| /* gzio.c -- IO on .gz files |
| * Copyright (C) 1995-1996 Jean-loup Gailly. |
| * For conditions of distribution and use, see copyright notice in zlib.h |
| */ |
| |
| /* $Id: gzio.c,v 1.14 1996/07/24 13:41:01 me Exp $ */ |
| |
| #include <stdio.h> |
| |
| #include "zutil.h" |
| |
| struct internal_state {int dummy;}; /* for buggy compilers */ |
| |
| #define Z_BUFSIZE 4096 |
| |
| #define ALLOC(size) malloc(size) |
| #define TRYFREE(p) {if (p) free(p);} |
| |
| static int gz_magic[2] = {0x1f, 0x8b}; /* gzip magic header */ |
| |
| /* gzip flag byte */ |
| #define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */ |
| #define HEAD_CRC 0x02 /* bit 1 set: header CRC present */ |
| #define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */ |
| #define ORIG_NAME 0x08 /* bit 3 set: original file name present */ |
| #define COMMENT 0x10 /* bit 4 set: file comment present */ |
| #define RESERVED 0xE0 /* bits 5..7: reserved */ |
| |
| typedef struct gz_stream { |
| z_stream stream; |
| int z_err; /* error code for last stream operation */ |
| int z_eof; /* set if end of input file */ |
| FILE *file; /* .gz file */ |
| Byte *inbuf; /* input buffer */ |
| Byte *outbuf; /* output buffer */ |
| uLong crc; /* crc32 of uncompressed data */ |
| char *msg; /* error message */ |
| char *path; /* path name for debugging only */ |
| int transparent; /* 1 if input file is not a .gz file */ |
| char mode; /* 'w' or 'r' */ |
| } gz_stream; |
| |
| |
| local gzFile gz_open OF((const char *path, const char *mode, int fd)); |
| local int get_byte OF((gz_stream *s)); |
| local void check_header OF((gz_stream *s)); |
| local int destroy OF((gz_stream *s)); |
| local void putLong OF((FILE *file, uLong x)); |
| local uLong getLong OF((gz_stream *s)); |
| |
| /* =========================================================================== |
| Opens a gzip (.gz) file for reading or writing. The mode parameter |
| is as in fopen ("rb" or "wb"). The file is given either by file descriptor |
| or path name (if fd == -1). |
| gz_open return NULL if the file could not be opened or if there was |
| insufficient memory to allocate the (de)compression state; errno |
| can be checked to distinguish the two cases (if errno is zero, the |
| zlib error is Z_MEM_ERROR). |
| */ |
| local gzFile gz_open (path, mode, fd) |
| const char *path; |
| const char *mode; |
| int fd; |
| { |
| int err; |
| int level = Z_DEFAULT_COMPRESSION; /* compression level */ |
| char *p = (char*)mode; |
| gz_stream *s; |
| char fmode[80]; /* copy of mode, without the compression level */ |
| char *m = fmode; |
| |
| if (!path || !mode) return Z_NULL; |
| |
| s = (gz_stream *)ALLOC(sizeof(gz_stream)); |
| if (!s) return Z_NULL; |
| |
| s->stream.zalloc = (alloc_func)0; |
| s->stream.zfree = (free_func)0; |
| s->stream.opaque = (voidpf)0; |
| s->stream.next_in = s->inbuf = Z_NULL; |
| s->stream.next_out = s->outbuf = Z_NULL; |
| s->stream.avail_in = s->stream.avail_out = 0; |
| s->file = NULL; |
| s->z_err = Z_OK; |
| s->z_eof = 0; |
| s->crc = crc32(0L, Z_NULL, 0); |
| s->msg = NULL; |
| s->transparent = 0; |
| |
| s->path = (char*)ALLOC(strlen(path)+1); |
| if (s->path == NULL) { |
| return destroy(s), (gzFile)Z_NULL; |
| } |
| strcpy(s->path, path); /* do this early for debugging */ |
| |
| s->mode = '\0'; |
| do { |
| if (*p == 'r') s->mode = 'r'; |
| if (*p == 'w' || *p == 'a') s->mode = 'w'; |
| if (*p >= '0' && *p <= '9') { |
| level = *p - '0'; |
| } else { |
| *m++ = *p; /* copy the mode */ |
| } |
| } while (*p++ && m != fmode + sizeof(fmode)); |
| if (s->mode == '\0') return destroy(s), (gzFile)Z_NULL; |
| |
| if (s->mode == 'w') { |
| err = deflateInit2(&(s->stream), level, |
| Z_DEFLATED, -MAX_WBITS, DEF_MEM_LEVEL, 0); |
| /* windowBits is passed < 0 to suppress zlib header */ |
| |
| s->stream.next_out = s->outbuf = (Byte*)ALLOC(Z_BUFSIZE); |
| |
| if (err != Z_OK || s->outbuf == Z_NULL) { |
| return destroy(s), (gzFile)Z_NULL; |
| } |
| } else { |
| err = inflateInit2(&(s->stream), -MAX_WBITS); |
| s->stream.next_in = s->inbuf = (Byte*)ALLOC(Z_BUFSIZE); |
| |
| if (err != Z_OK || s->inbuf == Z_NULL) { |
| return destroy(s), (gzFile)Z_NULL; |
| } |
| } |
| s->stream.avail_out = Z_BUFSIZE; |
| |
| errno = 0; |
| s->file = fd < 0 ? FOPEN(path, fmode) : (FILE*)fdopen(fd, fmode); |
| |
| if (s->file == NULL) { |
| return destroy(s), (gzFile)Z_NULL; |
| } |
| if (s->mode == 'w') { |
| /* Write a very simple .gz header: |
| */ |
| fprintf(s->file, "%c%c%c%c%c%c%c%c%c%c", gz_magic[0], gz_magic[1], |
| Z_DEFLATED, 0 /*flags*/, 0,0,0,0 /*time*/, 0 /*xflags*/, OS_CODE); |
| } else { |
| check_header(s); /* skip the .gz header */ |
| } |
| return (gzFile)s; |
| } |
| |
| /* =========================================================================== |
| Opens a gzip (.gz) file for reading or writing. |
| */ |
| gzFile gzopen (path, mode) |
| const char *path; |
| const char *mode; |
| { |
| return gz_open (path, mode, -1); |
| } |
| |
| /* =========================================================================== |
| Associate a gzFile with the file descriptor fd. fd is not dup'ed here |
| to mimic the behavio(u)r of fdopen. |
| */ |
| gzFile gzdopen (fd, mode) |
| int fd; |
| const char *mode; |
| { |
| char name[20]; |
| |
| if (fd < 0) return (gzFile)Z_NULL; |
| sprintf(name, "<fd:%d>", fd); /* for debugging */ |
| |
| return gz_open (name, mode, fd); |
| } |
| |
| /* =========================================================================== |
| Read a byte from a gz_stream; update next_in and avail_in. Return EOF |
| for end of file. |
| IN assertion: the stream s has been sucessfully opened for reading. |
| */ |
| local int get_byte(s) |
| gz_stream *s; |
| { |
| if (s->z_eof) return EOF; |
| if (s->stream.avail_in == 0) { |
| errno = 0; |
| s->stream.avail_in = fread(s->inbuf, 1, Z_BUFSIZE, s->file); |
| if (s->stream.avail_in == 0) { |
| s->z_eof = 1; |
| if (ferror(s->file)) s->z_err = Z_ERRNO; |
| return EOF; |
| } |
| s->stream.next_in = s->inbuf; |
| } |
| s->stream.avail_in--; |
| return *(s->stream.next_in)++; |
| } |
| |
| /* =========================================================================== |
| Check the gzip header of a gz_stream opened for reading. Set the stream |
| mode to transparent if the gzip magic header is not present; set s->err |
| to Z_DATA_ERROR if the magic header is present but the rest of the header |
| is incorrect. |
| IN assertion: the stream s has already been created sucessfully; |
| s->stream.avail_in is zero for the first time, but may be non-zero |
| for concatenated .gz files. |
| */ |
| local void check_header(s) |
| gz_stream *s; |
| { |
| int method; /* method byte */ |
| int flags; /* flags byte */ |
| uInt len; |
| int c; |
| |
| /* Check the gzip magic header */ |
| for (len = 0; len < 2; len++) { |
| c = get_byte(s); |
| if (c != gz_magic[len]) { |
| s->transparent = 1; |
| if (c != EOF) s->stream.avail_in++, s->stream.next_in--; |
| s->z_err = s->stream.avail_in != 0 ? Z_OK : Z_STREAM_END; |
| return; |
| } |
| } |
| method = get_byte(s); |
| flags = get_byte(s); |
| if (method != Z_DEFLATED || (flags & RESERVED) != 0) { |
| s->z_err = Z_DATA_ERROR; |
| return; |
| } |
| |
| /* Discard time, xflags and OS code: */ |
| for (len = 0; len < 6; len++) (void)get_byte(s); |
| |
| if ((flags & EXTRA_FIELD) != 0) { /* skip the extra field */ |
| len = (uInt)get_byte(s); |
| len += ((uInt)get_byte(s))<<8; |
| /* len is garbage if EOF but the loop below will quit anyway */ |
| while (len-- != 0 && get_byte(s) != EOF) ; |
| } |
| if ((flags & ORIG_NAME) != 0) { /* skip the original file name */ |
| while ((c = get_byte(s)) != 0 && c != EOF) ; |
| } |
| if ((flags & COMMENT) != 0) { /* skip the .gz file comment */ |
| while ((c = get_byte(s)) != 0 && c != EOF) ; |
| } |
| if ((flags & HEAD_CRC) != 0) { /* skip the header crc */ |
| for (len = 0; len < 2; len++) (void)get_byte(s); |
| } |
| s->z_err = s->z_eof ? Z_DATA_ERROR : Z_OK; |
| } |
| |
| /* =========================================================================== |
| * Cleanup then free the given gz_stream. Return a zlib error code. |
| Try freeing in the reverse order of allocations. |
| */ |
| local int destroy (s) |
| gz_stream *s; |
| { |
| int err = Z_OK; |
| |
| if (!s) return Z_STREAM_ERROR; |
| |
| TRYFREE(s->msg); |
| |
| if (s->stream.state != NULL) { |
| if (s->mode == 'w') { |
| err = deflateEnd(&(s->stream)); |
| } else if (s->mode == 'r') { |
| err = inflateEnd(&(s->stream)); |
| } |
| } |
| if (s->file != NULL && fclose(s->file)) { |
| err = Z_ERRNO; |
| } |
| if (s->z_err < 0) err = s->z_err; |
| |
| TRYFREE(s->inbuf); |
| TRYFREE(s->outbuf); |
| TRYFREE(s->path); |
| TRYFREE(s); |
| return err; |
| } |
| |
| /* =========================================================================== |
| Reads the given number of uncompressed bytes from the compressed file. |
| gzread returns the number of bytes actually read (0 for end of file). |
| */ |
| int gzread (file, buf, len) |
| gzFile file; |
| voidp buf; |
| unsigned len; |
| { |
| gz_stream *s = (gz_stream*)file; |
| Bytef *start = buf; /* starting point for crc computation */ |
| Byte *next_out; /* == stream.next_out but not forced far (for MSDOS) */ |
| |
| if (s == NULL || s->mode != 'r') return Z_STREAM_ERROR; |
| |
| if (s->z_err == Z_DATA_ERROR || s->z_err == Z_ERRNO) return -1; |
| if (s->z_err == Z_STREAM_END) return 0; /* EOF */ |
| |
| s->stream.next_out = next_out = buf; |
| s->stream.avail_out = len; |
| |
| while (s->stream.avail_out != 0) { |
| |
| if (s->transparent) { |
| /* Copy first the lookahead bytes: */ |
| uInt n = s->stream.avail_in; |
| if (n > s->stream.avail_out) n = s->stream.avail_out; |
| if (n > 0) { |
| zmemcpy(s->stream.next_out, s->stream.next_in, n); |
| next_out += n; |
| s->stream.next_out = next_out; |
| s->stream.next_in += n; |
| s->stream.avail_out -= n; |
| s->stream.avail_in -= n; |
| } |
| if (s->stream.avail_out > 0) { |
| s->stream.avail_out -= fread(next_out, 1, s->stream.avail_out, |
| s->file); |
| } |
| return (int)(len - s->stream.avail_out); |
| } |
| if (s->stream.avail_in == 0 && !s->z_eof) { |
| |
| errno = 0; |
| s->stream.avail_in = fread(s->inbuf, 1, Z_BUFSIZE, s->file); |
| if (s->stream.avail_in == 0) { |
| s->z_eof = 1; |
| if (ferror(s->file)) { |
| s->z_err = Z_ERRNO; |
| break; |
| } |
| } |
| s->stream.next_in = s->inbuf; |
| } |
| s->z_err = inflate(&(s->stream), Z_NO_FLUSH); |
| |
| if (s->z_err == Z_STREAM_END) { |
| /* Check CRC and original size */ |
| s->crc = crc32(s->crc, start, (uInt)(s->stream.next_out - start)); |
| start = s->stream.next_out; |
| |
| if (getLong(s) != s->crc || getLong(s) != s->stream.total_out) { |
| s->z_err = Z_DATA_ERROR; |
| } else { |
| /* Check for concatenated .gz files: */ |
| check_header(s); |
| if (s->z_err == Z_OK) { |
| inflateReset(&(s->stream)); |
| s->crc = crc32(0L, Z_NULL, 0); |
| } |
| } |
| } |
| if (s->z_err != Z_OK || s->z_eof) break; |
| } |
| s->crc = crc32(s->crc, start, (uInt)(s->stream.next_out - start)); |
| |
| return (int)(len - s->stream.avail_out); |
| } |
| |
| /* =========================================================================== |
| Writes the given number of uncompressed bytes into the compressed file. |
| gzwrite returns the number of bytes actually written (0 in case of error). |
| */ |
| int gzwrite (file, buf, len) |
| gzFile file; |
| const voidp buf; |
| unsigned len; |
| { |
| gz_stream *s = (gz_stream*)file; |
| |
| if (s == NULL || s->mode != 'w') return Z_STREAM_ERROR; |
| |
| s->stream.next_in = buf; |
| s->stream.avail_in = len; |
| |
| while (s->stream.avail_in != 0) { |
| |
| if (s->stream.avail_out == 0) { |
| |
| s->stream.next_out = s->outbuf; |
| if (fwrite(s->outbuf, 1, Z_BUFSIZE, s->file) != Z_BUFSIZE) { |
| s->z_err = Z_ERRNO; |
| break; |
| } |
| s->stream.avail_out = Z_BUFSIZE; |
| } |
| s->z_err = deflate(&(s->stream), Z_NO_FLUSH); |
| if (s->z_err != Z_OK) break; |
| } |
| s->crc = crc32(s->crc, buf, len); |
| |
| return (int)(len - s->stream.avail_in); |
| } |
| |
| /* =========================================================================== |
| Flushes all pending output into the compressed file. The parameter |
| flush is as in the deflate() function. |
| gzflush should be called only when strictly necessary because it can |
| degrade compression. |
| */ |
| int gzflush (file, flush) |
| gzFile file; |
| int flush; |
| { |
| uInt len; |
| int done = 0; |
| gz_stream *s = (gz_stream*)file; |
| |
| if (s == NULL || s->mode != 'w') return Z_STREAM_ERROR; |
| |
| s->stream.avail_in = 0; /* should be zero already anyway */ |
| |
| for (;;) { |
| len = Z_BUFSIZE - s->stream.avail_out; |
| |
| if (len != 0) { |
| if ((uInt)fwrite(s->outbuf, 1, len, s->file) != len) { |
| s->z_err = Z_ERRNO; |
| return Z_ERRNO; |
| } |
| s->stream.next_out = s->outbuf; |
| s->stream.avail_out = Z_BUFSIZE; |
| } |
| if (done) break; |
| s->z_err = deflate(&(s->stream), flush); |
| |
| /* deflate has finished flushing only when it hasn't used up |
| * all the available space in the output buffer: |
| */ |
| done = (s->stream.avail_out != 0 || s->z_err == Z_STREAM_END); |
| |
| if (s->z_err != Z_OK && s->z_err != Z_STREAM_END) break; |
| } |
| fflush(s->file); |
| return s->z_err == Z_STREAM_END ? Z_OK : s->z_err; |
| } |
| |
| /* =========================================================================== |
| Outputs a long in LSB order to the given file |
| */ |
| local void putLong (file, x) |
| FILE *file; |
| uLong x; |
| { |
| int n; |
| for (n = 0; n < 4; n++) { |
| fputc((int)(x & 0xff), file); |
| x >>= 8; |
| } |
| } |
| |
| /* =========================================================================== |
| Reads a long in LSB order from the given gz_stream. Sets |
| */ |
| local uLong getLong (s) |
| gz_stream *s; |
| { |
| uLong x = (uLong)get_byte(s); |
| int c; |
| |
| x += ((uLong)get_byte(s))<<8; |
| x += ((uLong)get_byte(s))<<16; |
| c = get_byte(s); |
| if (c == EOF) s->z_err = Z_DATA_ERROR; |
| x += ((uLong)c)<<24; |
| return x; |
| } |
| |
| /* =========================================================================== |
| Flushes all pending output if necessary, closes the compressed file |
| and deallocates all the (de)compression state. |
| */ |
| int gzclose (file) |
| gzFile file; |
| { |
| int err; |
| gz_stream *s = (gz_stream*)file; |
| |
| if (s == NULL) return Z_STREAM_ERROR; |
| |
| if (s->mode == 'w') { |
| err = gzflush (file, Z_FINISH); |
| if (err != Z_OK) return destroy(file); |
| |
| putLong (s->file, s->crc); |
| putLong (s->file, s->stream.total_in); |
| |
| } |
| return destroy(file); |
| } |
| |
| /* =========================================================================== |
| Returns the error message for the last error which occured on the |
| given compressed file. errnum is set to zlib error number. If an |
| error occured in the file system and not in the compression library, |
| errnum is set to Z_ERRNO and the application may consult errno |
| to get the exact error code. |
| */ |
| const char* gzerror (file, errnum) |
| gzFile file; |
| int *errnum; |
| { |
| char *m; |
| gz_stream *s = (gz_stream*)file; |
| |
| if (s == NULL) { |
| *errnum = Z_STREAM_ERROR; |
| return (const char*)ERR_MSG(Z_STREAM_ERROR); |
| } |
| *errnum = s->z_err; |
| if (*errnum == Z_OK) return (const char*)""; |
| |
| m = (char*)(*errnum == Z_ERRNO ? zstrerror(errno) : s->stream.msg); |
| |
| if (m == NULL || *m == '\0') m = (char*)ERR_MSG(s->z_err); |
| |
| TRYFREE(s->msg); |
| s->msg = (char*)ALLOC(strlen(s->path) + strlen(m) + 3); |
| strcpy(s->msg, s->path); |
| strcat(s->msg, ": "); |
| strcat(s->msg, m); |
| return (const char*)s->msg; |
| } |