197 lines
4.8 KiB
C
197 lines
4.8 KiB
C
/* minigzip.c -- simulate gzip using the zlib compression library
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* Copyright (C) 1995-2006, 2010, 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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/*
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* minigzip is a minimal implementation of the gzip utility. This is
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* only an example of using zlib and isn't meant to replace the
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* full-featured gzip. No attempt is made to deal with file systems
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* limiting names to 14 or 8+3 characters, etc... Error checking is
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* very limited. So use minigzip only for testing; use gzip for the
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* real thing. On MSDOS, use only on file names without extension
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* or in pipe mode.
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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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#ifndef GZ_SUFFIX
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# define GZ_SUFFIX ".gz"
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#endif
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#define SUFFIX_LEN (sizeof(GZ_SUFFIX)-1)
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#define BUFLEN 16384
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#define MAX_NAME_LEN 1024
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#ifdef MAXSEG_64K
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# define local static
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/* Needed for systems with limitation on stack size. */
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#else
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# define local
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#endif
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static char *prog;
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void error OF((const char *msg));
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void gz_compress OF((FILE *in, gzFile out));
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void gz_uncompress OF((gzFile in, FILE *out));
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void file_compress OF((char *file, char *mode));
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void file_uncompress OF((char *file));
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int main OF((int argc, char *argv[]));
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/* ===========================================================================
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* Compress input to output then close both files.
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*/
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void gz_compress(in, out)
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FILE *in;
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gzFile out;
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{
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local char buf[BUFLEN];
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int len;
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int ret = 0;
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for (;;) {
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len = (int)fread(buf, 1, sizeof(buf), in);
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if (len == 0) break;
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ret = gzwrite(out, buf, (unsigned)len);
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if (ret != len)
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printf("wrong gzwrite:%d,ret:%d\n", len, ret);
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}
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fclose(in);
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gzclose(out);
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}
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/* ===========================================================================
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* Compress the given file: create a corresponding .gz file and remove the
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* original.
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*/
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void file_compress(file, mode)
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char *file;
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char *mode;
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{
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local char outfile[MAX_NAME_LEN];
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FILE *in;
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gzFile out;
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if (strlen(file) + strlen(GZ_SUFFIX) >= sizeof(outfile)) {
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fprintf(stderr, "%s: filename too long\n", prog);
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exit(1);
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}
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#if !defined(NO_snprintf) && !defined(NO_vsnprintf)
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snprintf(outfile, sizeof(outfile), "%s%s", file, GZ_SUFFIX);
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#else
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strcpy(outfile, file);
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strcat(outfile, GZ_SUFFIX);
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#endif
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in = fopen(file, "rb");
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if (in == NULL) {
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perror(file);
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exit(1);
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}
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out = gzopen(outfile, mode);
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if (out == NULL) {
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fprintf(stderr, "%s: can't gzopen %s\n", prog, outfile);
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exit(1);
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}
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gz_compress(in, out);
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unlink(file);
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}
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/* ===========================================================================
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* Usage: minigzip [-c] [-d] [-f] [-h] [-r] [-1 to -9] [files...]
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* -c : write to standard output
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* -d : decompress
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* -f : compress with Z_FILTERED
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* -h : compress with Z_HUFFMAN_ONLY
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* -r : compress with Z_RLE
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* -1 to -9 : compression level
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*/
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int main(argc, argv)
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int argc;
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char *argv[];
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{
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int copyout = 0;
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int uncompr = 0;
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gzFile file;
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char *bname, outmode[20];
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#if !defined(NO_snprintf) && !defined(NO_vsnprintf)
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snprintf(outmode, sizeof(outmode), "%s", "wb6 ");
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#else
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strcpy(outmode, "wb6 ");
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#endif
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prog = argv[0];
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bname = strrchr(argv[0], '/');
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if (bname)
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bname++;
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else
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bname = argv[0];
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argc--, argv++;
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if (!strcmp(bname, "gunzip"))
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uncompr = 1;
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else if (!strcmp(bname, "zcat"))
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copyout = uncompr = 1;
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while (argc > 0) {
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if (strcmp(*argv, "-c") == 0)
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copyout = 1;
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else if (strcmp(*argv, "-d") == 0)
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uncompr = 1;
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else if (strcmp(*argv, "-f") == 0)
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outmode[3] = 'f';
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else if (strcmp(*argv, "-h") == 0)
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outmode[3] = 'h';
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else if (strcmp(*argv, "-r") == 0)
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outmode[3] = 'R';
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else if ((*argv)[0] == '-' && (*argv)[1] >= '1' && (*argv)[1] <= '9' &&
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(*argv)[2] == 0)
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outmode[2] = (*argv)[1];
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else
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break;
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argc--, argv++;
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}
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if (outmode[3] == ' ')
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outmode[3] = 0;
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{
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do {
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{
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if (copyout) {
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FILE * in = fopen(*argv, "rb");
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if (in == NULL) {
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perror(*argv);
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} else {
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file = gzdopen(fileno(stdout), outmode);
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if (file == NULL) printf("can't gzdopen stdout");
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gz_compress(in, file);
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}
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} else {
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printf("outmode:%s\n",outmode);
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file_compress(*argv, outmode);
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}
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}
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} while (argv++, --argc);
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}
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return 0;
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}
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