libpng: update to 1.2.45

third_party/libpng/pngerror.c

 
 /* pngerror.c - stub functions for i/o and memory allocation
  *
- * Last changed in libpng 1.2.41 [December 3, 2009]
- * Copyright (c) 1998-2009 Glenn Randers-Pehrson
+ * Last changed in libpng 1.2.45 [July 7, 2011]
+ * Copyright (c) 1998-2011 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
  * and license in png.h
  *
  * This file provides a location for all error handling.  Users who
  * need special error handling are expected to write replacement functions
  * and use png_set_error_fn() to use those functions.  See the instructions
@@ skipping 64 matching lines @@
       (*(png_ptr->error_fn))(png_ptr, error_message);
 
    /* If the custom handler doesn't exist, or if it returns,
       use the default handler, which will not return. */
    png_default_error(png_ptr, error_message);
 }
 #else
 void PNGAPI
 png_err(png_structp png_ptr)
 {
+   /* Prior to 1.2.45 the error_fn received a NULL pointer, expressed
+    * erroneously as '\0', instead of the empty string "".  This was
+    * apparently an error, introduced in libpng-1.2.20, and png_default_error
+    * will crash in this case.
+    */
    if (png_ptr != NULL && png_ptr->error_fn != NULL)
-      (*(png_ptr->error_fn))(png_ptr, '\0');
+      (*(png_ptr->error_fn))(png_ptr, "");
 
    /* If the custom handler doesn't exist, or if it returns,
       use the default handler, which will not return. */
-   png_default_error(png_ptr, '\0');
+   png_default_error(png_ptr, "");
 }
 #endif /* PNG_ERROR_TEXT_SUPPORTED */
 
 #ifdef PNG_WARNINGS_SUPPORTED
 /* This function is called whenever there is a non-fatal error.  This function
  * should not be changed.  If there is a need to handle warnings differently,
  * you should supply a replacement warning function and use
  * png_set_error_fn() to replace the warning function at run-time.
  */
 void PNGAPI
@@ skipping 68 matching lines @@
          buffer[iout++] = (png_byte)c;
       }
    }
 
    if (error_message == NULL)
       buffer[iout] = '\0';
    else
    {
       buffer[iout++] = ':';
       buffer[iout++] = ' ';
-      png_memcpy(buffer + iout, error_message, PNG_MAX_ERROR_TEXT);
-      buffer[iout + PNG_MAX_ERROR_TEXT - 1] = '\0';
+
+      iin = 0;
+      while (iin < PNG_MAX_ERROR_TEXT-1 && error_message[iin] != '\0')
+         buffer[iout++] = error_message[iin++];
+
+      /* iin < PNG_MAX_ERROR_TEXT, so the following is safe: */
+      buffer[iout] = '\0';
    }
 }
 
 #ifdef PNG_READ_SUPPORTED
 void PNGAPI
 png_chunk_error(png_structp png_ptr, png_const_charp error_message)
 {
    char msg[18+PNG_MAX_ERROR_TEXT];
    if (png_ptr == NULL)
      png_error(png_ptr, error_message);
@@ skipping 181 matching lines @@
 png_set_strip_error_numbers(png_structp png_ptr, png_uint_32 strip_mode)
 {
    if (png_ptr != NULL)
    {
      png_ptr->flags &=
        ((~(PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT))&strip_mode);
    }
 }
 #endif
 #endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */