| 1 | ␍␊ |
| 2 | /* pngwio.c - functions for data output␍␊ |
| 3 | *␍␊ |
| 4 | * Last changed in libpng 1.5.0 [January 6, 2011]␍␊ |
| 5 | * Copyright (c) 1998-2011 Glenn Randers-Pehrson␍␊ |
| 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 | *␍␊ |
| 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 | *␍␊ |
| 13 | * This file provides a location for all output. Users who need␍␊ |
| 14 | * special handling are expected to write functions that have the same␍␊ |
| 15 | * arguments as these and perform similar functions, but that possibly␍␊ |
| 16 | * use different output methods. Note that you shouldn't change these␍␊ |
| 17 | * functions, but rather write replacement functions and then change␍␊ |
| 18 | * them at run time with png_set_write_fn(...).␍␊ |
| 19 | */␍␊ |
| 20 | ␍␊ |
| 21 | #include "pngpriv.h"␍␊ |
| 22 | ␍␊ |
| 23 | #ifdef PNG_WRITE_SUPPORTED␍␊ |
| 24 | ␍␊ |
| 25 | /* Write the data to whatever output you are using. The default routine␍␊ |
| 26 | * writes to 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 writes. This should never be asked␍␊ |
| 29 | * to write more than 64K on a 16 bit machine.␍␊ |
| 30 | */␍␊ |
| 31 | ␍␊ |
| 32 | void /* PRIVATE */␍␊ |
| 33 | png_write_data(png_structp png_ptr, png_const_bytep data, png_size_t length)␍␊ |
| 34 | {␍␊ |
| 35 | /* NOTE: write_data_fn must not change the buffer! */␍␊ |
| 36 | if (png_ptr->write_data_fn != NULL )␍␊ |
| 37 | (*(png_ptr->write_data_fn))(png_ptr, (png_bytep)data, length);␍␊ |
| 38 | ␍␊ |
| 39 | else␍␊ |
| 40 | png_error(png_ptr, "Call to NULL write function");␍␊ |
| 41 | }␍␊ |
| 42 | ␍␊ |
| 43 | #ifdef PNG_STDIO_SUPPORTED␍␊ |
| 44 | /* This is the function that does the actual writing of data. If you are␍␊ |
| 45 | * not writing to a standard C stream, you should create a replacement␍␊ |
| 46 | * write_data function and use it at run time with png_set_write_fn(), rather␍␊ |
| 47 | * than changing the library.␍␊ |
| 48 | */␍␊ |
| 49 | #ifndef USE_FAR_KEYWORD␍␊ |
| 50 | void PNGCBAPI␍␊ |
| 51 | png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length)␍␊ |
| 52 | {␍␊ |
| 53 | png_size_t check;␍␊ |
| 54 | ␍␊ |
| 55 | if (png_ptr == NULL)␍␊ |
| 56 | return;␍␊ |
| 57 | ␍␊ |
| 58 | check = fwrite(data, 1, length, (png_FILE_p)(png_ptr->io_ptr));␍␊ |
| 59 | ␍␊ |
| 60 | if (check != length)␍␊ |
| 61 | png_error(png_ptr, "Write Error");␍␊ |
| 62 | }␍␊ |
| 63 | #else␍␊ |
| 64 | /* This is the model-independent version. Since the standard I/O library␍␊ |
| 65 | * can't handle far buffers in the medium and small models, we have to copy␍␊ |
| 66 | * the data.␍␊ |
| 67 | */␍␊ |
| 68 | ␍␊ |
| 69 | #define NEAR_BUF_SIZE 1024␍␊ |
| 70 | #define MIN(a,b) (a <= b ? a : b)␍␊ |
| 71 | ␍␊ |
| 72 | void PNGCBAPI␍␊ |
| 73 | png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length)␍␊ |
| 74 | {␍␊ |
| 75 | png_uint_32 check;␍␊ |
| 76 | png_byte *near_data; /* Needs to be "png_byte *" instead of "png_bytep" */␍␊ |
| 77 | png_FILE_p io_ptr;␍␊ |
| 78 | ␍␊ |
| 79 | if (png_ptr == NULL)␍␊ |
| 80 | return;␍␊ |
| 81 | ␍␊ |
| 82 | /* Check if data really is near. If so, use usual code. */␍␊ |
| 83 | near_data = (png_byte *)CVT_PTR_NOCHECK(data);␍␊ |
| 84 | io_ptr = (png_FILE_p)CVT_PTR(png_ptr->io_ptr);␍␊ |
| 85 | ␍␊ |
| 86 | if ((png_bytep)near_data == data)␍␊ |
| 87 | {␍␊ |
| 88 | check = fwrite(near_data, 1, length, io_ptr);␍␊ |
| 89 | }␍␊ |
| 90 | ␍␊ |
| 91 | else␍␊ |
| 92 | {␍␊ |
| 93 | png_byte buf[NEAR_BUF_SIZE];␍␊ |
| 94 | png_size_t written, remaining, err;␍␊ |
| 95 | check = 0;␍␊ |
| 96 | remaining = length;␍␊ |
| 97 | ␍␊ |
| 98 | do␍␊ |
| 99 | {␍␊ |
| 100 | written = MIN(NEAR_BUF_SIZE, remaining);␍␊ |
| 101 | png_memcpy(buf, data, written); /* Copy far buffer to near buffer */␍␊ |
| 102 | err = fwrite(buf, 1, written, io_ptr);␍␊ |
| 103 | ␍␊ |
| 104 | if (err != written)␍␊ |
| 105 | break;␍␊ |
| 106 | ␍␊ |
| 107 | else␍␊ |
| 108 | check += err;␍␊ |
| 109 | ␍␊ |
| 110 | data += written;␍␊ |
| 111 | remaining -= written;␍␊ |
| 112 | }␍␊ |
| 113 | while (remaining != 0);␍␊ |
| 114 | }␍␊ |
| 115 | ␍␊ |
| 116 | if (check != length)␍␊ |
| 117 | png_error(png_ptr, "Write Error");␍␊ |
| 118 | }␍␊ |
| 119 | ␍␊ |
| 120 | #endif␍␊ |
| 121 | #endif␍␊ |
| 122 | ␍␊ |
| 123 | /* This function is called to output any data pending writing (normally␍␊ |
| 124 | * to disk). After png_flush is called, there should be no data pending␍␊ |
| 125 | * writing in any buffers.␍␊ |
| 126 | */␍␊ |
| 127 | #ifdef PNG_WRITE_FLUSH_SUPPORTED␍␊ |
| 128 | void /* PRIVATE */␍␊ |
| 129 | png_flush(png_structp png_ptr)␍␊ |
| 130 | {␍␊ |
| 131 | if (png_ptr->output_flush_fn != NULL)␍␊ |
| 132 | (*(png_ptr->output_flush_fn))(png_ptr);␍␊ |
| 133 | }␍␊ |
| 134 | ␍␊ |
| 135 | # ifdef PNG_STDIO_SUPPORTED␍␊ |
| 136 | void PNGCBAPI␍␊ |
| 137 | png_default_flush(png_structp png_ptr)␍␊ |
| 138 | {␍␊ |
| 139 | png_FILE_p io_ptr;␍␊ |
| 140 | ␍␊ |
| 141 | if (png_ptr == NULL)␍␊ |
| 142 | return;␍␊ |
| 143 | ␍␊ |
| 144 | io_ptr = (png_FILE_p)CVT_PTR((png_ptr->io_ptr));␍␊ |
| 145 | fflush(io_ptr);␍␊ |
| 146 | }␍␊ |
| 147 | # endif␍␊ |
| 148 | #endif␍␊ |
| 149 | ␍␊ |
| 150 | /* This function allows the application to supply new output functions for␍␊ |
| 151 | * libpng if standard C streams aren't being used.␍␊ |
| 152 | *␍␊ |
| 153 | * This function takes as its arguments:␍␊ |
| 154 | * png_ptr - pointer to a png output data structure␍␊ |
| 155 | * io_ptr - pointer to user supplied structure containing info about␍␊ |
| 156 | * the output functions. May be NULL.␍␊ |
| 157 | * write_data_fn - pointer to a new output function that takes as its␍␊ |
| 158 | * arguments a pointer to a png_struct, a pointer to␍␊ |
| 159 | * data to be written, and a 32-bit unsigned int that is␍␊ |
| 160 | * the number of bytes to be written. The new write␍␊ |
| 161 | * function should call png_error(png_ptr, "Error msg")␍␊ |
| 162 | * to exit and output any fatal error messages. May be␍␊ |
| 163 | * NULL, in which case libpng's default function will␍␊ |
| 164 | * be used.␍␊ |
| 165 | * flush_data_fn - pointer to a new flush function that takes as its␍␊ |
| 166 | * arguments a pointer to a png_struct. After a call to␍␊ |
| 167 | * the flush function, there should be no data in any buffers␍␊ |
| 168 | * or pending transmission. If the output method doesn't do␍␊ |
| 169 | * any buffering of output, a function prototype must still be␍␊ |
| 170 | * supplied although it doesn't have to do anything. If␍␊ |
| 171 | * PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile␍␊ |
| 172 | * time, output_flush_fn will be ignored, although it must be␍␊ |
| 173 | * supplied for compatibility. May be NULL, in which case␍␊ |
| 174 | * libpng's default function will be used, if␍␊ |
| 175 | * PNG_WRITE_FLUSH_SUPPORTED is defined. This is not␍␊ |
| 176 | * a good idea if io_ptr does not point to a standard␍␊ |
| 177 | * *FILE structure.␍␊ |
| 178 | */␍␊ |
| 179 | void PNGAPI␍␊ |
| 180 | png_set_write_fn(png_structp png_ptr, png_voidp io_ptr,␍␊ |
| 181 | png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn)␍␊ |
| 182 | {␍␊ |
| 183 | if (png_ptr == NULL)␍␊ |
| 184 | return;␍␊ |
| 185 | ␍␊ |
| 186 | png_ptr->io_ptr = io_ptr;␍␊ |
| 187 | ␍␊ |
| 188 | #ifdef PNG_STDIO_SUPPORTED␍␊ |
| 189 | if (write_data_fn != NULL)␍␊ |
| 190 | png_ptr->write_data_fn = write_data_fn;␍␊ |
| 191 | ␍␊ |
| 192 | else␍␊ |
| 193 | png_ptr->write_data_fn = png_default_write_data;␍␊ |
| 194 | #else␍␊ |
| 195 | png_ptr->write_data_fn = write_data_fn;␍␊ |
| 196 | #endif␍␊ |
| 197 | ␍␊ |
| 198 | #ifdef PNG_WRITE_FLUSH_SUPPORTED␍␊ |
| 199 | # ifdef PNG_STDIO_SUPPORTED␍␊ |
| 200 | ␍␊ |
| 201 | if (output_flush_fn != NULL)␍␊ |
| 202 | png_ptr->output_flush_fn = output_flush_fn;␍␊ |
| 203 | ␍␊ |
| 204 | else␍␊ |
| 205 | png_ptr->output_flush_fn = png_default_flush;␍␊ |
| 206 | ␍␊ |
| 207 | # else␍␊ |
| 208 | png_ptr->output_flush_fn = output_flush_fn;␍␊ |
| 209 | # endif␍␊ |
| 210 | #endif /* PNG_WRITE_FLUSH_SUPPORTED */␍␊ |
| 211 | ␍␊ |
| 212 | /* It is an error to read while writing a png file */␍␊ |
| 213 | if (png_ptr->read_data_fn != NULL)␍␊ |
| 214 | {␍␊ |
| 215 | png_ptr->read_data_fn = NULL;␍␊ |
| 216 | ␍␊ |
| 217 | png_warning(png_ptr,␍␊ |
| 218 | "Can't set both read_data_fn and write_data_fn in the"␍␊ |
| 219 | " same structure");␍␊ |
| 220 | }␍␊ |
| 221 | }␍␊ |
| 222 | ␍␊ |
| 223 | #ifdef USE_FAR_KEYWORD␍␊ |
| 224 | # ifdef _MSC_VER␍␊ |
| 225 | void *png_far_to_near(png_structp png_ptr, png_voidp ptr, int check)␍␊ |
| 226 | {␍␊ |
| 227 | void *near_ptr;␍␊ |
| 228 | void FAR *far_ptr;␍␊ |
| 229 | FP_OFF(near_ptr) = FP_OFF(ptr);␍␊ |
| 230 | far_ptr = (void FAR *)near_ptr;␍␊ |
| 231 | ␍␊ |
| 232 | if (check != 0)␍␊ |
| 233 | if (FP_SEG(ptr) != FP_SEG(far_ptr))␍␊ |
| 234 | png_error(png_ptr, "segment lost in conversion");␍␊ |
| 235 | ␍␊ |
| 236 | return(near_ptr);␍␊ |
| 237 | }␍␊ |
| 238 | # else␍␊ |
| 239 | void *png_far_to_near(png_structp png_ptr, png_voidp ptr, int check)␍␊ |
| 240 | {␍␊ |
| 241 | void *near_ptr;␍␊ |
| 242 | void FAR *far_ptr;␍␊ |
| 243 | near_ptr = (void FAR *)ptr;␍␊ |
| 244 | far_ptr = (void FAR *)near_ptr;␍␊ |
| 245 | ␍␊ |
| 246 | if (check != 0)␍␊ |
| 247 | if (far_ptr != ptr)␍␊ |
| 248 | png_error(png_ptr, "segment lost in conversion");␍␊ |
| 249 | ␍␊ |
| 250 | return(near_ptr);␍␊ |
| 251 | }␍␊ |
| 252 | # endif␍␊ |
| 253 | #endif␍␊ |
| 254 | #endif /* PNG_WRITE_SUPPORTED */␍␊ |
| 255 | |
