X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/c801d85f158c4cba50b588807daabdcbd0ed3853..abd474ea63667f727940a009cc3e0b23ba9f418f:/src/png/pngpread.c

diff --git a/src/png/pngpread.c b/src/png/pngpread.c
index 0f0d466fa2..e33b4286fa 100644
--- a/src/png/pngpread.c
+++ b/src/png/pngpread.c
@@ -1,23 +1,39 @@
 
 /* pngpread.c - read a png file in push mode
  *
- * libpng 1.0.1
- * For conditions of distribution and use, see copyright notice in png.h
- * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
- * Copyright (c) 1996, 1997 Andreas Dilger
- * Copyright (c) 1998, Glenn Randers-Pehrson
- * March 15, 1998
+ * Last changed in libpng 1.4.3 [June 26, 2010]
+ * Copyright (c) 1998-2010 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
+#define PNG_NO_PEDANTIC_WARNINGS
 #include "png.h"
-
 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
-
-void
+#include "pngpriv.h"
+
+/* Push model modes */
+#define PNG_READ_SIG_MODE   0
+#define PNG_READ_CHUNK_MODE 1
+#define PNG_READ_IDAT_MODE  2
+#define PNG_SKIP_MODE       3
+#define PNG_READ_tEXt_MODE  4
+#define PNG_READ_zTXt_MODE  5
+#define PNG_READ_DONE_MODE  6
+#define PNG_READ_iTXt_MODE  7
+#define PNG_ERROR_MODE      8
+
+void PNGAPI
 png_process_data(png_structp png_ptr, png_infop info_ptr,
    png_bytep buffer, png_size_t buffer_size)
 {
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
    png_push_restore_buffer(png_ptr, buffer, buffer_size);
 
    while (png_ptr->buffer_size)
@@ -29,9 +45,12 @@ png_process_data(png_structp png_ptr, png_infop info_ptr,
 /* What we do with the incoming data depends on what we were previously
  * doing before we ran out of data...
  */
-void
+void /* PRIVATE */
 png_process_some_data(png_structp png_ptr, png_infop info_ptr)
 {
+   if (png_ptr == NULL)
+      return;
+
    switch (png_ptr->process_mode)
    {
       case PNG_READ_SIG_MODE:
@@ -39,35 +58,49 @@ png_process_some_data(png_structp png_ptr, png_infop info_ptr)
          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
+#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;
@@ -78,10 +111,11 @@ png_process_some_data(png_structp png_ptr, png_infop info_ptr)
 
 /* Read any remaining signature bytes from the stream and compare them with
  * the correct PNG signature.  It is possible that this routine is called
- * with bytes already read from the signature, whether because they have been
- * checked by the calling application, or from multiple calls to this routine.
+ * with bytes already read from the signature, either because they have been
+ * checked by the calling application, or because of multiple calls to this
+ * routine.
  */
-void
+void /* PRIVATE */
 png_push_read_sig(png_structp png_ptr, png_infop info_ptr)
 {
    png_size_t num_checked = png_ptr->sig_bytes,
@@ -92,9 +126,9 @@ png_push_read_sig(png_structp png_ptr, png_infop info_ptr)
       num_to_check = png_ptr->buffer_size;
    }
 
-   png_push_fill_buffer(png_ptr, &(info_ptr->signature[num_checked]), 
+   png_push_fill_buffer(png_ptr, &(info_ptr->signature[num_checked]),
       num_to_check);
-   png_ptr->sig_bytes += 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))
    {
@@ -113,16 +147,72 @@ png_push_read_sig(png_structp png_ptr, png_infop info_ptr)
    }
 }
 
-void
+void /* PRIVATE */
 png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
 {
+      PNG_IHDR;
+      PNG_IDAT;
+      PNG_IEND;
+      PNG_PLTE;
+#ifdef PNG_READ_bKGD_SUPPORTED
+      PNG_bKGD;
+#endif
+#ifdef PNG_READ_cHRM_SUPPORTED
+      PNG_cHRM;
+#endif
+#ifdef PNG_READ_gAMA_SUPPORTED
+      PNG_gAMA;
+#endif
+#ifdef PNG_READ_hIST_SUPPORTED
+      PNG_hIST;
+#endif
+#ifdef PNG_READ_iCCP_SUPPORTED
+      PNG_iCCP;
+#endif
+#ifdef PNG_READ_iTXt_SUPPORTED
+      PNG_iTXt;
+#endif
+#ifdef PNG_READ_oFFs_SUPPORTED
+      PNG_oFFs;
+#endif
+#ifdef PNG_READ_pCAL_SUPPORTED
+      PNG_pCAL;
+#endif
+#ifdef PNG_READ_pHYs_SUPPORTED
+      PNG_pHYs;
+#endif
+#ifdef PNG_READ_sBIT_SUPPORTED
+      PNG_sBIT;
+#endif
+#ifdef PNG_READ_sCAL_SUPPORTED
+      PNG_sCAL;
+#endif
+#ifdef PNG_READ_sRGB_SUPPORTED
+      PNG_sRGB;
+#endif
+#ifdef PNG_READ_sPLT_SUPPORTED
+      PNG_sPLT;
+#endif
+#ifdef PNG_READ_tEXt_SUPPORTED
+      PNG_tEXt;
+#endif
+#ifdef PNG_READ_tIME_SUPPORTED
+      PNG_tIME;
+#endif
+#ifdef PNG_READ_tRNS_SUPPORTED
+      PNG_tRNS;
+#endif
+#ifdef PNG_READ_zTXt_SUPPORTED
+      PNG_zTXt;
+#endif
+
    /* 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
     * sure we have enough data in the buffer for the 4 byte CRC at the
     * end of every chunk (except IDAT, which is handled separately).
     */
-   if (!(png_ptr->flags & PNG_FLAG_HAVE_CHUNK_HEADER))
+   if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
    {
       png_byte chunk_length[4];
 
@@ -133,14 +223,22 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
       }
 
       png_push_fill_buffer(png_ptr, chunk_length, 4);
-      png_ptr->push_length = png_get_uint_32(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->flags |= PNG_FLAG_HAVE_CHUNK_HEADER;
+      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_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);
@@ -149,7 +247,23 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
 
       png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length);
    }
-   else if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
+
+   else if (!png_memcmp(png_ptr->chunk_name, png_IEND, 4))
+   {
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         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))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
       {
@@ -157,44 +271,72 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_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_error(png_ptr, "Missing PLTE before IDAT");
+      }
+   }
+
+#endif
+   else if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
+   {
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
       png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length);
    }
+
    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_IDAT)
       {
-         if (png_ptr->push_length == 0)
-            return;
+         if (!(png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
+            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;
    }
-   else if (!png_memcmp(png_ptr->chunk_name, png_IEND, 4))
-   {
-      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
-      {
-         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);
-   }
-#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)
@@ -205,8 +347,9 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
 
       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)
@@ -217,8 +360,9 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
 
       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)
@@ -229,8 +373,9 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
 
       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)
@@ -241,8 +386,35 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
 
       png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length);
    }
+
+#endif
+#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)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
+      png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
 #endif
-#if defined(PNG_READ_tRNS_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)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
+      png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+#endif
+#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)
@@ -253,8 +425,9 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
 
       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)
@@ -265,8 +438,9 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
 
       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)
@@ -277,8 +451,9 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
 
       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)
@@ -289,8 +464,9 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
 
       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)
@@ -302,7 +478,8 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
       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)
@@ -313,8 +490,22 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
 
       png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length);
    }
+
+#endif
+#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)
+      {
+         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)
@@ -325,35 +516,68 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
 
       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)
+      {
+         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)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
       png_push_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length);
    }
+
+#endif
+#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)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
+      png_push_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
 #endif
    else
    {
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
       png_push_handle_unknown(png_ptr, info_ptr, png_ptr->push_length);
    }
 
-   png_ptr->flags &= ~PNG_FLAG_HAVE_CHUNK_HEADER;
+   png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
 }
 
-void
+void /* PRIVATE */
 png_push_crc_skip(png_structp png_ptr, png_uint_32 skip)
 {
    png_ptr->process_mode = PNG_SKIP_MODE;
    png_ptr->skip_length = skip;
 }
 
-void
+void /* PRIVATE */
 png_push_crc_finish(png_structp png_ptr)
 {
    if (png_ptr->skip_length && png_ptr->save_buffer_size)
@@ -401,11 +625,14 @@ png_push_crc_finish(png_structp png_ptr)
    }
 }
 
-void
+void PNGAPI
 png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
 {
    png_bytep ptr;
 
+   if (png_ptr == NULL)
+      return;
+
    ptr = buffer;
    if (png_ptr->save_buffer_size)
    {
@@ -429,6 +656,7 @@ png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
 
       if (length < png_ptr->current_buffer_size)
          save_size = length;
+
       else
          save_size = png_ptr->current_buffer_size;
 
@@ -439,20 +667,20 @@ png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
    }
 }
 
-void
+void /* PRIVATE */
 png_push_save_buffer(png_structp png_ptr)
 {
    if (png_ptr->save_buffer_size)
    {
       if (png_ptr->save_buffer_ptr != png_ptr->save_buffer)
       {
-         png_size_t i;
+         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 < png_ptr->save_buffer_size;
-            i++, sp++, dp++)
+            i < istop; i++, sp++, dp++)
          {
             *dp = *sp;
          }
@@ -464,10 +692,21 @@ png_push_save_buffer(png_structp png_ptr)
       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_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;
@@ -483,7 +722,7 @@ png_push_save_buffer(png_structp png_ptr)
    png_ptr->buffer_size = 0;
 }
 
-void
+void /* PRIVATE */
 png_push_restore_buffer(png_structp png_ptr, png_bytep buffer,
    png_size_t buffer_length)
 {
@@ -493,10 +732,11 @@ png_push_restore_buffer(png_structp png_ptr, png_bytep buffer,
    png_ptr->current_buffer_ptr = png_ptr->current_buffer;
 }
 
-void
+void /* PRIVATE */
 png_push_read_IDAT(png_structp png_ptr)
 {
-   if (!(png_ptr->flags & PNG_FLAG_HAVE_CHUNK_HEADER))
+   PNG_IDAT;
+   if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
    {
       png_byte chunk_length[4];
 
@@ -507,11 +747,10 @@ png_push_read_IDAT(png_structp png_ptr)
       }
 
       png_push_fill_buffer(png_ptr, chunk_length, 4);
-      png_ptr->push_length = png_get_uint_32(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->flags |= PNG_FLAG_HAVE_CHUNK_HEADER;
+      png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
 
       if (png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
       {
@@ -530,14 +769,16 @@ png_push_read_IDAT(png_structp png_ptr)
       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)
+
+         /* Check for overflow */
+         if ((png_uint_32)save_size != png_ptr->idat_size)
             png_error(png_ptr, "save_size overflowed in pngpread");
       }
       else
          save_size = png_ptr->save_buffer_size;
 
       png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
+
       png_process_IDAT_data(png_ptr, png_ptr->save_buffer_ptr, save_size);
 
       png_ptr->idat_size -= save_size;
@@ -552,14 +793,16 @@ png_push_read_IDAT(png_structp png_ptr)
       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)
+
+         /* Check for overflow */
+         if ((png_uint_32)save_size != png_ptr->idat_size)
             png_error(png_ptr, "save_size overflowed in pngpread");
       }
       else
          save_size = png_ptr->current_buffer_size;
 
       png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
+
       png_process_IDAT_data(png_ptr, png_ptr->current_buffer_ptr, save_size);
 
       png_ptr->idat_size -= save_size;
@@ -576,53 +819,113 @@ png_push_read_IDAT(png_structp png_ptr)
       }
 
       png_crc_finish(png_ptr, 0);
-      png_ptr->flags &= ~PNG_FLAG_HAVE_CHUNK_HEADER;
+      png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
+      png_ptr->mode |= PNG_AFTER_IDAT;
    }
 }
 
-void
+void /* PRIVATE */
 png_process_IDAT_data(png_structp png_ptr, png_bytep buffer,
    png_size_t buffer_length)
 {
-   int ret;
-
-   if ((png_ptr->flags & PNG_FLAG_ZLIB_FINISHED) && buffer_length)
-      png_error(png_ptr, "Extra compression data");
+   /* The caller checks for a non-zero buffer length. */
+   if (!(buffer_length > 0) || buffer == NULL)
+      png_error(png_ptr, "No IDAT data (internal error)");
 
+   /* 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_STREAM_END)
+      int ret;
+
+      /* We have data for zlib, but we must check that zlib
+       * has somewhere 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 (png_ptr->zstream.avail_in)
-            png_error(png_ptr, "Extra compressed data");
-         if (!(png_ptr->zstream.avail_out))
-         {
-            png_push_process_row(png_ptr);
-         }
+         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;
+      }
 
-         png_ptr->mode |= PNG_AFTER_IDAT;
+      /* Using Z_SYNC_FLUSH here means that an unterminated
+       * LZ stream can still be handled (a stream with a missing
+       * end code), 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;
-         break;
+
+         /* 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;
       }
-      else if (ret == Z_BUF_ERROR)
-         break;
-      else if (ret != Z_OK)
-         png_error(png_ptr, "Decompression Error");
-      if (!(png_ptr->zstream.avail_out))
+
+      /* Did inflate output any data? */
+      if (png_ptr->zstream.next_out != png_ptr->row_buf)
       {
-         png_push_process_row(png_ptr);
-         png_ptr->zstream.avail_out = (uInt)png_ptr->irowbytes;
-         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);
       }
-      else
-         break;
+
+      /* 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");
 }
 
-void
+void /* PRIVATE */
 png_push_process_row(png_structp png_ptr)
 {
    png_ptr->row_info.color_type = png_ptr->color_type;
@@ -630,40 +933,68 @@ png_push_process_row(png_structp png_ptr)
    png_ptr->row_info.channels = png_ptr->channels;
    png_ptr->row_info.bit_depth = png_ptr->bit_depth;
    png_ptr->row_info.pixel_depth = png_ptr->pixel_depth;
-   
-   png_ptr->row_info.rowbytes = ((png_ptr->row_info.width *
-      (png_uint_32)png_ptr->row_info.pixel_depth + 7) >> 3);
+
+   png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth,
+       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)
+   if (png_ptr->transformations || (png_ptr->flags&PNG_FLAG_STRIP_ALPHA))
       png_do_read_transformations(png_ptr);
 
-#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);
 
-      switch (png_ptr->pass)
-      {
+    switch (png_ptr->pass)
+    {
          case 0:
          {
             int i;
             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);
+               png_read_push_finish_row(png_ptr); /* Updates png_ptr->pass */
+            }
+
+            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, 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, NULL);
+                  png_read_push_finish_row(png_ptr);
+               }
             }
+
+            if (png_ptr->pass == 6 && png_ptr->height <= 4)
+            {
+                png_push_have_row(png_ptr, NULL);
+                png_read_push_finish_row(png_ptr);
+            }
+
             break;
          }
+
          case 1:
          {
             int i;
@@ -672,7 +1003,8 @@ png_push_process_row(png_structp png_ptr)
                png_push_have_row(png_ptr, png_ptr->row_buf + 1);
                png_read_push_finish_row(png_ptr);
             }
-            if (png_ptr->pass == 2)
+
+            if (png_ptr->pass == 2) /* Skip top 4 generated rows */
             {
                for (i = 0; i < 4 && png_ptr->pass == 2; i++)
                {
@@ -680,32 +1012,49 @@ png_push_process_row(png_structp png_ptr)
                   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, NULL);
                png_read_push_finish_row(png_ptr);
             }
+
+            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, 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)
+
+            if (png_ptr->pass == 4) /* Skip top two generated rows */
             {
                for (i = 0; i < 2 && png_ptr->pass == 4; i++)
                {
@@ -713,44 +1062,61 @@ png_push_process_row(png_structp png_ptr)
                   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, NULL);
                png_read_push_finish_row(png_ptr);
             }
+
+            if (png_ptr->pass == 6) /* Pass 5 might be empty */
+            {
+               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)
+
+            if (png_ptr->pass == 6) /* Skip top generated row */
             {
                png_push_have_row(png_ptr, NULL);
                png_read_push_finish_row(png_ptr);
             }
+
             break;
          }
          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, NULL);
             png_read_push_finish_row(png_ptr);
          }
@@ -764,61 +1130,85 @@ png_push_process_row(png_structp png_ptr)
    }
 }
 
-void
+void /* PRIVATE */
 png_read_push_finish_row(png_structp png_ptr)
 {
+   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+
+   /* Start of interlace block */
+   PNG_CONST int FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
+
+   /* Offset to next interlace block */
+   PNG_CONST int FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
+
+   /* Start of interlace block in the y direction */
+   PNG_CONST int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 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
+   PNG_CONST int FARDATA png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
+   */
+
    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_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++;
+
+         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_ptr->iwidth *
-            png_ptr->pixel_depth + 7) >> 3) + 1;
-
-         if (!(png_ptr->transformations & PNG_INTERLACE))
-         {
-            png_ptr->num_rows = (png_ptr->height +
-               png_pass_yinc[png_ptr->pass] - 1 -
-               png_pass_ystart[png_ptr->pass]) /
-               png_pass_yinc[png_ptr->pass];
-            if (!(png_ptr->num_rows))
-               continue;
-         }
          if (png_ptr->transformations & PNG_INTERLACE)
             break;
-      } while (png_ptr->iwidth == 0);
+
+         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];
+
+      } while (png_ptr->iwidth == 0 || png_ptr->num_rows == 0);
    }
+#endif /* PNG_READ_INTERLACING_SUPPORTED */
 }
 
-#if defined(PNG_READ_tEXt_SUPPORTED)
-void
-png_push_handle_tEXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+#ifdef PNG_READ_tEXt_SUPPORTED
+void /* PRIVATE */
+png_push_handle_tEXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
+   length)
 {
-   if (png_ptr->mode == PNG_BEFORE_IHDR || png_ptr->mode & PNG_HAVE_IEND)
+   if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
       {
          png_error(png_ptr, "Out of place tEXt");
-         /* to quiet some compiler warnings */
-         if(info_ptr == NULL) return;
+         info_ptr = info_ptr; /* To quiet some compiler warnings */
       }
 
 #ifdef PNG_MAX_MALLOC_64K
    png_ptr->skip_length = 0;  /* This may not be necessary */
 
-   if (length > (png_uint_32)65535L) /* Can't hold the entire string in memory */
+   if (length > (png_uint_32)65535L) /* Can't hold entire string in memory */
    {
       png_warning(png_ptr, "tEXt chunk too large to fit in memory");
       png_ptr->skip_length = length - (png_uint_32)65535L;
@@ -826,8 +1216,8 @@ png_push_handle_tEXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length
    }
 #endif
 
-   png_ptr->current_text = (png_charp)png_malloc(png_ptr, 
-         (png_uint_32)(length+1));
+   png_ptr->current_text = (png_charp)png_malloc(png_ptr,
+      (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;
@@ -835,7 +1225,7 @@ png_push_handle_tEXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length
    png_ptr->process_mode = PNG_READ_tEXt_MODE;
 }
 
-void
+void /* PRIVATE */
 png_push_read_tEXt(png_structp png_ptr, png_infop info_ptr)
 {
    if (png_ptr->buffer_size && png_ptr->current_text_left)
@@ -844,8 +1234,10 @@ png_push_read_tEXt(png_structp png_ptr, png_infop info_ptr)
 
       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;
@@ -855,6 +1247,7 @@ png_push_read_tEXt(png_structp png_ptr, png_infop info_ptr)
       png_textp text_ptr;
       png_charp text;
       png_charp key;
+      int ret;
 
       if (png_ptr->buffer_size < 4)
       {
@@ -864,41 +1257,50 @@ png_push_read_tEXt(png_structp png_ptr, png_infop info_ptr)
 
       png_push_crc_finish(png_ptr);
 
-#if defined(PNG_MAX_MALLOC_64K)
+#ifdef PNG_MAX_MALLOC_64K
       if (png_ptr->skip_length)
          return;
 #endif
 
       key = png_ptr->current_text;
-      png_ptr->current_text = 0;
 
       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)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->lang = NULL;
+      text_ptr->lang_key = NULL;
+#endif
       text_ptr->text = text;
 
-      png_set_text(png_ptr, info_ptr, text_ptr, 1);
+      ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
 
+      png_free(png_ptr, key);
       png_free(png_ptr, text_ptr);
+      png_ptr->current_text = NULL;
+
+      if (ret)
+        png_warning(png_ptr, "Insufficient memory to store text chunk");
    }
 }
 #endif
 
-#if defined(PNG_READ_zTXt_SUPPORTED)
-void
-png_push_handle_zTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+#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_BEFORE_IHDR || png_ptr->mode & PNG_HAVE_IEND)
+   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;
+         info_ptr = info_ptr; /* To quiet some compiler warnings */
       }
 
 #ifdef PNG_MAX_MALLOC_64K
@@ -915,7 +1317,7 @@ png_push_handle_zTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length
 #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;
@@ -923,7 +1325,7 @@ png_push_handle_zTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length
    png_ptr->process_mode = PNG_READ_zTXt_MODE;
 }
 
-void
+void /* PRIVATE */
 png_push_read_zTXt(png_structp png_ptr, png_infop info_ptr)
 {
    if (png_ptr->buffer_size && png_ptr->current_text_left)
@@ -932,8 +1334,10 @@ png_push_read_zTXt(png_structp png_ptr, png_infop info_ptr)
 
       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;
@@ -955,22 +1359,23 @@ png_push_read_zTXt(png_structp png_ptr, png_infop info_ptr)
       png_push_crc_finish(png_ptr);
 
       key = png_ptr->current_text;
-      png_ptr->current_text = 0;
 
       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);
          return;
       }
 
       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);
          return;
       }
@@ -995,6 +1400,7 @@ png_push_read_zTXt(png_structp png_ptr, png_infop info_ptr)
          {
             inflateReset(&png_ptr->zstream);
             png_ptr->zstream.avail_in = 0;
+            png_ptr->current_text = NULL;
             png_free(png_ptr, key);
             png_free(png_ptr, text);
             return;
@@ -1004,13 +1410,17 @@ png_push_read_zTXt(png_structp png_ptr, png_infop info_ptr)
             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_memcpy(text, key, key_size);
+
                text_size = key_size + png_ptr->zbuf_size -
                   png_ptr->zstream.avail_out;
+
                *(text + text_size) = '\0';
             }
             else
@@ -1019,12 +1429,15 @@ png_push_read_zTXt(png_structp png_ptr, png_infop info_ptr)
 
                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);
+
                text_size += png_ptr->zbuf_size - png_ptr->zstream.avail_out;
                *(text + text_size) = '\0';
             }
@@ -1048,64 +1461,263 @@ png_push_read_zTXt(png_structp png_ptr, png_infop info_ptr)
 
       if (ret != Z_STREAM_END)
       {
+         png_ptr->current_text = NULL;
          png_free(png_ptr, key);
          png_free(png_ptr, text);
          return;
       }
 
+      png_ptr->current_text = NULL;
       png_free(png_ptr, key);
       key = text;
       text += key_size;
 
-      text_ptr = (png_textp)png_malloc(png_ptr, (png_uint_32)sizeof(png_text));
+      text_ptr = (png_textp)png_malloc(png_ptr,
+          png_sizeof(png_text));
       text_ptr->compression = PNG_TEXT_COMPRESSION_zTXt;
       text_ptr->key = key;
+#ifdef PNG_iTXt_SUPPORTED
+      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);
+
+      png_free(png_ptr, key);
+      png_free(png_ptr, text_ptr);
+
+      if (ret)
+        png_warning(png_ptr, "Insufficient memory to store text chunk");
+   }
+}
+#endif
+
+#ifdef PNG_READ_iTXt_SUPPORTED
+void /* PRIVATE */
+png_push_handle_iTXt(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 iTXt");
+         info_ptr = info_ptr; /* To quiet some compiler warnings */
+      }
+
+#ifdef PNG_MAX_MALLOC_64K
+   png_ptr->skip_length = 0;  /* This may not be necessary */
+
+   if (length > (png_uint_32)65535L) /* Can't hold entire string in memory */
+   {
+      png_warning(png_ptr, "iTXt chunk too large to fit in memory");
+      png_ptr->skip_length = length - (png_uint_32)65535L;
+      length = (png_uint_32)65535L;
+   }
+#endif
+
+   png_ptr->current_text = (png_charp)png_malloc(png_ptr,
+      (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;
+   png_ptr->current_text_left = (png_size_t)length;
+   png_ptr->process_mode = PNG_READ_iTXt_MODE;
+}
+
+void /* PRIVATE */
+png_push_read_iTXt(png_structp png_ptr, png_infop info_ptr)
+{
+
+   if (png_ptr->buffer_size && png_ptr->current_text_left)
+   {
+      png_size_t text_size;
+
+      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;
+      png_charp key;
+      int comp_flag;
+      png_charp lang;
+      png_charp lang_key;
+      png_charp text;
+      int ret;
+
+      if (png_ptr->buffer_size < 4)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
+      png_push_crc_finish(png_ptr);
+
+#ifdef PNG_MAX_MALLOC_64K
+      if (png_ptr->skip_length)
+         return;
+#endif
+
+      key = png_ptr->current_text;
+
+      for (lang = key; *lang; lang++)
+         /* Empty loop */ ;
+
+      if (lang < key + png_ptr->current_text_size - 3)
+         lang++;
+
+      comp_flag = *lang++;
+      lang++;     /* Skip comp_type, always zero */
+
+      for (lang_key = lang; *lang_key; lang_key++)
+         /* Empty loop */ ;
+
+      lang_key++;        /* Skip NUL separator */
+
+      text=lang_key;
+
+      if (lang_key < key + png_ptr->current_text_size - 1)
+      {
+        for (; *text; text++)
+           /* Empty loop */ ;
+      }
+
+      if (text < key + png_ptr->current_text_size)
+         text++;
+
+      text_ptr = (png_textp)png_malloc(png_ptr,
+         png_sizeof(png_text));
+
+      text_ptr->compression = comp_flag + 2;
+      text_ptr->key = key;
+      text_ptr->lang = lang;
+      text_ptr->lang_key = lang_key;
       text_ptr->text = text;
+      text_ptr->text_length = 0;
+      text_ptr->itxt_length = png_strlen(text);
+
+      ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
 
-      png_set_text(png_ptr, info_ptr, text_ptr, 1);
+      png_ptr->current_text = NULL;
 
       png_free(png_ptr, text_ptr);
+      if (ret)
+         png_warning(png_ptr, "Insufficient memory to store iTXt chunk");
    }
 }
 #endif
 
 /* This function is called when we haven't found a handler for this
- * chunk.  In the future we will have code here which can handle
- * user-defined callback functions for unknown chunks before they are
- * ignored or cause an error.  If there isn't a problem with the
- * chunk itself (ie a bad chunk name or a critical chunk), the chunk
- * is (currently) silently ignored.
+ * chunk.  If there isn't a problem with the chunk itself (ie a bad chunk
+ * name or a critical chunk), the chunk is (currently) silently ignored.
  */
-void
-png_push_handle_unknown(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+void /* PRIVATE */
+png_push_handle_unknown(png_structp png_ptr, png_infop info_ptr, png_uint_32
+   length)
 {
-   png_check_chunk_name(png_ptr, png_ptr->chunk_name);
+   png_uint_32 skip = 0;
 
    if (!(png_ptr->chunk_name[0] & 0x20))
    {
-      png_chunk_error(png_ptr, "unknown critical chunk");
-      /* to quiet some compiler warnings */
-      if(info_ptr == NULL) return;
+#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");
+
+      info_ptr = info_ptr; /* To quiet some compiler warnings */
    }
 
-   png_push_crc_skip(png_ptr, length);
+#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;
+      }
+#endif
+      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_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;
+   png_push_crc_skip(png_ptr, skip);
 }
 
-void
+void /* PRIVATE */
 png_push_have_info(png_structp png_ptr, png_infop info_ptr)
 {
    if (png_ptr->info_fn != NULL)
       (*(png_ptr->info_fn))(png_ptr, info_ptr);
 }
 
-void
+void /* PRIVATE */
 png_push_have_end(png_structp png_ptr, png_infop info_ptr)
 {
    if (png_ptr->end_fn != NULL)
       (*(png_ptr->end_fn))(png_ptr, info_ptr);
 }
 
-void
+void /* PRIVATE */
 png_push_have_row(png_structp png_ptr, png_bytep row)
 {
    if (png_ptr->row_fn != NULL)
@@ -1113,19 +1725,28 @@ png_push_have_row(png_structp png_ptr, png_bytep row)
          (int)png_ptr->pass);
 }
 
-void
+void PNGAPI
 png_progressive_combine_row (png_structp png_ptr,
    png_bytep old_row, png_bytep new_row)
 {
-   if (new_row != NULL)
+   PNG_CONST int FARDATA png_pass_dsp_mask[7] =
+      {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
+
+   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
+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)
 {
+   if (png_ptr == NULL)
+      return;
+
    png_ptr->info_fn = info_fn;
    png_ptr->row_fn = row_fn;
    png_ptr->end_fn = end_fn;
@@ -1133,11 +1754,12 @@ png_set_progressive_read_fn(png_structp png_ptr, png_voidp progressive_ptr,
    png_set_read_fn(png_ptr, progressive_ptr, png_push_fill_buffer);
 }
 
-png_voidp
+png_voidp PNGAPI
 png_get_progressive_ptr(png_structp png_ptr)
 {
+   if (png_ptr == NULL)
+      return (NULL);
+
    return png_ptr->io_ptr;
 }
-
 #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
-