X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/706b88074de0c288b81edac13094dd052b6cc078..0fdeaabe4d828c3700813c16899c2e44b8f0c549:/src/png/png.c?ds=sidebyside

diff --git a/src/png/png.c b/src/png/png.c
index a0332b9abc..f2e5888fa0 100644
--- a/src/png/png.c
+++ b/src/png/png.c
@@ -1,86 +1,27 @@
 
 /* png.c - location for general purpose libpng functions
  *
- * libpng version 1.2.7 - September 12, 2004
- * For conditions of distribution and use, see copyright notice in png.h
- * Copyright (c) 1998-2004 Glenn Randers-Pehrson
+ * Last changed in libpng 1.4.2 [May 6, 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_EXTERN
+#define PNG_NO_PEDANTIC_WARNINGS
 #include "png.h"
+#include "pngpriv.h"
 
 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef version_1_2_7 Your_png_h_is_not_version_1_2_7;
+typedef version_1_4_4 Your_png_h_is_not_version_1_4_4;
 
 /* Version information for C files.  This had better match the version
- * string defined in png.h.  */
-
-#ifdef PNG_USE_GLOBAL_ARRAYS
-/* png_libpng_ver was changed to a function in version 1.0.5c */
-const char png_libpng_ver[18] = PNG_LIBPNG_VER_STRING;
-
-/* png_sig was changed to a function in version 1.0.5c */
-/* Place to hold the signature string for a PNG file. */
-const png_byte FARDATA png_sig[8] = {137, 80, 78, 71, 13, 10, 26, 10};
-
-/* Invoke global declarations for constant strings for known chunk types */
-PNG_IHDR;
-PNG_IDAT;
-PNG_IEND;
-PNG_PLTE;
-PNG_bKGD;
-PNG_cHRM;
-PNG_gAMA;
-PNG_hIST;
-PNG_iCCP;
-PNG_iTXt;
-PNG_oFFs;
-PNG_pCAL;
-PNG_sCAL;
-PNG_pHYs;
-PNG_sBIT;
-PNG_sPLT;
-PNG_sRGB;
-PNG_tEXt;
-PNG_tIME;
-PNG_tRNS;
-PNG_zTXt;
-
-/* 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 in the y direction */
-const int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
-
-/* offset to next interlace block in the y direction */
-const int FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
-
-/* width of interlace block (used in assembler routines only) */
-#ifdef PNG_HAVE_ASSEMBLER_COMBINE_ROW
-const int FARDATA png_pass_width[] = {8, 4, 4, 2, 2, 1, 1};
-#endif
-
-/* 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};
-*/
-
-/* Mask to determine which pixels are valid in a pass */
-const int FARDATA png_pass_mask[] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};
-
-/* Mask to determine which pixels to overwrite while displaying */
-const int FARDATA png_pass_dsp_mask[]
-   = {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
-
-#endif
+ * string defined in png.h.
+ */
 
 /* Tells libpng that we have already handled the first "num_bytes" bytes
  * of the PNG file signature.  If the PNG data is embedded into another
@@ -88,12 +29,17 @@ const int FARDATA png_pass_dsp_mask[]
  * or write any of the magic bytes before it starts on the IHDR.
  */
 
+#ifdef PNG_READ_SUPPORTED
 void PNGAPI
 png_set_sig_bytes(png_structp png_ptr, int num_bytes)
 {
-   png_debug(1, "in png_set_sig_bytes\n");
+   png_debug(1, "in png_set_sig_bytes");
+
+   if (png_ptr == NULL)
+      return;
+
    if (num_bytes > 8)
-      png_error(png_ptr, "Too many bytes for PNG signature.");
+      png_error(png_ptr, "Too many bytes for PNG signature");
 
    png_ptr->sig_bytes = (png_byte)(num_bytes < 0 ? 0 : num_bytes);
 }
@@ -113,10 +59,10 @@ png_sig_cmp(png_bytep sig, png_size_t start, png_size_t num_to_check)
    if (num_to_check > 8)
       num_to_check = 8;
    else if (num_to_check < 1)
-      return (0);
+      return (-1);
 
    if (start > 7)
-      return (0);
+      return (-1);
 
    if (start + num_to_check > 8)
       num_to_check = 8 - start;
@@ -124,64 +70,36 @@ png_sig_cmp(png_bytep sig, png_size_t start, png_size_t num_to_check)
    return ((int)(png_memcmp(&sig[start], &png_signature[start], num_to_check)));
 }
 
-/* (Obsolete) function to check signature bytes.  It does not allow one
- * to check a partial signature.  This function might be removed in the
- * future - use png_sig_cmp().  Returns true (nonzero) if the file is a PNG.
- */
-int PNGAPI
-png_check_sig(png_bytep sig, int num)
-{
-  return ((int)!png_sig_cmp(sig, (png_size_t)0, (png_size_t)num));
-}
+#endif /* PNG_READ_SUPPORTED */
 
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
 /* Function to allocate memory for zlib and clear it to 0. */
-#ifdef PNG_1_0_X
-voidpf PNGAPI
-#else
-voidpf /* private */
-#endif
+voidpf /* PRIVATE */
 png_zalloc(voidpf png_ptr, uInt items, uInt size)
 {
    png_voidp ptr;
-   png_structp p=(png_struct*)png_ptr;
+   png_structp p=(png_structp)png_ptr;
    png_uint_32 save_flags=p->flags;
-   png_uint_32 num_bytes;
+   png_alloc_size_t num_bytes;
 
+   if (png_ptr == NULL)
+      return (NULL);
    if (items > PNG_UINT_32_MAX/size)
    {
-     png_warning (png_ptr, "Potential overflow in png_zalloc()");
+     png_warning (p, "Potential overflow in png_zalloc()");
      return (NULL);
    }
-   num_bytes = (png_uint_32)items * size;
+   num_bytes = (png_alloc_size_t)items * size;
 
    p->flags|=PNG_FLAG_MALLOC_NULL_MEM_OK;
    ptr = (png_voidp)png_malloc((png_structp)png_ptr, num_bytes);
    p->flags=save_flags;
 
-#if defined(PNG_1_0_X) && !defined(PNG_NO_ZALLOC_ZERO)
-   if (ptr == NULL)
-       return ((voidpf)ptr);
-
-   if (num_bytes > (png_uint_32)0x8000L)
-   {
-      png_memset(ptr, 0, (png_size_t)0x8000L);
-      png_memset((png_bytep)ptr + (png_size_t)0x8000L, 0,
-         (png_size_t)(num_bytes - (png_uint_32)0x8000L));
-   }
-   else
-   {
-      png_memset(ptr, 0, (png_size_t)num_bytes);
-   }
-#endif
    return ((voidpf)ptr);
 }
 
-/* function to free memory for zlib */
-#ifdef PNG_1_0_X
-void PNGAPI
-#else
-void /* private */
-#endif
+/* Function to free memory for zlib */
+void /* PRIVATE */
 png_zfree(voidpf png_ptr, voidpf ptr)
 {
    png_free((png_structp)png_ptr, (png_voidp)ptr);
@@ -233,8 +151,11 @@ png_create_info_struct(png_structp png_ptr)
 {
    png_infop info_ptr;
 
-   png_debug(1, "in png_create_info_struct\n");
-   if(png_ptr == NULL) return (NULL);
+   png_debug(1, "in png_create_info_struct");
+
+   if (png_ptr == NULL)
+      return (NULL);
+
 #ifdef PNG_USER_MEM_SUPPORTED
    info_ptr = (png_infop)png_create_struct_2(PNG_STRUCT_INFO,
       png_ptr->malloc_fn, png_ptr->mem_ptr);
@@ -257,7 +178,11 @@ png_destroy_info_struct(png_structp png_ptr, png_infopp info_ptr_ptr)
 {
    png_infop info_ptr = NULL;
 
-   png_debug(1, "in png_destroy_info_struct\n");
+   png_debug(1, "in png_destroy_info_struct");
+
+   if (png_ptr == NULL)
+      return;
+
    if (info_ptr_ptr != NULL)
       info_ptr = *info_ptr_ptr;
 
@@ -279,293 +204,245 @@ png_destroy_info_struct(png_structp png_ptr, png_infopp info_ptr_ptr)
  * and applications using it are urged to use png_create_info_struct()
  * instead.
  */
-#undef png_info_init
-void PNGAPI
-png_info_init(png_infop info_ptr)
-{
-   /* We only come here via pre-1.0.12-compiled applications */
-   png_info_init_3(&info_ptr, 0);
-}
 
 void PNGAPI
 png_info_init_3(png_infopp ptr_ptr, png_size_t png_info_struct_size)
 {
    png_infop info_ptr = *ptr_ptr;
 
-   png_debug(1, "in png_info_init_3\n");
+   png_debug(1, "in png_info_init_3");
+
+   if (info_ptr == NULL)
+      return;
 
-   if(png_sizeof(png_info) > png_info_struct_size)
-     {
-       png_destroy_struct(info_ptr);
-       info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO);
-       *ptr_ptr = info_ptr;
-     }
+   if (png_sizeof(png_info) > png_info_struct_size)
+   {
+      png_destroy_struct(info_ptr);
+      info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO);
+      *ptr_ptr = info_ptr;
+   }
 
-   /* set everything to 0 */
-   png_memset(info_ptr, 0, png_sizeof (png_info));
+   /* Set everything to 0 */
+   png_memset(info_ptr, 0, png_sizeof(png_info));
 }
 
-#ifdef PNG_FREE_ME_SUPPORTED
 void PNGAPI
 png_data_freer(png_structp png_ptr, png_infop info_ptr,
    int freer, png_uint_32 mask)
 {
-   png_debug(1, "in png_data_freer\n");
+   png_debug(1, "in png_data_freer");
+
    if (png_ptr == NULL || info_ptr == NULL)
       return;
-   if(freer == PNG_DESTROY_WILL_FREE_DATA)
+
+   if (freer == PNG_DESTROY_WILL_FREE_DATA)
       info_ptr->free_me |= mask;
-   else if(freer == PNG_USER_WILL_FREE_DATA)
+   else if (freer == PNG_USER_WILL_FREE_DATA)
       info_ptr->free_me &= ~mask;
    else
       png_warning(png_ptr,
-         "Unknown freer parameter in png_data_freer.");
+         "Unknown freer parameter in png_data_freer");
 }
-#endif
 
 void PNGAPI
 png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask,
    int num)
 {
-   png_debug(1, "in png_free_data\n");
+   png_debug(1, "in png_free_data");
+
    if (png_ptr == NULL || info_ptr == NULL)
       return;
 
-#if defined(PNG_TEXT_SUPPORTED)
-/* free text item num or (if num == -1) all text items */
-#ifdef PNG_FREE_ME_SUPPORTED
-if ((mask & PNG_FREE_TEXT) & info_ptr->free_me)
-#else
-if (mask & PNG_FREE_TEXT)
-#endif
-{
-   if (num != -1)
+#ifdef PNG_TEXT_SUPPORTED
+   /* Free text item num or (if num == -1) all text items */
+   if ((mask & PNG_FREE_TEXT) & info_ptr->free_me)
    {
-     if (info_ptr->text && info_ptr->text[num].key)
-     {
-         png_free(png_ptr, info_ptr->text[num].key);
-         info_ptr->text[num].key = NULL;
-     }
-   }
-   else
-   {
-       int i;
-       for (i = 0; i < info_ptr->num_text; i++)
-           png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, i);
-       png_free(png_ptr, info_ptr->text);
-       info_ptr->text = NULL;
-       info_ptr->num_text=0;
+      if (num != -1)
+      {
+         if (info_ptr->text && info_ptr->text[num].key)
+         {
+            png_free(png_ptr, info_ptr->text[num].key);
+            info_ptr->text[num].key = NULL;
+         }
+      }
+      else
+      {
+         int i;
+         for (i = 0; i < info_ptr->num_text; i++)
+             png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, i);
+         png_free(png_ptr, info_ptr->text);
+         info_ptr->text = NULL;
+         info_ptr->num_text=0;
+      }
    }
-}
 #endif
 
-#if defined(PNG_tRNS_SUPPORTED)
-/* free any tRNS entry */
-#ifdef PNG_FREE_ME_SUPPORTED
-if ((mask & PNG_FREE_TRNS) & info_ptr->free_me)
-#else
-if ((mask & PNG_FREE_TRNS) && (png_ptr->flags & PNG_FLAG_FREE_TRNS))
-#endif
-{
-    png_free(png_ptr, info_ptr->trans);
-    info_ptr->valid &= ~PNG_INFO_tRNS;
-#ifndef PNG_FREE_ME_SUPPORTED
-    png_ptr->flags &= ~PNG_FLAG_FREE_TRNS;
-#endif
-    info_ptr->trans = NULL;
-}
+#ifdef PNG_tRNS_SUPPORTED
+   /* Free any tRNS entry */
+   if ((mask & PNG_FREE_TRNS) & info_ptr->free_me)
+   {
+      png_free(png_ptr, info_ptr->trans_alpha);
+      info_ptr->trans_alpha = NULL;
+      info_ptr->valid &= ~PNG_INFO_tRNS;
+   }
 #endif
 
-#if defined(PNG_sCAL_SUPPORTED)
-/* free any sCAL entry */
-#ifdef PNG_FREE_ME_SUPPORTED
-if ((mask & PNG_FREE_SCAL) & info_ptr->free_me)
-#else
-if (mask & PNG_FREE_SCAL)
-#endif
-{
+#ifdef PNG_sCAL_SUPPORTED
+   /* Free any sCAL entry */
+   if ((mask & PNG_FREE_SCAL) & info_ptr->free_me)
+   {
 #if defined(PNG_FIXED_POINT_SUPPORTED) && !defined(PNG_FLOATING_POINT_SUPPORTED)
-    png_free(png_ptr, info_ptr->scal_s_width);
-    png_free(png_ptr, info_ptr->scal_s_height);
-    info_ptr->scal_s_width = NULL;
-    info_ptr->scal_s_height = NULL;
+      png_free(png_ptr, info_ptr->scal_s_width);
+      png_free(png_ptr, info_ptr->scal_s_height);
+      info_ptr->scal_s_width = NULL;
+      info_ptr->scal_s_height = NULL;
 #endif
-    info_ptr->valid &= ~PNG_INFO_sCAL;
-}
+      info_ptr->valid &= ~PNG_INFO_sCAL;
+   }
 #endif
 
-#if defined(PNG_pCAL_SUPPORTED)
-/* free any pCAL entry */
-#ifdef PNG_FREE_ME_SUPPORTED
-if ((mask & PNG_FREE_PCAL) & info_ptr->free_me)
-#else
-if (mask & PNG_FREE_PCAL)
-#endif
-{
-    png_free(png_ptr, info_ptr->pcal_purpose);
-    png_free(png_ptr, info_ptr->pcal_units);
-    info_ptr->pcal_purpose = NULL;
-    info_ptr->pcal_units = NULL;
-    if (info_ptr->pcal_params != NULL)
-    {
-        int i;
-        for (i = 0; i < (int)info_ptr->pcal_nparams; i++)
-        {
-          png_free(png_ptr, info_ptr->pcal_params[i]);
-          info_ptr->pcal_params[i]=NULL;
-        }
-        png_free(png_ptr, info_ptr->pcal_params);
-        info_ptr->pcal_params = NULL;
-    }
-    info_ptr->valid &= ~PNG_INFO_pCAL;
-}
+#ifdef PNG_pCAL_SUPPORTED
+   /* Free any pCAL entry */
+   if ((mask & PNG_FREE_PCAL) & info_ptr->free_me)
+   {
+      png_free(png_ptr, info_ptr->pcal_purpose);
+      png_free(png_ptr, info_ptr->pcal_units);
+      info_ptr->pcal_purpose = NULL;
+      info_ptr->pcal_units = NULL;
+      if (info_ptr->pcal_params != NULL)
+         {
+            int i;
+            for (i = 0; i < (int)info_ptr->pcal_nparams; i++)
+            {
+               png_free(png_ptr, info_ptr->pcal_params[i]);
+               info_ptr->pcal_params[i] = NULL;
+            }
+            png_free(png_ptr, info_ptr->pcal_params);
+            info_ptr->pcal_params = NULL;
+         }
+      info_ptr->valid &= ~PNG_INFO_pCAL;
+   }
 #endif
 
-#if defined(PNG_iCCP_SUPPORTED)
-/* free any iCCP entry */
-#ifdef PNG_FREE_ME_SUPPORTED
-if ((mask & PNG_FREE_ICCP) & info_ptr->free_me)
-#else
-if (mask & PNG_FREE_ICCP)
-#endif
-{
-    png_free(png_ptr, info_ptr->iccp_name);
-    png_free(png_ptr, info_ptr->iccp_profile);
-    info_ptr->iccp_name = NULL;
-    info_ptr->iccp_profile = NULL;
-    info_ptr->valid &= ~PNG_INFO_iCCP;
-}
+#ifdef PNG_iCCP_SUPPORTED
+   /* Free any iCCP entry */
+   if ((mask & PNG_FREE_ICCP) & info_ptr->free_me)
+   {
+      png_free(png_ptr, info_ptr->iccp_name);
+      png_free(png_ptr, info_ptr->iccp_profile);
+      info_ptr->iccp_name = NULL;
+      info_ptr->iccp_profile = NULL;
+      info_ptr->valid &= ~PNG_INFO_iCCP;
+   }
 #endif
 
-#if defined(PNG_sPLT_SUPPORTED)
-/* free a given sPLT entry, or (if num == -1) all sPLT entries */
-#ifdef PNG_FREE_ME_SUPPORTED
-if ((mask & PNG_FREE_SPLT) & info_ptr->free_me)
-#else
-if (mask & PNG_FREE_SPLT)
-#endif
-{
-   if (num != -1)
+#ifdef PNG_sPLT_SUPPORTED
+   /* Free a given sPLT entry, or (if num == -1) all sPLT entries */
+   if ((mask & PNG_FREE_SPLT) & info_ptr->free_me)
    {
-      if(info_ptr->splt_palettes)
+      if (num != -1)
       {
-          png_free(png_ptr, info_ptr->splt_palettes[num].name);
-          png_free(png_ptr, info_ptr->splt_palettes[num].entries);
-          info_ptr->splt_palettes[num].name = NULL;
-          info_ptr->splt_palettes[num].entries = NULL;
+         if (info_ptr->splt_palettes)
+         {
+            png_free(png_ptr, info_ptr->splt_palettes[num].name);
+            png_free(png_ptr, info_ptr->splt_palettes[num].entries);
+            info_ptr->splt_palettes[num].name = NULL;
+            info_ptr->splt_palettes[num].entries = NULL;
+         }
+      }
+      else
+      {
+         if (info_ptr->splt_palettes_num)
+         {
+            int i;
+            for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
+               png_free_data(png_ptr, info_ptr, PNG_FREE_SPLT, i);
+
+            png_free(png_ptr, info_ptr->splt_palettes);
+            info_ptr->splt_palettes = NULL;
+            info_ptr->splt_palettes_num = 0;
+         }
+         info_ptr->valid &= ~PNG_INFO_sPLT;
       }
    }
-   else
-   {
-       if(info_ptr->splt_palettes_num)
-       {
-         int i;
-         for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
-            png_free_data(png_ptr, info_ptr, PNG_FREE_SPLT, i);
-
-         png_free(png_ptr, info_ptr->splt_palettes);
-         info_ptr->splt_palettes = NULL;
-         info_ptr->splt_palettes_num = 0;
-       }
-       info_ptr->valid &= ~PNG_INFO_sPLT;
-   }
-}
 #endif
 
-#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
-#ifdef PNG_FREE_ME_SUPPORTED
-if ((mask & PNG_FREE_UNKN) & info_ptr->free_me)
-#else
-if (mask & PNG_FREE_UNKN)
-#endif
-{
-   if (num != -1)
+#ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
+   if (png_ptr->unknown_chunk.data)
    {
-       if(info_ptr->unknown_chunks)
-       {
-          png_free(png_ptr, info_ptr->unknown_chunks[num].data);
-          info_ptr->unknown_chunks[num].data = NULL;
-       }
+      png_free(png_ptr, png_ptr->unknown_chunk.data);
+      png_ptr->unknown_chunk.data = NULL;
    }
-   else
+
+   if ((mask & PNG_FREE_UNKN) & info_ptr->free_me)
    {
-       int i;
+      if (num != -1)
+      {
+          if (info_ptr->unknown_chunks)
+          {
+             png_free(png_ptr, info_ptr->unknown_chunks[num].data);
+             info_ptr->unknown_chunks[num].data = NULL;
+          }
+      }
+      else
+      {
+         int i;
 
-       if(info_ptr->unknown_chunks_num)
-       {
-         for (i = 0; i < (int)info_ptr->unknown_chunks_num; i++)
-            png_free_data(png_ptr, info_ptr, PNG_FREE_UNKN, i);
+         if (info_ptr->unknown_chunks_num)
+         {
+            for (i = 0; i < (int)info_ptr->unknown_chunks_num; i++)
+               png_free_data(png_ptr, info_ptr, PNG_FREE_UNKN, i);
 
-         png_free(png_ptr, info_ptr->unknown_chunks);
-         info_ptr->unknown_chunks = NULL;
-         info_ptr->unknown_chunks_num = 0;
-       }
+            png_free(png_ptr, info_ptr->unknown_chunks);
+            info_ptr->unknown_chunks = NULL;
+            info_ptr->unknown_chunks_num = 0;
+         }
+      }
    }
-}
 #endif
 
-#if defined(PNG_hIST_SUPPORTED)
-/* free any hIST entry */
-#ifdef PNG_FREE_ME_SUPPORTED
-if ((mask & PNG_FREE_HIST)  & info_ptr->free_me)
-#else
-if ((mask & PNG_FREE_HIST) && (png_ptr->flags & PNG_FLAG_FREE_HIST))
-#endif
-{
-    png_free(png_ptr, info_ptr->hist);
-    info_ptr->hist = NULL;
-    info_ptr->valid &= ~PNG_INFO_hIST;
-#ifndef PNG_FREE_ME_SUPPORTED
-    png_ptr->flags &= ~PNG_FLAG_FREE_HIST;
-#endif
-}
+#ifdef PNG_hIST_SUPPORTED
+   /* Free any hIST entry */
+   if ((mask & PNG_FREE_HIST)  & info_ptr->free_me)
+   {
+      png_free(png_ptr, info_ptr->hist);
+      info_ptr->hist = NULL;
+      info_ptr->valid &= ~PNG_INFO_hIST;
+   }
 #endif
 
-/* free any PLTE entry that was internally allocated */
-#ifdef PNG_FREE_ME_SUPPORTED
-if ((mask & PNG_FREE_PLTE) & info_ptr->free_me)
-#else
-if ((mask & PNG_FREE_PLTE) && (png_ptr->flags & PNG_FLAG_FREE_PLTE))
-#endif
-{
-    png_zfree(png_ptr, info_ptr->palette);
-    info_ptr->palette = NULL;
-    info_ptr->valid &= ~PNG_INFO_PLTE;
-#ifndef PNG_FREE_ME_SUPPORTED
-    png_ptr->flags &= ~PNG_FLAG_FREE_PLTE;
-#endif
-    info_ptr->num_palette = 0;
-}
+   /* Free any PLTE entry that was internally allocated */
+   if ((mask & PNG_FREE_PLTE) & info_ptr->free_me)
+   {
+      png_zfree(png_ptr, info_ptr->palette);
+      info_ptr->palette = NULL;
+      info_ptr->valid &= ~PNG_INFO_PLTE;
+      info_ptr->num_palette = 0;
+   }
 
-#if defined(PNG_INFO_IMAGE_SUPPORTED)
-/* free any image bits attached to the info structure */
-#ifdef PNG_FREE_ME_SUPPORTED
-if ((mask & PNG_FREE_ROWS) & info_ptr->free_me)
-#else
-if (mask & PNG_FREE_ROWS)
-#endif
-{
-    if(info_ptr->row_pointers)
-    {
-       int row;
-       for (row = 0; row < (int)info_ptr->height; row++)
-       {
-          png_free(png_ptr, info_ptr->row_pointers[row]);
-          info_ptr->row_pointers[row]=NULL;
-       }
-       png_free(png_ptr, info_ptr->row_pointers);
-       info_ptr->row_pointers=NULL;
-    }
-    info_ptr->valid &= ~PNG_INFO_IDAT;
-}
+#ifdef PNG_INFO_IMAGE_SUPPORTED
+   /* Free any image bits attached to the info structure */
+   if ((mask & PNG_FREE_ROWS) & info_ptr->free_me)
+   {
+      if (info_ptr->row_pointers)
+      {
+         int row;
+         for (row = 0; row < (int)info_ptr->height; row++)
+         {
+            png_free(png_ptr, info_ptr->row_pointers[row]);
+            info_ptr->row_pointers[row] = NULL;
+         }
+         png_free(png_ptr, info_ptr->row_pointers);
+         info_ptr->row_pointers = NULL;
+      }
+      info_ptr->valid &= ~PNG_INFO_IDAT;
+   }
 #endif
 
-#ifdef PNG_FREE_ME_SUPPORTED
-   if(num == -1)
-     info_ptr->free_me &= ~mask;
+   if (num == -1)
+      info_ptr->free_me &= ~mask;
    else
-     info_ptr->free_me &= ~(mask & ~PNG_FREE_MUL);
-#endif
+      info_ptr->free_me &= ~(mask & ~PNG_FREE_MUL);
 }
 
 /* This is an internal routine to free any memory that the info struct is
@@ -575,21 +452,22 @@ if (mask & PNG_FREE_ROWS)
 void /* PRIVATE */
 png_info_destroy(png_structp png_ptr, png_infop info_ptr)
 {
-   png_debug(1, "in png_info_destroy\n");
+   png_debug(1, "in png_info_destroy");
 
    png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
 
-#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
    if (png_ptr->num_chunk_list)
    {
-       png_free(png_ptr, png_ptr->chunk_list);
-       png_ptr->chunk_list=NULL;
-       png_ptr->num_chunk_list=0;
+      png_free(png_ptr, png_ptr->chunk_list);
+      png_ptr->chunk_list = NULL;
+      png_ptr->num_chunk_list = 0;
    }
 #endif
 
    png_info_init_3(&info_ptr, png_sizeof(png_info));
 }
+#endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */
 
 /* This function returns a pointer to the io_ptr associated with the user
  * functions.  The application should free any memory associated with this
@@ -598,10 +476,13 @@ png_info_destroy(png_structp png_ptr, png_infop info_ptr)
 png_voidp PNGAPI
 png_get_io_ptr(png_structp png_ptr)
 {
+   if (png_ptr == NULL)
+      return (NULL);
    return (png_ptr->io_ptr);
 }
 
-#if !defined(PNG_NO_STDIO)
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+#ifdef PNG_STDIO_SUPPORTED
 /* Initialize the default input/output functions for the PNG file.  If you
  * use your own read or write routines, you can call either png_set_read_fn()
  * or png_set_write_fn() instead of png_init_io().  If you have defined
@@ -611,12 +492,16 @@ png_get_io_ptr(png_structp png_ptr)
 void PNGAPI
 png_init_io(png_structp png_ptr, png_FILE_p fp)
 {
-   png_debug(1, "in png_init_io\n");
+   png_debug(1, "in png_init_io");
+
+   if (png_ptr == NULL)
+      return;
+
    png_ptr->io_ptr = (png_voidp)fp;
 }
 #endif
 
-#if defined(PNG_TIME_RFC1123_SUPPORTED)
+#ifdef PNG_TIME_RFC1123_SUPPORTED
 /* Convert the supplied time into an RFC 1123 string suitable for use in
  * a "Creation Time" or other text-based time string.
  */
@@ -627,27 +512,18 @@ png_convert_to_rfc1123(png_structp png_ptr, png_timep ptime)
         {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
          "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
 
+   if (png_ptr == NULL)
+      return (NULL);
    if (png_ptr->time_buffer == NULL)
    {
       png_ptr->time_buffer = (png_charp)png_malloc(png_ptr, (png_uint_32)(29*
          png_sizeof(char)));
    }
 
-#if defined(_WIN32_WCE)
-   {
-      wchar_t time_buf[29];
-      wsprintf(time_buf, TEXT("%d %S %d %02d:%02d:%02d +0000"),
-          ptime->day % 32, short_months[(ptime->month - 1) % 12],
-        ptime->year, ptime->hour % 24, ptime->minute % 60,
-          ptime->second % 61);
-      WideCharToMultiByte(CP_ACP, 0, time_buf, -1, png_ptr->time_buffer, 29,
-          NULL, NULL);
-   }
-#else
 #ifdef USE_FAR_KEYWORD
    {
       char near_time_buf[29];
-      sprintf(near_time_buf, "%d %s %d %02d:%02d:%02d +0000",
+      png_snprintf6(near_time_buf, 29, "%d %s %d %02d:%02d:%02d +0000",
           ptime->day % 32, short_months[(ptime->month - 1) % 12],
           ptime->year, ptime->hour % 24, ptime->minute % 60,
           ptime->second % 61);
@@ -655,34 +531,38 @@ png_convert_to_rfc1123(png_structp png_ptr, png_timep ptime)
           29*png_sizeof(char));
    }
 #else
-   sprintf(png_ptr->time_buffer, "%d %s %d %02d:%02d:%02d +0000",
+   png_snprintf6(png_ptr->time_buffer, 29, "%d %s %d %02d:%02d:%02d +0000",
        ptime->day % 32, short_months[(ptime->month - 1) % 12],
        ptime->year, ptime->hour % 24, ptime->minute % 60,
        ptime->second % 61);
 #endif
-#endif /* _WIN32_WCE */
    return ((png_charp)png_ptr->time_buffer);
 }
 #endif /* PNG_TIME_RFC1123_SUPPORTED */
 
-#if 0
-/* Signature string for a PNG file. */
-png_bytep PNGAPI
-png_sig_bytes(void)
-{
-   return ((png_bytep)"\211\120\116\107\015\012\032\012");
-}
-#endif
+#endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */
 
 png_charp PNGAPI
 png_get_copyright(png_structp png_ptr)
 {
-   if (&png_ptr != NULL)  /* silence compiler warning about unused png_ptr */
-   return ((png_charp) "\n libpng version 1.2.7 - September 12, 2004\n\
-   Copyright (c) 1998-2004 Glenn Randers-Pehrson\n\
-   Copyright (c) 1996-1997 Andreas Dilger\n\
-   Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.\n");
-   return ((png_charp) "");
+   png_ptr = png_ptr;  /* Silence compiler warning about unused png_ptr */
+#ifdef PNG_STRING_COPYRIGHT
+      return PNG_STRING_COPYRIGHT
+#else
+#ifdef __STDC__
+   return ((png_charp) PNG_STRING_NEWLINE \
+     "libpng version 1.4.4 - September 23, 2010" PNG_STRING_NEWLINE \
+     "Copyright (c) 1998-2010 Glenn Randers-Pehrson" PNG_STRING_NEWLINE \
+     "Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \
+     "Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \
+     PNG_STRING_NEWLINE);
+#else
+      return ((png_charp) "libpng version 1.4.4 - September 23, 2010\
+      Copyright (c) 1998-2010 Glenn Randers-Pehrson\
+      Copyright (c) 1996-1997 Andreas Dilger\
+      Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.");
+#endif
+#endif
 }
 
 /* The following return the library version as a short string in the
@@ -697,52 +577,63 @@ png_charp PNGAPI
 png_get_libpng_ver(png_structp png_ptr)
 {
    /* Version of *.c files used when building libpng */
-   if (&png_ptr != NULL)  /* silence compiler warning about unused png_ptr */
-      return ((png_charp) PNG_LIBPNG_VER_STRING);
-   return ((png_charp) "");
+   png_ptr = png_ptr;  /* Silence compiler warning about unused png_ptr */
+   return ((png_charp) PNG_LIBPNG_VER_STRING);
 }
 
 png_charp PNGAPI
 png_get_header_ver(png_structp png_ptr)
 {
    /* Version of *.h files used when building libpng */
-   if (&png_ptr != NULL)  /* silence compiler warning about unused png_ptr */
-      return ((png_charp) PNG_LIBPNG_VER_STRING);
-   return ((png_charp) "");
+   png_ptr = png_ptr;  /* Silence compiler warning about unused png_ptr */
+   return ((png_charp) PNG_LIBPNG_VER_STRING);
 }
 
 png_charp PNGAPI
 png_get_header_version(png_structp png_ptr)
 {
    /* Returns longer string containing both version and date */
-   if (&png_ptr != NULL)  /* silence compiler warning about unused png_ptr */
-      return ((png_charp) PNG_HEADER_VERSION_STRING);
-   return ((png_charp) "");
+   png_ptr = png_ptr;  /* Silence compiler warning about unused png_ptr */
+#ifdef __STDC__
+   return ((png_charp) PNG_HEADER_VERSION_STRING
+#ifndef PNG_READ_SUPPORTED
+   "     (NO READ SUPPORT)"
+#endif
+   PNG_STRING_NEWLINE);
+#else
+   return ((png_charp) PNG_HEADER_VERSION_STRING);
+#endif
 }
 
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
 int PNGAPI
 png_handle_as_unknown(png_structp png_ptr, png_bytep chunk_name)
 {
-   /* check chunk_name and return "keep" value if it's on the list, else 0 */
+   /* Check chunk_name and return "keep" value if it's on the list, else 0 */
    int i;
    png_bytep p;
-   if((png_ptr == NULL && chunk_name == NULL) || png_ptr->num_chunk_list<=0)
+   if (png_ptr == NULL || chunk_name == NULL || png_ptr->num_chunk_list<=0)
       return 0;
-   p=png_ptr->chunk_list+png_ptr->num_chunk_list*5-5;
-   for (i = png_ptr->num_chunk_list; i; i--, p-=5)
+   p = png_ptr->chunk_list + png_ptr->num_chunk_list*5 - 5;
+   for (i = png_ptr->num_chunk_list; i; i--, p -= 5)
       if (!png_memcmp(chunk_name, p, 4))
-        return ((int)*(p+4));
+        return ((int)*(p + 4));
    return 0;
 }
 #endif
+#endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */
 
+#ifdef PNG_READ_SUPPORTED
 /* This function, added to libpng-1.0.6g, is untested. */
 int PNGAPI
 png_reset_zstream(png_structp png_ptr)
 {
+   if (png_ptr == NULL)
+      return Z_STREAM_ERROR;
    return (inflateReset(&png_ptr->zstream));
 }
+#endif /* PNG_READ_SUPPORTED */
 
 /* This function was added to libpng-1.0.7 */
 png_uint_32 PNGAPI
@@ -753,74 +644,275 @@ png_access_version_number(void)
 }
 
 
-#if !defined(PNG_1_0_X)
-#if defined(PNG_ASSEMBLER_CODE_SUPPORTED)
-    /* GRR:  could add this:   && defined(PNG_MMX_CODE_SUPPORTED) */
-/* this INTERNAL function was added to libpng 1.2.0 */
-void /* PRIVATE */
-png_init_mmx_flags (png_structp png_ptr)
-{
-    png_ptr->mmx_rowbytes_threshold = 0;
-    png_ptr->mmx_bitdepth_threshold = 0;
-
-#  if (defined(PNG_USE_PNGVCRD) || defined(PNG_USE_PNGGCCRD))
-
-    png_ptr->asm_flags |= PNG_ASM_FLAG_MMX_SUPPORT_COMPILED;
-
-    if (png_mmx_support() > 0) {
-        png_ptr->asm_flags |= PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU
-#    ifdef PNG_HAVE_ASSEMBLER_COMBINE_ROW
-                              | PNG_ASM_FLAG_MMX_READ_COMBINE_ROW
-#    endif
-#    ifdef PNG_HAVE_ASSEMBLER_READ_INTERLACE
-                              | PNG_ASM_FLAG_MMX_READ_INTERLACE
-#    endif
-#    ifndef PNG_HAVE_ASSEMBLER_READ_FILTER_ROW
-                              ;
-#    else
-                              | PNG_ASM_FLAG_MMX_READ_FILTER_SUB
-                              | PNG_ASM_FLAG_MMX_READ_FILTER_UP
-                              | PNG_ASM_FLAG_MMX_READ_FILTER_AVG
-                              | PNG_ASM_FLAG_MMX_READ_FILTER_PAETH ;
-
-        png_ptr->mmx_rowbytes_threshold = PNG_MMX_ROWBYTES_THRESHOLD_DEFAULT;
-        png_ptr->mmx_bitdepth_threshold = PNG_MMX_BITDEPTH_THRESHOLD_DEFAULT;
-#    endif
-    } else {
-        png_ptr->asm_flags &= ~( PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU
-                               | PNG_MMX_READ_FLAGS
-                               | PNG_MMX_WRITE_FLAGS );
-    }
-
-#  else /* !((PNGVCRD || PNGGCCRD) && PNG_ASSEMBLER_CODE_SUPPORTED)) */
-
-    /* clear all MMX flags; no support is compiled in */
-    png_ptr->asm_flags &= ~( PNG_MMX_FLAGS );
-
-#  endif /* ?(PNGVCRD || PNGGCCRD) */
-}
-
-#endif /* !(PNG_ASSEMBLER_CODE_SUPPORTED) */
-
-/* this function was added to libpng 1.2.0 */
-#if !defined(PNG_USE_PNGGCCRD) && \
-    !(defined(PNG_ASSEMBLER_CODE_SUPPORTED) && defined(PNG_USE_PNGVCRD))
-int PNGAPI
-png_mmx_support(void)
-{
-    return -1;
-}
-#endif
-#endif /* PNG_1_0_X */
 
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
 #ifdef PNG_SIZE_T
 /* Added at libpng version 1.2.6 */
    PNG_EXTERN png_size_t PNGAPI png_convert_size PNGARG((size_t size));
 png_size_t PNGAPI
 png_convert_size(size_t size)
 {
-  if (size > (png_size_t)-1)
-     PNG_ABORT();  /* We haven't got access to png_ptr, so no png_error() */
-  return ((png_size_t)size);
+   if (size > (png_size_t)-1)
+      PNG_ABORT();  /* We haven't got access to png_ptr, so no png_error() */
+   return ((png_size_t)size);
 }
 #endif /* PNG_SIZE_T */
+
+/* Added at libpng version 1.2.34 and 1.4.0 (moved from pngset.c) */
+#ifdef PNG_cHRM_SUPPORTED
+#ifdef PNG_CHECK_cHRM_SUPPORTED
+
+/*
+ *    Multiply two 32-bit numbers, V1 and V2, using 32-bit
+ *    arithmetic, to produce a 64 bit result in the HI/LO words.
+ *
+ *                  A B
+ *                x C D
+ *               ------
+ *              AD || BD
+ *        AC || CB || 0
+ *
+ *    where A and B are the high and low 16-bit words of V1,
+ *    C and D are the 16-bit words of V2, AD is the product of
+ *    A and D, and X || Y is (X << 16) + Y.
+*/
+
+void /* PRIVATE */
+png_64bit_product (long v1, long v2, unsigned long *hi_product,
+   unsigned long *lo_product)
+{
+   int a, b, c, d;
+   long lo, hi, x, y;
+
+   a = (v1 >> 16) & 0xffff;
+   b = v1 & 0xffff;
+   c = (v2 >> 16) & 0xffff;
+   d = v2 & 0xffff;
+
+   lo = b * d;                   /* BD */
+   x = a * d + c * b;            /* AD + CB */
+   y = ((lo >> 16) & 0xffff) + x;
+
+   lo = (lo & 0xffff) | ((y & 0xffff) << 16);
+   hi = (y >> 16) & 0xffff;
+
+   hi += a * c;                  /* AC */
+
+   *hi_product = (unsigned long)hi;
+   *lo_product = (unsigned long)lo;
+}
+
+int /* PRIVATE */
+png_check_cHRM_fixed(png_structp png_ptr,
+   png_fixed_point white_x, png_fixed_point white_y, png_fixed_point red_x,
+   png_fixed_point red_y, png_fixed_point green_x, png_fixed_point green_y,
+   png_fixed_point blue_x, png_fixed_point blue_y)
+{
+   int ret = 1;
+   unsigned long xy_hi,xy_lo,yx_hi,yx_lo;
+
+   png_debug(1, "in function png_check_cHRM_fixed");
+
+   if (png_ptr == NULL)
+      return 0;
+
+   if (white_x < 0 || white_y <= 0 ||
+         red_x < 0 ||   red_y <  0 ||
+       green_x < 0 || green_y <  0 ||
+        blue_x < 0 ||  blue_y <  0)
+   {
+      png_warning(png_ptr,
+        "Ignoring attempt to set negative chromaticity value");
+      ret = 0;
+   }
+   if (white_x > (png_fixed_point) PNG_UINT_31_MAX ||
+       white_y > (png_fixed_point) PNG_UINT_31_MAX ||
+         red_x > (png_fixed_point) PNG_UINT_31_MAX ||
+         red_y > (png_fixed_point) PNG_UINT_31_MAX ||
+       green_x > (png_fixed_point) PNG_UINT_31_MAX ||
+       green_y > (png_fixed_point) PNG_UINT_31_MAX ||
+        blue_x > (png_fixed_point) PNG_UINT_31_MAX ||
+        blue_y > (png_fixed_point) PNG_UINT_31_MAX )
+   {
+      png_warning(png_ptr,
+        "Ignoring attempt to set chromaticity value exceeding 21474.83");
+      ret = 0;
+   }
+   if (white_x > 100000L - white_y)
+   {
+      png_warning(png_ptr, "Invalid cHRM white point");
+      ret = 0;
+   }
+   if (red_x > 100000L - red_y)
+   {
+      png_warning(png_ptr, "Invalid cHRM red point");
+      ret = 0;
+   }
+   if (green_x > 100000L - green_y)
+   {
+      png_warning(png_ptr, "Invalid cHRM green point");
+      ret = 0;
+   }
+   if (blue_x > 100000L - blue_y)
+   {
+      png_warning(png_ptr, "Invalid cHRM blue point");
+      ret = 0;
+   }
+
+   png_64bit_product(green_x - red_x, blue_y - red_y, &xy_hi, &xy_lo);
+   png_64bit_product(green_y - red_y, blue_x - red_x, &yx_hi, &yx_lo);
+
+   if (xy_hi == yx_hi && xy_lo == yx_lo)
+   {
+      png_warning(png_ptr,
+         "Ignoring attempt to set cHRM RGB triangle with zero area");
+      ret = 0;
+   }
+
+   return ret;
+}
+#endif /* PNG_CHECK_cHRM_SUPPORTED */
+#endif /* PNG_cHRM_SUPPORTED */
+
+void /* PRIVATE */
+png_check_IHDR(png_structp png_ptr,
+   png_uint_32 width, png_uint_32 height, int bit_depth,
+   int color_type, int interlace_type, int compression_type,
+   int filter_type)
+{
+   int error = 0;
+
+   /* Check for width and height valid values */
+   if (width == 0)
+   {
+      png_warning(png_ptr, "Image width is zero in IHDR");
+      error = 1;
+   }
+
+   if (height == 0)
+   {
+      png_warning(png_ptr, "Image height is zero in IHDR");
+      error = 1;
+   }
+
+#ifdef PNG_SET_USER_LIMITS_SUPPORTED
+   if (width > png_ptr->user_width_max || width > PNG_USER_WIDTH_MAX)
+#else
+   if (width > PNG_USER_WIDTH_MAX)
+#endif
+   {
+      png_warning(png_ptr, "Image width exceeds user limit in IHDR");
+      error = 1;
+   }
+
+#ifdef PNG_SET_USER_LIMITS_SUPPORTED
+   if (height > png_ptr->user_height_max || height > PNG_USER_HEIGHT_MAX)
+#else
+   if (height > PNG_USER_HEIGHT_MAX)
+#endif
+   {
+      png_warning(png_ptr, "Image height exceeds user limit in IHDR");
+      error = 1;
+   }
+
+   if (width > PNG_UINT_31_MAX)
+   {
+      png_warning(png_ptr, "Invalid image width in IHDR");
+      error = 1;
+   }
+
+   if ( height > PNG_UINT_31_MAX)
+   {
+      png_warning(png_ptr, "Invalid image height in IHDR");
+      error = 1;
+   }
+
+   if ( width > (PNG_UINT_32_MAX
+                 >> 3)      /* 8-byte RGBA pixels */
+                 - 64       /* bigrowbuf hack */
+                 - 1        /* filter byte */
+                 - 7*8      /* rounding of width to multiple of 8 pixels */
+                 - 8)       /* extra max_pixel_depth pad */
+      png_warning(png_ptr, "Width is too large for libpng to process pixels");
+
+   /* Check other values */
+   if (bit_depth != 1 && bit_depth != 2 && bit_depth != 4 &&
+       bit_depth != 8 && bit_depth != 16)
+   {
+      png_warning(png_ptr, "Invalid bit depth in IHDR");
+      error = 1;
+   }
+
+   if (color_type < 0 || color_type == 1 ||
+       color_type == 5 || color_type > 6)
+   {
+      png_warning(png_ptr, "Invalid color type in IHDR");
+      error = 1;
+   }
+
+   if (((color_type == PNG_COLOR_TYPE_PALETTE) && bit_depth > 8) ||
+       ((color_type == PNG_COLOR_TYPE_RGB ||
+         color_type == PNG_COLOR_TYPE_GRAY_ALPHA ||
+         color_type == PNG_COLOR_TYPE_RGB_ALPHA) && bit_depth < 8))
+   {
+      png_warning(png_ptr, "Invalid color type/bit depth combination in IHDR");
+      error = 1;
+   }
+
+   if (interlace_type >= PNG_INTERLACE_LAST)
+   {
+      png_warning(png_ptr, "Unknown interlace method in IHDR");
+      error = 1;
+   }
+
+   if (compression_type != PNG_COMPRESSION_TYPE_BASE)
+   {
+      png_warning(png_ptr, "Unknown compression method in IHDR");
+      error = 1;
+   }
+
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+   /* Accept filter_method 64 (intrapixel differencing) only if
+    * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
+    * 2. Libpng did not read a PNG signature (this filter_method is only
+    *    used in PNG datastreams that are embedded in MNG datastreams) and
+    * 3. The application called png_permit_mng_features with a mask that
+    *    included PNG_FLAG_MNG_FILTER_64 and
+    * 4. The filter_method is 64 and
+    * 5. The color_type is RGB or RGBA
+    */
+   if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) &&
+       png_ptr->mng_features_permitted)
+      png_warning(png_ptr, "MNG features are not allowed in a PNG datastream");
+
+   if (filter_type != PNG_FILTER_TYPE_BASE)
+   {
+      if (!((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
+         (filter_type == PNG_INTRAPIXEL_DIFFERENCING) &&
+         ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) == 0) &&
+         (color_type == PNG_COLOR_TYPE_RGB ||
+         color_type == PNG_COLOR_TYPE_RGB_ALPHA)))
+      {
+         png_warning(png_ptr, "Unknown filter method in IHDR");
+         error = 1;
+      }
+
+      if (png_ptr->mode & PNG_HAVE_PNG_SIGNATURE)
+      {
+         png_warning(png_ptr, "Invalid filter method in IHDR");
+         error = 1;
+      }
+   }
+
+#else
+   if (filter_type != PNG_FILTER_TYPE_BASE)
+   {
+      png_warning(png_ptr, "Unknown filter method in IHDR");
+      error = 1;
+   }
+#endif
+
+   if (error == 1)
+      png_error(png_ptr, "Invalid IHDR data");
+}
+#endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */