zlib解压

/* minigzip.c -- simulate gzip using the zlib compression library * Copyright (C) 1995-2006, 2010, 2011, 2016 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 #if defined(_MSC_VER) && _MSC_VER < 1900 # define snprintf _snprintf #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 #ifdef Z_SOLO /* for Z_SOLO, create simplified gz* functions using deflate and inflate */ #if defined(Z_HAVE_UNISTD_H) || defined(Z_LARGE) # include <unistd.h> /* for unlink() */ #endif void *myalloc OF((void *, unsigned, unsigned)); void myfree OF((void *, void *)); void *myalloc(q, n, m) void *q; unsigned n, m; { (void)q; return calloc(n, m); } void myfree(q, p) void *q, *p; { (void)q; free(p); } typedef struct gzFile_s { FILE *file; int write; int err; char *msg; z_stream strm; } *gzFile; gzFile gzopen OF((const char *, const char *)); gzFile gzdopen OF((int, const char *)); gzFile gz_open OF((const char *, int, const char *)); gzFile gzopen(path, mode) const char *path; const char *mode; { return gz_open(path, -1, mode); } gzFile gzdopen(fd, mode) int fd; const char *mode; { return gz_open(NULL, fd, mode); } gzFile gz_open(path, fd, mode) const char *path; int fd; const char *mode; { gzFile gz; int ret; gz = malloc(sizeof(struct gzFile_s)); if (gz == NULL) return NULL; gz->write = strchr(mode, 'w') != NULL; gz->strm.zalloc = myalloc; gz->strm.zfree = myfree; gz->strm.opaque = Z_NULL; if (gz->write) ret = deflateInit2(&(gz->strm), -1, 8, 15 + 16, 8, 0); else { gz->strm.next_in = 0; gz->strm.avail_in = Z_NULL; ret = inflateInit2(&(gz->strm), 15 + 16); } if (ret != Z_OK) { free(gz); return NULL; } gz->file = path == NULL ? fdopen(fd, gz->write ? "wb" : "rb") : fopen(path, gz->write ? "wb" : "rb"); if (gz->file == NULL) { gz->write ? deflateEnd(&(gz->strm)) : inflateEnd(&(gz->strm)); free(gz); return NULL; } gz->err = 0; gz->msg = ""; return gz; } int gzwrite OF((gzFile, const void *, unsigned)); int gzwrite(gz, buf, len) gzFile gz; const void *buf; unsigned len; { z_stream *strm; unsigned char out[BUFLEN]; if (gz == NULL || !gz->write) return 0; strm = &(gz->strm); strm->next_in = (void *)buf; strm->avail_in = len; do { strm->next_out = out; strm->avail_out = BUFLEN; (void)deflate(strm, Z_NO_FLUSH); fwrite(out, 1, BUFLEN - strm->avail_out, gz->file); } while (strm->avail_out == 0); return len; } int gzread OF((gzFile, void *, unsigned)); int gzread(gz, buf, len) gzFile gz; void *buf; unsigned len; { int ret; unsigned got; unsigned char in[1]; z_stream *strm; if (gz == NULL || gz->write) return 0; if (gz->err) return 0; strm = &(gz->strm); strm->next_out = (void *)buf; strm->avail_out = len; do { got = fread(in, 1, 1, gz->file); if (got == 0) break; strm->next_in = in; strm->avail_in = 1; ret = inflate(strm, Z_NO_FLUSH); if (ret == Z_DATA_ERROR) { gz->err = Z_DATA_ERROR; gz->msg = strm->msg; return 0; } if (ret == Z_STREAM_END) inflateReset(strm); } while (strm->avail_out); return len - strm->avail_out; } int gzclose OF((gzFile)); int gzclose(gz) gzFile gz; { z_stream *strm; unsigned char out[BUFLEN]; if (gz == NULL) return Z_STREAM_ERROR; strm = &(gz->strm); if (gz->write) { strm->next_in = Z_NULL; strm->avail_in = 0; do { strm->next_out = out; strm->avail_out = BUFLEN; (void)deflate(strm, Z_FINISH); fwrite(out, 1, BUFLEN - strm->avail_out, gz->file); } while (strm->avail_out == 0); deflateEnd(strm); } else inflateEnd(strm); fclose(gz->file); free(gz); return Z_OK; } const char *gzerror OF((gzFile, int *)); const char *gzerror(gz, err) gzFile gz; int *err; { *err = gz->err; return gz->msg; } #endif static 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 <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; if (strlen(file) + strlen(GZ_SUFFIX) >= sizeof(outfile)) { fprintf(stderr, "%s: filename too long\n", prog); exit(1); } #if !defined(NO_snprintf) && !defined(NO_vsnprintf) snprintf(outfile, sizeof(outfile), "%s%s", file, GZ_SUFFIX); #else strcpy(outfile, file); strcat(outfile, GZ_SUFFIX); #endif 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; unsigned len = strlen(file); if (len + strlen(GZ_SUFFIX) >= sizeof(buf)) { fprintf(stderr, "%s: filename too long\n", prog); exit(1); } #if !defined(NO_snprintf) && !defined(NO_vsnprintf) snprintf(buf, sizeof(buf), "%s", file); #else strcpy(buf, file); #endif 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; #if !defined(NO_snprintf) && !defined(NO_vsnprintf) snprintf(buf + len, sizeof(buf) - len, "%s", GZ_SUFFIX); #else strcat(infile, GZ_SUFFIX); #endif } 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]; #if !defined(NO_snprintf) && !defined(NO_vsnprintf) snprintf(outmode, sizeof(outmode), "%s", "wb6 "); #else strcpy(outmode, "wb6 "); #endif 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; }

装上zlib-dev这个包后

执行gcc -zlib_decompress.c -o zlib_decompress -lz即可

---

zlib压缩

代码如下

#include <stdio.h> #include <stdlib.h> #include <zlib.h> /******************************************************************************* * Compress gzip data * @parm[data] data buffer to be compressed * @parm[dlen] data buffer length * @parm[zdata] data buffer to save the compressed datas * @parm[zdlen] compressed data buffer length * return: 0 - OK; -1 - FAIL *******************************************************************************/ int gzcompress(Bytef *data, uLong dlen, Bytef *zdata, uLong *zdlen) { int err = 0; z_stream c_stream; printf("%s: data=%p, dlen=%lu, zdata=%p, *zdlen=%lu\n", __func__, data, dlen, zdata, *zdlen); if(data && dlen > 0) { c_stream.zalloc = NULL; c_stream.zfree = NULL; c_stream.opaque = NULL; //use parm 'MAX_WBITS+16' so that gzip headers are contained if(deflateInit2(&c_stream, Z_DEFAULT_COMPRESSION, Z_DEFLATED, MAX_WBITS + 16, 8, Z_DEFAULT_STRATEGY) != Z_OK) { printf("%s: deflateinit2 failed!\n",__func__); return -1; } c_stream.next_in = data; c_stream.avail_in = dlen; c_stream.next_out = zdata; c_stream.avail_out = *zdlen; while(c_stream.avail_in != 0 && c_stream.total_out < *zdlen) { if(deflate(&c_stream, Z_NO_FLUSH) != Z_OK) { printf("%s: deflate failed!\n",__func__); return -1; } } if(c_stream.avail_in != 0) { printf("%s: avail_in not zero!\n",__func__); return c_stream.avail_in; } for(;;) { if((err = deflate(&c_stream, Z_FINISH)) == Z_STREAM_END) break; if(err != Z_OK) { printf("%s: deflate finish fail: %d\n",__func__, err); return -1; } } if(deflateEnd(&c_stream) != Z_OK) { printf("%s: deflate end failed!\n",__func__); return -1; } *zdlen = c_stream.total_out; return 0; } return -1; } /******************************************************************************* * Compress a file into a gzip file * @parm[input_name] the file path to be compressed * @parm[output_name] output path of compressed gzip file * return: 0 - OK; -1 - FAIL *******************************************************************************/ int compress_file_to_gzip(char * input_name, char * output_name) { FILE *fp = NULL; uLong flen, clen; unsigned char * fbuf = NULL; unsigned char * cbuf = NULL; char def_output_name[PATH_MAX] = {0}; if((fp = fopen(input_name, "rb")) == NULL) { printf("%s: can not open %s!\n", __func__, input_name); return -1; } /*load file content to buffer*/ fseek(fp, 0L, SEEK_END); flen = ftell(fp); fseek(fp, 0L, SEEK_SET); fbuf = (unsigned char *)malloc(flen * sizeof(unsigned char)); if(NULL == fbuf){ printf("%s: no enough memory!\n", __func__); goto __error; } fread(fbuf, sizeof(unsigned char), flen, fp); fclose(fp); fp = NULL; /*compute compressBound*/ clen = compressBound(flen); cbuf = (unsigned char *)malloc(clen * sizeof(unsigned char)); if(NULL == cbuf) { printf("%s: no enough memory!\n", __func__); goto __error; } if(gzcompress(fbuf, flen, cbuf, &clen)) { printf("%s: compress %s failed!\n", __func__, input_name); goto __error; } if(NULL == output_name) { snprintf(def_output_name, sizeof(def_output_name), "%s.gz", input_name); output_name = def_output_name; } if((fp = fopen(output_name, "wb")) == NULL) { printf("%s: can not open %s!\n", __func__, output_name); goto __error; } fwrite(cbuf, sizeof(unsigned char), clen, fp); fclose(fp); free(fbuf); free(cbuf); return 0; __error: if(fp) fclose(fp); if(fbuf) free(fbuf); if(cbuf) free(cbuf); return -1; } int main(int argc, char * argv[]) { if(argc < 2) { printf("too few args!\n"); return 0; } if(argc < 3) { return compress_file_to_gzip(argv[1],NULL); } return compress_file_to_gzip(argv[1], argv[2]); }

装上zlib-dev后

gcc zlib_compress.c -o zlib_compress -lz即可