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# minigzip.c

    00001 /* minigzip.c -- simulate gzip using the zlib compression library
    00002  * Copyright (C) 1995-2002 Jean-loup Gailly.
    00003  * For conditions of distribution and use, see copyright notice in zlib.h
    00004  */
    00005
    00006 /*
    00007  * minigzip is a minimal implementation of the gzip utility. This is
    00008  * only an example of using zlib and isn't meant to replace the
    00009  * full-featured gzip. No attempt is made to deal with file systems
    00010  * limiting names to 14 or 8+3 characters, etc... Error checking is
    00011  * very limited. So use minigzip only for testing; use gzip for the
    00012  * real thing. On MSDOS, use only on file names without extension
    00013  * or in pipe mode.
    00014  */
    00015
    00016 /* @(#) $Id: minigzip.c,v 1.1 2003/11/09 01:37:56 gabest Exp $ */
    00017
    00018 #include <stdio.h>
    00019 #include "zlib.h"
    00020
    00021 #ifdef STDC
    00022 #  include <string.h>
    00023 #  include <stdlib.h>
    00024 #else
    00025    extern void exit  OF((int));
    00026 #endif
    00027
    00028 #ifdef USE_MMAP
    00029 #  include <sys/types.h>
    00030 #  include <sys/mman.h>
    00031 #  include <sys/stat.h>
    00032 #endif
    00033
    00034 #if defined(MSDOS) || defined(OS2) || defined(WIN32)
    00035 #  include <fcntl.h>
    00036 #  include <io.h>
    00037 #  define SET_BINARY_MODE(file) setmode(fileno(file), O_BINARY)
    00038 #else
    00039 #  define SET_BINARY_MODE(file)
    00040 #endif
    00041
    00042 #ifdef VMS
    00043 #  define unlink delete
    00044 #  define GZ_SUFFIX "-gz"
    00045 #endif
    00046 #ifdef RISCOS
    00047 #  define unlink remove
    00048 #  define GZ_SUFFIX "-gz"
    00049 #  define fileno(file) file->__file
    00050 #endif
    00051 #if defined(__MWERKS__) && __dest_os != __be_os && __dest_os != __win32_os
    00052 #  include <unix.h> /* for fileno */
    00053 #endif
    00054
    00055 #ifndef WIN32 /* unlink already in stdio.h for WIN32 */
    00056   extern int unlink OF((const char *));
    00057 #endif
    00058
    00059 #ifndef GZ_SUFFIX
    00060 #  define GZ_SUFFIX ".gz"
    00061 #endif
    00062 #define SUFFIX_LEN (sizeof(GZ_SUFFIX)-1)
    00063
    00064 #define BUFLEN      16384
    00065 #define MAX_NAME_LEN 1024
    00066
    00067 #ifdef MAXSEG_64K
    00068 #  define local static
    00069    /* Needed for systems with limitation on stack size. */
    00070 #else
    00071 #  define local
    00072 #endif
    00073
    00074 char *prog;
    00075
    00076 void error            OF((const char *msg));
    00077 void gz_compress      OF((FILE   *in, gzFile out));
    00078 #ifdef USE_MMAP
    00079 int  gz_compress_mmap OF((FILE   *in, gzFile out));
    00080 #endif
    00081 void gz_uncompress    OF((gzFile in, FILE   *out));
    00082 void file_compress    OF((char  *file, char *mode));
    00083 void file_uncompress  OF((char  *file));
    00084 int  main             OF((int argc, char *argv[]));
    00085
    00086 /* ===========================================================================
    00087  * Display error message and exit
    00088  */
    00089 void error(msg)
    00090     const char *msg;
    00091 {
    00092     fprintf(stderr, "%s: %s\n", prog, msg);
    00093     exit(1);
    00094 }
    00095
    00096 /* ===========================================================================
    00097  * Compress input to output then close both files.
    00098  */
    00099
    00100 void gz_compress(in, out)
    00101     FILE   *in;
    00102     gzFile out;
    00103 {
    00104     local char buf[BUFLEN];
    00105     int len;
    00106     int err;
    00107
    00108 #ifdef USE_MMAP
    00109     /* Try first compressing with mmap. If mmap fails (minigzip used in a
    00110      * pipe), use the normal fread loop.
    00111      */
    00112     if (gz_compress_mmap(in, out) == Z_OK) return;
    00113 #endif
    00114     for (;;) {
    00115         len = fread(buf, 1, sizeof(buf), in);
    00116         if (ferror(in)) {
    00117             perror("fread");
    00118             exit(1);
    00119         }
    00120         if (len == 0) break;
    00121
    00122         if (gzwrite(out, buf, (unsigned)len) != len) error(gzerror(out, &err));
    00123     }
    00124     fclose(in);
    00125     if (gzclose(out) != Z_OK) error("failed gzclose");
    00126 }
    00127
    00128 #ifdef USE_MMAP /* MMAP version, Miguel Albrecht <malbrech@eso.org> */
    00129
    00130 /* Try compressing the input file at once using mmap. Return Z_OK if
    00131  * if success, Z_ERRNO otherwise.
    00132  */
    00133 int gz_compress_mmap(in, out)
    00134     FILE   *in;
    00135     gzFile out;
    00136 {
    00137     int len;
    00138     int err;
    00139     int ifd = fileno(in);
    00140     caddr_t buf;    /* mmap'ed buffer for the entire input file */
    00141     off_t buf_len;  /* length of the input file */
    00142     struct stat sb;
    00143
    00144     /* Determine the size of the file, needed for mmap: */
    00145     if (fstat(ifd, &sb) < 0) return Z_ERRNO;
    00146     buf_len = sb.st_size;
    00147     if (buf_len <= 0) return Z_ERRNO;
    00148
    00149     /* Now do the actual mmap: */
    00150     buf = mmap((caddr_t) 0, buf_len, PROT_READ, MAP_SHARED, ifd, (off_t)0);
    00151     if (buf == (caddr_t)(-1)) return Z_ERRNO;
    00152
    00153     /* Compress the whole file at once: */
    00154     len = gzwrite(out, (char *)buf, (unsigned)buf_len);
    00155
    00156     if (len != (int)buf_len) error(gzerror(out, &err));
    00157
    00158     munmap(buf, buf_len);
    00159     fclose(in);
    00160     if (gzclose(out) != Z_OK) error("failed gzclose");
    00161     return Z_OK;
    00162 }
    00163 #endif /* USE_MMAP */
    00164
    00165 /* ===========================================================================
    00166  * Uncompress input to output then close both files.
    00167  */
    00168 void gz_uncompress(in, out)
    00169     gzFile in;
    00170     FILE   *out;
    00171 {
    00172     local char buf[BUFLEN];
    00173     int len;
    00174     int err;
    00175
    00176     for (;;) {
    00177         len = gzread(in, buf, sizeof(buf));
    00178         if (len < 0) error (gzerror(in, &err));
    00179         if (len == 0) break;
    00180
    00181         if ((int)fwrite(buf, 1, (unsigned)len, out) != len) {
    00182             error("failed fwrite");
    00183         }
    00184     }
    00185     if (fclose(out)) error("failed fclose");
    00186
    00187     if (gzclose(in) != Z_OK) error("failed gzclose");
    00188 }
    00189
    00190
    00191 /* ===========================================================================
    00192  * Compress the given file: create a corresponding .gz file and remove the
    00193  * original.
    00194  */
    00195 void file_compress(file, mode)
    00196     char  *file;
    00197     char  *mode;
    00198 {
    00199     local char outfile[MAX_NAME_LEN];
    00200     FILE  *in;
    00201     gzFile out;
    00202
    00203     strcpy(outfile, file);
    00204     strcat(outfile, GZ_SUFFIX);
    00205
    00206     in = fopen(file, "rb");
    00207     if (in == NULL) {
    00208         perror(file);
    00209         exit(1);
    00210     }
    00211     out = gzopen(outfile, mode);
    00212     if (out == NULL) {
    00213         fprintf(stderr, "%s: can't gzopen %s\n", prog, outfile);
    00214         exit(1);
    00215     }
    00216     gz_compress(in, out);
    00217
    00218     unlink(file);
    00219 }
    00220
    00221
    00222 /* ===========================================================================
    00223  * Uncompress the given file and remove the original.
    00224  */
    00225 void file_uncompress(file)
    00226     char  *file;
    00227 {
    00228     local char buf[MAX_NAME_LEN];
    00229     char *infile, *outfile;
    00230     FILE  *out;
    00231     gzFile in;
    00232     int len = strlen(file);
    00233
    00234     strcpy(buf, file);
    00235
    00236     if (len > SUFFIX_LEN && strcmp(file+len-SUFFIX_LEN, GZ_SUFFIX) == 0) {
    00237         infile = file;
    00238         outfile = buf;
    00239         outfile[len-3] = '\0';
    00240     } else {
    00241         outfile = file;
    00242         infile = buf;
    00243         strcat(infile, GZ_SUFFIX);
    00244     }
    00245     in = gzopen(infile, "rb");
    00246     if (in == NULL) {
    00247         fprintf(stderr, "%s: can't gzopen %s\n", prog, infile);
    00248         exit(1);
    00249     }
    00250     out = fopen(outfile, "wb");
    00251     if (out == NULL) {
    00252         perror(file);
    00253         exit(1);
    00254     }
    00255
    00256     gz_uncompress(in, out);
    00257
    00258     unlink(infile);
    00259 }
    00260
    00261
    00262 /* ===========================================================================
    00263  * Usage:  minigzip [-d] [-f] [-h] [-1 to -9] [files...]
    00264  *   -d : decompress
    00265  *   -f : compress with Z_FILTERED
    00266  *   -h : compress with Z_HUFFMAN_ONLY
    00267  *   -1 to -9 : compression level
    00268  */
    00269
    00270 int main(argc, argv)
    00271     int argc;
    00272     char *argv[];
    00273 {
    00274     int uncompr = 0;
    00275     gzFile file;
    00276     char outmode[20];
    00277
    00278     strcpy(outmode, "wb6 ");
    00279
    00280     prog = argv[0];
    00281     argc--, argv++;
    00282
    00283     while (argc > 0) {
    00284       if (strcmp(*argv, "-d") == 0)
    00285         uncompr = 1;
    00286       else if (strcmp(*argv, "-f") == 0)
    00287         outmode[3] = 'f';
    00288       else if (strcmp(*argv, "-h") == 0)
    00289         outmode[3] = 'h';
    00290       else if ((*argv)[0] == '-' && (*argv)[1] >= '1' && (*argv)[1] <= '9' &&
    00291                (*argv)[2] == 0)
    00292         outmode[2] = (*argv)[1];
    00293       else
    00294         break;
    00295       argc--, argv++;
    00296     }
    00297     if (argc == 0) {
    00298         SET_BINARY_MODE(stdin);
    00299         SET_BINARY_MODE(stdout);
    00300         if (uncompr) {
    00301             file = gzdopen(fileno(stdin), "rb");
    00302             if (file == NULL) error("can't gzdopen stdin");
    00303             gz_uncompress(file, stdout);
    00304         } else {
    00305             file = gzdopen(fileno(stdout), outmode);
    00306             if (file == NULL) error("can't gzdopen stdout");
    00307             gz_compress(stdin, file);
    00308         }
    00309     } else {
    00310         do {
    00311             if (uncompr) {
    00312                 file_uncompress(*argv);
    00313             } else {
    00314                 file_compress(*argv, outmode);
    00315             }
    00316         } while (argv++, --argc);
    00317     }
    00318     exit(0);
    00319     return 0; /* to avoid warning */
    00320 }