The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1 | |
| 2 | /* pngrio.c - functions for data input |
| 3 | * |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame^] | 4 | * Last changed in libpng 1.6.0 [February 14, 2013] |
| 5 | * Copyright (c) 1998-2013 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 |
| 29 | * to read more then 64K on a 16 bit machine. |
| 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"); |
| 41 | } |
| 42 | |
Patrick Scott | 5f6bd84 | 2010-06-28 16:55:16 -0400 | [diff] [blame] | 43 | #ifdef PNG_STDIO_SUPPORTED |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 44 | /* 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] | 45 | * not reading from a standard C stream, you should create a replacement |
| 46 | * read_data function and use it at run time with png_set_read_fn(), rather |
| 47 | * than changing the library. |
| 48 | */ |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame^] | 49 | void PNGCBAPI |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 50 | png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length) |
| 51 | { |
| 52 | png_size_t check; |
| 53 | |
Patrick Scott | a0bb96c | 2009-07-22 11:50:02 -0400 | [diff] [blame] | 54 | if (png_ptr == NULL) |
| 55 | return; |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame^] | 56 | |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 57 | /* fread() returns 0 on error, so it is OK to store this in a png_size_t |
| 58 | * instead of an int, which is what fread() actually returns. |
| 59 | */ |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame^] | 60 | 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] | 61 | |
| 62 | if (check != length) |
| 63 | png_error(png_ptr, "Read Error"); |
| 64 | } |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 65 | #endif |
| 66 | |
| 67 | /* This function allows the application to supply a new input function |
Patrick Scott | a0bb96c | 2009-07-22 11:50:02 -0400 | [diff] [blame] | 68 | * for libpng if standard C streams aren't being used. |
| 69 | * |
| 70 | * This function takes as its arguments: |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame^] | 71 | * |
Patrick Scott | a0bb96c | 2009-07-22 11:50:02 -0400 | [diff] [blame] | 72 | * png_ptr - pointer to a png input data structure |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame^] | 73 | * |
Patrick Scott | a0bb96c | 2009-07-22 11:50:02 -0400 | [diff] [blame] | 74 | * io_ptr - pointer to user supplied structure containing info about |
| 75 | * the input functions. May be NULL. |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame^] | 76 | * |
Patrick Scott | a0bb96c | 2009-07-22 11:50:02 -0400 | [diff] [blame] | 77 | * read_data_fn - pointer to a new input function that takes as its |
| 78 | * arguments a pointer to a png_struct, a pointer to |
| 79 | * a location where input data can be stored, and a 32-bit |
| 80 | * unsigned int that is the number of bytes to be read. |
| 81 | * To exit and output any fatal error messages the new write |
| 82 | * function should call png_error(png_ptr, "Error msg"). |
| 83 | * May be NULL, in which case libpng's default function will |
| 84 | * be used. |
| 85 | */ |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 86 | void PNGAPI |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame^] | 87 | 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] | 88 | png_rw_ptr read_data_fn) |
| 89 | { |
Patrick Scott | a0bb96c | 2009-07-22 11:50:02 -0400 | [diff] [blame] | 90 | if (png_ptr == NULL) |
| 91 | return; |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame^] | 92 | |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 93 | png_ptr->io_ptr = io_ptr; |
| 94 | |
Patrick Scott | 5f6bd84 | 2010-06-28 16:55:16 -0400 | [diff] [blame] | 95 | #ifdef PNG_STDIO_SUPPORTED |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 96 | if (read_data_fn != NULL) |
| 97 | png_ptr->read_data_fn = read_data_fn; |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame^] | 98 | |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 99 | else |
| 100 | png_ptr->read_data_fn = png_default_read_data; |
| 101 | #else |
| 102 | png_ptr->read_data_fn = read_data_fn; |
| 103 | #endif |
| 104 | |
| 105 | /* It is an error to write to a read device */ |
| 106 | if (png_ptr->write_data_fn != NULL) |
| 107 | { |
| 108 | png_ptr->write_data_fn = NULL; |
| 109 | png_warning(png_ptr, |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame^] | 110 | "Can't set both read_data_fn and write_data_fn in the" |
| 111 | " same structure"); |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 112 | } |
| 113 | |
Patrick Scott | 5f6bd84 | 2010-06-28 16:55:16 -0400 | [diff] [blame] | 114 | #ifdef PNG_WRITE_FLUSH_SUPPORTED |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 115 | png_ptr->output_flush_fn = NULL; |
| 116 | #endif |
| 117 | } |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 118 | #endif /* PNG_READ_SUPPORTED */ |