/* 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 1.1.1.2 2002/03/11 21:53:26 tromey Exp $ */ #include #include "zlib.h" #ifdef STDC # include # include #else extern void exit OF((int)); #endif #ifdef USE_MMAP # include # include # include #endif #if defined(MSDOS) || defined(OS2) || defined(WIN32) || defined(__CYGWIN__) # include # include # 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 /* 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: %s\n", 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 = (int)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 */ /* 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 %s\n", 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; uInt len = (uInt)strlen(file); strcpy(buf, file); if (len > SUFFIX_LEN && strcmp(file+len-SUFFIX_LEN, GZ_SUFFIX) == 0) { infile = file; outfile = buf; outfile[len-3] = '\0'; } else { outfile = file; infile = buf; strcat(infile, GZ_SUFFIX); } in = gzopen(infile, "rb"); if (in == NULL) { fprintf(stderr, "%s: can't gzopen %s\n", 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] [-r] [-1 to -9] [files...] * -d : decompress * -f : compress with Z_FILTERED * -h : compress with Z_HUFFMAN_ONLY * -r : compress with Z_RLE * -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 (strcmp(*argv, "-r") == 0) outmode[3] = 'R'; 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); } return 0; }