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288 lines
7.0 KiB
288 lines
7.0 KiB
/* example.c -- usage example of the zlib compression library |
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* Copyright (C) 1995 Jean-loup Gailly. |
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* For conditions of distribution and use, see copyright notice in zlib.h |
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*/ |
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/* $Id: example.c,v 1.7 1995/05/01 16:57:22 jloup Exp $ */ |
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#include <stdio.h> |
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#include "zlib.h" |
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#ifdef STDC |
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# include <string.h> |
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#endif |
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extern void exit __P((int)); |
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#define BUFLEN 4096 |
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#define local static |
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/* For MSDOS and other systems with limitation on stack size. For Unix, |
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#define local |
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works also. |
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*/ |
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#define CHECK_ERR(err, msg) { \ |
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if (err != Z_OK) { \ |
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fprintf(stderr, "%s error: %d\n", msg, err); \ |
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exit(1); \ |
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} \ |
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} |
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char *hello = "hello world"; |
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void test_compress __P((void)); |
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void test_gzio __P((char *out, char *in)); |
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void test_deflate __P((Byte compr[])); |
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void test_inflate __P((Byte compr[])); |
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void main __P((int argc, char *argv[])); |
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/* =========================================================================== |
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* Test compress() and uncompress() |
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*/ |
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void test_compress() |
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{ |
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local Byte compr[BUFLEN]; |
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uLong comprLen = sizeof(compr); |
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local Byte uncompr[BUFLEN]; |
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uLong uncomprLen = sizeof(uncompr); |
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int err; |
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uLong len = strlen(hello)+1; |
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err = compress(compr, &comprLen, (Byte*)hello, len); |
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CHECK_ERR(err, "compress"); |
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strcpy((char*)uncompr, "garbage"); |
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err = uncompress(uncompr, &uncomprLen, compr, comprLen); |
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CHECK_ERR(err, "uncompress"); |
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if (strcmp((char*)uncompr, hello)) { |
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fprintf(stderr, "bad uncompress\n"); |
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} else { |
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printf("uncompress(): %s\n", uncompr); |
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} |
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} |
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/* =========================================================================== |
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* Test read/write of .gz files |
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*/ |
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void test_gzio(out, in) |
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char *out; /* output file */ |
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char *in; /* input file */ |
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{ |
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local Byte uncompr[BUFLEN]; |
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int uncomprLen = sizeof(uncompr); |
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int err; |
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int len = strlen(hello)+1; |
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gzFile file; |
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file = gzopen(out, "wb"); |
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if (file == NULL) { |
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fprintf(stderr, "gzopen error\n"); |
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exit(1); |
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} |
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if (gzwrite(file, hello, len) != len) { |
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fprintf(stderr, "gzwrite err: %s\n", gzerror(file, &err)); |
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} |
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gzclose(file); |
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file = gzopen(in, "rb"); |
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if (file == NULL) { |
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fprintf(stderr, "gzopen error\n"); |
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} |
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strcpy((char*)uncompr, "garbage"); |
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uncomprLen = gzread(file, uncompr, uncomprLen); |
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if (uncomprLen != len) { |
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fprintf(stderr, "gzread err: %s\n", gzerror(file, &err)); |
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} |
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gzclose(file); |
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if (strcmp((char*)uncompr, hello)) { |
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fprintf(stderr, "bad gzread\n"); |
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} else { |
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printf("gzread(): %s\n", uncompr); |
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} |
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} |
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/* =========================================================================== |
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* Test deflate() with small buffers |
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*/ |
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void test_deflate(compr) |
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Byte compr[]; |
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{ |
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z_stream c_stream; /* compression stream */ |
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int err; |
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int len = strlen(hello)+1; |
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c_stream.zalloc = (alloc_func)0; |
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c_stream.zfree = (free_func)0; |
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err = deflateInit(&c_stream, Z_DEFAULT_COMPRESSION); |
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CHECK_ERR(err, "deflateInit"); |
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c_stream.next_in = (Byte*)hello; |
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c_stream.next_out = compr; |
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while (c_stream.total_in != (uLong)len) { |
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c_stream.avail_in = c_stream.avail_out = 1; /* force small buffers */ |
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err = deflate(&c_stream, Z_NO_FLUSH); |
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CHECK_ERR(err, "deflate"); |
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} |
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/* Finish the stream, still forcing small buffers: */ |
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for (;;) { |
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c_stream.avail_out = 1; |
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err = deflate(&c_stream, Z_FINISH); |
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if (err == Z_STREAM_END) break; |
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CHECK_ERR(err, "deflate"); |
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} |
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err = deflateEnd(&c_stream); |
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CHECK_ERR(err, "deflateEnd"); |
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} |
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/* =========================================================================== |
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* Test inflate() with small buffers |
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*/ |
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void test_inflate(compr) |
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Byte compr[]; |
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{ |
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local Byte uncompr[BUFLEN]; |
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int err; |
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z_stream d_stream; /* decompression stream */ |
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strcpy((char*)uncompr, "garbage"); |
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d_stream.zalloc = (alloc_func)0; |
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d_stream.zfree = (free_func)0; |
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err = inflateInit(&d_stream); |
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CHECK_ERR(err, "inflateInit"); |
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d_stream.next_in = compr; |
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d_stream.next_out = uncompr; |
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for (;;) { |
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d_stream.avail_in = d_stream.avail_out = 1; /* force small buffers */ |
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err = inflate(&d_stream, Z_NO_FLUSH); |
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if (err == Z_STREAM_END) break; |
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CHECK_ERR(err, "inflate"); |
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} |
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err = inflateEnd(&d_stream); |
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CHECK_ERR(err, "inflateEnd"); |
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if (strcmp((char*)uncompr, hello)) { |
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fprintf(stderr, "bad inflate\n"); |
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} else { |
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printf("inflate(): %s\n", uncompr); |
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} |
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} |
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/* =========================================================================== |
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* Test deflate() with full flush |
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*/ |
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void test_flush(compr) |
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Byte compr[]; |
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{ |
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z_stream c_stream; /* compression stream */ |
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int err; |
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int len = strlen(hello)+1; |
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c_stream.zalloc = (alloc_func)0; |
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c_stream.zfree = (free_func)0; |
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err = deflateInit(&c_stream, Z_DEFAULT_COMPRESSION); |
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CHECK_ERR(err, "deflateInit"); |
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c_stream.next_in = (Byte*)hello; |
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c_stream.next_out = compr; |
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c_stream.avail_in = 3; |
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c_stream.avail_out = BUFLEN; |
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err = deflate(&c_stream, Z_FULL_FLUSH); |
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CHECK_ERR(err, "deflate"); |
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compr[3]++; /* force an error in first compressed block */ |
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c_stream.avail_in = len - 3; |
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err = deflate(&c_stream, Z_FINISH); |
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if (err != Z_STREAM_END) { |
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CHECK_ERR(err, "deflate"); |
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} |
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err = deflateEnd(&c_stream); |
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CHECK_ERR(err, "deflateEnd"); |
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} |
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/* =========================================================================== |
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* Test inflateSync() |
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*/ |
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void test_sync(compr) |
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Byte compr[]; |
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{ |
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local Byte uncompr[BUFLEN]; |
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int err; |
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z_stream d_stream; /* decompression stream */ |
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strcpy((char*)uncompr, "garbage"); |
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d_stream.zalloc = (alloc_func)0; |
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d_stream.zfree = (free_func)0; |
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err = inflateInit(&d_stream); |
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CHECK_ERR(err, "inflateInit"); |
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d_stream.next_in = compr; |
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d_stream.next_out = uncompr; |
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d_stream.avail_in = 2; /* just read the zlib header */ |
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d_stream.avail_out = sizeof(uncompr); |
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inflate(&d_stream, Z_NO_FLUSH); |
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CHECK_ERR(err, "inflate"); |
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d_stream.avail_in = BUFLEN-2; /* let inflate read all compressed data */ |
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err = inflateSync(&d_stream); /* skip the damaged part */ |
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CHECK_ERR(err, "inflateSync"); |
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err = inflate(&d_stream, Z_FINISH); |
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if (err != Z_DATA_ERROR) { |
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fprintf(stderr, "inflate should report DATA_ERROR\n"); |
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/* Because of incorrect adler32 */ |
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} |
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err = inflateEnd(&d_stream); |
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CHECK_ERR(err, "inflateEnd"); |
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printf("after inflateSync(): %s\n", uncompr); |
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} |
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/* =========================================================================== |
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* Usage: example [output.gz [input.gz]] |
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*/ |
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void main(argc, argv) |
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int argc; |
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char *argv[]; |
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{ |
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local Byte compr[BUFLEN]; |
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if (zlib_version[0] != ZLIB_VERSION[0]) { |
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fprintf(stderr, "incompatible zlib version\n"); |
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exit(1); |
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} else if (strcmp(zlib_version, ZLIB_VERSION) != 0) { |
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fprintf(stderr, "warning: different zlib version\n"); |
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} |
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test_compress(); |
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test_gzio((argc > 1 ? argv[1] : "foo.gz"), |
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(argc > 2 ? argv[2] : "foo.gz")); |
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test_deflate(compr); |
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test_inflate(compr); |
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test_flush(compr); |
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test_sync(compr); |
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exit(0); |
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}
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