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/* minigzip.c -- simulate gzip using the zlib compression library
* Copyright (C) 1995-2006, 2010 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. */
/* @(#) $Id$ */
#include "zlib.h"
#include <stdio.h>
#ifdef STDC
# include <string.h>
# include <stdlib.h>
#endif
#ifdef USE_MMAP
# include <sys/types.h>
# include <sys/mman.h>
# include <sys/stat.h>
#endif
#if defined(MSDOS) || defined(OS2) || defined(WIN32) || defined(__CYGWIN__)
# include <fcntl.h>
# include <io.h>
# ifdef UNDER_CE
# include <stdlib.h>
# endif
# 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
#if !defined(Z_HAVE_UNISTD_H) && !defined(_LARGEFILE64_SOURCE)
#ifndef WIN32 /* unlink already in stdio.h for WIN32 */
extern int unlink OF((const char *)); #endif
#endif
#if defined(UNDER_CE)
# include <windows.h>
# define perror(s) pwinerror(s)
/* Map the Windows error number in ERROR to a locale-dependent error
message string and return a pointer to it. Typically, the values for ERROR come from GetLastError.
The string pointed to shall not be modified by the application, but may be overwritten by a subsequent call to strwinerror
The strwinerror function does not change the current setting of GetLastError. */
static char *strwinerror (error) DWORD error; { static char buf[1024];
wchar_t *msgbuf; DWORD lasterr = GetLastError(); DWORD chars = FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_ALLOCATE_BUFFER, NULL, error, 0, /* Default language */ (LPVOID)&msgbuf, 0, NULL); if (chars != 0) { /* If there is an \r\n appended, zap it. */ if (chars >= 2 && msgbuf[chars - 2] == '\r' && msgbuf[chars - 1] == '\n') { chars -= 2; msgbuf[chars] = 0; }
if (chars > sizeof (buf) - 1) { chars = sizeof (buf) - 1; msgbuf[chars] = 0; }
wcstombs(buf, msgbuf, chars + 1); LocalFree(msgbuf); } else { sprintf(buf, "unknown win32 error (%ld)", error); }
SetLastError(lasterr); return buf; }
static void pwinerror (s) const char *s; { if (s && *s) fprintf(stderr, "%s: %s\n", s, strwinerror(GetLastError ())); else fprintf(stderr, "%s\n", strwinerror(GetLastError ())); }
#endif /* UNDER_CE */
#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 <[email protected]> */
/* 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;
if (strlen(file) + strlen(GZ_SUFFIX) >= sizeof(outfile)) { fprintf(stderr, "%s: filename too long\n", prog); exit(1); }
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; size_t len = strlen(file);
if (len + strlen(GZ_SUFFIX) >= sizeof(buf)) { fprintf(stderr, "%s: filename too long\n", prog); exit(1); }
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 [-c] [-d] [-f] [-h] [-r] [-1 to -9] [files...] * -c : write to standard output * -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 copyout = 0; int uncompr = 0; gzFile file; char *bname, outmode[20];
strcpy(outmode, "wb6 ");
prog = argv[0]; bname = strrchr(argv[0], '/'); if (bname) bname++; else bname = argv[0]; argc--, argv++;
if (!strcmp(bname, "gunzip")) uncompr = 1; else if (!strcmp(bname, "zcat")) copyout = uncompr = 1;
while (argc > 0) { if (strcmp(*argv, "-c") == 0) copyout = 1; else 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 (outmode[3] == ' ') outmode[3] = 0; 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 { if (copyout) { SET_BINARY_MODE(stdout); } do { if (uncompr) { if (copyout) { file = gzopen(*argv, "rb"); if (file == NULL) fprintf(stderr, "%s: can't gzopen %s\n", prog, *argv); else gz_uncompress(file, stdout); } else { file_uncompress(*argv); } } else { if (copyout) { FILE * in = fopen(*argv, "rb");
if (in == NULL) { perror(*argv); } else { file = gzdopen(fileno(stdout), outmode); if (file == NULL) error("can't gzdopen stdout");
gz_compress(in, file); }
} else { file_compress(*argv, outmode); } } } while (argv++, --argc); } return 0; }
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