans && (png_ptr->transformations & PNG_EXPAND)) ||
 #endif
-#if defined(PNG_READ_FILLER_SUPPORTED)
+#ifdef PNG_READ_FILLER_SUPPORTED
         (png_ptr->transformations & (PNG_FILLER)) ||
 #endif
         png_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
@@ -3207,9 +3313,15 @@ defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
    if (row_bytes + 64 > png_ptr->old_big_row_buf_size)
    {
      png_free(png_ptr, png_ptr->big_row_buf);
-     png_ptr->big_row_buf = (png_bytep)png_malloc(png_ptr, row_bytes + 64);
      if (png_ptr->interlaced)
-       png_memset(png_ptr->big_row_buf, 0, row_bytes + 64);
+        png_ptr->big_row_buf = (png_bytep)png_calloc(png_ptr,
+            row_bytes + 64);
+     else
+        png_ptr->big_row_buf = (png_bytep)png_malloc(png_ptr,
+            row_bytes + 64);
+     png_ptr->old_big_row_buf_size = row_bytes + 64;
+
+     /* Use 32 bytes of padding before and after row_buf. */
      png_ptr->row_buf = png_ptr->big_row_buf + 32;
      png_ptr->old_big_row_buf_size = row_bytes + 64;
    }
@@ -3237,7 +3349,8 @@ defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
    png_debug1(3, "iwidth = %lu,", png_ptr->iwidth);
    png_debug1(3, "num_rows = %lu,", png_ptr->num_rows);
    png_debug1(3, "rowbytes = %lu,", png_ptr->rowbytes);
-   png_debug1(3, "irowbytes = %lu", png_ptr->irowbytes);
+   png_debug1(3, "irowbytes = %lu",
+       PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->iwidth) + 1);
 
    png_ptr->flags |= PNG_FLAG_ROW_INIT;
 }