|
Carlos Lopez |
a09598 |
|
|
Carlos Lopez |
a09598 |
/* pngrio.c - functions for data input
|
|
Carlos Lopez |
a09598 |
*
|
|
Carlos Lopez |
a09598 |
* libpng 1.2.5 - October 3, 2002
|
|
Carlos Lopez |
a09598 |
* For conditions of distribution and use, see copyright notice in png.h
|
|
Carlos Lopez |
a09598 |
* Copyright (c) 1998-2002 Glenn Randers-Pehrson
|
|
Carlos Lopez |
a09598 |
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
|
|
Carlos Lopez |
a09598 |
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
|
|
Carlos Lopez |
a09598 |
*
|
|
Carlos Lopez |
a09598 |
* This file provides a location for all input. Users who need
|
|
Carlos Lopez |
a09598 |
* special handling are expected to write a function that has the same
|
|
Carlos Lopez |
a09598 |
* arguments as this and performs a similar function, but that possibly
|
|
Carlos Lopez |
a09598 |
* has a different input method. Note that you shouldn't change this
|
|
Carlos Lopez |
a09598 |
* function, but rather write a replacement function and then make
|
|
Carlos Lopez |
a09598 |
* libpng use it at run time with png_set_read_fn(...).
|
|
Carlos Lopez |
a09598 |
*/
|
|
Carlos Lopez |
a09598 |
|
|
Carlos Lopez |
a09598 |
#define PNG_INTERNAL
|
|
Carlos Lopez |
a09598 |
#include "png.h"
|
|
Carlos Lopez |
a09598 |
|
|
Carlos Lopez |
a09598 |
/* Read the data from whatever input you are using. The default routine
|
|
Carlos Lopez |
a09598 |
reads from a file pointer. Note that this routine sometimes gets called
|
|
Carlos Lopez |
a09598 |
with very small lengths, so you should implement some kind of simple
|
|
Carlos Lopez |
a09598 |
buffering if you are using unbuffered reads. This should never be asked
|
|
Carlos Lopez |
a09598 |
to read more then 64K on a 16 bit machine. */
|
|
Carlos Lopez |
a09598 |
void /* PRIVATE */
|
|
Carlos Lopez |
a09598 |
png_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
|
|
Carlos Lopez |
a09598 |
{
|
|
Carlos Lopez |
a09598 |
png_debug1(4,"reading %d bytes\n", (int)length);
|
|
Carlos Lopez |
a09598 |
if (png_ptr->read_data_fn != NULL)
|
|
Carlos Lopez |
a09598 |
(*(png_ptr->read_data_fn))(png_ptr, data, length);
|
|
Carlos Lopez |
a09598 |
else
|
|
Carlos Lopez |
a09598 |
png_error(png_ptr, "Call to NULL read function");
|
|
Carlos Lopez |
a09598 |
}
|
|
Carlos Lopez |
a09598 |
|
|
Carlos Lopez |
a09598 |
#if !defined(PNG_NO_STDIO)
|
|
Carlos Lopez |
a09598 |
/* This is the function that does the actual reading of data. If you are
|
|
Carlos Lopez |
a09598 |
not reading from a standard C stream, you should create a replacement
|
|
Carlos Lopez |
a09598 |
read_data function and use it at run time with png_set_read_fn(), rather
|
|
Carlos Lopez |
a09598 |
than changing the library. */
|
|
Carlos Lopez |
a09598 |
#ifndef USE_FAR_KEYWORD
|
|
Carlos Lopez |
a09598 |
void PNGAPI
|
|
Carlos Lopez |
a09598 |
png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
|
|
Carlos Lopez |
a09598 |
{
|
|
Carlos Lopez |
a09598 |
png_size_t check;
|
|
Carlos Lopez |
a09598 |
|
|
Carlos Lopez |
a09598 |
/* fread() returns 0 on error, so it is OK to store this in a png_size_t
|
|
Carlos Lopez |
a09598 |
* instead of an int, which is what fread() actually returns.
|
|
Carlos Lopez |
a09598 |
*/
|
|
Carlos Lopez |
a09598 |
#if defined(_WIN32_WCE)
|
|
Carlos Lopez |
a09598 |
if ( !ReadFile((HANDLE)(png_ptr->io_ptr), data, length, &check, NULL) )
|
|
Carlos Lopez |
a09598 |
check = 0;
|
|
Carlos Lopez |
a09598 |
#else
|
|
Carlos Lopez |
a09598 |
check = (png_size_t)fread(data, (png_size_t)1, length,
|
|
Carlos Lopez |
a09598 |
(png_FILE_p)png_ptr->io_ptr);
|
|
Carlos Lopez |
a09598 |
#endif
|
|
Carlos Lopez |
a09598 |
|
|
Carlos Lopez |
a09598 |
if (check != length)
|
|
Carlos Lopez |
a09598 |
png_error(png_ptr, "Read Error");
|
|
Carlos Lopez |
a09598 |
}
|
|
Carlos Lopez |
a09598 |
#else
|
|
Carlos Lopez |
a09598 |
/* this is the model-independent version. Since the standard I/O library
|
|
Carlos Lopez |
a09598 |
can't handle far buffers in the medium and small models, we have to copy
|
|
Carlos Lopez |
a09598 |
the data.
|
|
Carlos Lopez |
a09598 |
*/
|
|
Carlos Lopez |
a09598 |
|
|
Carlos Lopez |
a09598 |
#define NEAR_BUF_SIZE 1024
|
|
Carlos Lopez |
a09598 |
#define MIN(a,b) (a <= b ? a : b)
|
|
Carlos Lopez |
a09598 |
|
|
Carlos Lopez |
a09598 |
static void /* PRIVATE */
|
|
Carlos Lopez |
a09598 |
png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
|
|
Carlos Lopez |
a09598 |
{
|
|
Carlos Lopez |
a09598 |
int check;
|
|
Carlos Lopez |
a09598 |
png_byte *n_data;
|
|
Carlos Lopez |
a09598 |
png_FILE_p io_ptr;
|
|
Carlos Lopez |
a09598 |
|
|
Carlos Lopez |
a09598 |
/* Check if data really is near. If so, use usual code. */
|
|
Carlos Lopez |
a09598 |
n_data = (png_byte *)CVT_PTR_NOCHECK(data);
|
|
Carlos Lopez |
a09598 |
io_ptr = (png_FILE_p)CVT_PTR(png_ptr->io_ptr);
|
|
Carlos Lopez |
a09598 |
if ((png_bytep)n_data == data)
|
|
Carlos Lopez |
a09598 |
{
|
|
Carlos Lopez |
a09598 |
#if defined(_WIN32_WCE)
|
|
Carlos Lopez |
a09598 |
if ( !ReadFile((HANDLE)(png_ptr->io_ptr), data, length, &check, NULL) )
|
|
Carlos Lopez |
a09598 |
check = 0;
|
|
Carlos Lopez |
a09598 |
#else
|
|
Carlos Lopez |
a09598 |
check = fread(n_data, 1, length, io_ptr);
|
|
Carlos Lopez |
a09598 |
#endif
|
|
Carlos Lopez |
a09598 |
}
|
|
Carlos Lopez |
a09598 |
else
|
|
Carlos Lopez |
a09598 |
{
|
|
Carlos Lopez |
a09598 |
png_byte buf[NEAR_BUF_SIZE];
|
|
Carlos Lopez |
a09598 |
png_size_t read, remaining, err;
|
|
Carlos Lopez |
a09598 |
check = 0;
|
|
Carlos Lopez |
a09598 |
remaining = length;
|
|
Carlos Lopez |
a09598 |
do
|
|
Carlos Lopez |
a09598 |
{
|
|
Carlos Lopez |
a09598 |
read = MIN(NEAR_BUF_SIZE, remaining);
|
|
Carlos Lopez |
a09598 |
#if defined(_WIN32_WCE)
|
|
Carlos Lopez |
a09598 |
if ( !ReadFile((HANDLE)(io_ptr), buf, read, &err, NULL) )
|
|
Carlos Lopez |
a09598 |
err = 0;
|
|
Carlos Lopez |
a09598 |
#else
|
|
Carlos Lopez |
a09598 |
err = fread(buf, (png_size_t)1, read, io_ptr);
|
|
Carlos Lopez |
a09598 |
#endif
|
|
Carlos Lopez |
a09598 |
png_memcpy(data, buf, read); /* copy far buffer to near buffer */
|
|
Carlos Lopez |
a09598 |
if(err != read)
|
|
Carlos Lopez |
a09598 |
break;
|
|
Carlos Lopez |
a09598 |
else
|
|
Carlos Lopez |
a09598 |
check += err;
|
|
Carlos Lopez |
a09598 |
data += read;
|
|
Carlos Lopez |
a09598 |
remaining -= read;
|
|
Carlos Lopez |
a09598 |
}
|
|
Carlos Lopez |
a09598 |
while (remaining != 0);
|
|
Carlos Lopez |
a09598 |
}
|
|
Carlos Lopez |
a09598 |
if ((png_uint_32)check != (png_uint_32)length)
|
|
Carlos Lopez |
a09598 |
png_error(png_ptr, "read Error");
|
|
Carlos Lopez |
a09598 |
}
|
|
Carlos Lopez |
a09598 |
#endif
|
|
Carlos Lopez |
a09598 |
#endif
|
|
Carlos Lopez |
a09598 |
|
|
Carlos Lopez |
a09598 |
/* This function allows the application to supply a new input function
|
|
Carlos Lopez |
a09598 |
for libpng if standard C streams aren't being used.
|
|
Carlos Lopez |
a09598 |
|
|
Carlos Lopez |
a09598 |
This function takes as its arguments:
|
|
Carlos Lopez |
a09598 |
png_ptr - pointer to a png input data structure
|
|
Carlos Lopez |
a09598 |
io_ptr - pointer to user supplied structure containing info about
|
|
Carlos Lopez |
a09598 |
the input functions. May be NULL.
|
|
Carlos Lopez |
a09598 |
read_data_fn - pointer to a new input function that takes as its
|
|
Carlos Lopez |
a09598 |
arguments a pointer to a png_struct, a pointer to
|
|
Carlos Lopez |
a09598 |
a location where input data can be stored, and a 32-bit
|
|
Carlos Lopez |
a09598 |
unsigned int that is the number of bytes to be read.
|
|
Carlos Lopez |
a09598 |
To exit and output any fatal error messages the new write
|
|
Carlos Lopez |
a09598 |
function should call png_error(png_ptr, "Error msg"). */
|
|
Carlos Lopez |
a09598 |
void PNGAPI
|
|
Carlos Lopez |
a09598 |
png_set_read_fn(png_structp png_ptr, png_voidp io_ptr,
|
|
Carlos Lopez |
a09598 |
png_rw_ptr read_data_fn)
|
|
Carlos Lopez |
a09598 |
{
|
|
Carlos Lopez |
a09598 |
png_ptr->io_ptr = io_ptr;
|
|
Carlos Lopez |
a09598 |
|
|
Carlos Lopez |
a09598 |
#if !defined(PNG_NO_STDIO)
|
|
Carlos Lopez |
a09598 |
if (read_data_fn != NULL)
|
|
Carlos Lopez |
a09598 |
png_ptr->read_data_fn = read_data_fn;
|
|
Carlos Lopez |
a09598 |
else
|
|
Carlos Lopez |
a09598 |
png_ptr->read_data_fn = png_default_read_data;
|
|
Carlos Lopez |
a09598 |
#else
|
|
Carlos Lopez |
a09598 |
png_ptr->read_data_fn = read_data_fn;
|
|
Carlos Lopez |
a09598 |
#endif
|
|
Carlos Lopez |
a09598 |
|
|
Carlos Lopez |
a09598 |
/* It is an error to write to a read device */
|
|
Carlos Lopez |
a09598 |
if (png_ptr->write_data_fn != NULL)
|
|
Carlos Lopez |
a09598 |
{
|
|
Carlos Lopez |
a09598 |
png_ptr->write_data_fn = NULL;
|
|
Carlos Lopez |
a09598 |
png_warning(png_ptr,
|
|
Carlos Lopez |
a09598 |
"It's an error to set both read_data_fn and write_data_fn in the ");
|
|
Carlos Lopez |
a09598 |
png_warning(png_ptr,
|
|
Carlos Lopez |
a09598 |
"same structure. Resetting write_data_fn to NULL.");
|
|
Carlos Lopez |
a09598 |
}
|
|
Carlos Lopez |
a09598 |
|
|
Carlos Lopez |
a09598 |
#if defined(PNG_WRITE_FLUSH_SUPPORTED)
|
|
Carlos Lopez |
a09598 |
png_ptr->output_flush_fn = NULL;
|
|
Carlos Lopez |
a09598 |
#endif
|
|
Carlos Lopez |
a09598 |
}
|