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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 04:37:17 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 OF((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, hello!";
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35 /* "hello world" would be more standard, but the repeated "hello"
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36 * stresses the compression code better, sorry...
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37 */
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38
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39 void test_compress OF((void));
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40 void test_gzio OF((char *out, char *in));
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41 void test_deflate OF((Byte compr[]));
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42 void test_inflate OF((Byte compr[]));
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43 void test_flush OF((Byte compr[]));
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44 void test_sync OF((Byte compr[]));
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45 int main OF((int argc, char *argv[]));
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46
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47 /* ===========================================================================
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48 * Test compress() and uncompress()
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49 */
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50 void test_compress()
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51 {
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52 local Byte compr[BUFLEN];
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53 uLong comprLen = sizeof(compr);
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54 local Byte uncompr[BUFLEN];
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55 uLong uncomprLen = sizeof(uncompr);
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56 int err;
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57 uLong len = strlen(hello)+1;
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58
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59 err = compress(compr, &comprLen, (Byte*)hello, len);
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60 CHECK_ERR(err, "compress");
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61
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62 strcpy((char*)uncompr, "garbage");
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63
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64 err = uncompress(uncompr, &uncomprLen, compr, comprLen);
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65 CHECK_ERR(err, "uncompress");
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66
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67 if (strcmp((char*)uncompr, hello)) {
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68 fprintf(stderr, "bad uncompress\n");
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69 } else {
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70 printf("uncompress(): %s\n", uncompr);
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71 }
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72 }
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73
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74 /* ===========================================================================
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75 * Test read/write of .gz files
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76 */
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77 void test_gzio(out, in)
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78 char *out; /* output file */
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79 char *in; /* input file */
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80 {
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81 local Byte uncompr[BUFLEN];
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82 int uncomprLen = sizeof(uncompr);
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83 int err;
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84 int len = strlen(hello)+1;
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85 gzFile file;
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86
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87 file = gzopen(out, "wb");
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88 if (file == NULL) {
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89 fprintf(stderr, "gzopen error\n");
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90 exit(1);
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91 }
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92
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93 if (gzwrite(file, hello, len) != len) {
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94 fprintf(stderr, "gzwrite err: %s\n", gzerror(file, &err));
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95 }
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96 gzclose(file);
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97
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98 file = gzopen(in, "rb");
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99 if (file == NULL) {
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100 fprintf(stderr, "gzopen error\n");
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101 }
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102 strcpy((char*)uncompr, "garbage");
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103
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104 uncomprLen = gzread(file, uncompr, uncomprLen);
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105 if (uncomprLen != len) {
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106 fprintf(stderr, "gzread err: %s\n", gzerror(file, &err));
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107 }
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108 gzclose(file);
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109
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110 if (strcmp((char*)uncompr, hello)) {
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111 fprintf(stderr, "bad gzread\n");
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112 } else {
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113 printf("gzread(): %s\n", uncompr);
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114 }
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115 }
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116
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117 /* ===========================================================================
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118 * Test deflate() with small buffers
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119 */
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120 void test_deflate(compr)
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121 Byte compr[];
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122 {
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123 z_stream c_stream; /* compression stream */
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124 int err;
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125 int len = strlen(hello)+1;
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126
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127 c_stream.zalloc = (alloc_func)0;
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128 c_stream.zfree = (free_func)0;
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129
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130 err = deflateInit(&c_stream, Z_DEFAULT_COMPRESSION);
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131 CHECK_ERR(err, "deflateInit");
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132
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133 c_stream.next_in = (Byte*)hello;
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134 c_stream.next_out = compr;
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135
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136 while (c_stream.total_in != (uLong)len) {
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137 c_stream.avail_in = c_stream.avail_out = 1; /* force small buffers */
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138 err = deflate(&c_stream, Z_NO_FLUSH);
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139 CHECK_ERR(err, "deflate");
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140 }
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141 /* Finish the stream, still forcing small buffers: */
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142 for (;;) {
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143 c_stream.avail_out = 1;
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144 err = deflate(&c_stream, Z_FINISH);
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145 if (err == Z_STREAM_END) break;
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146 CHECK_ERR(err, "deflate");
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147 }
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148
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149 err = deflateEnd(&c_stream);
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150 CHECK_ERR(err, "deflateEnd");
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151 }
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152
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153 /* ===========================================================================
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154 * Test inflate() with small buffers
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155 */
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156 void test_inflate(compr)
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157 Byte compr[];
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158 {
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159 local Byte uncompr[BUFLEN];
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160 int err;
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161 z_stream d_stream; /* decompression stream */
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162
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163 strcpy((char*)uncompr, "garbage");
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164
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165 d_stream.zalloc = (alloc_func)0;
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166 d_stream.zfree = (free_func)0;
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167
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168 err = inflateInit(&d_stream);
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169 CHECK_ERR(err, "inflateInit");
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170
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171 d_stream.next_in = compr;
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172 d_stream.next_out = uncompr;
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173
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174 for (;;) {
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175 d_stream.avail_in = d_stream.avail_out = 1; /* force small buffers */
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176 err = inflate(&d_stream, Z_NO_FLUSH);
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177 if (err == Z_STREAM_END) break;
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178 CHECK_ERR(err, "inflate");
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179 }
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180
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181 err = inflateEnd(&d_stream);
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182 CHECK_ERR(err, "inflateEnd");
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183
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184 if (strcmp((char*)uncompr, hello)) {
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185 fprintf(stderr, "bad inflate\n");
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186 } else {
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187 printf("inflate(): %s\n", uncompr);
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188 }
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189 }
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190
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191 /* ===========================================================================
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192 * Test deflate() with full flush
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193 */
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194 void test_flush(compr)
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195 Byte compr[];
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196 {
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197 z_stream c_stream; /* compression stream */
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198 int err;
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199 int len = strlen(hello)+1;
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200
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201 c_stream.zalloc = (alloc_func)0;
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202 c_stream.zfree = (free_func)0;
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203
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204 err = deflateInit(&c_stream, Z_DEFAULT_COMPRESSION);
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205 CHECK_ERR(err, "deflateInit");
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206
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207 c_stream.next_in = (Byte*)hello;
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208 c_stream.next_out = compr;
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209 c_stream.avail_in = 3;
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210 c_stream.avail_out = BUFLEN;
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211 err = deflate(&c_stream, Z_FULL_FLUSH);
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212 CHECK_ERR(err, "deflate");
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213
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214 compr[3]++; /* force an error in first compressed block */
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215 c_stream.avail_in = len - 3;
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216
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217 err = deflate(&c_stream, Z_FINISH);
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218 if (err != Z_STREAM_END) {
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219 CHECK_ERR(err, "deflate");
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220 }
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221 err = deflateEnd(&c_stream);
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222 CHECK_ERR(err, "deflateEnd");
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223 }
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224
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225 /* ===========================================================================
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226 * Test inflateSync()
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227 */
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228 void test_sync(compr)
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229 Byte compr[];
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230 {
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231 local Byte uncompr[BUFLEN];
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232 int err;
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233 z_stream d_stream; /* decompression stream */
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234
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235 strcpy((char*)uncompr, "garbage");
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236
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237 d_stream.zalloc = (alloc_func)0;
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238 d_stream.zfree = (free_func)0;
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239
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240 err = inflateInit(&d_stream);
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241 CHECK_ERR(err, "inflateInit");
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242
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243 d_stream.next_in = compr;
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244 d_stream.next_out = uncompr;
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245 d_stream.avail_in = 2; /* just read the zlib header */
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246 d_stream.avail_out = sizeof(uncompr);
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247
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248 inflate(&d_stream, Z_NO_FLUSH);
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249 CHECK_ERR(err, "inflate");
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250
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251 d_stream.avail_in = BUFLEN-2; /* let inflate read all compressed data */
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252 err = inflateSync(&d_stream); /* skip the damaged part */
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253 CHECK_ERR(err, "inflateSync");
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254
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255 err = inflate(&d_stream, Z_FINISH);
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256 if (err != Z_DATA_ERROR) {
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257 fprintf(stderr, "inflate should report DATA_ERROR\n");
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258 /* Because of incorrect adler32 */
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259 }
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260 err = inflateEnd(&d_stream);
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261 CHECK_ERR(err, "inflateEnd");
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262
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263 printf("after inflateSync(): hel%s\n", uncompr);
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264 }
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265
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266 /* ===========================================================================
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267 * Usage: example [output.gz [input.gz]]
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268 */
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269
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270 int main(argc, argv)
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271 int argc;
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272 char *argv[];
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273 {
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274 local Byte compr[BUFLEN];
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275
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276 if (zlib_version[0] != ZLIB_VERSION[0]) {
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277 fprintf(stderr, "incompatible zlib version\n");
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278 exit(1);
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279
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280 } else if (strcmp(zlib_version, ZLIB_VERSION) != 0) {
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281 fprintf(stderr, "warning: different zlib version\n");
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282 }
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283 test_compress();
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284
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285 test_gzio((argc > 1 ? argv[1] : "foo.gz"),
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286 (argc > 2 ? argv[2] : "foo.gz"));
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287
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288 test_deflate(compr);
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289 test_inflate(compr);
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290
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291 test_flush(compr);
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292 test_sync(compr);
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293
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294 exit(0);
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295 return 0; /* to avoid warning */
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296 }
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