*** empty log message ***

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

diff --git a/src/png/pngrio.c b/src/png/pngrio.c
index 7adb48f54c940c70beb3346acdc9e512e32ea122..23bbb2b6603512a7765355c312a0e202748222bc 100644 (file)
--- a/src/png/pngrio.c
+++ b/src/png/pngrio.c
@@ -1,17 +1,16 @@
 
 /* pngrio.c - functions for data input
  *
- * libpng 1.0.1
+ * libpng 1.0.3 - January 14, 1999
  * 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
+ * Copyright (c) 1998, 1999 Glenn Randers-Pehrson
  *
- * This file provides a location for all input.  Users which need
- * special handling are expected to write a function which has the same
- * arguments as this, and perform a similar function, but possibly has
- * a different input method.  Note that you shouldn't change this
+ * This file provides a location for all input.  Users who need
+ * special handling are expected to write a function that has the same
+ * arguments as this and performs a similar function, but that possibly
+ * has a different input method.  Note that you shouldn't change this
  * function, but rather write a replacement function and then make
  * libpng use it at run time with png_set_read_fn(...).
  */
@@ -35,7 +34,7 @@ png_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
 }
 
 #if !defined(PNG_NO_STDIO)
-/* This is the function which does the actual reading of data.  If you are
+/* This is the function that does the actual reading of data.  If you are
    not reading from a standard C stream, you should create a replacement
    read_data function and use it at run time with png_set_read_fn(), rather
    than changing the library. */
@@ -61,10 +60,10 @@ png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
    can't handle far buffers in the medium and small models, we have to copy
    the data.
 */
- 
+
 #define NEAR_BUF_SIZE 1024
 #define MIN(a,b) (a <= b ? a : b)
- 
+
 static void
 png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
 {
@@ -114,10 +113,10 @@ png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
    png_ptr      - pointer to a png input data structure
    io_ptr       - pointer to user supplied structure containing info about
                   the input functions.  May be NULL.
-   read_data_fn - pointer to a new input function which takes as it's
+   read_data_fn - pointer to a new input function that takes as its
                   arguments a pointer to a png_struct, a pointer to
                   a location where input data can be stored, and a 32-bit
-                  unsigned int which is the number of bytes to be read.
+                  unsigned int that is the number of bytes to be read.
                   To exit and output any fatal error messages the new write
                   function should call png_error(png_ptr, "Error msg"). */
 void
@@ -136,7 +135,14 @@ png_set_read_fn(png_structp png_ptr, png_voidp io_ptr,
 #endif
 
    /* It is an error to write to a read device */
-   png_ptr->write_data_fn = NULL;
+   if (png_ptr->write_data_fn != NULL)
+   {
+      png_ptr->write_data_fn = NULL;
+      png_warning(png_ptr,
+         "It's an error to set both read_data_fn and write_data_fn in the ");
+      png_warning(png_ptr,
+         "same structure.  Resetting write_data_fn to NULL.");
+   }
 
 #if defined(PNG_WRITE_FLUSH_SUPPORTED)
    png_ptr->output_flush_fn = NULL;