media/libpng/pngrio.c@97036ab72558 (annotated)
media/libpng/pngrio.c
Tue, 06 Jan 2015 21:39:09 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Tue, 06 Jan 2015 21:39:09 +0100
- branch
- TOR_BUG_9701
- changeset 8
- 97036ab72558
- permissions
- -rw-r--r--
Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.
| michael@0 | 1 | |
| michael@0 | 2 | /* pngrio.c - functions for data input |
| michael@0 | 3 | * |
| michael@0 | 4 | * Last changed in libpng 1.6.9 [February 6, 2014] |
| michael@0 | 5 | * Copyright (c) 1998-2014 Glenn Randers-Pehrson |
| michael@0 | 6 | * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) |
| michael@0 | 7 | * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) |
| michael@0 | 8 | * |
| michael@0 | 9 | * This code is released under the libpng license. |
| michael@0 | 10 | * For conditions of distribution and use, see the disclaimer |
| michael@0 | 11 | * and license in png.h |
| michael@0 | 12 | * |
| michael@0 | 13 | * This file provides a location for all input. Users who need |
| michael@0 | 14 | * special handling are expected to write a function that has the same |
| michael@0 | 15 | * arguments as this and performs a similar function, but that possibly |
| michael@0 | 16 | * has a different input method. Note that you shouldn't change this |
| michael@0 | 17 | * function, but rather write a replacement function and then make |
| michael@0 | 18 | * libpng use it at run time with png_set_read_fn(...). |
| michael@0 | 19 | */ |
| michael@0 | 20 | |
| michael@0 | 21 | #include "pngpriv.h" |
| michael@0 | 22 | |
| michael@0 | 23 | #ifdef PNG_READ_SUPPORTED |
| michael@0 | 24 | |
| michael@0 | 25 | /* Read the data from whatever input you are using. The default routine |
| michael@0 | 26 | * reads from a file pointer. Note that this routine sometimes gets called |
| michael@0 | 27 | * with very small lengths, so you should implement some kind of simple |
| michael@0 | 28 | * buffering if you are using unbuffered reads. This should never be asked |
| michael@0 | 29 | * to read more then 64K on a 16 bit machine. |
| michael@0 | 30 | */ |
| michael@0 | 31 | void /* PRIVATE */ |
| michael@0 | 32 | png_read_data(png_structrp png_ptr, png_bytep data, png_size_t length) |
| michael@0 | 33 | { |
| michael@0 | 34 | png_debug1(4, "reading %d bytes", (int)length); |
| michael@0 | 35 | |
| michael@0 | 36 | if (png_ptr->read_data_fn != NULL) |
| michael@0 | 37 | (*(png_ptr->read_data_fn))(png_ptr, data, length); |
| michael@0 | 38 | |
| michael@0 | 39 | else |
| michael@0 | 40 | png_error(png_ptr, "Call to NULL read function"); |
| michael@0 | 41 | } |
| michael@0 | 42 | |
| michael@0 | 43 | #ifdef PNG_STDIO_SUPPORTED |
| michael@0 | 44 | /* This is the function that does the actual reading of data. If you are |
| michael@0 | 45 | * not reading from a standard C stream, you should create a replacement |
| michael@0 | 46 | * read_data function and use it at run time with png_set_read_fn(), rather |
| michael@0 | 47 | * than changing the library. |
| michael@0 | 48 | */ |
| michael@0 | 49 | void PNGCBAPI |
| michael@0 | 50 | png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length) |
| michael@0 | 51 | { |
| michael@0 | 52 | png_size_t check; |
| michael@0 | 53 | |
| michael@0 | 54 | if (png_ptr == NULL) |
| michael@0 | 55 | return; |
| michael@0 | 56 | |
| michael@0 | 57 | /* fread() returns 0 on error, so it is OK to store this in a png_size_t |
| michael@0 | 58 | * instead of an int, which is what fread() actually returns. |
| michael@0 | 59 | */ |
| michael@0 | 60 | check = fread(data, 1, length, png_voidcast(png_FILE_p, png_ptr->io_ptr)); |
| michael@0 | 61 | |
| michael@0 | 62 | if (check != length) |
| michael@0 | 63 | png_error(png_ptr, "Read Error"); |
| michael@0 | 64 | } |
| michael@0 | 65 | #endif |
| michael@0 | 66 | |
| michael@0 | 67 | /* This function allows the application to supply a new input function |
| michael@0 | 68 | * for libpng if standard C streams aren't being used. |
| michael@0 | 69 | * |
| michael@0 | 70 | * This function takes as its arguments: |
| michael@0 | 71 | * |
| michael@0 | 72 | * png_ptr - pointer to a png input data structure |
| michael@0 | 73 | * |
| michael@0 | 74 | * io_ptr - pointer to user supplied structure containing info about |
| michael@0 | 75 | * the input functions. May be NULL. |
| michael@0 | 76 | * |
| michael@0 | 77 | * read_data_fn - pointer to a new input function that takes as its |
| michael@0 | 78 | * arguments a pointer to a png_struct, a pointer to |
| michael@0 | 79 | * a location where input data can be stored, and a 32-bit |
| michael@0 | 80 | * unsigned int that is the number of bytes to be read. |
| michael@0 | 81 | * To exit and output any fatal error messages the new write |
| michael@0 | 82 | * function should call png_error(png_ptr, "Error msg"). |
| michael@0 | 83 | * May be NULL, in which case libpng's default function will |
| michael@0 | 84 | * be used. |
| michael@0 | 85 | */ |
| michael@0 | 86 | void PNGAPI |
| michael@0 | 87 | png_set_read_fn(png_structrp png_ptr, png_voidp io_ptr, |
| michael@0 | 88 | png_rw_ptr read_data_fn) |
| michael@0 | 89 | { |
| michael@0 | 90 | if (png_ptr == NULL) |
| michael@0 | 91 | return; |
| michael@0 | 92 | |
| michael@0 | 93 | png_ptr->io_ptr = io_ptr; |
| michael@0 | 94 | |
| michael@0 | 95 | #ifdef PNG_STDIO_SUPPORTED |
| michael@0 | 96 | if (read_data_fn != NULL) |
| michael@0 | 97 | png_ptr->read_data_fn = read_data_fn; |
| michael@0 | 98 | |
| michael@0 | 99 | else |
| michael@0 | 100 | png_ptr->read_data_fn = png_default_read_data; |
| michael@0 | 101 | #else |
| michael@0 | 102 | png_ptr->read_data_fn = read_data_fn; |
| michael@0 | 103 | #endif |
| michael@0 | 104 | |
| michael@0 | 105 | #ifdef PNG_WRITE_SUPPORTED |
| michael@0 | 106 | /* It is an error to write to a read device */ |
| michael@0 | 107 | if (png_ptr->write_data_fn != NULL) |
| michael@0 | 108 | { |
| michael@0 | 109 | png_ptr->write_data_fn = NULL; |
| michael@0 | 110 | png_warning(png_ptr, |
| michael@0 | 111 | "Can't set both read_data_fn and write_data_fn in the" |
| michael@0 | 112 | " same structure"); |
| michael@0 | 113 | } |
| michael@0 | 114 | #endif |
| michael@0 | 115 | |
| michael@0 | 116 | #ifdef PNG_WRITE_FLUSH_SUPPORTED |
| michael@0 | 117 | png_ptr->output_flush_fn = NULL; |
| michael@0 | 118 | #endif |
| michael@0 | 119 | } |
| michael@0 | 120 | #endif /* PNG_READ_SUPPORTED */ |
