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10
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1 /* example.c -- usage example of 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 /* $Id: example.c,v 1.1.1.1 1997/12/06 04:37:16 darius Exp $ */
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7
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8 #include <stdio.h>
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9 #include "zlib.h"
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10
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11 #ifdef STDC
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12 # include <string.h>
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13 #endif
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14
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15 #ifndef __GO32__
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16 extern void exit __P((int));
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17 #endif
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18
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19 #define BUFLEN 4096
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20
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21 #define local static
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22 /* For MSDOS and other systems with limitation on stack size. For Unix,
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23 #define local
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24 works also.
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25 */
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26
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27 #define CHECK_ERR(err, msg) { \
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28 if (err != Z_OK) { \
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29 fprintf(stderr, "%s error: %d\n", msg, err); \
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30 exit(1); \
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31 } \
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32 }
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33
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34 char *hello = "hello world";
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35
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36 void test_compress __P((void));
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37 void test_gzio __P((char *out, char *in));
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38 void test_deflate __P((Byte compr[]));
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39 void test_inflate __P((Byte compr[]));
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40 void main __P((int argc, char *argv[]));
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41
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42 /* ===========================================================================
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43 * Test compress() and uncompress()
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44 */
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45 void test_compress()
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46 {
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47 local Byte compr[BUFLEN];
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48 uLong comprLen = sizeof(compr);
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49 local Byte uncompr[BUFLEN];
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50 uLong uncomprLen = sizeof(uncompr);
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51 int err;
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52 uLong len = strlen(hello)+1;
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53
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54 err = compress(compr, &comprLen, (Byte*)hello, len);
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55 CHECK_ERR(err, "compress");
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56
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57 strcpy((char*)uncompr, "garbage");
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58
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59 err = uncompress(uncompr, &uncomprLen, compr, comprLen);
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60 CHECK_ERR(err, "uncompress");
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61
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62 if (strcmp((char*)uncompr, hello)) {
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63 fprintf(stderr, "bad uncompress\n");
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64 } else {
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65 printf("uncompress(): %s\n", uncompr);
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66 }
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67 }
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68
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69 /* ===========================================================================
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70 * Test read/write of .gz files
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71 */
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72 void test_gzio(out, in)
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73 char *out; /* output file */
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74 char *in; /* input file */
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75 {
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76 local Byte uncompr[BUFLEN];
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77 int uncomprLen = sizeof(uncompr);
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78 int err;
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79 int len = strlen(hello)+1;
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80 gzFile file;
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81
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82 file = gzopen(out, "wb");
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83 if (file == NULL) {
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84 fprintf(stderr, "gzopen error\n");
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85 exit(1);
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86 }
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87
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88 if (gzwrite(file, hello, len) != len) {
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89 fprintf(stderr, "gzwrite err: %s\n", gzerror(file, &err));
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90 }
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91 gzclose(file);
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92
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93 file = gzopen(in, "rb");
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94 if (file == NULL) {
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95 fprintf(stderr, "gzopen error\n");
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96 }
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97 strcpy((char*)uncompr, "garbage");
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98
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99 uncomprLen = gzread(file, uncompr, uncomprLen);
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100 if (uncomprLen != len) {
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101 fprintf(stderr, "gzread err: %s\n", gzerror(file, &err));
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102 }
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103 gzclose(file);
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104
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105 if (strcmp((char*)uncompr, hello)) {
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106 fprintf(stderr, "bad gzread\n");
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107 } else {
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108 printf("gzread(): %s\n", uncompr);
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109 }
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110 }
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111
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112 /* ===========================================================================
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113 * Test deflate() with small buffers
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114 */
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115 void test_deflate(compr)
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116 Byte compr[];
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117 {
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118 z_stream c_stream; /* compression stream */
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119 int err;
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120 int len = strlen(hello)+1;
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121
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122 c_stream.zalloc = (alloc_func)0;
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123 c_stream.zfree = (free_func)0;
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124
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125 err = deflateInit(&c_stream, Z_DEFAULT_COMPRESSION);
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126 CHECK_ERR(err, "deflateInit");
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127
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128 c_stream.next_in = (Byte*)hello;
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129 c_stream.next_out = compr;
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130
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131 while (c_stream.total_in != (uLong)len) {
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132 c_stream.avail_in = c_stream.avail_out = 1; /* force small buffers */
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133 err = deflate(&c_stream, Z_NO_FLUSH);
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134 CHECK_ERR(err, "deflate");
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135 }
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136 /* Finish the stream, still forcing small buffers: */
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137 for (;;) {
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138 c_stream.avail_out = 1;
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139 err = deflate(&c_stream, Z_FINISH);
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140 if (err == Z_STREAM_END) break;
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141 CHECK_ERR(err, "deflate");
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142 }
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143
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144 err = deflateEnd(&c_stream);
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145 CHECK_ERR(err, "deflateEnd");
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146 }
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147
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148 /* ===========================================================================
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149 * Test inflate() with small buffers
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150 */
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151 void test_inflate(compr)
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152 Byte compr[];
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153 {
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154 local Byte uncompr[BUFLEN];
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155 int err;
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156 z_stream d_stream; /* decompression stream */
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157
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158 strcpy((char*)uncompr, "garbage");
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159
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160 d_stream.zalloc = (alloc_func)0;
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161 d_stream.zfree = (free_func)0;
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162
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163 err = inflateInit(&d_stream);
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164 CHECK_ERR(err, "inflateInit");
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165
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166 d_stream.next_in = compr;
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167 d_stream.next_out = uncompr;
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168
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169 for (;;) {
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170 d_stream.avail_in = d_stream.avail_out = 1; /* force small buffers */
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171 err = inflate(&d_stream, Z_NO_FLUSH);
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172 if (err == Z_STREAM_END) break;
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173 CHECK_ERR(err, "inflate");
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174 }
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175
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176 err = inflateEnd(&d_stream);
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177 CHECK_ERR(err, "inflateEnd");
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178
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179 if (strcmp((char*)uncompr, hello)) {
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180 fprintf(stderr, "bad inflate\n");
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181 } else {
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182 printf("inflate(): %s\n", uncompr);
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183 }
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184 }
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185
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186 /* ===========================================================================
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187 * Test deflate() with full flush
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188 */
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189 void test_flush(compr)
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190 Byte compr[];
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191 {
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192 z_stream c_stream; /* compression stream */
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193 int err;
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194 int len = strlen(hello)+1;
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195
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196 c_stream.zalloc = (alloc_func)0;
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197 c_stream.zfree = (free_func)0;
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198
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199 err = deflateInit(&c_stream, Z_DEFAULT_COMPRESSION);
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200 CHECK_ERR(err, "deflateInit");
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201
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202 c_stream.next_in = (Byte*)hello;
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203 c_stream.next_out = compr;
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204 c_stream.avail_in = 3;
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205 c_stream.avail_out = BUFLEN;
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206 err = deflate(&c_stream, Z_FULL_FLUSH);
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207 CHECK_ERR(err, "deflate");
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208
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209 compr[3]++; /* force an error in first compressed block */
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210 c_stream.avail_in = len - 3;
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211
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212 err = deflate(&c_stream, Z_FINISH);
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213 if (err != Z_STREAM_END) {
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214 CHECK_ERR(err, "deflate");
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215 }
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216 err = deflateEnd(&c_stream);
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217 CHECK_ERR(err, "deflateEnd");
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218 }
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219
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220 /* ===========================================================================
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221 * Test inflateSync()
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222 */
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223 void test_sync(compr)
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224 Byte compr[];
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225 {
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226 local Byte uncompr[BUFLEN];
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227 int err;
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228 z_stream d_stream; /* decompression stream */
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229
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230 strcpy((char*)uncompr, "garbage");
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231
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232 d_stream.zalloc = (alloc_func)0;
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233 d_stream.zfree = (free_func)0;
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234
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235 err = inflateInit(&d_stream);
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236 CHECK_ERR(err, "inflateInit");
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237
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238 d_stream.next_in = compr;
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239 d_stream.next_out = uncompr;
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240 d_stream.avail_in = 2; /* just read the zlib header */
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241 d_stream.avail_out = sizeof(uncompr);
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242
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243 inflate(&d_stream, Z_NO_FLUSH);
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244 CHECK_ERR(err, "inflate");
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245
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246 d_stream.avail_in = BUFLEN-2; /* let inflate read all compressed data */
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247 err = inflateSync(&d_stream); /* skip the damaged part */
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248 CHECK_ERR(err, "inflateSync");
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249
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250 err = inflate(&d_stream, Z_FINISH);
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251 if (err != Z_DATA_ERROR) {
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252 fprintf(stderr, "inflate should report DATA_ERROR\n");
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253 /* Because of incorrect adler32 */
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254 }
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255 err = inflateEnd(&d_stream);
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256 CHECK_ERR(err, "inflateEnd");
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257
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258 printf("after inflateSync(): hel%s\n", uncompr);
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259 }
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260
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261 /* ===========================================================================
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262 * Usage: example [output.gz [input.gz]]
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263 */
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264
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265 void main(argc, argv)
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266 int argc;
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267 char *argv[];
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268 {
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269 local Byte compr[BUFLEN];
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270
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271 if (zlib_version[0] != ZLIB_VERSION[0]) {
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272 fprintf(stderr, "incompatible zlib version\n");
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273 exit(1);
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274
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275 } else if (strcmp(zlib_version, ZLIB_VERSION) != 0) {
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276 fprintf(stderr, "warning: different zlib version\n");
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277 }
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278 test_compress();
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279
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280 test_gzio((argc > 1 ? argv[1] : "foo.gz"),
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281 (argc > 2 ? argv[2] : "foo.gz"));
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282
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283 test_deflate(compr);
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284 test_inflate(compr);
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285
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286 test_flush(compr);
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287 test_sync(compr);
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288
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289 exit(0);
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290 }
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