Fix history in wxWebViewIE when using a custom file scheme.

[wxWidgets.git] / src / png / pngtrans.c

diff --git a/src/png/pngtrans.c b/src/png/pngtrans.c
index de02574c6f5dd43ca3a91890948b26e4aa94f59a..741daf45b7c6d75b3dc2e8432838ecffcc782f39 100644 (file)
--- a/src/png/pngtrans.c
+++ b/src/png/pngtrans.c
@@ -1,43 +1,57 @@
 
 /* pngtrans.c - transforms the data in a row (used by both readers and writers)
  *
 
 /* pngtrans.c - transforms the data in a row (used by both readers and writers)
  *

- * libpng 1.2.6 - August 15, 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 [April 29, 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.)
  * (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"
 #include "png.h"

+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+#include "pngpriv.h"

 
 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
 
 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)

-/* turn on BGR-to-RGB mapping */
+/* Turn on BGR-to-RGB mapping */

 void PNGAPI
 png_set_bgr(png_structp png_ptr)
 {
 void PNGAPI
 png_set_bgr(png_structp png_ptr)
 {

-   png_debug(1, "in png_set_bgr\n");
+   png_debug(1, "in png_set_bgr");
+
+   if (png_ptr == NULL)
+      return;

    png_ptr->transformations |= PNG_BGR;
 }
 #endif
 
 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
    png_ptr->transformations |= PNG_BGR;
 }
 #endif
 
 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)

-/* turn on 16 bit byte swapping */
+/* Turn on 16 bit byte swapping */

 void PNGAPI
 png_set_swap(png_structp png_ptr)
 {
 void PNGAPI
 png_set_swap(png_structp png_ptr)
 {

-   png_debug(1, "in png_set_swap\n");
+   png_debug(1, "in png_set_swap");
+
+   if (png_ptr == NULL)
+      return;

    if (png_ptr->bit_depth == 16)
       png_ptr->transformations |= PNG_SWAP_BYTES;
 }
 #endif
 
 #if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
    if (png_ptr->bit_depth == 16)
       png_ptr->transformations |= PNG_SWAP_BYTES;
 }
 #endif
 
 #if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)

-/* turn on pixel packing */
+/* Turn on pixel packing */

 void PNGAPI
 png_set_packing(png_structp png_ptr)
 {
 void PNGAPI
 png_set_packing(png_structp png_ptr)
 {

-   png_debug(1, "in png_set_packing\n");
+   png_debug(1, "in png_set_packing");
+
+   if (png_ptr == NULL)
+      return;

    if (png_ptr->bit_depth < 8)
    {
       png_ptr->transformations |= PNG_PACK;
    if (png_ptr->bit_depth < 8)
    {
       png_ptr->transformations |= PNG_PACK;


@@ -47,11 +61,14 @@ png_set_packing(png_structp png_ptr)
 #endif
 
 #if defined(PNG_READ_PACKSWAP_SUPPORTED)||defined(PNG_WRITE_PACKSWAP_SUPPORTED)
 #endif
 
 #if defined(PNG_READ_PACKSWAP_SUPPORTED)||defined(PNG_WRITE_PACKSWAP_SUPPORTED)

-/* turn on packed pixel swapping */
+/* Turn on packed pixel swapping */

 void PNGAPI
 png_set_packswap(png_structp png_ptr)
 {
 void PNGAPI
 png_set_packswap(png_structp png_ptr)
 {

-   png_debug(1, "in png_set_packswap\n");
+   png_debug(1, "in png_set_packswap");
+
+   if (png_ptr == NULL)
+      return;

    if (png_ptr->bit_depth < 8)
       png_ptr->transformations |= PNG_PACKSWAP;
 }
    if (png_ptr->bit_depth < 8)
       png_ptr->transformations |= PNG_PACKSWAP;
 }


@@ -61,7 +78,10 @@ png_set_packswap(png_structp png_ptr)
 void PNGAPI
 png_set_shift(png_structp png_ptr, png_color_8p true_bits)
 {
 void PNGAPI
 png_set_shift(png_structp png_ptr, png_color_8p true_bits)
 {

-   png_debug(1, "in png_set_shift\n");
+   png_debug(1, "in png_set_shift");
+
+   if (png_ptr == NULL)
+      return;

    png_ptr->transformations |= PNG_SHIFT;
    png_ptr->shift = *true_bits;
 }
    png_ptr->transformations |= PNG_SHIFT;
    png_ptr->shift = *true_bits;
 }


@@ -72,8 +92,9 @@ png_set_shift(png_structp png_ptr, png_color_8p true_bits)
 int PNGAPI
 png_set_interlace_handling(png_structp png_ptr)
 {
 int PNGAPI
 png_set_interlace_handling(png_structp png_ptr)
 {

-   png_debug(1, "in png_set_interlace handling\n");
-   if (png_ptr->interlaced)
+   png_debug(1, "in png_set_interlace handling");
+
+   if (png_ptr && png_ptr->interlaced)

    {
       png_ptr->transformations |= PNG_INTERLACE;
       return (7);
    {
       png_ptr->transformations |= PNG_INTERLACE;
       return (7);


@@ -92,15 +113,18 @@ png_set_interlace_handling(png_structp png_ptr)
 void PNGAPI
 png_set_filler(png_structp png_ptr, png_uint_32 filler, int filler_loc)
 {
 void PNGAPI
 png_set_filler(png_structp png_ptr, png_uint_32 filler, int filler_loc)
 {

-   png_debug(1, "in png_set_filler\n");
+   png_debug(1, "in png_set_filler");
+
+   if (png_ptr == NULL)
+      return;

    png_ptr->transformations |= PNG_FILLER;
    png_ptr->transformations |= PNG_FILLER;

-   png_ptr->filler = (png_byte)filler;
+   png_ptr->filler = (png_uint_16)filler;

    if (filler_loc == PNG_FILLER_AFTER)
       png_ptr->flags |= PNG_FLAG_FILLER_AFTER;
    else
       png_ptr->flags &= ~PNG_FLAG_FILLER_AFTER;
 
    if (filler_loc == PNG_FILLER_AFTER)
       png_ptr->flags |= PNG_FLAG_FILLER_AFTER;
    else
       png_ptr->flags &= ~PNG_FLAG_FILLER_AFTER;
 

-   /* This should probably go in the "do_filler" routine.
+   /* This should probably go in the "do_read_filler" routine.

     * I attempted to do that in libpng-1.0.1a but that caused problems
     * so I restored it in libpng-1.0.2a
    */
     * I attempted to do that in libpng-1.0.1a but that caused problems
     * so I restored it in libpng-1.0.2a
    */


@@ -118,6 +142,19 @@ png_set_filler(png_structp png_ptr, png_uint_32 filler, int filler_loc)
       png_ptr->usr_channels = 2;
    }
 }
       png_ptr->usr_channels = 2;
    }
 }

+
+/* Added to libpng-1.2.7 */
+void PNGAPI
+png_set_add_alpha(png_structp png_ptr, png_uint_32 filler, int filler_loc)
+{
+   png_debug(1, "in png_set_add_alpha");
+
+   if (png_ptr == NULL)
+      return;
+   png_set_filler(png_ptr, filler, filler_loc);
+   png_ptr->transformations |= PNG_ADD_ALPHA;
+}
+

 #endif
 
 #if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \
 #endif
 
 #if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \


@@ -125,7 +162,10 @@ png_set_filler(png_structp png_ptr, png_uint_32 filler, int filler_loc)
 void PNGAPI
 png_set_swap_alpha(png_structp png_ptr)
 {
 void PNGAPI
 png_set_swap_alpha(png_structp png_ptr)
 {

-   png_debug(1, "in png_set_swap_alpha\n");
+   png_debug(1, "in png_set_swap_alpha");
+
+   if (png_ptr == NULL)
+      return;

    png_ptr->transformations |= PNG_SWAP_ALPHA;
 }
 #endif
    png_ptr->transformations |= PNG_SWAP_ALPHA;
 }
 #endif


@@ -135,7 +175,10 @@ png_set_swap_alpha(png_structp png_ptr)
 void PNGAPI
 png_set_invert_alpha(png_structp png_ptr)
 {
 void PNGAPI
 png_set_invert_alpha(png_structp png_ptr)
 {

-   png_debug(1, "in png_set_invert_alpha\n");
+   png_debug(1, "in png_set_invert_alpha");
+
+   if (png_ptr == NULL)
+      return;

    png_ptr->transformations |= PNG_INVERT_ALPHA;
 }
 #endif
    png_ptr->transformations |= PNG_INVERT_ALPHA;
 }
 #endif


@@ -144,22 +187,22 @@ png_set_invert_alpha(png_structp png_ptr)
 void PNGAPI
 png_set_invert_mono(png_structp png_ptr)
 {
 void PNGAPI
 png_set_invert_mono(png_structp png_ptr)
 {

-   png_debug(1, "in png_set_invert_mono\n");
+   png_debug(1, "in png_set_invert_mono");
+
+   if (png_ptr == NULL)
+      return;

    png_ptr->transformations |= PNG_INVERT_MONO;
 }
 
    png_ptr->transformations |= PNG_INVERT_MONO;
 }
 

-/* invert monochrome grayscale data */
+/* Invert monochrome grayscale data */

 void /* PRIVATE */
 png_do_invert(png_row_infop row_info, png_bytep row)
 {
 void /* PRIVATE */
 png_do_invert(png_row_infop row_info, png_bytep row)
 {

-   png_debug(1, "in png_do_invert\n");
+   png_debug(1, "in png_do_invert");
+

   /* This test removed from libpng version 1.0.13 and 1.2.0:
    *   if (row_info->bit_depth == 1 &&
    */
   /* This test removed from libpng version 1.0.13 and 1.2.0:
    *   if (row_info->bit_depth == 1 &&
    */

-#if defined(PNG_USELESS_TESTS_SUPPORTED)
-   if (row == NULL || row_info == NULL)
-     return;
-#endif

    if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
    {
       png_bytep rp = row;
    if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
    {
       png_bytep rp = row;


@@ -203,15 +246,13 @@ png_do_invert(png_row_infop row_info, png_bytep row)
 #endif
 
 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
 #endif
 
 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)

-/* swaps byte order on 16 bit depth images */
+/* Swaps byte order on 16 bit depth images */

 void /* PRIVATE */
 png_do_swap(png_row_infop row_info, png_bytep row)
 {
 void /* PRIVATE */
 png_do_swap(png_row_infop row_info, png_bytep row)
 {

-   png_debug(1, "in png_do_swap\n");
+   png_debug(1, "in png_do_swap");
+

    if (
    if (

-#if defined(PNG_USELESS_TESTS_SUPPORTED)
-       row != NULL && row_info != NULL &&
-#endif

        row_info->bit_depth == 16)
    {
       png_bytep rp = row;
        row_info->bit_depth == 16)
    {
       png_bytep rp = row;


@@ -229,7 +270,7 @@ png_do_swap(png_row_infop row_info, png_bytep row)
 #endif
 
 #if defined(PNG_READ_PACKSWAP_SUPPORTED)||defined(PNG_WRITE_PACKSWAP_SUPPORTED)
 #endif
 
 #if defined(PNG_READ_PACKSWAP_SUPPORTED)||defined(PNG_WRITE_PACKSWAP_SUPPORTED)

-static png_byte onebppswaptable[256] = {
+static PNG_CONST png_byte onebppswaptable[256] = {

    0x00, 0x80, 0x40, 0xC0, 0x20, 0xA0, 0x60, 0xE0,
    0x10, 0x90, 0x50, 0xD0, 0x30, 0xB0, 0x70, 0xF0,
    0x08, 0x88, 0x48, 0xC8, 0x28, 0xA8, 0x68, 0xE8,
    0x00, 0x80, 0x40, 0xC0, 0x20, 0xA0, 0x60, 0xE0,
    0x10, 0x90, 0x50, 0xD0, 0x30, 0xB0, 0x70, 0xF0,
    0x08, 0x88, 0x48, 0xC8, 0x28, 0xA8, 0x68, 0xE8,


@@ -264,7 +305,7 @@ static png_byte onebppswaptable[256] = {
    0x1F, 0x9F, 0x5F, 0xDF, 0x3F, 0xBF, 0x7F, 0xFF
 };
 
    0x1F, 0x9F, 0x5F, 0xDF, 0x3F, 0xBF, 0x7F, 0xFF
 };
 

-static png_byte twobppswaptable[256] = {
+static PNG_CONST png_byte twobppswaptable[256] = {

    0x00, 0x40, 0x80, 0xC0, 0x10, 0x50, 0x90, 0xD0,
    0x20, 0x60, 0xA0, 0xE0, 0x30, 0x70, 0xB0, 0xF0,
    0x04, 0x44, 0x84, 0xC4, 0x14, 0x54, 0x94, 0xD4,
    0x00, 0x40, 0x80, 0xC0, 0x10, 0x50, 0x90, 0xD0,
    0x20, 0x60, 0xA0, 0xE0, 0x30, 0x70, 0xB0, 0xF0,
    0x04, 0x44, 0x84, 0xC4, 0x14, 0x54, 0x94, 0xD4,


@@ -299,7 +340,7 @@ static png_byte twobppswaptable[256] = {
    0x2F, 0x6F, 0xAF, 0xEF, 0x3F, 0x7F, 0xBF, 0xFF
 };
 
    0x2F, 0x6F, 0xAF, 0xEF, 0x3F, 0x7F, 0xBF, 0xFF
 };
 

-static png_byte fourbppswaptable[256] = {
+static PNG_CONST png_byte fourbppswaptable[256] = {

    0x00, 0x10, 0x20, 0x30, 0x40, 0x50, 0x60, 0x70,
    0x80, 0x90, 0xA0, 0xB0, 0xC0, 0xD0, 0xE0, 0xF0,
    0x01, 0x11, 0x21, 0x31, 0x41, 0x51, 0x61, 0x71,
    0x00, 0x10, 0x20, 0x30, 0x40, 0x50, 0x60, 0x70,
    0x80, 0x90, 0xA0, 0xB0, 0xC0, 0xD0, 0xE0, 0xF0,
    0x01, 0x11, 0x21, 0x31, 0x41, 0x51, 0x61, 0x71,


@@ -334,15 +375,13 @@ static png_byte fourbppswaptable[256] = {
    0x8F, 0x9F, 0xAF, 0xBF, 0xCF, 0xDF, 0xEF, 0xFF
 };
 
    0x8F, 0x9F, 0xAF, 0xBF, 0xCF, 0xDF, 0xEF, 0xFF
 };
 

-/* swaps pixel packing order within bytes */
+/* Swaps pixel packing order within bytes */

 void /* PRIVATE */
 png_do_packswap(png_row_infop row_info, png_bytep row)
 {
 void /* PRIVATE */
 png_do_packswap(png_row_infop row_info, png_bytep row)
 {

-   png_debug(1, "in png_do_packswap\n");
+   png_debug(1, "in png_do_packswap");
+

    if (
    if (

-#if defined(PNG_USELESS_TESTS_SUPPORTED)
-       row != NULL && row_info != NULL &&
-#endif

        row_info->bit_depth < 8)
    {
       png_bytep rp, end, table;
        row_info->bit_depth < 8)
    {
       png_bytep rp, end, table;


@@ -350,11 +389,11 @@ png_do_packswap(png_row_infop row_info, png_bytep row)
       end = row + row_info->rowbytes;
 
       if (row_info->bit_depth == 1)
       end = row + row_info->rowbytes;
 
       if (row_info->bit_depth == 1)

-         table = onebppswaptable;
+         table = (png_bytep)onebppswaptable;

       else if (row_info->bit_depth == 2)
       else if (row_info->bit_depth == 2)

-         table = twobppswaptable;
+         table = (png_bytep)twobppswaptable;

       else if (row_info->bit_depth == 4)
       else if (row_info->bit_depth == 4)

-         table = fourbppswaptable;
+         table = (png_bytep)fourbppswaptable;

       else
          return;
 
       else
          return;
 


@@ -366,25 +405,22 @@ png_do_packswap(png_row_infop row_info, png_bytep row)
 
 #if defined(PNG_WRITE_FILLER_SUPPORTED) || \
     defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
 
 #if defined(PNG_WRITE_FILLER_SUPPORTED) || \
     defined(PNG_READ_STRIP_ALPHA_SUPPORTED)

-/* remove filler or alpha byte(s) */
+/* Remove filler or alpha byte(s) */

 void /* PRIVATE */
 png_do_strip_filler(png_row_infop row_info, png_bytep row, png_uint_32 flags)
 {
 void /* PRIVATE */
 png_do_strip_filler(png_row_infop row_info, png_bytep row, png_uint_32 flags)
 {

-   png_debug(1, "in png_do_strip_filler\n");
-#if defined(PNG_USELESS_TESTS_SUPPORTED)
-   if (row != NULL && row_info != NULL)
-#endif
+   png_debug(1, "in png_do_strip_filler");
+

    {
    {

-/*
-      if (row_info->color_type == PNG_COLOR_TYPE_RGB ||
-          row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
-*/

       png_bytep sp=row;
       png_bytep dp=row;
       png_uint_32 row_width=row_info->width;
       png_uint_32 i;
 
       png_bytep sp=row;
       png_bytep dp=row;
       png_uint_32 row_width=row_info->width;
       png_uint_32 i;
 

-      if (row_info->channels == 4)
+      if ((row_info->color_type == PNG_COLOR_TYPE_RGB ||
+          (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA &&
+          (flags & PNG_FLAG_STRIP_ALPHA))) &&
+          row_info->channels == 4)

       {
          if (row_info->bit_depth == 8)
          {
       {
          if (row_info->bit_depth == 8)
          {


@@ -461,13 +497,11 @@ png_do_strip_filler(png_row_infop row_info, png_bytep row, png_uint_32 flags)
             row_info->rowbytes = row_width * 6;
          }
          row_info->channels = 3;
             row_info->rowbytes = row_width * 6;
          }
          row_info->channels = 3;

-         row_info->color_type &= ~PNG_COLOR_MASK_ALPHA;

       }
       }

-/*
-      else if (row_info->color_type == PNG_COLOR_TYPE_GRAY ||
-               row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
-*/
-      else if (row_info->channels == 2)
+      else if ((row_info->color_type == PNG_COLOR_TYPE_GRAY ||
+         (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA &&
+         (flags & PNG_FLAG_STRIP_ALPHA))) &&
+          row_info->channels == 2)

       {
          if (row_info->bit_depth == 8)
          {
       {
          if (row_info->bit_depth == 8)
          {


@@ -519,22 +553,21 @@ png_do_strip_filler(png_row_infop row_info, png_bytep row, png_uint_32 flags)
             row_info->rowbytes = row_width * 2;
          }
          row_info->channels = 1;
             row_info->rowbytes = row_width * 2;
          }
          row_info->channels = 1;

-         row_info->color_type &= ~PNG_COLOR_MASK_ALPHA;

       }
       }

+      if (flags & PNG_FLAG_STRIP_ALPHA)
+        row_info->color_type &= ~PNG_COLOR_MASK_ALPHA;

    }
 }
 #endif
 
 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
    }
 }
 #endif
 
 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)

-/* swaps red and blue bytes within a pixel */
+/* Swaps red and blue bytes within a pixel */

 void /* PRIVATE */
 png_do_bgr(png_row_infop row_info, png_bytep row)
 {
 void /* PRIVATE */
 png_do_bgr(png_row_infop row_info, png_bytep row)
 {

-   png_debug(1, "in png_do_bgr\n");
+   png_debug(1, "in png_do_bgr");
+

    if (
    if (

-#if defined(PNG_USELESS_TESTS_SUPPORTED)
-       row != NULL && row_info != NULL &&
-#endif

        (row_info->color_type & PNG_COLOR_MASK_COLOR))
    {
       png_uint_32 row_width = row_info->width;
        (row_info->color_type & PNG_COLOR_MASK_COLOR))
    {
       png_uint_32 row_width = row_info->width;


@@ -603,24 +636,25 @@ png_do_bgr(png_row_infop row_info, png_bytep row)
 #endif /* PNG_READ_BGR_SUPPORTED or PNG_WRITE_BGR_SUPPORTED */
 
 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
 #endif /* PNG_READ_BGR_SUPPORTED or PNG_WRITE_BGR_SUPPORTED */
 
 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \

-    defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) || \
-    defined(PNG_LEGACY_SUPPORTED)
+    defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)

 void PNGAPI
 png_set_user_transform_info(png_structp png_ptr, png_voidp
    user_transform_ptr, int user_transform_depth, int user_transform_channels)
 {
 void PNGAPI
 png_set_user_transform_info(png_structp png_ptr, png_voidp
    user_transform_ptr, int user_transform_depth, int user_transform_channels)
 {

-   png_debug(1, "in png_set_user_transform_info\n");
-#if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
+   png_debug(1, "in png_set_user_transform_info");
+
+   if (png_ptr == NULL)
+      return;
+#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED

    png_ptr->user_transform_ptr = user_transform_ptr;
    png_ptr->user_transform_depth = (png_byte)user_transform_depth;
    png_ptr->user_transform_channels = (png_byte)user_transform_channels;
 #else
    png_ptr->user_transform_ptr = user_transform_ptr;
    png_ptr->user_transform_depth = (png_byte)user_transform_depth;
    png_ptr->user_transform_channels = (png_byte)user_transform_channels;
 #else

-   if(user_transform_ptr || user_transform_depth || user_transform_channels)
+   if (user_transform_ptr || user_transform_depth || user_transform_channels)

       png_warning(png_ptr,
         "This version of libpng does not support user transform info");
 #endif
 }
       png_warning(png_ptr,
         "This version of libpng does not support user transform info");
 #endif
 }

-#endif

 
 /* This function returns a pointer to the user_transform_ptr associated with
  * the user transform functions.  The application should free any memory
 
 /* This function returns a pointer to the user_transform_ptr associated with
  * the user transform functions.  The application should free any memory


@@ -630,11 +664,14 @@ png_set_user_transform_info(png_structp png_ptr, png_voidp
 png_voidp PNGAPI
 png_get_user_transform_ptr(png_structp png_ptr)
 {
 png_voidp PNGAPI
 png_get_user_transform_ptr(png_structp png_ptr)
 {

-#if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
+   if (png_ptr == NULL)
+      return (NULL);
+#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED

    return ((png_voidp)png_ptr->user_transform_ptr);
 #else
    return ((png_voidp)png_ptr->user_transform_ptr);
 #else

-   if(png_ptr)
-     return (NULL);

    return (NULL);
 #endif
 }
    return (NULL);
 #endif
 }

+#endif /* PNG_READ_USER_TRANSFORM_SUPPORTED ||
+          PNG_WRITE_USER_TRANSFORM_SUPPORTED */
+#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */