minigzip.c
上传用户:zhongxx05
上传日期:2007-06-06
资源大小:33641k
文件大小:8k
- /* minigzip.c -- simulate gzip using the zlib compression library
- * Copyright (C) 1995-2002 Jean-loup Gailly.
- * For conditions of distribution and use, see copyright notice in zlib.h
- */
- /*
- * minigzip is a minimal implementation of the gzip utility. This is
- * only an example of using zlib and isn't meant to replace the
- * full-featured gzip. No attempt is made to deal with file systems
- * limiting names to 14 or 8+3 characters, etc... Error checking is
- * very limited. So use minigzip only for testing; use gzip for the
- * real thing. On MSDOS, use only on file names without extension
- * or in pipe mode.
- */
- /* @(#) $Id: minigzip.c,v 1.1.1.1 2002/10/18 01:43:41 ping Exp $ */
- #include <stdio.h>
- #include "zlib.h"
- #ifdef STDC
- # include <string.h>
- # include <stdlib.h>
- #else
- extern void exit OF((int));
- #endif
- #ifdef USE_MMAP
- # include <sys/types.h>
- # include <sys/mman.h>
- # include <sys/stat.h>
- #endif
- #if defined(MSDOS) || defined(OS2) || defined(WIN32)
- # include <fcntl.h>
- # include <io.h>
- # define SET_BINARY_MODE(file) setmode(fileno(file), O_BINARY)
- #else
- # define SET_BINARY_MODE(file)
- #endif
- #ifdef VMS
- # define unlink delete
- # define GZ_SUFFIX "-gz"
- #endif
- #ifdef RISCOS
- # define unlink remove
- # define GZ_SUFFIX "-gz"
- # define fileno(file) file->__file
- #endif
- #if defined(__MWERKS__) && __dest_os != __be_os && __dest_os != __win32_os
- # include <unix.h> /* for fileno */
- #endif
- #ifndef WIN32 /* unlink already in stdio.h for WIN32 */
- extern int unlink OF((const char *));
- #endif
- #ifndef GZ_SUFFIX
- # define GZ_SUFFIX ".gz"
- #endif
- #define SUFFIX_LEN (sizeof(GZ_SUFFIX)-1)
- #define BUFLEN 16384
- #define MAX_NAME_LEN 1024
- #ifdef MAXSEG_64K
- # define local static
- /* Needed for systems with limitation on stack size. */
- #else
- # define local
- #endif
- char *prog;
- void error OF((const char *msg));
- void gz_compress OF((FILE *in, gzFile out));
- #ifdef USE_MMAP
- int gz_compress_mmap OF((FILE *in, gzFile out));
- #endif
- void gz_uncompress OF((gzFile in, FILE *out));
- void file_compress OF((char *file, char *mode));
- void file_uncompress OF((char *file));
- int main OF((int argc, char *argv[]));
- /* ===========================================================================
- * Display error message and exit
- */
- void error(msg)
- const char *msg;
- {
- fprintf(stderr, "%s: %sn", prog, msg);
- exit(1);
- }
- /* ===========================================================================
- * Compress input to output then close both files.
- */
- void gz_compress(in, out)
- FILE *in;
- gzFile out;
- {
- local char buf[BUFLEN];
- int len;
- int err;
- #ifdef USE_MMAP
- /* Try first compressing with mmap. If mmap fails (minigzip used in a
- * pipe), use the normal fread loop.
- */
- if (gz_compress_mmap(in, out) == Z_OK) return;
- #endif
- for (;;) {
- len = fread(buf, 1, sizeof(buf), in);
- if (ferror(in)) {
- perror("fread");
- exit(1);
- }
- if (len == 0) break;
- if (gzwrite(out, buf, (unsigned)len) != len) error(gzerror(out, &err));
- }
- fclose(in);
- if (gzclose(out) != Z_OK) error("failed gzclose");
- }
- #ifdef USE_MMAP /* MMAP version, Miguel Albrecht <malbrech@eso.org> */
- /* Try compressing the input file at once using mmap. Return Z_OK if
- * if success, Z_ERRNO otherwise.
- */
- int gz_compress_mmap(in, out)
- FILE *in;
- gzFile out;
- {
- int len;
- int err;
- int ifd = fileno(in);
- caddr_t buf; /* mmap'ed buffer for the entire input file */
- off_t buf_len; /* length of the input file */
- struct stat sb;
- /* Determine the size of the file, needed for mmap: */
- if (fstat(ifd, &sb) < 0) return Z_ERRNO;
- buf_len = sb.st_size;
- if (buf_len <= 0) return Z_ERRNO;
- /* Now do the actual mmap: */
- buf = mmap((caddr_t) 0, buf_len, PROT_READ, MAP_SHARED, ifd, (off_t)0);
- if (buf == (caddr_t)(-1)) return Z_ERRNO;
- /* Compress the whole file at once: */
- len = gzwrite(out, (char *)buf, (unsigned)buf_len);
- if (len != (int)buf_len) error(gzerror(out, &err));
- munmap(buf, buf_len);
- fclose(in);
- if (gzclose(out) != Z_OK) error("failed gzclose");
- return Z_OK;
- }
- #endif /* USE_MMAP */
- /* ===========================================================================
- * Uncompress input to output then close both files.
- */
- void gz_uncompress(in, out)
- gzFile in;
- FILE *out;
- {
- local char buf[BUFLEN];
- int len;
- int err;
- for (;;) {
- len = gzread(in, buf, sizeof(buf));
- if (len < 0) error (gzerror(in, &err));
- if (len == 0) break;
- if ((int)fwrite(buf, 1, (unsigned)len, out) != len) {
- error("failed fwrite");
- }
- }
- if (fclose(out)) error("failed fclose");
- if (gzclose(in) != Z_OK) error("failed gzclose");
- }
- /* ===========================================================================
- * Compress the given file: create a corresponding .gz file and remove the
- * original.
- */
- void file_compress(file, mode)
- char *file;
- char *mode;
- {
- local char outfile[MAX_NAME_LEN];
- FILE *in;
- gzFile out;
- strcpy(outfile, file);
- strcat(outfile, GZ_SUFFIX);
- in = fopen(file, "rb");
- if (in == NULL) {
- perror(file);
- exit(1);
- }
- out = gzopen(outfile, mode);
- if (out == NULL) {
- fprintf(stderr, "%s: can't gzopen %sn", prog, outfile);
- exit(1);
- }
- gz_compress(in, out);
- unlink(file);
- }
- /* ===========================================================================
- * Uncompress the given file and remove the original.
- */
- void file_uncompress(file)
- char *file;
- {
- local char buf[MAX_NAME_LEN];
- char *infile, *outfile;
- FILE *out;
- gzFile in;
- int len = strlen(file);
- strcpy(buf, file);
- if (len > SUFFIX_LEN && strcmp(file+len-SUFFIX_LEN, GZ_SUFFIX) == 0) {
- infile = file;
- outfile = buf;
- outfile[len-3] = ' ';
- } else {
- outfile = file;
- infile = buf;
- strcat(infile, GZ_SUFFIX);
- }
- in = gzopen(infile, "rb");
- if (in == NULL) {
- fprintf(stderr, "%s: can't gzopen %sn", prog, infile);
- exit(1);
- }
- out = fopen(outfile, "wb");
- if (out == NULL) {
- perror(file);
- exit(1);
- }
- gz_uncompress(in, out);
- unlink(infile);
- }
- /* ===========================================================================
- * Usage: minigzip [-d] [-f] [-h] [-1 to -9] [files...]
- * -d : decompress
- * -f : compress with Z_FILTERED
- * -h : compress with Z_HUFFMAN_ONLY
- * -1 to -9 : compression level
- */
- int main(argc, argv)
- int argc;
- char *argv[];
- {
- int uncompr = 0;
- gzFile file;
- char outmode[20];
- strcpy(outmode, "wb6 ");
- prog = argv[0];
- argc--, argv++;
- while (argc > 0) {
- if (strcmp(*argv, "-d") == 0)
- uncompr = 1;
- else if (strcmp(*argv, "-f") == 0)
- outmode[3] = 'f';
- else if (strcmp(*argv, "-h") == 0)
- outmode[3] = 'h';
- else if ((*argv)[0] == '-' && (*argv)[1] >= '1' && (*argv)[1] <= '9' &&
- (*argv)[2] == 0)
- outmode[2] = (*argv)[1];
- else
- break;
- argc--, argv++;
- }
- if (argc == 0) {
- SET_BINARY_MODE(stdin);
- SET_BINARY_MODE(stdout);
- if (uncompr) {
- file = gzdopen(fileno(stdin), "rb");
- if (file == NULL) error("can't gzdopen stdin");
- gz_uncompress(file, stdout);
- } else {
- file = gzdopen(fileno(stdout), outmode);
- if (file == NULL) error("can't gzdopen stdout");
- gz_compress(stdin, file);
- }
- } else {
- do {
- if (uncompr) {
- file_uncompress(*argv);
- } else {
- file_compress(*argv, outmode);
- }
- } while (argv++, --argc);
- }
- exit(0);
- return 0; /* to avoid warning */
- }