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3
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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 05:41:38 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 __P((int));
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23 #endif
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24 extern int unlink __P((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 #ifdef MSDOS
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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 #define BUFLEN 4096
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39 #define MAX_NAME_LEN 1024
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40
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41 #define local static
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42 /* For MSDOS and other systems with limitation on stack size. For Unix,
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43 #define local
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44 works also.
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45 */
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46
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47 char *prog;
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48
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49 void error __P((char *msg));
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50 void gz_compress __P((FILE *in, gzFile out));
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51 void gz_uncompress __P((gzFile in, FILE *out));
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52 void file_compress __P((char *file));
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53 void file_uncompress __P((char *file));
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54 void main __P((int argc, char *argv[]));
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55
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56 /* ===========================================================================
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57 * Display error message and exit
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58 */
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59 void error(msg)
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60 char *msg;
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61 {
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62 fprintf(stderr, "%s: %s\n", prog, msg);
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63 exit(1);
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64 }
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65
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66 /* ===========================================================================
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67 * Compress input to output then close both files.
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68 */
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69 void gz_compress(in, out)
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70 FILE *in;
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71 gzFile out;
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72 {
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73 local char buf[BUFLEN];
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74 int len;
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75 int err;
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76
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77 for (;;) {
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78 len = fread(buf, 1, sizeof(buf), in);
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79 if (ferror(in)) {
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80 perror("fread");
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81 exit(1);
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82 }
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83 if (len == 0) break;
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84
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85 if (gzwrite(out, buf, len) != len) error(gzerror(out, &err));
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86 }
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87 fclose(in);
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88 if (gzclose(out) != Z_OK) error("failed gzclose");
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89 }
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90
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91 /* ===========================================================================
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92 * Uncompress input to output then close both files.
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93 */
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94 void gz_uncompress(in, out)
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95 gzFile in;
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96 FILE *out;
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97 {
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98 local char buf[BUFLEN];
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99 int len;
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100 int err;
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101
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102 for (;;) {
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103 len = gzread(in, buf, sizeof(buf));
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104 if (len < 0) error (gzerror(in, &err));
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105 if (len == 0) break;
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106
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107 if (fwrite(buf, 1, len, out) != (uInt)len) error("failed fwrite");
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108 }
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109 if (fclose(out)) error("failed fclose");
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110
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111 if (gzclose(in) != Z_OK) error("failed gzclose");
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112 }
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113
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114
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115 /* ===========================================================================
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116 * Compress the given file: create a corresponding .gz file and remove the
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117 * original.
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118 */
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119 void file_compress(file)
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120 char *file;
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121 {
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122 local char outfile[MAX_NAME_LEN];
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123 FILE *in;
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124 gzFile out;
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125
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126 strcpy(outfile, file);
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127 strcat(outfile, ".gz");
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128
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129 in = fopen(file, "rb");
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130 if (in == NULL) {
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131 perror(file);
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132 exit(1);
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133 }
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134 out = gzopen(outfile, "wb");
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135 if (out == NULL) {
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136 fprintf(stderr, "%s: can't gzopen %s\n", prog, outfile);
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137 exit(1);
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138 }
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139 gz_compress(in, out);
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140
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141 unlink(file);
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142 }
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143
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144
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145 /* ===========================================================================
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146 * Uncompress the given file and remove the original.
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147 */
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148 void file_uncompress(file)
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149 char *file;
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150 {
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151 local char buf[MAX_NAME_LEN];
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152 char *infile, *outfile;
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153 FILE *out;
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154 gzFile in;
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155 int len = strlen(file);
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156
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157 strcpy(buf, file);
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158
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159 if (len > 3 && strcmp(file+len-3, ".gz") == 0) {
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160 infile = file;
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161 outfile = buf;
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162 outfile[len-3] = '\0';
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163 } else {
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164 outfile = file;
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165 infile = buf;
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166 strcat(infile, ".gz");
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167 }
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168 in = gzopen(infile, "rb");
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169 if (in == NULL) {
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170 fprintf(stderr, "%s: can't gzopen %s\n", prog, infile);
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171 exit(1);
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172 }
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173 out = fopen(outfile, "wb");
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174 if (out == NULL) {
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175 perror(file);
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176 exit(1);
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177 }
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178
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179 gz_uncompress(in, out);
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180
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181 unlink(infile);
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182 }
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183
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184
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185 /* ===========================================================================
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186 * Usage: minigzip [-d] [files...]
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187 */
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188
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189 void main(argc, argv)
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190 int argc;
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191 char *argv[];
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192 {
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193 int uncompr = 0;
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194 gzFile file;
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195
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196 prog = argv[0];
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197 argc--, argv++;
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198
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199 if (argc > 0) {
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200 uncompr = (strcmp(*argv, "-d") == 0);
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201 if (uncompr) {
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202 argc--, argv++;
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203 }
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204 }
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205 if (argc == 0) {
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206 SET_BINARY_MODE(stdin);
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207 SET_BINARY_MODE(stdout);
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208 if (uncompr) {
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209 file = gzdopen(fileno(stdin), "rb");
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210 if (file == NULL) error("can't gzdopen stdin");
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211 gz_uncompress(file, stdout);
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212 } else {
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213 file = gzdopen(fileno(stdout), "wb");
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214 if (file == NULL) error("can't gzdopen stdout");
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215 gz_compress(stdin, file);
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216 }
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217 } else {
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218 do {
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219 if (uncompr) {
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220 file_uncompress(*argv);
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221 } else {
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222 file_compress(*argv);
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223 }
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224 } while (argv++, --argc);
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225 }
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226 exit(0);
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227 }
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