+++ /dev/null
-
-/* pngrio.c - functions for data input
- *
- * Last changed in libpng 1.2.13 November 13, 2006
- * For conditions of distribution and use, see copyright notice in png.h
- * 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 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(...).
- */
-
-#define PNG_INTERNAL
-#include "png.h"
-
-#if defined(PNG_READ_SUPPORTED)
-
-/* 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. */
-void /* PRIVATE */
-png_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
-{
- png_debug1(4,"reading %d bytes\n", (int)length);
- if (png_ptr->read_data_fn != NULL)
- (*(png_ptr->read_data_fn))(png_ptr, data, length);
- else
- png_error(png_ptr, "Call to NULL read function");
-}
-
-#if !defined(PNG_NO_STDIO)
-/* 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. */
-#ifndef USE_FAR_KEYWORD
-void PNGAPI
-png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
-{
- png_size_t check;
-
- if(png_ptr == NULL) return;
- /* 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.
- */
-#if defined(_WIN32_WCE)
- if ( !ReadFile((HANDLE)(png_ptr->io_ptr), data, length, &check, NULL) )
- check = 0;
-#else
- check = (png_size_t)fread(data, (png_size_t)1, length,
- (png_FILE_p)png_ptr->io_ptr);
-#endif
-
- if (check != length)
- png_error(png_ptr, "Read Error");
-}
-#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)
-
-static void PNGAPI
-png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
-{
- int check;
- png_byte *n_data;
- png_FILE_p io_ptr;
-
- if(png_ptr == NULL) return;
- /* Check if data really is near. If so, use usual code. */
- n_data = (png_byte *)CVT_PTR_NOCHECK(data);
- io_ptr = (png_FILE_p)CVT_PTR(png_ptr->io_ptr);
- if ((png_bytep)n_data == data)
- {
-#if defined(_WIN32_WCE)
- if ( !ReadFile((HANDLE)(png_ptr->io_ptr), data, length, &check, NULL) )
- check = 0;
-#else
- check = fread(n_data, 1, length, io_ptr);
-#endif
- }
- else
- {
- png_byte buf[NEAR_BUF_SIZE];
- png_size_t read, remaining, err;
- check = 0;
- remaining = length;
- do
- {
- read = MIN(NEAR_BUF_SIZE, remaining);
-#if defined(_WIN32_WCE)
- if ( !ReadFile((HANDLE)(io_ptr), buf, read, &err, NULL) )
- err = 0;
-#else
- err = fread(buf, (png_size_t)1, read, io_ptr);
-#endif
- png_memcpy(data, buf, read); /* copy far buffer to near buffer */
- if(err != read)
- break;
- else
- check += err;
- data += read;
- remaining -= read;
- }
- while (remaining != 0);
- }
- if ((png_uint_32)check != (png_uint_32)length)
- png_error(png_ptr, "read Error");
-}
-#endif
-#endif
-
-/* This function allows the application to supply a new input function
- for libpng if standard C streams aren't being used.
-
- This function takes as its arguments:
- 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 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 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 PNGAPI
-png_set_read_fn(png_structp png_ptr, png_voidp io_ptr,
- png_rw_ptr read_data_fn)
-{
- if(png_ptr == NULL) return;
- png_ptr->io_ptr = io_ptr;
-
-#if !defined(PNG_NO_STDIO)
- if (read_data_fn != NULL)
- png_ptr->read_data_fn = read_data_fn;
- else
- png_ptr->read_data_fn = png_default_read_data;
-#else
- png_ptr->read_data_fn = read_data_fn;
-#endif
-
- /* It is an error to write to a read device */
- 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;
-#endif
-}
-#endif /* PNG_READ_SUPPORTED */
projects / opencv / blobdiff