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10
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1 /* minigzip.c -- simulate gzip using the zlib compression library
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2 * Copyright (C) 1995 Jean-loup Gailly.
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3 * For conditions of distribution and use, see copyright notice in zlib.h
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4 */
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5
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6 /*
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7 * minigzip is a minimal implementation of the gzip utility. This is
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8 * only an example of using zlib and isn't meant to replace the
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9 * full-featured gzip. No attempt is made to deal with file systems
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10 * limiting names to 14 or 8+3 characters, etc... Error checking is
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11 * very limited. So use minigzip only for testing; use gzip for the
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12 * real thing. On MSDOS, use only on file names without extension
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13 * or in pipe mode.
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14 */
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15
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16 /* $Id: minigzip.c,v 1.1.1.1 1997/12/06 04:37:18 darius Exp $ */
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17
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18 #include <stdio.h>
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19 #include "zlib.h"
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20
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21 #ifndef __GO32__
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22 extern void exit OF((int));
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23 #endif
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24 extern int unlink OF((const char *));
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25
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26 #ifdef STDC
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27 # include <string.h>
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28 #endif
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29
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30 #if defined(MSDOS) || defined(OS2) || defined(WIN32)
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31 # include <fcntl.h>
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32 # include <io.h>
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33 # define SET_BINARY_MODE(file) setmode(fileno(file), O_BINARY)
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34 #else
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35 # define SET_BINARY_MODE(file)
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36 #endif
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37
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38 #ifdef VMS
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39 # define GZ_SUFFIX "-gz"
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40 #else
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41 # define GZ_SUFFIX ".gz"
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42 #endif
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43 #define SUFFIX_LEN sizeof(GZ_SUFFIX)
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44
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45 #define BUFLEN 4096
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46 #define MAX_NAME_LEN 1024
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47
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48 #define local static
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49 /* For MSDOS and other systems with limitation on stack size. For Unix,
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50 #define local
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51 works also.
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52 */
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53
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54 char *prog;
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55
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56 void error OF((char *msg));
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57 void gz_compress OF((FILE *in, gzFile out));
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58 void gz_uncompress OF((gzFile in, FILE *out));
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59 void file_compress OF((char *file));
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60 void file_uncompress OF((char *file));
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61 int main OF((int argc, char *argv[]));
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62
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63 /* ===========================================================================
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64 * Display error message and exit
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65 */
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66 void error(msg)
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67 char *msg;
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68 {
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69 fprintf(stderr, "%s: %s\n", prog, msg);
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70 exit(1);
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71 }
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72
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73 /* ===========================================================================
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74 * Compress input to output then close both files.
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75 */
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76 void gz_compress(in, out)
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77 FILE *in;
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78 gzFile out;
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79 {
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80 local char buf[BUFLEN];
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81 int len;
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82 int err;
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83
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84 for (;;) {
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85 len = fread(buf, 1, sizeof(buf), in);
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86 if (ferror(in)) {
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87 perror("fread");
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88 exit(1);
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89 }
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90 if (len == 0) break;
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91
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92 if (gzwrite(out, buf, len) != len) error(gzerror(out, &err));
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93 }
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94 fclose(in);
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95 if (gzclose(out) != Z_OK) error("failed gzclose");
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96 }
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97
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98 /* ===========================================================================
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99 * Uncompress input to output then close both files.
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100 */
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101 void gz_uncompress(in, out)
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102 gzFile in;
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103 FILE *out;
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104 {
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105 local char buf[BUFLEN];
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106 int len;
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107 int err;
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108
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109 for (;;) {
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110 len = gzread(in, buf, sizeof(buf));
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111 if (len < 0) error (gzerror(in, &err));
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112 if (len == 0) break;
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113
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114 if (fwrite(buf, 1, len, out) != (uInt)len) error("failed fwrite");
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115 }
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116 if (fclose(out)) error("failed fclose");
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117
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118 if (gzclose(in) != Z_OK) error("failed gzclose");
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119 }
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120
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121
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122 /* ===========================================================================
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123 * Compress the given file: create a corresponding .gz file and remove the
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124 * original.
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125 */
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126 void file_compress(file)
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127 char *file;
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128 {
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129 local char outfile[MAX_NAME_LEN];
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130 FILE *in;
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131 gzFile out;
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132
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133 strcpy(outfile, file);
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134 strcat(outfile, GZ_SUFFIX);
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135
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136 in = fopen(file, "rb");
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137 if (in == NULL) {
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138 perror(file);
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139 exit(1);
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140 }
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141 out = gzopen(outfile, "wb"); /* use "wb9" for maximal compression */
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142 if (out == NULL) {
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143 fprintf(stderr, "%s: can't gzopen %s\n", prog, outfile);
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144 exit(1);
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145 }
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146 gz_compress(in, out);
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147
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148 unlink(file);
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149 }
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150
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151
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152 /* ===========================================================================
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153 * Uncompress the given file and remove the original.
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154 */
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155 void file_uncompress(file)
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156 char *file;
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157 {
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158 local char buf[MAX_NAME_LEN];
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159 char *infile, *outfile;
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160 FILE *out;
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161 gzFile in;
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162 int len = strlen(file);
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163
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164 strcpy(buf, file);
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165
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166 if (len > SUFFIX_LEN && strcmp(file+len-SUFFIX_LEN, GZ_SUFFIX) == 0) {
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167 infile = file;
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168 outfile = buf;
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169 outfile[len-3] = '\0';
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170 } else {
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171 outfile = file;
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172 infile = buf;
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173 strcat(infile, GZ_SUFFIX);
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174 }
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175 in = gzopen(infile, "rb");
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176 if (in == NULL) {
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177 fprintf(stderr, "%s: can't gzopen %s\n", prog, infile);
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178 exit(1);
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179 }
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180 out = fopen(outfile, "wb");
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181 if (out == NULL) {
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182 perror(file);
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183 exit(1);
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184 }
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185
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186 gz_uncompress(in, out);
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187
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188 unlink(infile);
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189 }
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190
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191
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192 /* ===========================================================================
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193 * Usage: minigzip [-d] [files...]
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194 */
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195
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196 int main(argc, argv)
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197 int argc;
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198 char *argv[];
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199 {
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200 int uncompr = 0;
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201 gzFile file;
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202
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203 prog = argv[0];
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204 argc--, argv++;
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205
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206 if (argc > 0) {
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207 uncompr = (strcmp(*argv, "-d") == 0);
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208 if (uncompr) {
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209 argc--, argv++;
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210 }
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211 }
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212 if (argc == 0) {
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213 SET_BINARY_MODE(stdin);
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214 SET_BINARY_MODE(stdout);
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215 if (uncompr) {
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216 file = gzdopen(fileno(stdin), "rb");
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217 if (file == NULL) error("can't gzdopen stdin");
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218 gz_uncompress(file, stdout);
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219 } else {
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220 file = gzdopen(fileno(stdout), "wb"); /* "wb9" for max compr. */
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221 if (file == NULL) error("can't gzdopen stdout");
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222 gz_compress(stdin, file);
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223 }
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224 } else {
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225 do {
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226 if (uncompr) {
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227 file_uncompress(*argv);
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228 } else {
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229 file_compress(*argv);
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230 }
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231 } while (argv++, --argc);
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232 }
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233 exit(0);
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234 return 0; /* to avoid warning */
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235 }
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