Imported from libpng-1.2.9beta9.tar

pngwrite.c

@@ -1,7 +1,7 @@
 
 /* pngwrite.c - general routines to write a PNG file
  *
- * Last changed in libpng 1.2.9 March 9, 2006
+ * Last changed in libpng 1.2.9 March 10, 2006
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2006 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
@@ -26,6 +26,8 @@ void PNGAPI
 png_write_info_before_PLTE(png_structp png_ptr, png_infop info_ptr)
 {
    png_debug(1, "in png_write_info_before_PLTE\n");
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
    if (!(png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE))
    {
    png_write_sig(png_ptr); /* write PNG signature */
@@ -128,6 +130,9 @@ png_write_info(png_structp png_ptr, png_infop info_ptr)
 
    png_debug(1, "in png_write_info\n");
 
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
    png_write_info_before_PLTE(png_ptr, info_ptr);
 
    if (info_ptr->valid & PNG_INFO_PLTE)
@@ -290,6 +295,8 @@ void PNGAPI
 png_write_end(png_structp png_ptr, png_infop info_ptr)
 {
    png_debug(1, "in png_write_end\n");
+   if (png_ptr == NULL)
+      return;
    if (!(png_ptr->mode & PNG_HAVE_IDAT))
       png_error(png_ptr, "No IDATs written into file");
 
@@ -617,6 +624,10 @@ png_write_init_3(png_structpp ptr_ptr, png_const_charp user_png_ver,
 #ifdef PNG_SETJMP_SUPPORTED
    jmp_buf tmp_jmp; /* to save current jump buffer */
 #endif
+
+   if (png_ptr == NULL)
+      return;
+
    int i = 0;
    do
    {
@@ -694,6 +705,10 @@ png_write_rows(png_structp png_ptr, png_bytepp row,
    png_bytepp rp; /* row pointer */
 
    png_debug(1, "in png_write_rows\n");
+
+   if (png_ptr == NULL)
+      return;
+
    /* loop through the rows */
    for (i = 0, rp = row; i < num_rows; i++, rp++)
    {
@@ -711,6 +726,9 @@ png_write_image(png_structp png_ptr, png_bytepp image)
    int pass, num_pass; /* pass variables */
    png_bytepp rp; /* points to current row */
 
+   if (png_ptr == NULL)
+      return;
+
    png_debug(1, "in png_write_image\n");
 #if defined(PNG_WRITE_INTERLACING_SUPPORTED)
    /* intialize interlace handling.  If image is not interlaced,
@@ -734,8 +752,11 @@ png_write_image(png_structp png_ptr, png_bytepp image)
 void PNGAPI
 png_write_row(png_structp png_ptr, png_bytep row)
 {
+   if (png_ptr == NULL)
+      return;
    png_debug2(1, "in png_write_row (row %ld, pass %d)\n",
       png_ptr->row_number, png_ptr->pass);
+
    /* initialize transformations and other stuff if first time */
    if (png_ptr->row_number == 0 && png_ptr->pass == 0)
    {
@@ -909,6 +930,8 @@ void PNGAPI
 png_set_flush(png_structp png_ptr, int nrows)
 {
    png_debug(1, "in png_set_flush\n");
+   if (png_ptr == NULL)
+      return;
    png_ptr->flush_dist = (nrows < 0 ? 0 : nrows);
 }
 
@@ -919,6 +942,8 @@ png_write_flush(png_structp png_ptr)
    int wrote_IDAT;
 
    png_debug(1, "in png_write_flush\n");
+   if (png_ptr == NULL)
+      return;
    /* We have already written out all of the data */
    if (png_ptr->row_number >= png_ptr->num_rows)
      return;
@@ -1095,6 +1120,8 @@ void PNGAPI
 png_set_filter(png_structp png_ptr, int method, int filters)
 {
    png_debug(1, "in png_set_filter\n");
+   if (png_ptr == NULL)
+      return;
 #if defined(PNG_MNG_FEATURES_SUPPORTED)
    if((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
       (method == PNG_INTRAPIXEL_DIFFERENCING))
@@ -1203,6 +1230,8 @@ png_set_filter_heuristics(png_structp png_ptr, int heuristic_method,
    int i;
 
    png_debug(1, "in png_set_filter_heuristics\n");
+   if (png_ptr == NULL)
+      return;
    if (heuristic_method >= PNG_FILTER_HEURISTIC_LAST)
    {
       png_warning(png_ptr, "Unknown filter heuristic method");
@@ -1315,6 +1344,8 @@ void PNGAPI
 png_set_compression_level(png_structp png_ptr, int level)
 {
    png_debug(1, "in png_set_compression_level\n");
+   if (png_ptr == NULL)
+      return;
    png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_LEVEL;
    png_ptr->zlib_level = level;
 }
@@ -1323,6 +1354,8 @@ void PNGAPI
 png_set_compression_mem_level(png_structp png_ptr, int mem_level)
 {
    png_debug(1, "in png_set_compression_mem_level\n");
+   if (png_ptr == NULL)
+      return;
    png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_MEM_LEVEL;
    png_ptr->zlib_mem_level = mem_level;
 }
@@ -1331,6 +1364,8 @@ void PNGAPI
 png_set_compression_strategy(png_structp png_ptr, int strategy)
 {
    png_debug(1, "in png_set_compression_strategy\n");
+   if (png_ptr == NULL)
+      return;
    png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_STRATEGY;
    png_ptr->zlib_strategy = strategy;
 }
@@ -1338,6 +1373,8 @@ png_set_compression_strategy(png_structp png_ptr, int strategy)
 void PNGAPI
 png_set_compression_window_bits(png_structp png_ptr, int window_bits)
 {
+   if (png_ptr == NULL)
+      return;
    if (window_bits > 15)
       png_warning(png_ptr, "Only compression windows <= 32k supported by PNG");
    else if (window_bits < 8)
@@ -1358,6 +1395,8 @@ void PNGAPI
 png_set_compression_method(png_structp png_ptr, int method)
 {
    png_debug(1, "in png_set_compression_method\n");
+   if (png_ptr == NULL)
+      return;
    if (method != 8)
       png_warning(png_ptr, "Only compression method 8 is supported by PNG");
    png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_METHOD;
@@ -1367,6 +1406,8 @@ png_set_compression_method(png_structp png_ptr, int method)
 void PNGAPI
 png_set_write_status_fn(png_structp png_ptr, png_write_status_ptr write_row_fn)
 {
+   if (png_ptr == NULL)
+      return;
    png_ptr->write_row_fn = write_row_fn;
 }
 
@@ -1376,6 +1417,8 @@ png_set_write_user_transform_fn(png_structp png_ptr, png_user_transform_ptr
    write_user_transform_fn)
 {
    png_debug(1, "in png_set_write_user_transform_fn\n");
+   if (png_ptr == NULL)
+      return;
    png_ptr->transformations |= PNG_USER_TRANSFORM;
    png_ptr->write_user_transform_fn = write_user_transform_fn;
 }
@@ -1387,6 +1430,8 @@ void PNGAPI
 png_write_png(png_structp png_ptr, png_infop info_ptr,
               int transforms, voidp params)
 {
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
 #if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
    /* invert the alpha channel from opacity to transparency */
    if (transforms & PNG_TRANSFORM_INVERT_ALPHA)