1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/media/libpng/pngrio.c Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,120 @@
1.4 +
1.5 +/* pngrio.c - functions for data input
1.6 + *
1.7 + * Last changed in libpng 1.6.9 [February 6, 2014]
1.8 + * Copyright (c) 1998-2014 Glenn Randers-Pehrson
1.9 + * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
1.10 + * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
1.11 + *
1.12 + * This code is released under the libpng license.
1.13 + * For conditions of distribution and use, see the disclaimer
1.14 + * and license in png.h
1.15 + *
1.16 + * This file provides a location for all input. Users who need
1.17 + * special handling are expected to write a function that has the same
1.18 + * arguments as this and performs a similar function, but that possibly
1.19 + * has a different input method. Note that you shouldn't change this
1.20 + * function, but rather write a replacement function and then make
1.21 + * libpng use it at run time with png_set_read_fn(...).
1.22 + */
1.23 +
1.24 +#include "pngpriv.h"
1.25 +
1.26 +#ifdef PNG_READ_SUPPORTED
1.27 +
1.28 +/* Read the data from whatever input you are using. The default routine
1.29 + * reads from a file pointer. Note that this routine sometimes gets called
1.30 + * with very small lengths, so you should implement some kind of simple
1.31 + * buffering if you are using unbuffered reads. This should never be asked
1.32 + * to read more then 64K on a 16 bit machine.
1.33 + */
1.34 +void /* PRIVATE */
1.35 +png_read_data(png_structrp png_ptr, png_bytep data, png_size_t length)
1.36 +{
1.37 + png_debug1(4, "reading %d bytes", (int)length);
1.38 +
1.39 + if (png_ptr->read_data_fn != NULL)
1.40 + (*(png_ptr->read_data_fn))(png_ptr, data, length);
1.41 +
1.42 + else
1.43 + png_error(png_ptr, "Call to NULL read function");
1.44 +}
1.45 +
1.46 +#ifdef PNG_STDIO_SUPPORTED
1.47 +/* This is the function that does the actual reading of data. If you are
1.48 + * not reading from a standard C stream, you should create a replacement
1.49 + * read_data function and use it at run time with png_set_read_fn(), rather
1.50 + * than changing the library.
1.51 + */
1.52 +void PNGCBAPI
1.53 +png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
1.54 +{
1.55 + png_size_t check;
1.56 +
1.57 + if (png_ptr == NULL)
1.58 + return;
1.59 +
1.60 + /* fread() returns 0 on error, so it is OK to store this in a png_size_t
1.61 + * instead of an int, which is what fread() actually returns.
1.62 + */
1.63 + check = fread(data, 1, length, png_voidcast(png_FILE_p, png_ptr->io_ptr));
1.64 +
1.65 + if (check != length)
1.66 + png_error(png_ptr, "Read Error");
1.67 +}
1.68 +#endif
1.69 +
1.70 +/* This function allows the application to supply a new input function
1.71 + * for libpng if standard C streams aren't being used.
1.72 + *
1.73 + * This function takes as its arguments:
1.74 + *
1.75 + * png_ptr - pointer to a png input data structure
1.76 + *
1.77 + * io_ptr - pointer to user supplied structure containing info about
1.78 + * the input functions. May be NULL.
1.79 + *
1.80 + * read_data_fn - pointer to a new input function that takes as its
1.81 + * arguments a pointer to a png_struct, a pointer to
1.82 + * a location where input data can be stored, and a 32-bit
1.83 + * unsigned int that is the number of bytes to be read.
1.84 + * To exit and output any fatal error messages the new write
1.85 + * function should call png_error(png_ptr, "Error msg").
1.86 + * May be NULL, in which case libpng's default function will
1.87 + * be used.
1.88 + */
1.89 +void PNGAPI
1.90 +png_set_read_fn(png_structrp png_ptr, png_voidp io_ptr,
1.91 + png_rw_ptr read_data_fn)
1.92 +{
1.93 + if (png_ptr == NULL)
1.94 + return;
1.95 +
1.96 + png_ptr->io_ptr = io_ptr;
1.97 +
1.98 +#ifdef PNG_STDIO_SUPPORTED
1.99 + if (read_data_fn != NULL)
1.100 + png_ptr->read_data_fn = read_data_fn;
1.101 +
1.102 + else
1.103 + png_ptr->read_data_fn = png_default_read_data;
1.104 +#else
1.105 + png_ptr->read_data_fn = read_data_fn;
1.106 +#endif
1.107 +
1.108 +#ifdef PNG_WRITE_SUPPORTED
1.109 + /* It is an error to write to a read device */
1.110 + if (png_ptr->write_data_fn != NULL)
1.111 + {
1.112 + png_ptr->write_data_fn = NULL;
1.113 + png_warning(png_ptr,
1.114 + "Can't set both read_data_fn and write_data_fn in the"
1.115 + " same structure");
1.116 + }
1.117 +#endif
1.118 +
1.119 +#ifdef PNG_WRITE_FLUSH_SUPPORTED
1.120 + png_ptr->output_flush_fn = NULL;
1.121 +#endif
1.122 +}
1.123 +#endif /* PNG_READ_SUPPORTED */
