jdk/src/share/native/sun/awt/libpng/pngpread.c
changeset 10576 db3409425573
parent 5506 202f599c92aa
--- a/jdk/src/share/native/sun/awt/libpng/pngpread.c	Fri Sep 09 17:22:03 2011 -0700
+++ b/jdk/src/share/native/sun/awt/libpng/pngpread.c	Mon Sep 19 05:56:44 2011 -0700
@@ -29,19 +29,21 @@
  * However, the following notice accompanied the original version of this
  * file and, per its terms, should not be removed:
  *
- * Last changed in libpng 1.2.17 May 15, 2007
- * For conditions of distribution and use, see copyright notice in png.h
- * Copyright (c) 1998-2007 Glenn Randers-Pehrson
+ * Last changed in libpng 1.5.2 [March 31, 2011]
+ * Copyright (c) 1998-2011 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
  */
 
-#define PNG_INTERNAL
-#include "png.h"
+#include "pngpriv.h"
 
 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
 
-/* push model modes */
+/* Push model modes */
 #define PNG_READ_SIG_MODE   0
 #define PNG_READ_CHUNK_MODE 1
 #define PNG_READ_IDAT_MODE  2
@@ -54,9 +56,11 @@
 
 void PNGAPI
 png_process_data(png_structp png_ptr, png_infop info_ptr,
-   png_bytep buffer, png_size_t buffer_size)
+    png_bytep buffer, png_size_t buffer_size)
 {
-   if(png_ptr == NULL) return;
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
    png_push_restore_buffer(png_ptr, buffer, buffer_size);
 
    while (png_ptr->buffer_size)
@@ -65,13 +69,73 @@
    }
 }
 
+png_size_t PNGAPI
+png_process_data_pause(png_structp png_ptr, int save)
+{
+   if (png_ptr != NULL)
+   {
+      /* It's easiest for the caller if we do the save, then the caller doesn't
+       * have to supply the same data again:
+       */
+      if (save)
+         png_push_save_buffer(png_ptr);
+      else
+      {
+         /* This includes any pending saved bytes: */
+         png_size_t remaining = png_ptr->buffer_size;
+         png_ptr->buffer_size = 0;
+
+         /* So subtract the saved buffer size, unless all the data
+          * is actually 'saved', in which case we just return 0
+          */
+         if (png_ptr->save_buffer_size < remaining)
+            return remaining - png_ptr->save_buffer_size;
+      }
+   }
+
+   return 0;
+}
+
+png_uint_32 PNGAPI
+png_process_data_skip(png_structp png_ptr)
+{
+   png_uint_32 remaining = 0;
+
+   if (png_ptr != NULL && png_ptr->process_mode == PNG_SKIP_MODE &&
+      png_ptr->skip_length > 0)
+   {
+      /* At the end of png_process_data the buffer size must be 0 (see the loop
+       * above) so we can detect a broken call here:
+       */
+      if (png_ptr->buffer_size != 0)
+         png_error(png_ptr,
+            "png_process_data_skip called inside png_process_data");
+
+      /* If is impossible for there to be a saved buffer at this point -
+       * otherwise we could not be in SKIP mode.  This will also happen if
+       * png_process_skip is called inside png_process_data (but only very
+       * rarely.)
+       */
+      if (png_ptr->save_buffer_size != 0)
+         png_error(png_ptr, "png_process_data_skip called with saved data");
+
+      remaining = png_ptr->skip_length;
+      png_ptr->skip_length = 0;
+      png_ptr->process_mode = PNG_READ_CHUNK_MODE;
+   }
+
+   return remaining;
+}
+
 /* What we do with the incoming data depends on what we were previously
  * doing before we ran out of data...
  */
 void /* PRIVATE */
 png_process_some_data(png_structp png_ptr, png_infop info_ptr)
 {
-   if(png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
+
    switch (png_ptr->process_mode)
    {
       case PNG_READ_SIG_MODE:
@@ -79,42 +143,49 @@
          png_push_read_sig(png_ptr, info_ptr);
          break;
       }
+
       case PNG_READ_CHUNK_MODE:
       {
          png_push_read_chunk(png_ptr, info_ptr);
          break;
       }
+
       case PNG_READ_IDAT_MODE:
       {
          png_push_read_IDAT(png_ptr);
          break;
       }
-#if defined(PNG_READ_tEXt_SUPPORTED)
+
+#ifdef PNG_READ_tEXt_SUPPORTED
       case PNG_READ_tEXt_MODE:
       {
          png_push_read_tEXt(png_ptr, info_ptr);
          break;
       }
+
 #endif
-#if defined(PNG_READ_zTXt_SUPPORTED)
+#ifdef PNG_READ_zTXt_SUPPORTED
       case PNG_READ_zTXt_MODE:
       {
          png_push_read_zTXt(png_ptr, info_ptr);
          break;
       }
+
 #endif
-#if defined(PNG_READ_iTXt_SUPPORTED)
+#ifdef PNG_READ_iTXt_SUPPORTED
       case PNG_READ_iTXt_MODE:
       {
          png_push_read_iTXt(png_ptr, info_ptr);
          break;
       }
+
 #endif
       case PNG_SKIP_MODE:
       {
          png_push_crc_finish(png_ptr);
          break;
       }
+
       default:
       {
          png_ptr->buffer_size = 0;
@@ -141,14 +212,15 @@
    }
 
    png_push_fill_buffer(png_ptr, &(info_ptr->signature[num_checked]),
-      num_to_check);
-   png_ptr->sig_bytes = (png_byte)(png_ptr->sig_bytes+num_to_check);
+       num_to_check);
+   png_ptr->sig_bytes = (png_byte)(png_ptr->sig_bytes + num_to_check);
 
    if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
    {
       if (num_checked < 4 &&
           png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
          png_error(png_ptr, "Not a PNG file");
+
       else
          png_error(png_ptr, "PNG file corrupted by ASCII conversion");
    }
@@ -164,63 +236,62 @@
 void /* PRIVATE */
 png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
 {
-#ifdef PNG_USE_LOCAL_ARRAYS
       PNG_IHDR;
       PNG_IDAT;
       PNG_IEND;
       PNG_PLTE;
-#if defined(PNG_READ_bKGD_SUPPORTED)
+#ifdef PNG_READ_bKGD_SUPPORTED
       PNG_bKGD;
 #endif
-#if defined(PNG_READ_cHRM_SUPPORTED)
+#ifdef PNG_READ_cHRM_SUPPORTED
       PNG_cHRM;
 #endif
-#if defined(PNG_READ_gAMA_SUPPORTED)
+#ifdef PNG_READ_gAMA_SUPPORTED
       PNG_gAMA;
 #endif
-#if defined(PNG_READ_hIST_SUPPORTED)
+#ifdef PNG_READ_hIST_SUPPORTED
       PNG_hIST;
 #endif
-#if defined(PNG_READ_iCCP_SUPPORTED)
+#ifdef PNG_READ_iCCP_SUPPORTED
       PNG_iCCP;
 #endif
-#if defined(PNG_READ_iTXt_SUPPORTED)
+#ifdef PNG_READ_iTXt_SUPPORTED
       PNG_iTXt;
 #endif
-#if defined(PNG_READ_oFFs_SUPPORTED)
+#ifdef PNG_READ_oFFs_SUPPORTED
       PNG_oFFs;
 #endif
-#if defined(PNG_READ_pCAL_SUPPORTED)
+#ifdef PNG_READ_pCAL_SUPPORTED
       PNG_pCAL;
 #endif
-#if defined(PNG_READ_pHYs_SUPPORTED)
+#ifdef PNG_READ_pHYs_SUPPORTED
       PNG_pHYs;
 #endif
-#if defined(PNG_READ_sBIT_SUPPORTED)
+#ifdef PNG_READ_sBIT_SUPPORTED
       PNG_sBIT;
 #endif
-#if defined(PNG_READ_sCAL_SUPPORTED)
+#ifdef PNG_READ_sCAL_SUPPORTED
       PNG_sCAL;
 #endif
-#if defined(PNG_READ_sRGB_SUPPORTED)
+#ifdef PNG_READ_sRGB_SUPPORTED
       PNG_sRGB;
 #endif
-#if defined(PNG_READ_sPLT_SUPPORTED)
+#ifdef PNG_READ_sPLT_SUPPORTED
       PNG_sPLT;
 #endif
-#if defined(PNG_READ_tEXt_SUPPORTED)
+#ifdef PNG_READ_tEXt_SUPPORTED
       PNG_tEXt;
 #endif
-#if defined(PNG_READ_tIME_SUPPORTED)
+#ifdef PNG_READ_tIME_SUPPORTED
       PNG_tIME;
 #endif
-#if defined(PNG_READ_tRNS_SUPPORTED)
+#ifdef PNG_READ_tRNS_SUPPORTED
       PNG_tRNS;
 #endif
-#if defined(PNG_READ_zTXt_SUPPORTED)
+#ifdef PNG_READ_zTXt_SUPPORTED
       PNG_zTXt;
 #endif
-#endif /* PNG_USE_LOCAL_ARRAYS */
+
    /* First we make sure we have enough data for the 4 byte chunk name
     * and the 4 byte chunk length before proceeding with decoding the
     * chunk data.  To fully decode each of these chunks, we also make
@@ -238,25 +309,31 @@
       }
 
       png_push_fill_buffer(png_ptr, chunk_length, 4);
-      png_ptr->push_length = png_get_uint_31(png_ptr,chunk_length);
+      png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
       png_reset_crc(png_ptr);
       png_crc_read(png_ptr, png_ptr->chunk_name, 4);
+      png_check_chunk_name(png_ptr, png_ptr->chunk_name);
       png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
    }
 
-   if (!png_memcmp(png_ptr->chunk_name, (png_bytep)png_IDAT, 4))
-     if(png_ptr->mode & PNG_AFTER_IDAT)
-        png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
+   if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
+      if (png_ptr->mode & PNG_AFTER_IDAT)
+         png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
 
    if (!png_memcmp(png_ptr->chunk_name, png_IHDR, 4))
    {
+      if (png_ptr->push_length != 13)
+         png_error(png_ptr, "Invalid IHDR length");
+
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
       {
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length);
    }
+
    else if (!png_memcmp(png_ptr->chunk_name, png_IEND, 4))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
@@ -264,11 +341,13 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_handle_IEND(png_ptr, info_ptr, png_ptr->push_length);
 
       png_ptr->process_mode = PNG_READ_DONE_MODE;
       png_push_have_end(png_ptr, info_ptr);
    }
+
 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
    else if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name))
    {
@@ -277,20 +356,26 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
          png_ptr->mode |= PNG_HAVE_IDAT;
+
       png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length);
+
       if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
          png_ptr->mode |= PNG_HAVE_PLTE;
+
       else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
       {
          if (!(png_ptr->mode & PNG_HAVE_IHDR))
             png_error(png_ptr, "Missing IHDR before IDAT");
+
          else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
-                  !(png_ptr->mode & PNG_HAVE_PLTE))
+             !(png_ptr->mode & PNG_HAVE_PLTE))
             png_error(png_ptr, "Missing PLTE before IDAT");
       }
    }
+
 #endif
    else if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
    {
@@ -301,37 +386,43 @@
       }
       png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length);
    }
-   else if (!png_memcmp(png_ptr->chunk_name, (png_bytep)png_IDAT, 4))
+
+   else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
    {
       /* If we reach an IDAT chunk, this means we have read all of the
        * header chunks, and we can start reading the image (or if this
        * is called after the image has been read - we have an error).
        */
-     if (!(png_ptr->mode & PNG_HAVE_IHDR))
-       png_error(png_ptr, "Missing IHDR before IDAT");
-     else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
-         !(png_ptr->mode & PNG_HAVE_PLTE))
-       png_error(png_ptr, "Missing PLTE before IDAT");
+
+      if (!(png_ptr->mode & PNG_HAVE_IHDR))
+         png_error(png_ptr, "Missing IHDR before IDAT");
+
+      else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
+          !(png_ptr->mode & PNG_HAVE_PLTE))
+         png_error(png_ptr, "Missing PLTE before IDAT");
 
       if (png_ptr->mode & PNG_HAVE_IDAT)
       {
          if (!(png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
-           if (png_ptr->push_length == 0)
-              return;
+            if (png_ptr->push_length == 0)
+               return;
 
          if (png_ptr->mode & PNG_AFTER_IDAT)
-            png_error(png_ptr, "Too many IDAT's found");
+            png_benign_error(png_ptr, "Too many IDATs found");
       }
 
       png_ptr->idat_size = png_ptr->push_length;
       png_ptr->mode |= PNG_HAVE_IDAT;
       png_ptr->process_mode = PNG_READ_IDAT_MODE;
       png_push_have_info(png_ptr, info_ptr);
-      png_ptr->zstream.avail_out = (uInt)png_ptr->irowbytes;
+      png_ptr->zstream.avail_out =
+          (uInt) PNG_ROWBYTES(png_ptr->pixel_depth,
+          png_ptr->iwidth) + 1;
       png_ptr->zstream.next_out = png_ptr->row_buf;
       return;
    }
-#if defined(PNG_READ_gAMA_SUPPORTED)
+
+#ifdef PNG_READ_gAMA_SUPPORTED
    else if (!png_memcmp(png_ptr->chunk_name, png_gAMA, 4))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
@@ -339,10 +430,12 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_handle_gAMA(png_ptr, info_ptr, png_ptr->push_length);
    }
+
 #endif
-#if defined(PNG_READ_sBIT_SUPPORTED)
+#ifdef PNG_READ_sBIT_SUPPORTED
    else if (!png_memcmp(png_ptr->chunk_name, png_sBIT, 4))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
@@ -350,10 +443,12 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_handle_sBIT(png_ptr, info_ptr, png_ptr->push_length);
    }
+
 #endif
-#if defined(PNG_READ_cHRM_SUPPORTED)
+#ifdef PNG_READ_cHRM_SUPPORTED
    else if (!png_memcmp(png_ptr->chunk_name, png_cHRM, 4))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
@@ -361,10 +456,12 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_handle_cHRM(png_ptr, info_ptr, png_ptr->push_length);
    }
+
 #endif
-#if defined(PNG_READ_sRGB_SUPPORTED)
+#ifdef PNG_READ_sRGB_SUPPORTED
    else if (!png_memcmp(png_ptr->chunk_name, png_sRGB, 4))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
@@ -372,10 +469,12 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length);
    }
+
 #endif
-#if defined(PNG_READ_iCCP_SUPPORTED)
+#ifdef PNG_READ_iCCP_SUPPORTED
    else if (!png_memcmp(png_ptr->chunk_name, png_iCCP, 4))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
@@ -383,10 +482,12 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length);
    }
+
 #endif
-#if defined(PNG_READ_sPLT_SUPPORTED)
+#ifdef PNG_READ_sPLT_SUPPORTED
    else if (!png_memcmp(png_ptr->chunk_name, png_sPLT, 4))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
@@ -394,10 +495,12 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length);
    }
+
 #endif
-#if defined(PNG_READ_tRNS_SUPPORTED)
+#ifdef PNG_READ_tRNS_SUPPORTED
    else if (!png_memcmp(png_ptr->chunk_name, png_tRNS, 4))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
@@ -405,10 +508,12 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_handle_tRNS(png_ptr, info_ptr, png_ptr->push_length);
    }
+
 #endif
-#if defined(PNG_READ_bKGD_SUPPORTED)
+#ifdef PNG_READ_bKGD_SUPPORTED
    else if (!png_memcmp(png_ptr->chunk_name, png_bKGD, 4))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
@@ -416,10 +521,12 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_handle_bKGD(png_ptr, info_ptr, png_ptr->push_length);
    }
+
 #endif
-#if defined(PNG_READ_hIST_SUPPORTED)
+#ifdef PNG_READ_hIST_SUPPORTED
    else if (!png_memcmp(png_ptr->chunk_name, png_hIST, 4))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
@@ -427,10 +534,12 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_handle_hIST(png_ptr, info_ptr, png_ptr->push_length);
    }
+
 #endif
-#if defined(PNG_READ_pHYs_SUPPORTED)
+#ifdef PNG_READ_pHYs_SUPPORTED
    else if (!png_memcmp(png_ptr->chunk_name, png_pHYs, 4))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
@@ -438,10 +547,12 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_handle_pHYs(png_ptr, info_ptr, png_ptr->push_length);
    }
+
 #endif
-#if defined(PNG_READ_oFFs_SUPPORTED)
+#ifdef PNG_READ_oFFs_SUPPORTED
    else if (!png_memcmp(png_ptr->chunk_name, png_oFFs, 4))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
@@ -449,10 +560,12 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_handle_oFFs(png_ptr, info_ptr, png_ptr->push_length);
    }
 #endif
-#if defined(PNG_READ_pCAL_SUPPORTED)
+
+#ifdef PNG_READ_pCAL_SUPPORTED
    else if (!png_memcmp(png_ptr->chunk_name, png_pCAL, 4))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
@@ -460,10 +573,12 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length);
    }
+
 #endif
-#if defined(PNG_READ_sCAL_SUPPORTED)
+#ifdef PNG_READ_sCAL_SUPPORTED
    else if (!png_memcmp(png_ptr->chunk_name, png_sCAL, 4))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
@@ -471,10 +586,12 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length);
    }
+
 #endif
-#if defined(PNG_READ_tIME_SUPPORTED)
+#ifdef PNG_READ_tIME_SUPPORTED
    else if (!png_memcmp(png_ptr->chunk_name, png_tIME, 4))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
@@ -482,10 +599,12 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length);
    }
+
 #endif
-#if defined(PNG_READ_tEXt_SUPPORTED)
+#ifdef PNG_READ_tEXt_SUPPORTED
    else if (!png_memcmp(png_ptr->chunk_name, png_tEXt, 4))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
@@ -493,10 +612,12 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_push_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length);
    }
+
 #endif
-#if defined(PNG_READ_zTXt_SUPPORTED)
+#ifdef PNG_READ_zTXt_SUPPORTED
    else if (!png_memcmp(png_ptr->chunk_name, png_zTXt, 4))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
@@ -504,10 +625,12 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_push_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length);
    }
+
 #endif
-#if defined(PNG_READ_iTXt_SUPPORTED)
+#ifdef PNG_READ_iTXt_SUPPORTED
    else if (!png_memcmp(png_ptr->chunk_name, png_iTXt, 4))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
@@ -515,8 +638,10 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_push_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length);
    }
+
 #endif
    else
    {
@@ -543,32 +668,45 @@
 {
    if (png_ptr->skip_length && png_ptr->save_buffer_size)
    {
-      png_size_t save_size;
+      png_size_t save_size = png_ptr->save_buffer_size;
+      png_uint_32 skip_length = png_ptr->skip_length;
 
-      if (png_ptr->skip_length < (png_uint_32)png_ptr->save_buffer_size)
-         save_size = (png_size_t)png_ptr->skip_length;
+      /* We want the smaller of 'skip_length' and 'save_buffer_size', but
+       * they are of different types and we don't know which variable has the
+       * fewest bits.  Carefully select the smaller and cast it to the type of
+       * the larger - this cannot overflow.  Do not cast in the following test
+       * - it will break on either 16 or 64 bit platforms.
+       */
+      if (skip_length < save_size)
+         save_size = (png_size_t)skip_length;
+
       else
-         save_size = png_ptr->save_buffer_size;
+         skip_length = (png_uint_32)save_size;
 
       png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
 
-      png_ptr->skip_length -= save_size;
+      png_ptr->skip_length -= skip_length;
       png_ptr->buffer_size -= save_size;
       png_ptr->save_buffer_size -= save_size;
       png_ptr->save_buffer_ptr += save_size;
    }
    if (png_ptr->skip_length && png_ptr->current_buffer_size)
    {
-      png_size_t save_size;
+      png_size_t save_size = png_ptr->current_buffer_size;
+      png_uint_32 skip_length = png_ptr->skip_length;
 
-      if (png_ptr->skip_length < (png_uint_32)png_ptr->current_buffer_size)
-         save_size = (png_size_t)png_ptr->skip_length;
+      /* We want the smaller of 'skip_length' and 'current_buffer_size', here,
+       * the same problem exists as above and the same solution.
+       */
+      if (skip_length < save_size)
+         save_size = (png_size_t)skip_length;
+
       else
-         save_size = png_ptr->current_buffer_size;
+         skip_length = (png_uint_32)save_size;
 
       png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
 
-      png_ptr->skip_length -= save_size;
+      png_ptr->skip_length -= skip_length;
       png_ptr->buffer_size -= save_size;
       png_ptr->current_buffer_size -= save_size;
       png_ptr->current_buffer_ptr += save_size;
@@ -586,12 +724,14 @@
    }
 }
 
-void PNGAPI
+void PNGCBAPI
 png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
 {
    png_bytep ptr;
 
-   if(png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
+
    ptr = buffer;
    if (png_ptr->save_buffer_size)
    {
@@ -599,6 +739,7 @@
 
       if (length < png_ptr->save_buffer_size)
          save_size = length;
+
       else
          save_size = png_ptr->save_buffer_size;
 
@@ -615,6 +756,7 @@
 
       if (length < png_ptr->current_buffer_size)
          save_size = length;
+
       else
          save_size = png_ptr->current_buffer_size;
 
@@ -632,33 +774,41 @@
    {
       if (png_ptr->save_buffer_ptr != png_ptr->save_buffer)
       {
-         png_size_t i,istop;
+         png_size_t i, istop;
          png_bytep sp;
          png_bytep dp;
 
          istop = png_ptr->save_buffer_size;
          for (i = 0, sp = png_ptr->save_buffer_ptr, dp = png_ptr->save_buffer;
-            i < istop; i++, sp++, dp++)
+             i < istop; i++, sp++, dp++)
          {
             *dp = *sp;
          }
       }
    }
    if (png_ptr->save_buffer_size + png_ptr->current_buffer_size >
-      png_ptr->save_buffer_max)
+       png_ptr->save_buffer_max)
    {
       png_size_t new_max;
       png_bytep old_buffer;
 
       if (png_ptr->save_buffer_size > PNG_SIZE_MAX -
-         (png_ptr->current_buffer_size + 256))
+          (png_ptr->current_buffer_size + 256))
       {
-        png_error(png_ptr, "Potential overflow of save_buffer");
+         png_error(png_ptr, "Potential overflow of save_buffer");
       }
+
       new_max = png_ptr->save_buffer_size + png_ptr->current_buffer_size + 256;
       old_buffer = png_ptr->save_buffer;
-      png_ptr->save_buffer = (png_bytep)png_malloc(png_ptr,
-         (png_uint_32)new_max);
+      png_ptr->save_buffer = (png_bytep)png_malloc_warn(png_ptr,
+          (png_size_t)new_max);
+
+      if (png_ptr->save_buffer == NULL)
+      {
+         png_free(png_ptr, old_buffer);
+         png_error(png_ptr, "Insufficient memory for save_buffer");
+      }
+
       png_memcpy(png_ptr->save_buffer, old_buffer, png_ptr->save_buffer_size);
       png_free(png_ptr, old_buffer);
       png_ptr->save_buffer_max = new_max;
@@ -687,9 +837,7 @@
 void /* PRIVATE */
 png_push_read_IDAT(png_structp png_ptr)
 {
-#ifdef PNG_USE_LOCAL_ARRAYS
    PNG_IDAT;
-#endif
    if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
    {
       png_byte chunk_length[4];
@@ -701,16 +849,18 @@
       }
 
       png_push_fill_buffer(png_ptr, chunk_length, 4);
-      png_ptr->push_length = png_get_uint_31(png_ptr,chunk_length);
+      png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
       png_reset_crc(png_ptr);
       png_crc_read(png_ptr, png_ptr->chunk_name, 4);
       png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
 
-      if (png_memcmp(png_ptr->chunk_name, (png_bytep)png_IDAT, 4))
+      if (png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
       {
          png_ptr->process_mode = PNG_READ_CHUNK_MODE;
+
          if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
             png_error(png_ptr, "Not enough compressed data");
+
          return;
       }
 
@@ -718,45 +868,52 @@
    }
    if (png_ptr->idat_size && png_ptr->save_buffer_size)
    {
-      png_size_t save_size;
+      png_size_t save_size = png_ptr->save_buffer_size;
+      png_uint_32 idat_size = png_ptr->idat_size;
 
-      if (png_ptr->idat_size < (png_uint_32)png_ptr->save_buffer_size)
-      {
-         save_size = (png_size_t)png_ptr->idat_size;
-         /* check for overflow */
-         if((png_uint_32)save_size != png_ptr->idat_size)
-            png_error(png_ptr, "save_size overflowed in pngpread");
-      }
+      /* We want the smaller of 'idat_size' and 'current_buffer_size', but they
+       * are of different types and we don't know which variable has the fewest
+       * bits.  Carefully select the smaller and cast it to the type of the
+       * larger - this cannot overflow.  Do not cast in the following test - it
+       * will break on either 16 or 64 bit platforms.
+       */
+      if (idat_size < save_size)
+         save_size = (png_size_t)idat_size;
+
       else
-         save_size = png_ptr->save_buffer_size;
+         idat_size = (png_uint_32)save_size;
 
       png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
-      if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
-         png_process_IDAT_data(png_ptr, png_ptr->save_buffer_ptr, save_size);
-      png_ptr->idat_size -= save_size;
+
+      png_process_IDAT_data(png_ptr, png_ptr->save_buffer_ptr, save_size);
+
+      png_ptr->idat_size -= idat_size;
       png_ptr->buffer_size -= save_size;
       png_ptr->save_buffer_size -= save_size;
       png_ptr->save_buffer_ptr += save_size;
    }
+
    if (png_ptr->idat_size && png_ptr->current_buffer_size)
    {
-      png_size_t save_size;
+      png_size_t save_size = png_ptr->current_buffer_size;
+      png_uint_32 idat_size = png_ptr->idat_size;
 
-      if (png_ptr->idat_size < (png_uint_32)png_ptr->current_buffer_size)
-      {
-         save_size = (png_size_t)png_ptr->idat_size;
-         /* check for overflow */
-         if((png_uint_32)save_size != png_ptr->idat_size)
-            png_error(png_ptr, "save_size overflowed in pngpread");
-      }
+      /* We want the smaller of 'idat_size' and 'current_buffer_size', but they
+       * are of different types and we don't know which variable has the fewest
+       * bits.  Carefully select the smaller and cast it to the type of the
+       * larger - this cannot overflow.
+       */
+      if (idat_size < save_size)
+         save_size = (png_size_t)idat_size;
+
       else
-         save_size = png_ptr->current_buffer_size;
+         idat_size = (png_uint_32)save_size;
 
       png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
-      if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
-        png_process_IDAT_data(png_ptr, png_ptr->current_buffer_ptr, save_size);
 
-      png_ptr->idat_size -= save_size;
+      png_process_IDAT_data(png_ptr, png_ptr->current_buffer_ptr, save_size);
+
+      png_ptr->idat_size -= idat_size;
       png_ptr->buffer_size -= save_size;
       png_ptr->current_buffer_size -= save_size;
       png_ptr->current_buffer_ptr += save_size;
@@ -779,57 +936,104 @@
 png_process_IDAT_data(png_structp png_ptr, png_bytep buffer,
    png_size_t buffer_length)
 {
-   int ret;
+   /* The caller checks for a non-zero buffer length. */
+   if (!(buffer_length > 0) || buffer == NULL)
+      png_error(png_ptr, "No IDAT data (internal error)");
 
-   if ((png_ptr->flags & PNG_FLAG_ZLIB_FINISHED) && buffer_length)
-      png_error(png_ptr, "Extra compression data");
-
+   /* This routine must process all the data it has been given
+    * before returning, calling the row callback as required to
+    * handle the uncompressed results.
+    */
    png_ptr->zstream.next_in = buffer;
    png_ptr->zstream.avail_in = (uInt)buffer_length;
-   for(;;)
+
+   /* Keep going until the decompressed data is all processed
+    * or the stream marked as finished.
+    */
+   while (png_ptr->zstream.avail_in > 0 &&
+          !(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
    {
-      ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
-      if (ret != Z_OK)
-      {
-         if (ret == Z_STREAM_END)
-         {
-            if (png_ptr->zstream.avail_in)
-               png_error(png_ptr, "Extra compressed data");
-            if (!(png_ptr->zstream.avail_out))
-            {
-               png_push_process_row(png_ptr);
-            }
+      int ret;
 
-            png_ptr->mode |= PNG_AFTER_IDAT;
-            png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
-            break;
-         }
-         else if (ret == Z_BUF_ERROR)
-            break;
-         else
-            png_error(png_ptr, "Decompression Error");
-      }
-      if (!(png_ptr->zstream.avail_out))
+      /* We have data for zlib, but we must check that zlib
+       * has someplace to put the results.  It doesn't matter
+       * if we don't expect any results -- it may be the input
+       * data is just the LZ end code.
+       */
+      if (!(png_ptr->zstream.avail_out > 0))
       {
-         if ((
-#if defined(PNG_READ_INTERLACING_SUPPORTED)
-             png_ptr->interlaced && png_ptr->pass > 6) ||
-             (!png_ptr->interlaced &&
-#endif
-             png_ptr->row_number == png_ptr->num_rows))
-         {
-           if (png_ptr->zstream.avail_in)
-             png_warning(png_ptr, "Too much data in IDAT chunks");
-           png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
-           break;
-         }
-         png_push_process_row(png_ptr);
-         png_ptr->zstream.avail_out = (uInt)png_ptr->irowbytes;
+         png_ptr->zstream.avail_out =
+             (uInt) PNG_ROWBYTES(png_ptr->pixel_depth,
+             png_ptr->iwidth) + 1;
+
          png_ptr->zstream.next_out = png_ptr->row_buf;
       }
-      else
-         break;
+
+      /* Using Z_SYNC_FLUSH here means that an unterminated
+       * LZ stream (a stream with a missing end code) can still
+       * be handled, otherwise (Z_NO_FLUSH) a future zlib
+       * implementation might defer output and therefore
+       * change the current behavior (see comments in inflate.c
+       * for why this doesn't happen at present with zlib 1.2.5).
+       */
+      ret = inflate(&png_ptr->zstream, Z_SYNC_FLUSH);
+
+      /* Check for any failure before proceeding. */
+      if (ret != Z_OK && ret != Z_STREAM_END)
+      {
+         /* Terminate the decompression. */
+         png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
+
+         /* This may be a truncated stream (missing or
+          * damaged end code).  Treat that as a warning.
+          */
+         if (png_ptr->row_number >= png_ptr->num_rows ||
+             png_ptr->pass > 6)
+            png_warning(png_ptr, "Truncated compressed data in IDAT");
+
+         else
+            png_error(png_ptr, "Decompression error in IDAT");
+
+         /* Skip the check on unprocessed input */
+         return;
+      }
+
+      /* Did inflate output any data? */
+      if (png_ptr->zstream.next_out != png_ptr->row_buf)
+      {
+         /* Is this unexpected data after the last row?
+          * If it is, artificially terminate the LZ output
+          * here.
+          */
+         if (png_ptr->row_number >= png_ptr->num_rows ||
+             png_ptr->pass > 6)
+         {
+            /* Extra data. */
+            png_warning(png_ptr, "Extra compressed data in IDAT");
+            png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
+
+            /* Do no more processing; skip the unprocessed
+             * input check below.
+             */
+            return;
+         }
+
+         /* Do we have a complete row? */
+         if (png_ptr->zstream.avail_out == 0)
+            png_push_process_row(png_ptr);
+      }
+
+      /* And check for the end of the stream. */
+      if (ret == Z_STREAM_END)
+         png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
    }
+
+   /* All the data should have been processed, if anything
+    * is left at this point we have bytes of IDAT data
+    * after the zlib end code.
+    */
+   if (png_ptr->zstream.avail_in > 0)
+      png_warning(png_ptr, "Extra compression data in IDAT");
 }
 
 void /* PRIVATE */
@@ -845,23 +1049,24 @@
        png_ptr->row_info.width);
 
    png_read_filter_row(png_ptr, &(png_ptr->row_info),
-      png_ptr->row_buf + 1, png_ptr->prev_row + 1,
-      (int)(png_ptr->row_buf[0]));
+       png_ptr->row_buf + 1, png_ptr->prev_row + 1,
+       (int)(png_ptr->row_buf[0]));
 
-   png_memcpy_check(png_ptr, png_ptr->prev_row, png_ptr->row_buf,
-      png_ptr->rowbytes + 1);
+   png_memcpy(png_ptr->prev_row, png_ptr->row_buf, png_ptr->rowbytes + 1);
 
-   if (png_ptr->transformations || (png_ptr->flags&PNG_FLAG_STRIP_ALPHA))
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+   if (png_ptr->transformations)
       png_do_read_transformations(png_ptr);
+#endif
 
-#if defined(PNG_READ_INTERLACING_SUPPORTED)
-   /* blow up interlaced rows to full size */
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+   /* Blow up interlaced rows to full size */
    if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
    {
       if (png_ptr->pass < 6)
 /*       old interface (pre-1.0.9):
          png_do_read_interlace(&(png_ptr->row_info),
-            png_ptr->row_buf + 1, png_ptr->pass, png_ptr->transformations);
+             png_ptr->row_buf + 1, png_ptr->pass, png_ptr->transformations);
  */
          png_do_read_interlace(png_ptr);
 
@@ -873,31 +1078,36 @@
             for (i = 0; i < 8 && png_ptr->pass == 0; i++)
             {
                png_push_have_row(png_ptr, png_ptr->row_buf + 1);
-               png_read_push_finish_row(png_ptr); /* updates png_ptr->pass */
+               png_read_push_finish_row(png_ptr); /* Updates png_ptr->pass */
             }
-            if (png_ptr->pass == 2) /* pass 1 might be empty */
+
+            if (png_ptr->pass == 2) /* Pass 1 might be empty */
             {
                for (i = 0; i < 4 && png_ptr->pass == 2; i++)
                {
-                  png_push_have_row(png_ptr, png_bytep_NULL);
+                  png_push_have_row(png_ptr, NULL);
                   png_read_push_finish_row(png_ptr);
                }
             }
+
             if (png_ptr->pass == 4 && png_ptr->height <= 4)
             {
                for (i = 0; i < 2 && png_ptr->pass == 4; i++)
                {
-                  png_push_have_row(png_ptr, png_bytep_NULL);
+                  png_push_have_row(png_ptr, NULL);
                   png_read_push_finish_row(png_ptr);
                }
             }
+
             if (png_ptr->pass == 6 && png_ptr->height <= 4)
             {
-                png_push_have_row(png_ptr, png_bytep_NULL);
+                png_push_have_row(png_ptr, NULL);
                 png_read_push_finish_row(png_ptr);
             }
+
             break;
          }
+
          case 1:
          {
             int i;
@@ -906,99 +1116,123 @@
                png_push_have_row(png_ptr, png_ptr->row_buf + 1);
                png_read_push_finish_row(png_ptr);
             }
-            if (png_ptr->pass == 2) /* skip top 4 generated rows */
+
+            if (png_ptr->pass == 2) /* Skip top 4 generated rows */
             {
                for (i = 0; i < 4 && png_ptr->pass == 2; i++)
                {
-                  png_push_have_row(png_ptr, png_bytep_NULL);
+                  png_push_have_row(png_ptr, NULL);
                   png_read_push_finish_row(png_ptr);
                }
             }
+
             break;
          }
+
          case 2:
          {
             int i;
+
             for (i = 0; i < 4 && png_ptr->pass == 2; i++)
             {
                png_push_have_row(png_ptr, png_ptr->row_buf + 1);
                png_read_push_finish_row(png_ptr);
             }
+
             for (i = 0; i < 4 && png_ptr->pass == 2; i++)
             {
-               png_push_have_row(png_ptr, png_bytep_NULL);
+               png_push_have_row(png_ptr, NULL);
                png_read_push_finish_row(png_ptr);
             }
-            if (png_ptr->pass == 4) /* pass 3 might be empty */
+
+            if (png_ptr->pass == 4) /* Pass 3 might be empty */
             {
                for (i = 0; i < 2 && png_ptr->pass == 4; i++)
                {
-                  png_push_have_row(png_ptr, png_bytep_NULL);
+                  png_push_have_row(png_ptr, NULL);
                   png_read_push_finish_row(png_ptr);
                }
             }
+
             break;
          }
+
          case 3:
          {
             int i;
+
             for (i = 0; i < 4 && png_ptr->pass == 3; i++)
             {
                png_push_have_row(png_ptr, png_ptr->row_buf + 1);
                png_read_push_finish_row(png_ptr);
             }
-            if (png_ptr->pass == 4) /* skip top two generated rows */
+
+            if (png_ptr->pass == 4) /* Skip top two generated rows */
             {
                for (i = 0; i < 2 && png_ptr->pass == 4; i++)
                {
-                  png_push_have_row(png_ptr, png_bytep_NULL);
+                  png_push_have_row(png_ptr, NULL);
                   png_read_push_finish_row(png_ptr);
                }
             }
+
             break;
          }
+
          case 4:
          {
             int i;
+
             for (i = 0; i < 2 && png_ptr->pass == 4; i++)
             {
                png_push_have_row(png_ptr, png_ptr->row_buf + 1);
                png_read_push_finish_row(png_ptr);
             }
+
             for (i = 0; i < 2 && png_ptr->pass == 4; i++)
             {
-               png_push_have_row(png_ptr, png_bytep_NULL);
+               png_push_have_row(png_ptr, NULL);
                png_read_push_finish_row(png_ptr);
             }
-            if (png_ptr->pass == 6) /* pass 5 might be empty */
+
+            if (png_ptr->pass == 6) /* Pass 5 might be empty */
             {
-               png_push_have_row(png_ptr, png_bytep_NULL);
+               png_push_have_row(png_ptr, NULL);
                png_read_push_finish_row(png_ptr);
             }
+
             break;
          }
+
          case 5:
          {
             int i;
+
             for (i = 0; i < 2 && png_ptr->pass == 5; i++)
             {
                png_push_have_row(png_ptr, png_ptr->row_buf + 1);
                png_read_push_finish_row(png_ptr);
             }
-            if (png_ptr->pass == 6) /* skip top generated row */
+
+            if (png_ptr->pass == 6) /* Skip top generated row */
             {
-               png_push_have_row(png_ptr, png_bytep_NULL);
+               png_push_have_row(png_ptr, NULL);
                png_read_push_finish_row(png_ptr);
             }
+
             break;
          }
+
+         default:
          case 6:
          {
             png_push_have_row(png_ptr, png_ptr->row_buf + 1);
             png_read_push_finish_row(png_ptr);
+
             if (png_ptr->pass != 6)
                break;
-            png_push_have_row(png_ptr, png_bytep_NULL);
+
+            png_push_have_row(png_ptr, NULL);
             png_read_push_finish_row(png_ptr);
          }
       }
@@ -1014,84 +1248,77 @@
 void /* PRIVATE */
 png_read_push_finish_row(png_structp png_ptr)
 {
-#ifdef PNG_USE_LOCAL_ARRAYS
-   /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
 
-   /* start of interlace block */
-   const int FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
-
-   /* offset to next interlace block */
-   const int FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
+   /* Start of interlace block */
+   PNG_CONST int FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
 
-   /* start of interlace block in the y direction */
-   const int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
+   /* Offset to next interlace block */
+   PNG_CONST int FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
 
-   /* offset to next interlace block in the y direction */
-   const int FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
+   /* Start of interlace block in the y direction */
+   PNG_CONST int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
 
-   /* Width of interlace block.  This is not currently used - if you need
-    * it, uncomment it here and in png.h
-   const int FARDATA png_pass_width[] = {8, 4, 4, 2, 2, 1, 1};
-   */
+   /* Offset to next interlace block in the y direction */
+   PNG_CONST int FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
 
    /* Height of interlace block.  This is not currently used - if you need
     * it, uncomment it here and in png.h
-   const int FARDATA png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
+   PNG_CONST int FARDATA png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
    */
-#endif
 
    png_ptr->row_number++;
    if (png_ptr->row_number < png_ptr->num_rows)
       return;
 
+#ifdef PNG_READ_INTERLACING_SUPPORTED
    if (png_ptr->interlaced)
    {
       png_ptr->row_number = 0;
-      png_memset_check(png_ptr, png_ptr->prev_row, 0,
-         png_ptr->rowbytes + 1);
+      png_memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
+
       do
       {
          png_ptr->pass++;
          if ((png_ptr->pass == 1 && png_ptr->width < 5) ||
              (png_ptr->pass == 3 && png_ptr->width < 3) ||
              (png_ptr->pass == 5 && png_ptr->width < 2))
-           png_ptr->pass++;
+            png_ptr->pass++;
 
          if (png_ptr->pass > 7)
             png_ptr->pass--;
+
          if (png_ptr->pass >= 7)
             break;
 
          png_ptr->iwidth = (png_ptr->width +
-            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;
+             png_pass_inc[png_ptr->pass] - 1 -
+             png_pass_start[png_ptr->pass]) /
+             png_pass_inc[png_ptr->pass];
 
          if (png_ptr->transformations & PNG_INTERLACE)
             break;
 
          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];
+             png_pass_yinc[png_ptr->pass] - 1 -
+             png_pass_ystart[png_ptr->pass]) /
+             png_pass_yinc[png_ptr->pass];
 
       } while (png_ptr->iwidth == 0 || png_ptr->num_rows == 0);
    }
+#endif /* PNG_READ_INTERLACING_SUPPORTED */
 }
 
-#if defined(PNG_READ_tEXt_SUPPORTED)
+#ifdef PNG_READ_tEXt_SUPPORTED
 void /* PRIVATE */
 png_push_handle_tEXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
-   length)
+    length)
 {
    if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
       {
+         PNG_UNUSED(info_ptr) /* To quiet some compiler warnings */
          png_error(png_ptr, "Out of place tEXt");
-         /* to quiet some compiler warnings */
-         if(info_ptr == NULL) return;
+         /* NOT REACHED */
       }
 
 #ifdef PNG_MAX_MALLOC_64K
@@ -1106,7 +1333,7 @@
 #endif
 
    png_ptr->current_text = (png_charp)png_malloc(png_ptr,
-         (png_uint_32)(length+1));
+       (png_size_t)(length + 1));
    png_ptr->current_text[length] = '\0';
    png_ptr->current_text_ptr = png_ptr->current_text;
    png_ptr->current_text_size = (png_size_t)length;
@@ -1123,8 +1350,10 @@
 
       if (png_ptr->buffer_size < png_ptr->current_text_left)
          text_size = png_ptr->buffer_size;
+
       else
          text_size = png_ptr->current_text_left;
+
       png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
       png_ptr->current_text_left -= text_size;
       png_ptr->current_text_ptr += text_size;
@@ -1144,7 +1373,7 @@
 
       png_push_crc_finish(png_ptr);
 
-#if defined(PNG_MAX_MALLOC_64K)
+#ifdef PNG_MAX_MALLOC_64K
       if (png_ptr->skip_length)
          return;
 #endif
@@ -1152,19 +1381,17 @@
       key = png_ptr->current_text;
 
       for (text = key; *text; text++)
-         /* empty loop */ ;
+         /* Empty loop */ ;
 
-      if (text != key + png_ptr->current_text_size)
+      if (text < key + png_ptr->current_text_size)
          text++;
 
-      text_ptr = (png_textp)png_malloc(png_ptr,
-         (png_uint_32)png_sizeof(png_text));
+      text_ptr = (png_textp)png_malloc(png_ptr, png_sizeof(png_text));
       text_ptr->compression = PNG_TEXT_COMPRESSION_NONE;
       text_ptr->key = key;
-#ifdef PNG_iTXt_SUPPORTED
+      text_ptr->itxt_length = 0;
       text_ptr->lang = NULL;
       text_ptr->lang_key = NULL;
-#endif
       text_ptr->text = text;
 
       ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
@@ -1174,22 +1401,22 @@
       png_ptr->current_text = NULL;
 
       if (ret)
-        png_warning(png_ptr, "Insufficient memory to store text chunk.");
+         png_warning(png_ptr, "Insufficient memory to store text chunk");
    }
 }
 #endif
 
-#if defined(PNG_READ_zTXt_SUPPORTED)
+#ifdef PNG_READ_zTXt_SUPPORTED
 void /* PRIVATE */
 png_push_handle_zTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
    length)
 {
    if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
-      {
-         png_error(png_ptr, "Out of place zTXt");
-         /* to quiet some compiler warnings */
-         if(info_ptr == NULL) return;
-      }
+   {
+      PNG_UNUSED(info_ptr) /* To quiet some compiler warnings */
+      png_error(png_ptr, "Out of place zTXt");
+      /* NOT REACHED */
+   }
 
 #ifdef PNG_MAX_MALLOC_64K
    /* We can't handle zTXt chunks > 64K, since we don't have enough space
@@ -1205,7 +1432,7 @@
 #endif
 
    png_ptr->current_text = (png_charp)png_malloc(png_ptr,
-       (png_uint_32)(length+1));
+       (png_size_t)(length + 1));
    png_ptr->current_text[length] = '\0';
    png_ptr->current_text_ptr = png_ptr->current_text;
    png_ptr->current_text_size = (png_size_t)length;
@@ -1222,8 +1449,10 @@
 
       if (png_ptr->buffer_size < (png_uint_32)png_ptr->current_text_left)
          text_size = png_ptr->buffer_size;
+
       else
          text_size = png_ptr->current_text_left;
+
       png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
       png_ptr->current_text_left -= text_size;
       png_ptr->current_text_ptr += text_size;
@@ -1247,10 +1476,10 @@
       key = png_ptr->current_text;
 
       for (text = key; *text; text++)
-         /* empty loop */ ;
+         /* Empty loop */ ;
 
       /* zTXt can't have zero text */
-      if (text == key + png_ptr->current_text_size)
+      if (text >= key + png_ptr->current_text_size)
       {
          png_ptr->current_text = NULL;
          png_free(png_ptr, key);
@@ -1259,7 +1488,7 @@
 
       text++;
 
-      if (*text != PNG_TEXT_COMPRESSION_zTXt) /* check compression byte */
+      if (*text != PNG_TEXT_COMPRESSION_zTXt) /* Check compression byte */
       {
          png_ptr->current_text = NULL;
          png_free(png_ptr, key);
@@ -1268,9 +1497,9 @@
 
       text++;
 
-      png_ptr->zstream.next_in = (png_bytep )text;
+      png_ptr->zstream.next_in = (png_bytep)text;
       png_ptr->zstream.avail_in = (uInt)(png_ptr->current_text_size -
-         (text - key));
+          (text - key));
       png_ptr->zstream.next_out = png_ptr->zbuf;
       png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
 
@@ -1291,35 +1520,45 @@
             png_free(png_ptr, text);
             return;
          }
+
          if (!(png_ptr->zstream.avail_out) || ret == Z_STREAM_END)
          {
             if (text == NULL)
             {
                text = (png_charp)png_malloc(png_ptr,
-                  (png_uint_32)(png_ptr->zbuf_size - png_ptr->zstream.avail_out
-                     + key_size + 1));
+                   (png_ptr->zbuf_size
+                   - png_ptr->zstream.avail_out + key_size + 1));
+
                png_memcpy(text + key_size, png_ptr->zbuf,
-                  png_ptr->zbuf_size - png_ptr->zstream.avail_out);
+                   png_ptr->zbuf_size - png_ptr->zstream.avail_out);
+
                png_memcpy(text, key, key_size);
+
                text_size = key_size + png_ptr->zbuf_size -
-                  png_ptr->zstream.avail_out;
+                   png_ptr->zstream.avail_out;
+
                *(text + text_size) = '\0';
             }
+
             else
             {
                png_charp tmp;
 
                tmp = text;
                text = (png_charp)png_malloc(png_ptr, text_size +
-                  (png_uint_32)(png_ptr->zbuf_size - png_ptr->zstream.avail_out
-                   + 1));
+                   (png_ptr->zbuf_size
+                   - png_ptr->zstream.avail_out + 1));
+
                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);
+                   png_ptr->zbuf_size - png_ptr->zstream.avail_out);
+
                text_size += png_ptr->zbuf_size - png_ptr->zstream.avail_out;
                *(text + text_size) = '\0';
             }
+
             if (ret != Z_STREAM_END)
             {
                png_ptr->zstream.next_out = png_ptr->zbuf;
@@ -1352,13 +1591,12 @@
       text += key_size;
 
       text_ptr = (png_textp)png_malloc(png_ptr,
-          (png_uint_32)png_sizeof(png_text));
+          png_sizeof(png_text));
       text_ptr->compression = PNG_TEXT_COMPRESSION_zTXt;
       text_ptr->key = key;
-#ifdef PNG_iTXt_SUPPORTED
+      text_ptr->itxt_length = 0;
       text_ptr->lang = NULL;
       text_ptr->lang_key = NULL;
-#endif
       text_ptr->text = text;
 
       ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
@@ -1367,22 +1605,22 @@
       png_free(png_ptr, text_ptr);
 
       if (ret)
-        png_warning(png_ptr, "Insufficient memory to store text chunk.");
+         png_warning(png_ptr, "Insufficient memory to store text chunk");
    }
 }
 #endif
 
-#if defined(PNG_READ_iTXt_SUPPORTED)
+#ifdef PNG_READ_iTXt_SUPPORTED
 void /* PRIVATE */
 png_push_handle_iTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
-   length)
+    length)
 {
    if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
-      {
-         png_error(png_ptr, "Out of place iTXt");
-         /* to quiet some compiler warnings */
-         if(info_ptr == NULL) return;
-      }
+   {
+      PNG_UNUSED(info_ptr) /* To quiet some compiler warnings */
+      png_error(png_ptr, "Out of place iTXt");
+      /* NOT REACHED */
+   }
 
 #ifdef PNG_MAX_MALLOC_64K
    png_ptr->skip_length = 0;  /* This may not be necessary */
@@ -1396,7 +1634,7 @@
 #endif
 
    png_ptr->current_text = (png_charp)png_malloc(png_ptr,
-         (png_uint_32)(length+1));
+       (png_size_t)(length + 1));
    png_ptr->current_text[length] = '\0';
    png_ptr->current_text_ptr = png_ptr->current_text;
    png_ptr->current_text_size = (png_size_t)length;
@@ -1414,12 +1652,15 @@
 
       if (png_ptr->buffer_size < png_ptr->current_text_left)
          text_size = png_ptr->buffer_size;
+
       else
          text_size = png_ptr->current_text_left;
+
       png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
       png_ptr->current_text_left -= text_size;
       png_ptr->current_text_ptr += text_size;
    }
+
    if (!(png_ptr->current_text_left))
    {
       png_textp text_ptr;
@@ -1438,7 +1679,7 @@
 
       png_push_crc_finish(png_ptr);
 
-#if defined(PNG_MAX_MALLOC_64K)
+#ifdef PNG_MAX_MALLOC_64K
       if (png_ptr->skip_length)
          return;
 #endif
@@ -1446,26 +1687,33 @@
       key = png_ptr->current_text;
 
       for (lang = key; *lang; lang++)
-         /* empty loop */ ;
+         /* Empty loop */ ;
 
-      if (lang != key + png_ptr->current_text_size)
+      if (lang < key + png_ptr->current_text_size - 3)
          lang++;
 
       comp_flag = *lang++;
-      lang++;     /* skip comp_type, always zero */
+      lang++;     /* Skip comp_type, always zero */
 
       for (lang_key = lang; *lang_key; lang_key++)
-         /* empty loop */ ;
-      lang_key++;        /* skip NUL separator */
+         /* Empty loop */ ;
+
+      lang_key++;        /* Skip NUL separator */
+
+      text=lang_key;
 
-      for (text = lang_key; *text; text++)
-         /* empty loop */ ;
+      if (lang_key < key + png_ptr->current_text_size - 1)
+      {
+         for (; *text; text++)
+            /* Empty loop */ ;
+      }
 
-      if (text != key + png_ptr->current_text_size)
+      if (text < key + png_ptr->current_text_size)
          text++;
 
       text_ptr = (png_textp)png_malloc(png_ptr,
-         (png_uint_32)png_sizeof(png_text));
+          png_sizeof(png_text));
+
       text_ptr->compression = comp_flag + 2;
       text_ptr->key = key;
       text_ptr->lang = lang;
@@ -1480,7 +1728,7 @@
 
       png_free(png_ptr, text_ptr);
       if (ret)
-        png_warning(png_ptr, "Insufficient memory to store iTXt chunk.");
+         png_warning(png_ptr, "Insufficient memory to store iTXt chunk");
    }
 }
 #endif
@@ -1491,69 +1739,83 @@
  */
 void /* PRIVATE */
 png_push_handle_unknown(png_structp png_ptr, png_infop info_ptr, png_uint_32
-   length)
+    length)
 {
-   png_uint_32 skip=0;
-   png_check_chunk_name(png_ptr, png_ptr->chunk_name);
+   png_uint_32 skip = 0;
 
    if (!(png_ptr->chunk_name[0] & 0x20))
    {
-#if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
-      if(png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
-           PNG_HANDLE_CHUNK_ALWAYS
-#if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
-           && png_ptr->read_user_chunk_fn == NULL
+#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
+      if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
+          PNG_HANDLE_CHUNK_ALWAYS
+#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
+          && png_ptr->read_user_chunk_fn == NULL
 #endif
-         )
+          )
 #endif
          png_chunk_error(png_ptr, "unknown critical chunk");
 
-      /* to quiet compiler warnings about unused info_ptr */
-      if (info_ptr == NULL)
-         return;
+      PNG_UNUSED(info_ptr) /* To quiet some compiler warnings */
    }
 
-#if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
+#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
    if (png_ptr->flags & PNG_FLAG_KEEP_UNKNOWN_CHUNKS)
    {
 #ifdef PNG_MAX_MALLOC_64K
-       if (length > (png_uint_32)65535L)
-       {
-           png_warning(png_ptr, "unknown chunk too large to fit in memory");
-           skip = length - (png_uint_32)65535L;
-           length = (png_uint_32)65535L;
-       }
+      if (length > (png_uint_32)65535L)
+      {
+         png_warning(png_ptr, "unknown chunk too large to fit in memory");
+         skip = length - (png_uint_32)65535L;
+         length = (png_uint_32)65535L;
+      }
 #endif
-       png_strcpy((png_charp)png_ptr->unknown_chunk.name,
-         (png_charp)png_ptr->chunk_name);
-       png_ptr->unknown_chunk.data = (png_bytep)png_malloc(png_ptr, length);
-       png_ptr->unknown_chunk.size = (png_size_t)length;
-       png_crc_read(png_ptr, (png_bytep)png_ptr->unknown_chunk.data, length);
-#if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
-       if(png_ptr->read_user_chunk_fn != NULL)
-       {
-          /* callback to user unknown chunk handler */
-          int ret;
-          ret = (*(png_ptr->read_user_chunk_fn))
-            (png_ptr, &png_ptr->unknown_chunk);
-          if (ret < 0)
-             png_chunk_error(png_ptr, "error in user chunk");
-          if (ret == 0)
-          {
-             if (!(png_ptr->chunk_name[0] & 0x20))
-                if(png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
-                     PNG_HANDLE_CHUNK_ALWAYS)
-                   png_chunk_error(png_ptr, "unknown critical chunk");
-                png_set_unknown_chunks(png_ptr, info_ptr,
-                   &png_ptr->unknown_chunk, 1);
-          }
-       }
-#else
-       png_set_unknown_chunks(png_ptr, info_ptr, &png_ptr->unknown_chunk, 1);
+      png_memcpy((png_charp)png_ptr->unknown_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.size = (png_size_t)length;
+
+      if (length == 0)
+         png_ptr->unknown_chunk.data = NULL;
+
+      else
+      {
+         png_ptr->unknown_chunk.data = (png_bytep)png_malloc(png_ptr,
+             (png_size_t)length);
+         png_crc_read(png_ptr, (png_bytep)png_ptr->unknown_chunk.data, length);
+      }
+
+#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
+      if (png_ptr->read_user_chunk_fn != NULL)
+      {
+         /* Callback to user unknown chunk handler */
+         int ret;
+         ret = (*(png_ptr->read_user_chunk_fn))
+             (png_ptr, &png_ptr->unknown_chunk);
+
+         if (ret < 0)
+            png_chunk_error(png_ptr, "error in user chunk");
+
+         if (ret == 0)
+         {
+            if (!(png_ptr->chunk_name[0] & 0x20))
+               if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
+                   PNG_HANDLE_CHUNK_ALWAYS)
+                  png_chunk_error(png_ptr, "unknown critical chunk");
+            png_set_unknown_chunks(png_ptr, info_ptr,
+                &png_ptr->unknown_chunk, 1);
+         }
+      }
+
+      else
 #endif
-       png_free(png_ptr, png_ptr->unknown_chunk.data);
-       png_ptr->unknown_chunk.data = NULL;
+         png_set_unknown_chunks(png_ptr, info_ptr, &png_ptr->unknown_chunk, 1);
+      png_free(png_ptr, png_ptr->unknown_chunk.data);
+      png_ptr->unknown_chunk.data = NULL;
    }
+
    else
 #endif
       skip=length;
@@ -1583,24 +1845,27 @@
 }
 
 void PNGAPI
-png_progressive_combine_row (png_structp png_ptr,
-   png_bytep old_row, png_bytep new_row)
+png_progressive_combine_row (png_structp png_ptr, png_bytep old_row,
+    png_const_bytep new_row)
 {
-#ifdef PNG_USE_LOCAL_ARRAYS
-   const int FARDATA png_pass_dsp_mask[7] =
+   PNG_CONST int FARDATA png_pass_dsp_mask[7] =
       {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
-#endif
-   if(png_ptr == NULL) return;
+
+   if (png_ptr == NULL)
+      return;
+
    if (new_row != NULL)    /* new_row must == png_ptr->row_buf here. */
       png_combine_row(png_ptr, old_row, png_pass_dsp_mask[png_ptr->pass]);
 }
 
 void PNGAPI
 png_set_progressive_read_fn(png_structp png_ptr, png_voidp progressive_ptr,
-   png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn,
-   png_progressive_end_ptr end_fn)
+    png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn,
+    png_progressive_end_ptr end_fn)
 {
-   if(png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
+
    png_ptr->info_fn = info_fn;
    png_ptr->row_fn = row_fn;
    png_ptr->end_fn = end_fn;
@@ -1609,9 +1874,11 @@
 }
 
 png_voidp PNGAPI
-png_get_progressive_ptr(png_structp png_ptr)
+png_get_progressive_ptr(png_const_structp png_ptr)
 {
-   if(png_ptr == NULL) return (NULL);
+   if (png_ptr == NULL)
+      return (NULL);
+
    return png_ptr->io_ptr;
 }
 #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */