Back to index

tetex-bin  3.0
minigzip.c
Go to the documentation of this file.
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 /* @(#) $Id$ */
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) || defined(__CYGWIN__)
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 = (int)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     uInt len = (uInt)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] [-r] [-1 to -9] [files...]
00264  *   -d : decompress
00265  *   -f : compress with Z_FILTERED
00266  *   -h : compress with Z_HUFFMAN_ONLY
00267  *   -r : compress with Z_RLE
00268  *   -1 to -9 : compression level
00269  */
00270 
00271 int main(argc, argv)
00272     int argc;
00273     char *argv[];
00274 {
00275     int uncompr = 0;
00276     gzFile file;
00277     char outmode[20];
00278 
00279     strcpy(outmode, "wb6 ");
00280 
00281     prog = argv[0];
00282     argc--, argv++;
00283 
00284     while (argc > 0) {
00285       if (strcmp(*argv, "-d") == 0)
00286         uncompr = 1;
00287       else if (strcmp(*argv, "-f") == 0)
00288         outmode[3] = 'f';
00289       else if (strcmp(*argv, "-h") == 0)
00290         outmode[3] = 'h';
00291       else if (strcmp(*argv, "-r") == 0)
00292         outmode[3] = 'R';
00293       else if ((*argv)[0] == '-' && (*argv)[1] >= '1' && (*argv)[1] <= '9' &&
00294                (*argv)[2] == 0)
00295         outmode[2] = (*argv)[1];
00296       else
00297         break;
00298       argc--, argv++;
00299     }
00300     if (argc == 0) {
00301         SET_BINARY_MODE(stdin);
00302         SET_BINARY_MODE(stdout);
00303         if (uncompr) {
00304             file = gzdopen(fileno(stdin), "rb");
00305             if (file == NULL) error("can't gzdopen stdin");
00306             gz_uncompress(file, stdout);
00307         } else {
00308             file = gzdopen(fileno(stdout), outmode);
00309             if (file == NULL) error("can't gzdopen stdout");
00310             gz_compress(stdin, file);
00311         }
00312     } else {
00313         do {
00314             if (uncompr) {
00315                 file_uncompress(*argv);
00316             } else {
00317                 file_compress(*argv, outmode);
00318             }
00319         } while (argv++, --argc);
00320     }
00321     return 0;
00322 }