The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1 | |
| 2 | /* pngrio.c - functions for data input |
| 3 | * |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 4 | * Last changed in libpng 1.6.17 [March 26, 2015] |
| 5 | * Copyright (c) 1998-2015 Glenn Randers-Pehrson |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 6 | * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) |
| 7 | * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) |
| 8 | * |
Patrick Scott | a0bb96c | 2009-07-22 11:50:02 -0400 | [diff] [blame] | 9 | * This code is released under the libpng license. |
| 10 | * For conditions of distribution and use, see the disclaimer |
| 11 | * and license in png.h |
| 12 | * |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 13 | * This file provides a location for all input. Users who need |
| 14 | * special handling are expected to write a function that has the same |
| 15 | * arguments as this and performs a similar function, but that possibly |
| 16 | * has a different input method. Note that you shouldn't change this |
| 17 | * function, but rather write a replacement function and then make |
| 18 | * libpng use it at run time with png_set_read_fn(...). |
| 19 | */ |
| 20 | |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 21 | #include "pngpriv.h" |
| 22 | |
Patrick Scott | 5f6bd84 | 2010-06-28 16:55:16 -0400 | [diff] [blame] | 23 | #ifdef PNG_READ_SUPPORTED |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 24 | |
| 25 | /* Read the data from whatever input you are using. The default routine |
Patrick Scott | a0bb96c | 2009-07-22 11:50:02 -0400 | [diff] [blame] | 26 | * reads from a file pointer. Note that this routine sometimes gets called |
| 27 | * with very small lengths, so you should implement some kind of simple |
| 28 | * buffering if you are using unbuffered reads. This should never be asked |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 29 | * to read more than 64K on a 16-bit machine. |
Patrick Scott | a0bb96c | 2009-07-22 11:50:02 -0400 | [diff] [blame] | 30 | */ |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 31 | void /* PRIVATE */ |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 32 | png_read_data(png_structrp png_ptr, png_bytep data, png_size_t length) |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 33 | { |
The Android Open Source Project | 4215dd1 | 2009-03-09 11:52:12 -0700 | [diff] [blame] | 34 | png_debug1(4, "reading %d bytes", (int)length); |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 35 | |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 36 | if (png_ptr->read_data_fn != NULL) |
| 37 | (*(png_ptr->read_data_fn))(png_ptr, data, length); |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 38 | |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 39 | else |
| 40 | png_error(png_ptr, "Call to NULL read function"); |
Sireesh Tripurari | b0277d0 | 2014-05-09 15:39:12 +0530 | [diff] [blame] | 41 | #ifdef PNG_INDEX_SUPPORTED |
| 42 | png_ptr->total_data_read += length; |
| 43 | #endif |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 44 | } |
| 45 | |
Sireesh Tripurari | b0277d0 | 2014-05-09 15:39:12 +0530 | [diff] [blame] | 46 | #ifdef PNG_INDEX_SUPPORTED |
| 47 | void /* PRIVATE */ |
| 48 | png_seek_data(png_structp png_ptr, png_uint_32 offset) |
| 49 | { |
| 50 | if (png_ptr->seek_data_fn != NULL) |
| 51 | (*(png_ptr->seek_data_fn))(png_ptr, offset); |
| 52 | else |
| 53 | png_error(png_ptr, "Call to NULL seek function"); |
| 54 | } |
| 55 | #endif |
| 56 | |
Patrick Scott | 5f6bd84 | 2010-06-28 16:55:16 -0400 | [diff] [blame] | 57 | #ifdef PNG_STDIO_SUPPORTED |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 58 | /* This is the function that does the actual reading of data. If you are |
Patrick Scott | a0bb96c | 2009-07-22 11:50:02 -0400 | [diff] [blame] | 59 | * not reading from a standard C stream, you should create a replacement |
| 60 | * read_data function and use it at run time with png_set_read_fn(), rather |
| 61 | * than changing the library. |
| 62 | */ |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 63 | void PNGCBAPI |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 64 | png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length) |
| 65 | { |
| 66 | png_size_t check; |
| 67 | |
Patrick Scott | a0bb96c | 2009-07-22 11:50:02 -0400 | [diff] [blame] | 68 | if (png_ptr == NULL) |
| 69 | return; |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 70 | |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 71 | /* fread() returns 0 on error, so it is OK to store this in a png_size_t |
| 72 | * instead of an int, which is what fread() actually returns. |
| 73 | */ |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 74 | check = fread(data, 1, length, png_voidcast(png_FILE_p, png_ptr->io_ptr)); |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 75 | |
| 76 | if (check != length) |
| 77 | png_error(png_ptr, "Read Error"); |
| 78 | } |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 79 | #endif |
| 80 | |
| 81 | /* This function allows the application to supply a new input function |
Patrick Scott | a0bb96c | 2009-07-22 11:50:02 -0400 | [diff] [blame] | 82 | * for libpng if standard C streams aren't being used. |
| 83 | * |
| 84 | * This function takes as its arguments: |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 85 | * |
Patrick Scott | a0bb96c | 2009-07-22 11:50:02 -0400 | [diff] [blame] | 86 | * png_ptr - pointer to a png input data structure |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 87 | * |
Patrick Scott | a0bb96c | 2009-07-22 11:50:02 -0400 | [diff] [blame] | 88 | * io_ptr - pointer to user supplied structure containing info about |
| 89 | * the input functions. May be NULL. |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 90 | * |
Patrick Scott | a0bb96c | 2009-07-22 11:50:02 -0400 | [diff] [blame] | 91 | * read_data_fn - pointer to a new input function that takes as its |
| 92 | * arguments a pointer to a png_struct, a pointer to |
| 93 | * a location where input data can be stored, and a 32-bit |
| 94 | * unsigned int that is the number of bytes to be read. |
| 95 | * To exit and output any fatal error messages the new write |
| 96 | * function should call png_error(png_ptr, "Error msg"). |
| 97 | * May be NULL, in which case libpng's default function will |
| 98 | * be used. |
| 99 | */ |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 100 | void PNGAPI |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 101 | png_set_read_fn(png_structrp png_ptr, png_voidp io_ptr, |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 102 | png_rw_ptr read_data_fn) |
| 103 | { |
Patrick Scott | a0bb96c | 2009-07-22 11:50:02 -0400 | [diff] [blame] | 104 | if (png_ptr == NULL) |
| 105 | return; |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 106 | |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 107 | png_ptr->io_ptr = io_ptr; |
| 108 | |
Patrick Scott | 5f6bd84 | 2010-06-28 16:55:16 -0400 | [diff] [blame] | 109 | #ifdef PNG_STDIO_SUPPORTED |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 110 | if (read_data_fn != NULL) |
| 111 | png_ptr->read_data_fn = read_data_fn; |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 112 | |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 113 | else |
| 114 | png_ptr->read_data_fn = png_default_read_data; |
| 115 | #else |
| 116 | png_ptr->read_data_fn = read_data_fn; |
| 117 | #endif |
| 118 | |
Sireesh Tripurari | b478e66 | 2014-05-09 15:15:10 +0530 | [diff] [blame] | 119 | #ifdef PNG_WRITE_SUPPORTED |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 120 | /* It is an error to write to a read device */ |
| 121 | if (png_ptr->write_data_fn != NULL) |
| 122 | { |
| 123 | png_ptr->write_data_fn = NULL; |
| 124 | png_warning(png_ptr, |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 125 | "Can't set both read_data_fn and write_data_fn in the" |
| 126 | " same structure"); |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 127 | } |
Sireesh Tripurari | b478e66 | 2014-05-09 15:15:10 +0530 | [diff] [blame] | 128 | #endif |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 129 | |
Patrick Scott | 5f6bd84 | 2010-06-28 16:55:16 -0400 | [diff] [blame] | 130 | #ifdef PNG_WRITE_FLUSH_SUPPORTED |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 131 | png_ptr->output_flush_fn = NULL; |
| 132 | #endif |
| 133 | } |
Sireesh Tripurari | b0277d0 | 2014-05-09 15:39:12 +0530 | [diff] [blame] | 134 | |
| 135 | #ifdef PNG_INDEX_SUPPORTED |
| 136 | void PNGAPI |
| 137 | png_set_seek_fn(png_structp png_ptr, png_seek_ptr seek_data_fn) |
| 138 | { |
| 139 | if (png_ptr == NULL) |
| 140 | return; |
| 141 | png_ptr->seek_data_fn = seek_data_fn; |
| 142 | } |
| 143 | #endif |
| 144 | |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame^] | 145 | #endif /* READ */ |