1 | /* |
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2 | * wrjpgcom.c |
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3 | * |
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4 | * Copyright (C) 1994-1997, Thomas G. Lane. |
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5 | * This file is part of the Independent JPEG Group's software. |
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6 | * For conditions of distribution and use, see the accompanying README file. |
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7 | * |
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8 | * This file contains a very simple stand-alone application that inserts |
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9 | * user-supplied text as a COM (comment) marker in a JFIF file. |
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10 | * This may be useful as an example of the minimum logic needed to parse |
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11 | * JPEG markers. |
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12 | */ |
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13 | |
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14 | #define JPEG_CJPEG_DJPEG /* to get the command-line config symbols */ |
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15 | #include "jinclude.h" /* get auto-config symbols, <stdio.h> */ |
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16 | |
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17 | #ifndef HAVE_STDLIB_H /* <stdlib.h> should declare malloc() */ |
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18 | extern void * malloc (); |
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19 | #endif |
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20 | #include <ctype.h> /* to declare isupper(), tolower() */ |
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21 | #ifdef USE_SETMODE |
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22 | #include <fcntl.h> /* to declare setmode()'s parameter macros */ |
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23 | /* If you have setmode() but not <io.h>, just delete this line: */ |
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24 | #include <io.h> /* to declare setmode() */ |
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25 | #endif |
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26 | |
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27 | #ifdef USE_CCOMMAND /* command-line reader for Macintosh */ |
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28 | #ifdef __MWERKS__ |
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29 | #include <SIOUX.h> /* Metrowerks needs this */ |
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30 | #include <console.h> /* ... and this */ |
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31 | #endif |
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32 | #ifdef THINK_C |
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33 | #include <console.h> /* Think declares it here */ |
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34 | #endif |
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35 | #endif |
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36 | |
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37 | #ifdef DONT_USE_B_MODE /* define mode parameters for fopen() */ |
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38 | #define READ_BINARY "r" |
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39 | #define WRITE_BINARY "w" |
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40 | #else |
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41 | #ifdef VMS /* VMS is very nonstandard */ |
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42 | #define READ_BINARY "rb", "ctx=stm" |
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43 | #define WRITE_BINARY "wb", "ctx=stm" |
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44 | #else /* standard ANSI-compliant case */ |
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45 | #define READ_BINARY "rb" |
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46 | #define WRITE_BINARY "wb" |
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47 | #endif |
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48 | #endif |
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49 | |
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50 | #ifndef EXIT_FAILURE /* define exit() codes if not provided */ |
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51 | #define EXIT_FAILURE 1 |
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52 | #endif |
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53 | #ifndef EXIT_SUCCESS |
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54 | #ifdef VMS |
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55 | #define EXIT_SUCCESS 1 /* VMS is very nonstandard */ |
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56 | #else |
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57 | #define EXIT_SUCCESS 0 |
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58 | #endif |
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59 | #endif |
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60 | |
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61 | /* Reduce this value if your malloc() can't allocate blocks up to 64K. |
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62 | * On DOS, compiling in large model is usually a better solution. |
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63 | */ |
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64 | |
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65 | #ifndef MAX_COM_LENGTH |
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66 | #define MAX_COM_LENGTH 65000L /* must be <= 65533 in any case */ |
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67 | #endif |
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68 | |
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69 | |
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70 | /* |
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71 | * These macros are used to read the input file and write the output file. |
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72 | * To reuse this code in another application, you might need to change these. |
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73 | */ |
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74 | |
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75 | static FILE * infile; /* input JPEG file */ |
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76 | |
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77 | /* Return next input byte, or EOF if no more */ |
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78 | #define NEXTBYTE() getc(infile) |
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79 | |
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80 | static FILE * outfile; /* output JPEG file */ |
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81 | |
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82 | /* Emit an output byte */ |
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83 | #define PUTBYTE(x) putc((x), outfile) |
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84 | |
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85 | |
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86 | /* Error exit handler */ |
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87 | #define ERREXIT(msg) (fprintf(stderr, "%s\n", msg), exit(EXIT_FAILURE)) |
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88 | |
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89 | |
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90 | /* Read one byte, testing for EOF */ |
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91 | static int |
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92 | read_1_byte (void) |
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93 | { |
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94 | int c; |
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95 | |
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96 | c = NEXTBYTE(); |
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97 | if (c == EOF) |
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98 | ERREXIT("Premature EOF in JPEG file"); |
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99 | return c; |
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100 | } |
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101 | |
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102 | /* Read 2 bytes, convert to unsigned int */ |
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103 | /* All 2-byte quantities in JPEG markers are MSB first */ |
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104 | static unsigned int |
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105 | read_2_bytes (void) |
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106 | { |
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107 | int c1, c2; |
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108 | |
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109 | c1 = NEXTBYTE(); |
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110 | if (c1 == EOF) |
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111 | ERREXIT("Premature EOF in JPEG file"); |
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112 | c2 = NEXTBYTE(); |
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113 | if (c2 == EOF) |
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114 | ERREXIT("Premature EOF in JPEG file"); |
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115 | return (((unsigned int) c1) << 8) + ((unsigned int) c2); |
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116 | } |
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117 | |
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118 | |
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119 | /* Routines to write data to output file */ |
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120 | |
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121 | static void |
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122 | write_1_byte (int c) |
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123 | { |
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124 | PUTBYTE(c); |
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125 | } |
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126 | |
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127 | static void |
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128 | write_2_bytes (unsigned int val) |
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129 | { |
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130 | PUTBYTE((val >> 8) & 0xFF); |
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131 | PUTBYTE(val & 0xFF); |
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132 | } |
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133 | |
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134 | static void |
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135 | write_marker (int marker) |
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136 | { |
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137 | PUTBYTE(0xFF); |
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138 | PUTBYTE(marker); |
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139 | } |
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140 | |
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141 | static void |
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142 | copy_rest_of_file (void) |
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143 | { |
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144 | int c; |
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145 | |
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146 | while ((c = NEXTBYTE()) != EOF) |
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147 | PUTBYTE(c); |
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148 | } |
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149 | |
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150 | |
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151 | /* |
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152 | * JPEG markers consist of one or more 0xFF bytes, followed by a marker |
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153 | * code byte (which is not an FF). Here are the marker codes of interest |
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154 | * in this program. (See jdmarker.c for a more complete list.) |
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155 | */ |
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156 | |
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157 | #define M_SOF0 0xC0 /* Start Of Frame N */ |
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158 | #define M_SOF1 0xC1 /* N indicates which compression process */ |
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159 | #define M_SOF2 0xC2 /* Only SOF0-SOF2 are now in common use */ |
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160 | #define M_SOF3 0xC3 |
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161 | #define M_SOF5 0xC5 /* NB: codes C4 and CC are NOT SOF markers */ |
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162 | #define M_SOF6 0xC6 |
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163 | #define M_SOF7 0xC7 |
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164 | #define M_SOF9 0xC9 |
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165 | #define M_SOF10 0xCA |
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166 | #define M_SOF11 0xCB |
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167 | #define M_SOF13 0xCD |
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168 | #define M_SOF14 0xCE |
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169 | #define M_SOF15 0xCF |
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170 | #define M_SOI 0xD8 /* Start Of Image (beginning of datastream) */ |
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171 | #define M_EOI 0xD9 /* End Of Image (end of datastream) */ |
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172 | #define M_SOS 0xDA /* Start Of Scan (begins compressed data) */ |
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173 | #define M_COM 0xFE /* COMment */ |
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174 | |
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175 | |
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176 | /* |
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177 | * Find the next JPEG marker and return its marker code. |
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178 | * We expect at least one FF byte, possibly more if the compressor used FFs |
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179 | * to pad the file. (Padding FFs will NOT be replicated in the output file.) |
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180 | * There could also be non-FF garbage between markers. The treatment of such |
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181 | * garbage is unspecified; we choose to skip over it but emit a warning msg. |
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182 | * NB: this routine must not be used after seeing SOS marker, since it will |
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183 | * not deal correctly with FF/00 sequences in the compressed image data... |
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184 | */ |
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185 | |
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186 | static int |
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187 | next_marker (void) |
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188 | { |
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189 | int c; |
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190 | int discarded_bytes = 0; |
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191 | |
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192 | /* Find 0xFF byte; count and skip any non-FFs. */ |
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193 | c = read_1_byte(); |
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194 | while (c != 0xFF) { |
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195 | discarded_bytes++; |
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196 | c = read_1_byte(); |
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197 | } |
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198 | /* Get marker code byte, swallowing any duplicate FF bytes. Extra FFs |
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199 | * are legal as pad bytes, so don't count them in discarded_bytes. |
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200 | */ |
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201 | do { |
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202 | c = read_1_byte(); |
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203 | } while (c == 0xFF); |
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204 | |
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205 | if (discarded_bytes != 0) { |
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206 | fprintf(stderr, "Warning: garbage data found in JPEG file\n"); |
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207 | } |
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208 | |
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209 | return c; |
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210 | } |
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211 | |
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212 | |
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213 | /* |
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214 | * Read the initial marker, which should be SOI. |
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215 | * For a JFIF file, the first two bytes of the file should be literally |
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216 | * 0xFF M_SOI. To be more general, we could use next_marker, but if the |
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217 | * input file weren't actually JPEG at all, next_marker might read the whole |
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218 | * file and then return a misleading error message... |
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219 | */ |
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220 | |
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221 | static int |
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222 | first_marker (void) |
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223 | { |
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224 | int c1, c2; |
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225 | |
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226 | c1 = NEXTBYTE(); |
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227 | c2 = NEXTBYTE(); |
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228 | if (c1 != 0xFF || c2 != M_SOI) |
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229 | ERREXIT("Not a JPEG file"); |
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230 | return c2; |
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231 | } |
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232 | |
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233 | |
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234 | /* |
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235 | * Most types of marker are followed by a variable-length parameter segment. |
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236 | * This routine skips over the parameters for any marker we don't otherwise |
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237 | * want to process. |
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238 | * Note that we MUST skip the parameter segment explicitly in order not to |
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239 | * be fooled by 0xFF bytes that might appear within the parameter segment; |
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240 | * such bytes do NOT introduce new markers. |
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241 | */ |
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242 | |
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243 | static void |
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244 | copy_variable (void) |
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245 | /* Copy an unknown or uninteresting variable-length marker */ |
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246 | { |
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247 | unsigned int length; |
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248 | |
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249 | /* Get the marker parameter length count */ |
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250 | length = read_2_bytes(); |
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251 | write_2_bytes(length); |
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252 | /* Length includes itself, so must be at least 2 */ |
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253 | if (length < 2) |
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254 | ERREXIT("Erroneous JPEG marker length"); |
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255 | length -= 2; |
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256 | /* Skip over the remaining bytes */ |
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257 | while (length > 0) { |
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258 | write_1_byte(read_1_byte()); |
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259 | length--; |
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260 | } |
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261 | } |
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262 | |
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263 | static void |
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264 | skip_variable (void) |
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265 | /* Skip over an unknown or uninteresting variable-length marker */ |
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266 | { |
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267 | unsigned int length; |
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268 | |
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269 | /* Get the marker parameter length count */ |
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270 | length = read_2_bytes(); |
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271 | /* Length includes itself, so must be at least 2 */ |
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272 | if (length < 2) |
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273 | ERREXIT("Erroneous JPEG marker length"); |
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274 | length -= 2; |
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275 | /* Skip over the remaining bytes */ |
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276 | while (length > 0) { |
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277 | (void) read_1_byte(); |
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278 | length--; |
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279 | } |
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280 | } |
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281 | |
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282 | |
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283 | /* |
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284 | * Parse the marker stream until SOFn or EOI is seen; |
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285 | * copy data to output, but discard COM markers unless keep_COM is true. |
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286 | */ |
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287 | |
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288 | static int |
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289 | scan_JPEG_header (int keep_COM) |
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290 | { |
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291 | int marker; |
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292 | |
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293 | /* Expect SOI at start of file */ |
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294 | if (first_marker() != M_SOI) |
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295 | ERREXIT("Expected SOI marker first"); |
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296 | write_marker(M_SOI); |
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297 | |
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298 | /* Scan miscellaneous markers until we reach SOFn. */ |
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299 | for (;;) { |
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300 | marker = next_marker(); |
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301 | switch (marker) { |
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302 | /* Note that marker codes 0xC4, 0xC8, 0xCC are not, and must not be, |
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303 | * treated as SOFn. C4 in particular is actually DHT. |
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304 | */ |
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305 | case M_SOF0: /* Baseline */ |
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306 | case M_SOF1: /* Extended sequential, Huffman */ |
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307 | case M_SOF2: /* Progressive, Huffman */ |
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308 | case M_SOF3: /* Lossless, Huffman */ |
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309 | case M_SOF5: /* Differential sequential, Huffman */ |
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310 | case M_SOF6: /* Differential progressive, Huffman */ |
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311 | case M_SOF7: /* Differential lossless, Huffman */ |
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312 | case M_SOF9: /* Extended sequential, arithmetic */ |
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313 | case M_SOF10: /* Progressive, arithmetic */ |
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314 | case M_SOF11: /* Lossless, arithmetic */ |
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315 | case M_SOF13: /* Differential sequential, arithmetic */ |
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316 | case M_SOF14: /* Differential progressive, arithmetic */ |
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317 | case M_SOF15: /* Differential lossless, arithmetic */ |
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318 | return marker; |
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319 | |
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320 | case M_SOS: /* should not see compressed data before SOF */ |
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321 | ERREXIT("SOS without prior SOFn"); |
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322 | break; |
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323 | |
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324 | case M_EOI: /* in case it's a tables-only JPEG stream */ |
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325 | return marker; |
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326 | |
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327 | case M_COM: /* Existing COM: conditionally discard */ |
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328 | if (keep_COM) { |
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329 | write_marker(marker); |
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330 | copy_variable(); |
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331 | } else { |
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332 | skip_variable(); |
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333 | } |
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334 | break; |
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335 | |
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336 | default: /* Anything else just gets copied */ |
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337 | write_marker(marker); |
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338 | copy_variable(); /* we assume it has a parameter count... */ |
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339 | break; |
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340 | } |
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341 | } /* end loop */ |
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342 | } |
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343 | |
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344 | |
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345 | /* Command line parsing code */ |
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346 | |
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347 | static const char * progname; /* program name for error messages */ |
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348 | |
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349 | |
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350 | static void |
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351 | usage (void) |
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352 | /* complain about bad command line */ |
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353 | { |
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354 | fprintf(stderr, "wrjpgcom inserts a textual comment in a JPEG file.\n"); |
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355 | fprintf(stderr, "You can add to or replace any existing comment(s).\n"); |
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356 | |
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357 | fprintf(stderr, "Usage: %s [switches] ", progname); |
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358 | #ifdef TWO_FILE_COMMANDLINE |
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359 | fprintf(stderr, "inputfile outputfile\n"); |
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360 | #else |
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361 | fprintf(stderr, "[inputfile]\n"); |
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362 | #endif |
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363 | |
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364 | fprintf(stderr, "Switches (names may be abbreviated):\n"); |
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365 | fprintf(stderr, " -replace Delete any existing comments\n"); |
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366 | fprintf(stderr, " -comment \"text\" Insert comment with given text\n"); |
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367 | fprintf(stderr, " -cfile name Read comment from named file\n"); |
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368 | fprintf(stderr, "Notice that you must put quotes around the comment text\n"); |
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369 | fprintf(stderr, "when you use -comment.\n"); |
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370 | fprintf(stderr, "If you do not give either -comment or -cfile on the command line,\n"); |
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371 | fprintf(stderr, "then the comment text is read from standard input.\n"); |
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372 | fprintf(stderr, "It can be multiple lines, up to %u characters total.\n", |
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373 | (unsigned int) MAX_COM_LENGTH); |
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374 | #ifndef TWO_FILE_COMMANDLINE |
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375 | fprintf(stderr, "You must specify an input JPEG file name when supplying\n"); |
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376 | fprintf(stderr, "comment text from standard input.\n"); |
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377 | #endif |
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378 | |
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379 | exit(EXIT_FAILURE); |
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380 | } |
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381 | |
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382 | |
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383 | static int |
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384 | keymatch (char * arg, const char * keyword, int minchars) |
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385 | /* Case-insensitive matching of (possibly abbreviated) keyword switches. */ |
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386 | /* keyword is the constant keyword (must be lower case already), */ |
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387 | /* minchars is length of minimum legal abbreviation. */ |
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388 | { |
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389 | register int ca, ck; |
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390 | register int nmatched = 0; |
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391 | |
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392 | while ((ca = *arg++) != '\0') { |
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393 | if ((ck = *keyword++) == '\0') |
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394 | return 0; /* arg longer than keyword, no good */ |
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395 | if (isupper(ca)) /* force arg to lcase (assume ck is already) */ |
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396 | ca = tolower(ca); |
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397 | if (ca != ck) |
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398 | return 0; /* no good */ |
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399 | nmatched++; /* count matched characters */ |
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400 | } |
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401 | /* reached end of argument; fail if it's too short for unique abbrev */ |
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402 | if (nmatched < minchars) |
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403 | return 0; |
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404 | return 1; /* A-OK */ |
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405 | } |
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406 | |
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407 | |
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408 | /* |
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409 | * The main program. |
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410 | */ |
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411 | |
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412 | int |
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413 | main (int argc, char **argv) |
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414 | { |
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415 | int argn; |
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416 | char * arg; |
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417 | int keep_COM = 1; |
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418 | char * comment_arg = NULL; |
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419 | FILE * comment_file = NULL; |
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420 | unsigned int comment_length = 0; |
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421 | int marker; |
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422 | |
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423 | /* On Mac, fetch a command line. */ |
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424 | #ifdef USE_CCOMMAND |
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425 | argc = ccommand(&argv); |
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426 | #endif |
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427 | |
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428 | progname = argv[0]; |
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429 | if (progname == NULL || progname[0] == 0) |
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430 | progname = "wrjpgcom"; /* in case C library doesn't provide it */ |
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431 | |
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432 | /* Parse switches, if any */ |
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433 | for (argn = 1; argn < argc; argn++) { |
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434 | arg = argv[argn]; |
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435 | if (arg[0] != '-') |
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436 | break; /* not switch, must be file name */ |
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437 | arg++; /* advance over '-' */ |
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438 | if (keymatch(arg, "replace", 1)) { |
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439 | keep_COM = 0; |
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440 | } else if (keymatch(arg, "cfile", 2)) { |
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441 | if (++argn >= argc) usage(); |
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442 | if ((comment_file = fopen(argv[argn], "r")) == NULL) { |
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443 | fprintf(stderr, "%s: can't open %s\n", progname, argv[argn]); |
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444 | exit(EXIT_FAILURE); |
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445 | } |
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446 | } else if (keymatch(arg, "comment", 1)) { |
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447 | if (++argn >= argc) usage(); |
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448 | comment_arg = argv[argn]; |
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449 | /* If the comment text starts with '"', then we are probably running |
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450 | * under MS-DOG and must parse out the quoted string ourselves. Sigh. |
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451 | */ |
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452 | if (comment_arg[0] == '"') { |
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453 | comment_arg = (char *) malloc((size_t) MAX_COM_LENGTH); |
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454 | if (comment_arg == NULL) |
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455 | ERREXIT("Insufficient memory"); |
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456 | strcpy(comment_arg, argv[argn]+1); |
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457 | for (;;) { |
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458 | comment_length = (unsigned int) strlen(comment_arg); |
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459 | if (comment_length > 0 && comment_arg[comment_length-1] == '"') { |
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460 | comment_arg[comment_length-1] = '\0'; /* zap terminating quote */ |
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461 | break; |
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462 | } |
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463 | if (++argn >= argc) |
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464 | ERREXIT("Missing ending quote mark"); |
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465 | strcat(comment_arg, " "); |
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466 | strcat(comment_arg, argv[argn]); |
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467 | } |
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468 | } |
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469 | comment_length = (unsigned int) strlen(comment_arg); |
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470 | } else |
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471 | usage(); |
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472 | } |
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473 | |
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474 | /* Cannot use both -comment and -cfile. */ |
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475 | if (comment_arg != NULL && comment_file != NULL) |
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476 | usage(); |
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477 | /* If there is neither -comment nor -cfile, we will read the comment text |
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478 | * from stdin; in this case there MUST be an input JPEG file name. |
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479 | */ |
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480 | if (comment_arg == NULL && comment_file == NULL && argn >= argc) |
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481 | usage(); |
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482 | |
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483 | /* Open the input file. */ |
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484 | if (argn < argc) { |
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485 | if ((infile = fopen(argv[argn], READ_BINARY)) == NULL) { |
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486 | fprintf(stderr, "%s: can't open %s\n", progname, argv[argn]); |
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487 | exit(EXIT_FAILURE); |
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488 | } |
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489 | } else { |
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490 | /* default input file is stdin */ |
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491 | #ifdef USE_SETMODE /* need to hack file mode? */ |
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492 | setmode(fileno(stdin), O_BINARY); |
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493 | #endif |
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494 | #ifdef USE_FDOPEN /* need to re-open in binary mode? */ |
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495 | if ((infile = fdopen(fileno(stdin), READ_BINARY)) == NULL) { |
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496 | fprintf(stderr, "%s: can't open stdin\n", progname); |
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497 | exit(EXIT_FAILURE); |
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498 | } |
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499 | #else |
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500 | infile = stdin; |
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501 | #endif |
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502 | } |
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503 | |
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504 | /* Open the output file. */ |
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505 | #ifdef TWO_FILE_COMMANDLINE |
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506 | /* Must have explicit output file name */ |
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507 | if (argn != argc-2) { |
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508 | fprintf(stderr, "%s: must name one input and one output file\n", |
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509 | progname); |
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510 | usage(); |
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511 | } |
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512 | if ((outfile = fopen(argv[argn+1], WRITE_BINARY)) == NULL) { |
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513 | fprintf(stderr, "%s: can't open %s\n", progname, argv[argn+1]); |
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514 | exit(EXIT_FAILURE); |
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515 | } |
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516 | #else |
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517 | /* Unix style: expect zero or one file name */ |
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518 | if (argn < argc-1) { |
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519 | fprintf(stderr, "%s: only one input file\n", progname); |
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520 | usage(); |
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521 | } |
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522 | /* default output file is stdout */ |
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523 | #ifdef USE_SETMODE /* need to hack file mode? */ |
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524 | setmode(fileno(stdout), O_BINARY); |
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525 | #endif |
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526 | #ifdef USE_FDOPEN /* need to re-open in binary mode? */ |
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527 | if ((outfile = fdopen(fileno(stdout), WRITE_BINARY)) == NULL) { |
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528 | fprintf(stderr, "%s: can't open stdout\n", progname); |
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529 | exit(EXIT_FAILURE); |
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530 | } |
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531 | #else |
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532 | outfile = stdout; |
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533 | #endif |
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534 | #endif /* TWO_FILE_COMMANDLINE */ |
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535 | |
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536 | /* Collect comment text from comment_file or stdin, if necessary */ |
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537 | if (comment_arg == NULL) { |
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538 | FILE * src_file; |
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539 | int c; |
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540 | |
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541 | comment_arg = (char *) malloc((size_t) MAX_COM_LENGTH); |
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542 | if (comment_arg == NULL) |
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543 | ERREXIT("Insufficient memory"); |
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544 | comment_length = 0; |
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545 | src_file = (comment_file != NULL ? comment_file : stdin); |
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546 | while ((c = getc(src_file)) != EOF) { |
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547 | if (comment_length >= (unsigned int) MAX_COM_LENGTH) { |
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548 | fprintf(stderr, "Comment text may not exceed %u bytes\n", |
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549 | (unsigned int) MAX_COM_LENGTH); |
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550 | exit(EXIT_FAILURE); |
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551 | } |
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552 | comment_arg[comment_length++] = (char) c; |
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553 | } |
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554 | if (comment_file != NULL) |
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555 | fclose(comment_file); |
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556 | } |
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557 | |
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558 | /* Copy JPEG headers until SOFn marker; |
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559 | * we will insert the new comment marker just before SOFn. |
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560 | * This (a) causes the new comment to appear after, rather than before, |
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561 | * existing comments; and (b) ensures that comments come after any JFIF |
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562 | * or JFXX markers, as required by the JFIF specification. |
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563 | */ |
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564 | marker = scan_JPEG_header(keep_COM); |
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565 | /* Insert the new COM marker, but only if nonempty text has been supplied */ |
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566 | if (comment_length > 0) { |
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567 | write_marker(M_COM); |
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568 | write_2_bytes(comment_length + 2); |
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569 | while (comment_length > 0) { |
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570 | write_1_byte(*comment_arg++); |
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571 | comment_length--; |
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572 | } |
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573 | } |
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574 | /* Duplicate the remainder of the source file. |
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575 | * Note that any COM markers occuring after SOF will not be touched. |
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576 | */ |
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577 | write_marker(marker); |
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578 | copy_rest_of_file(); |
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579 | |
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580 | /* All done. */ |
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581 | exit(EXIT_SUCCESS); |
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582 | return 0; /* suppress no-return-value warnings */ |
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583 | } |
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