- * 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) 1998-2006 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 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(...).
*/
* function, but rather write a replacement function and then make
* libpng use it at run time with png_set_read_fn(...).
*/
/* Read the data from whatever input you are using. The default routine
reads from a file pointer. Note that this routine sometimes gets called
with very small lengths, so you should implement some kind of simple
buffering if you are using unbuffered reads. This should never be asked
to read more then 64K on a 16 bit machine. */
/* Read the data from whatever input you are using. The default routine
reads from a file pointer. Note that this routine sometimes gets called
with very small lengths, so you should implement some kind of simple
buffering if you are using unbuffered reads. This should never be asked
to read more then 64K on a 16 bit machine. */
if (png_ptr->read_data_fn != NULL)
(*(png_ptr->read_data_fn))(png_ptr, data, length);
else
if (png_ptr->read_data_fn != NULL)
(*(png_ptr->read_data_fn))(png_ptr, data, length);
else
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. */
#ifndef USE_FAR_KEYWORD
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. */
#ifndef USE_FAR_KEYWORD
/* fread() returns 0 on error, so it is OK to store this in a png_size_t
* instead of an int, which is what fread() actually returns.
*/
/* fread() returns 0 on error, so it is OK to store this in a png_size_t
* instead of an int, which is what fread() actually returns.
*/
check = (png_size_t)fread(data, (png_size_t)1, length,
check = (png_size_t)fread(data, (png_size_t)1, length,
}
#else
/* this is the model-independent version. Since the standard I/O library
can't handle far buffers in the medium and small models, we have to copy
the data.
*/
}
#else
/* this is the model-independent version. Since the standard I/O library
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)
#define NEAR_BUF_SIZE 1024
#define MIN(a,b) (a <= b ? a : b)
/* Check if data really is near. If so, use usual code. */
n_data = (png_byte *)CVT_PTR_NOCHECK(data);
/* Check if data really is near. If so, use usual code. */
n_data = (png_byte *)CVT_PTR_NOCHECK(data);
check = fread(n_data, 1, length, io_ptr);
check = fread(n_data, 1, length, io_ptr);
err = fread(buf, (png_size_t)1, read, io_ptr);
err = fread(buf, (png_size_t)1, read, io_ptr);
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.
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.
arguments a pointer to a png_struct, a pointer to
a location where input data can be stored, and a 32-bit
arguments a pointer to a png_struct, a pointer to
a location where input data can be stored, and a 32-bit
To exit and output any fatal error messages the new write
function should call png_error(png_ptr, "Error msg"). */
To exit and output any fatal error messages the new write
function should call png_error(png_ptr, "Error msg"). */
- 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.");
+ }