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546 lines
15 KiB
546 lines
15 KiB
/* example.c -- usage example of the zlib compression library |
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* Copyright (C) 1995-2006, 2011, 2016 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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/* @(#) $Id$ */ |
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#include "zlib.h" |
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#include <stdio.h> |
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#ifdef STDC |
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# include <string.h> |
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# include <stdlib.h> |
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#endif |
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#if defined(VMS) || defined(RISCOS) |
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# define TESTFILE "foo-gz" |
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#else |
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# define TESTFILE "foo.gz" |
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#endif |
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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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static z_const char hello[] = "hello, hello!"; |
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/* "hello world" would be more standard, but the repeated "hello" |
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* stresses the compression code better, sorry... |
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*/ |
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static const char dictionary[] = "hello"; |
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static uLong dictId; /* Adler32 value of the dictionary */ |
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#ifdef Z_SOLO |
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static void *myalloc(void *q, unsigned n, unsigned m) { |
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(void)q; |
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return calloc(n, m); |
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} |
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static void myfree(void *q, void *p) { |
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(void)q; |
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free(p); |
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} |
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static alloc_func zalloc = myalloc; |
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static free_func zfree = myfree; |
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#else /* !Z_SOLO */ |
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static alloc_func zalloc = (alloc_func)0; |
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static free_func zfree = (free_func)0; |
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/* =========================================================================== |
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* Test compress() and uncompress() |
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*/ |
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static void test_compress(Byte *compr, uLong comprLen, Byte *uncompr, |
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uLong uncomprLen) { |
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int err; |
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uLong len = (uLong)strlen(hello)+1; |
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err = compress(compr, &comprLen, (const Bytef*)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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exit(1); |
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} else { |
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printf("uncompress(): %s\n", (char *)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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static void test_gzio(const char *fname, Byte *uncompr, uLong uncomprLen) { |
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#ifdef NO_GZCOMPRESS |
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fprintf(stderr, "NO_GZCOMPRESS -- gz* functions cannot compress\n"); |
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#else |
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int err; |
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int len = (int)strlen(hello)+1; |
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gzFile file; |
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z_off_t pos; |
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file = gzopen(fname, "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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gzputc(file, 'h'); |
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if (gzputs(file, "ello") != 4) { |
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fprintf(stderr, "gzputs err: %s\n", gzerror(file, &err)); |
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exit(1); |
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} |
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if (gzprintf(file, ", %s!", "hello") != 8) { |
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fprintf(stderr, "gzprintf err: %s\n", gzerror(file, &err)); |
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exit(1); |
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} |
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gzseek(file, 1L, SEEK_CUR); /* add one zero byte */ |
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gzclose(file); |
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file = gzopen(fname, "rb"); |
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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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strcpy((char*)uncompr, "garbage"); |
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if (gzread(file, uncompr, (unsigned)uncomprLen) != len) { |
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fprintf(stderr, "gzread err: %s\n", gzerror(file, &err)); |
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exit(1); |
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} |
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if (strcmp((char*)uncompr, hello)) { |
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fprintf(stderr, "bad gzread: %s\n", (char*)uncompr); |
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exit(1); |
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} else { |
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printf("gzread(): %s\n", (char*)uncompr); |
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} |
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pos = gzseek(file, -8L, SEEK_CUR); |
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if (pos != 6 || gztell(file) != pos) { |
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fprintf(stderr, "gzseek error, pos=%ld, gztell=%ld\n", |
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(long)pos, (long)gztell(file)); |
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exit(1); |
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} |
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if (gzgetc(file) != ' ') { |
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fprintf(stderr, "gzgetc error\n"); |
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exit(1); |
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} |
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if (gzungetc(' ', file) != ' ') { |
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fprintf(stderr, "gzungetc error\n"); |
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exit(1); |
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} |
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gzgets(file, (char*)uncompr, (int)uncomprLen); |
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if (strlen((char*)uncompr) != 7) { /* " hello!" */ |
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fprintf(stderr, "gzgets err after gzseek: %s\n", gzerror(file, &err)); |
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exit(1); |
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} |
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if (strcmp((char*)uncompr, hello + 6)) { |
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fprintf(stderr, "bad gzgets after gzseek\n"); |
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exit(1); |
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} else { |
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printf("gzgets() after gzseek: %s\n", (char*)uncompr); |
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} |
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gzclose(file); |
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#endif |
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} |
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#endif /* Z_SOLO */ |
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/* =========================================================================== |
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* Test deflate() with small buffers |
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*/ |
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static void test_deflate(Byte *compr, uLong comprLen) { |
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z_stream c_stream; /* compression stream */ |
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int err; |
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uLong len = (uLong)strlen(hello)+1; |
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c_stream.zalloc = zalloc; |
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c_stream.zfree = zfree; |
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c_stream.opaque = (voidpf)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 = (z_const unsigned char *)hello; |
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c_stream.next_out = compr; |
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while (c_stream.total_in != len && c_stream.total_out < comprLen) { |
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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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static void test_inflate(Byte *compr, uLong comprLen, Byte *uncompr, |
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uLong uncomprLen) { |
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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 = zalloc; |
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d_stream.zfree = zfree; |
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d_stream.opaque = (voidpf)0; |
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d_stream.next_in = compr; |
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d_stream.avail_in = 0; |
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d_stream.next_out = uncompr; |
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err = inflateInit(&d_stream); |
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CHECK_ERR(err, "inflateInit"); |
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while (d_stream.total_out < uncomprLen && d_stream.total_in < comprLen) { |
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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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exit(1); |
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} else { |
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printf("inflate(): %s\n", (char *)uncompr); |
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} |
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} |
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/* =========================================================================== |
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* Test deflate() with large buffers and dynamic change of compression level |
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*/ |
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static void test_large_deflate(Byte *compr, uLong comprLen, Byte *uncompr, |
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uLong uncomprLen) { |
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z_stream c_stream; /* compression stream */ |
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int err; |
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c_stream.zalloc = zalloc; |
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c_stream.zfree = zfree; |
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c_stream.opaque = (voidpf)0; |
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err = deflateInit(&c_stream, Z_BEST_SPEED); |
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CHECK_ERR(err, "deflateInit"); |
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c_stream.next_out = compr; |
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c_stream.avail_out = (uInt)comprLen; |
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/* At this point, uncompr is still mostly zeroes, so it should compress |
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* very well: |
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*/ |
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c_stream.next_in = uncompr; |
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c_stream.avail_in = (uInt)uncomprLen; |
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err = deflate(&c_stream, Z_NO_FLUSH); |
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CHECK_ERR(err, "deflate"); |
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if (c_stream.avail_in != 0) { |
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fprintf(stderr, "deflate not greedy\n"); |
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exit(1); |
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} |
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/* Feed in already compressed data and switch to no compression: */ |
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deflateParams(&c_stream, Z_NO_COMPRESSION, Z_DEFAULT_STRATEGY); |
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c_stream.next_in = compr; |
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c_stream.avail_in = (uInt)uncomprLen/2; |
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err = deflate(&c_stream, Z_NO_FLUSH); |
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CHECK_ERR(err, "deflate"); |
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/* Switch back to compressing mode: */ |
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deflateParams(&c_stream, Z_BEST_COMPRESSION, Z_FILTERED); |
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c_stream.next_in = uncompr; |
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c_stream.avail_in = (uInt)uncomprLen; |
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err = deflate(&c_stream, Z_NO_FLUSH); |
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CHECK_ERR(err, "deflate"); |
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err = deflate(&c_stream, Z_FINISH); |
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if (err != Z_STREAM_END) { |
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fprintf(stderr, "deflate should report Z_STREAM_END\n"); |
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exit(1); |
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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 large buffers |
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*/ |
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static void test_large_inflate(Byte *compr, uLong comprLen, Byte *uncompr, |
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uLong uncomprLen) { |
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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 = zalloc; |
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d_stream.zfree = zfree; |
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d_stream.opaque = (voidpf)0; |
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d_stream.next_in = compr; |
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d_stream.avail_in = (uInt)comprLen; |
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err = inflateInit(&d_stream); |
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CHECK_ERR(err, "inflateInit"); |
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for (;;) { |
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d_stream.next_out = uncompr; /* discard the output */ |
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d_stream.avail_out = (uInt)uncomprLen; |
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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, "large 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 (d_stream.total_out != 2*uncomprLen + uncomprLen/2) { |
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fprintf(stderr, "bad large inflate: %ld\n", d_stream.total_out); |
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exit(1); |
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} else { |
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printf("large_inflate(): OK\n"); |
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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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static void test_flush(Byte *compr, uLong *comprLen) { |
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z_stream c_stream; /* compression stream */ |
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int err; |
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uInt len = (uInt)strlen(hello)+1; |
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c_stream.zalloc = zalloc; |
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c_stream.zfree = zfree; |
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c_stream.opaque = (voidpf)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 = (z_const unsigned char *)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 = (uInt)*comprLen; |
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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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*comprLen = c_stream.total_out; |
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} |
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/* =========================================================================== |
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* Test inflateSync() |
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*/ |
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static void test_sync(Byte *compr, uLong comprLen, Byte *uncompr, |
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uLong uncomprLen) { |
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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 = zalloc; |
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d_stream.zfree = zfree; |
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d_stream.opaque = (voidpf)0; |
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d_stream.next_in = compr; |
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d_stream.avail_in = 2; /* just read the zlib header */ |
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err = inflateInit(&d_stream); |
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CHECK_ERR(err, "inflateInit"); |
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d_stream.next_out = uncompr; |
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d_stream.avail_out = (uInt)uncomprLen; |
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err = inflate(&d_stream, Z_NO_FLUSH); |
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CHECK_ERR(err, "inflate"); |
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d_stream.avail_in = (uInt)comprLen-2; /* read all compressed data */ |
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err = inflateSync(&d_stream); /* but 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_STREAM_END) { |
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fprintf(stderr, "inflate should report Z_STREAM_END\n"); |
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exit(1); |
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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(): hel%s\n", (char *)uncompr); |
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} |
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/* =========================================================================== |
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* Test deflate() with preset dictionary |
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*/ |
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static void test_dict_deflate(Byte *compr, uLong comprLen) { |
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z_stream c_stream; /* compression stream */ |
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int err; |
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c_stream.zalloc = zalloc; |
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c_stream.zfree = zfree; |
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c_stream.opaque = (voidpf)0; |
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err = deflateInit(&c_stream, Z_BEST_COMPRESSION); |
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CHECK_ERR(err, "deflateInit"); |
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err = deflateSetDictionary(&c_stream, |
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(const Bytef*)dictionary, (int)sizeof(dictionary)); |
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CHECK_ERR(err, "deflateSetDictionary"); |
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dictId = c_stream.adler; |
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c_stream.next_out = compr; |
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c_stream.avail_out = (uInt)comprLen; |
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c_stream.next_in = (z_const unsigned char *)hello; |
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c_stream.avail_in = (uInt)strlen(hello)+1; |
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err = deflate(&c_stream, Z_FINISH); |
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if (err != Z_STREAM_END) { |
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fprintf(stderr, "deflate should report Z_STREAM_END\n"); |
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exit(1); |
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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 a preset dictionary |
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*/ |
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static void test_dict_inflate(Byte *compr, uLong comprLen, Byte *uncompr, |
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uLong uncomprLen) { |
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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 = zalloc; |
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d_stream.zfree = zfree; |
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d_stream.opaque = (voidpf)0; |
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d_stream.next_in = compr; |
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d_stream.avail_in = (uInt)comprLen; |
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err = inflateInit(&d_stream); |
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CHECK_ERR(err, "inflateInit"); |
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d_stream.next_out = uncompr; |
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d_stream.avail_out = (uInt)uncomprLen; |
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for (;;) { |
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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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if (err == Z_NEED_DICT) { |
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if (d_stream.adler != dictId) { |
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fprintf(stderr, "unexpected dictionary"); |
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exit(1); |
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} |
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err = inflateSetDictionary(&d_stream, (const Bytef*)dictionary, |
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(int)sizeof(dictionary)); |
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} |
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CHECK_ERR(err, "inflate with dict"); |
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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 with dict\n"); |
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exit(1); |
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} else { |
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printf("inflate with dictionary: %s\n", (char *)uncompr); |
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} |
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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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int main(int argc, char *argv[]) { |
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Byte *compr, *uncompr; |
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uLong uncomprLen = 20000; |
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uLong comprLen = 3 * uncomprLen; |
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static const char* myVersion = ZLIB_VERSION; |
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if (zlibVersion()[0] != myVersion[0]) { |
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fprintf(stderr, "incompatible zlib version\n"); |
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exit(1); |
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} else if (strcmp(zlibVersion(), ZLIB_VERSION) != 0) { |
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fprintf(stderr, "warning: different zlib version linked: %s\n", |
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zlibVersion()); |
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} |
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printf("zlib version %s = 0x%04x, compile flags = 0x%lx\n", |
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ZLIB_VERSION, ZLIB_VERNUM, zlibCompileFlags()); |
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compr = (Byte*)calloc((uInt)comprLen, 1); |
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uncompr = (Byte*)calloc((uInt)uncomprLen, 1); |
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/* compr and uncompr are cleared to avoid reading uninitialized |
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* data and to ensure that uncompr compresses well. |
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*/ |
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if (compr == Z_NULL || uncompr == Z_NULL) { |
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printf("out of memory\n"); |
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exit(1); |
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} |
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#ifdef Z_SOLO |
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(void)argc; |
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(void)argv; |
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#else |
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test_compress(compr, comprLen, uncompr, uncomprLen); |
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test_gzio((argc > 1 ? argv[1] : TESTFILE), |
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uncompr, uncomprLen); |
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#endif |
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test_deflate(compr, comprLen); |
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test_inflate(compr, comprLen, uncompr, uncomprLen); |
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test_large_deflate(compr, comprLen, uncompr, uncomprLen); |
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test_large_inflate(compr, comprLen, uncompr, uncomprLen); |
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test_flush(compr, &comprLen); |
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test_sync(compr, comprLen, uncompr, uncomprLen); |
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comprLen = 3 * uncomprLen; |
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test_dict_deflate(compr, comprLen); |
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test_dict_inflate(compr, comprLen, uncompr, uncomprLen); |
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free(compr); |
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free(uncompr); |
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return 0; |
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}
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