WebSVN - shark - Blame - Rev 96 - /shark/trunk/ports/png/pngrio.c

Rev	Author	Line No.	Line
96	giacomo	1
		2	/* pngrio.c - functions for data input
		3	*
		4	* libpng 1.2.5 - October 3, 2002
		5	* For conditions of distribution and use, see copyright notice in png.h
		6	* Copyright (c) 1998-2002 Glenn Randers-Pehrson
		7	* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
		8	* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
		9	*
		10	* This file provides a location for all input. Users who need
		11	* special handling are expected to write a function that has the same
		12	* arguments as this and performs a similar function, but that possibly
		13	* has a different input method. Note that you shouldn't change this
		14	* function, but rather write a replacement function and then make
		15	* libpng use it at run time with png_set_read_fn(...).
		16	*/
		17
		18	#define PNG_INTERNAL
		19	#include "png.h"
		20
		21	/* Read the data from whatever input you are using. The default routine
		22	reads from a file pointer. Note that this routine sometimes gets called
		23	with very small lengths, so you should implement some kind of simple
		24	buffering if you are using unbuffered reads. This should never be asked
		25	to read more then 64K on a 16 bit machine. */
		26	void /* PRIVATE */
		27	png_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
		28	{
		29	png_debug1(4,"reading %d bytes\n", (int)length);
		30	if (png_ptr->read_data_fn != NULL)
		31	(*(png_ptr->read_data_fn))(png_ptr, data, length);
		32	else
		33	png_error(png_ptr, "Call to NULL read function");
		34	}
		35
		36	#if !defined(PNG_NO_STDIO)
		37	/* This is the function that does the actual reading of data. If you are
		38	not reading from a standard C stream, you should create a replacement
		39	read_data function and use it at run time with png_set_read_fn(), rather
		40	than changing the library. */
		41	#ifndef USE_FAR_KEYWORD
		42	void PNGAPI
		43	png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
		44	{
		45	png_size_t check;
		46
		47	/* fread() returns 0 on error, so it is OK to store this in a png_size_t
		48	* instead of an int, which is what fread() actually returns.
		49	*/
		50	#if defined(_WIN32_WCE)
		51	if ( !ReadFile((HANDLE)(png_ptr->io_ptr), data, length, &check, NULL) )
		52	check = 0;
		53	#else
		54	check = (png_size_t)fread(data, (png_size_t)1, length,
		55	(png_FILE_p)png_ptr->io_ptr);
		56	#endif
		57
		58	if (check != length)
		59	png_error(png_ptr, "Read Error");
		60	}
		61	#else
		62	/* this is the model-independent version. Since the standard I/O library
		63	can't handle far buffers in the medium and small models, we have to copy
		64	the data.
		65	*/
		66
		67	#define NEAR_BUF_SIZE 1024
		68	#define MIN(a,b) (a <= b ? a : b)
		69
		70	static void /* PRIVATE */
		71	png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
		72	{
		73	int check;
		74	png_byte *n_data;
		75	png_FILE_p io_ptr;
		76
		77	/* Check if data really is near. If so, use usual code. */
		78	n_data = (png_byte *)CVT_PTR_NOCHECK(data);
		79	io_ptr = (png_FILE_p)CVT_PTR(png_ptr->io_ptr);
		80	if ((png_bytep)n_data == data)
		81	{
		82	#if defined(_WIN32_WCE)
		83	if ( !ReadFile((HANDLE)(png_ptr->io_ptr), data, length, &check, NULL) )
		84	check = 0;
		85	#else
		86	check = fread(n_data, 1, length, io_ptr);
		87	#endif
		88	}
		89	else
		90	{
		91	png_byte buf[NEAR_BUF_SIZE];
		92	png_size_t read, remaining, err;
		93	check = 0;
		94	remaining = length;
		95	do
		96	{
		97	read = MIN(NEAR_BUF_SIZE, remaining);
		98	#if defined(_WIN32_WCE)
		99	if ( !ReadFile((HANDLE)(io_ptr), buf, read, &err, NULL) )
		100	err = 0;
		101	#else
		102	err = fread(buf, (png_size_t)1, read, io_ptr);
		103	#endif
		104	png_memcpy(data, buf, read); /* copy far buffer to near buffer */
		105	if(err != read)
		106	break;
		107	else
		108	check += err;
		109	data += read;
		110	remaining -= read;
		111	}
		112	while (remaining != 0);
		113	}
		114	if ((png_uint_32)check != (png_uint_32)length)
		115	png_error(png_ptr, "read Error");
		116	}
		117	#endif
		118	#endif
		119
		120	/* This function allows the application to supply a new input function
		121	for libpng if standard C streams aren't being used.
		122
		123	This function takes as its arguments:
		124	png_ptr - pointer to a png input data structure
		125	io_ptr - pointer to user supplied structure containing info about
		126	the input functions. May be NULL.
		127	read_data_fn - pointer to a new input function that takes as its
		128	arguments a pointer to a png_struct, a pointer to
		129	a location where input data can be stored, and a 32-bit
		130	unsigned int that is the number of bytes to be read.
		131	To exit and output any fatal error messages the new write
		132	function should call png_error(png_ptr, "Error msg"). */
		133	void PNGAPI
		134	png_set_read_fn(png_structp png_ptr, png_voidp io_ptr,
		135	png_rw_ptr read_data_fn)
		136	{
		137	png_ptr->io_ptr = io_ptr;
		138
		139	#if !defined(PNG_NO_STDIO)
		140	if (read_data_fn != NULL)
		141	png_ptr->read_data_fn = read_data_fn;
		142	else
		143	png_ptr->read_data_fn = png_default_read_data;
		144	#else
		145	png_ptr->read_data_fn = read_data_fn;
		146	#endif
		147
		148	/* It is an error to write to a read device */
		149	if (png_ptr->write_data_fn != NULL)
		150	{
		151	png_ptr->write_data_fn = NULL;
		152	png_warning(png_ptr,
		153	"It's an error to set both read_data_fn and write_data_fn in the ");
		154	png_warning(png_ptr,
		155	"same structure. Resetting write_data_fn to NULL.");
		156	}
		157
		158	#if defined(PNG_WRITE_FLUSH_SUPPORTED)
		159	png_ptr->output_flush_fn = NULL;
		160	#endif
		161	}

Subversion Repositories shark

(root)/shark/trunk/ports/png/pngrio.c @ 706 - Rev 96