| /* gzio.c -- IO on .gz files |
| * Copyright (C) 1995 Jean-loup Gailly. |
| * For conditions of distribution and use, see copyright notice in zlib.h |
| */ |
| |
| /* $Id: gzio.c,v 1.8 1995/05/03 17:27:09 jloup 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);} |
| |
| #define GZ_MAGIC_1 0x1f |
| #define GZ_MAGIC_2 0x8b |
| |
| /* 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 */ |
| |
| #ifndef SEEK_CUR |
| # define SEEK_CUR 1 |
| #endif |
| |
| 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 int destroy OF((gz_stream *s)); |
| local gzFile gz_open OF((char *path, char *mode, int fd)); |
| local void putLong OF((FILE *file, uLong x)); |
| local uLong getLong OF((Bytef *buf)); |
| |
| /* =========================================================================== |
| * Cleanup then free the given gz_stream. Return a zlib error code. |
| */ |
| local int destroy (s) |
| gz_stream *s; |
| { |
| int err = Z_OK; |
| |
| if (!s) return Z_STREAM_ERROR; |
| |
| TRYFREE(s->inbuf); |
| TRYFREE(s->outbuf); |
| TRYFREE(s->path); |
| 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); |
| return err; |
| } |
| |
| /* =========================================================================== |
| 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) |
| char *path; |
| char *mode; |
| int fd; |
| { |
| int err; |
| int level = Z_DEFAULT_COMPRESSION; /* compression level */ |
| char *p = mode; |
| gz_stream *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') s->mode = 'w'; |
| if (*p >= '1' && *p <= '9') level = *p - '0'; |
| } while (*p++); |
| 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, mode) : (FILE*)fdopen(fd, mode); |
| |
| 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_1, GZ_MAGIC_2, |
| Z_DEFLATED, 0 /*flags*/, 0,0,0,0 /*time*/, 0 /*xflags*/, OS_CODE); |
| } else { |
| /* Check and skip the header: |
| */ |
| Byte c1 = 0, c2 = 0; |
| Byte method = 0; |
| Byte flags = 0; |
| Byte xflags = 0; |
| Byte time[4]; |
| Byte osCode; |
| int c; |
| |
| s->stream.avail_in = fread(s->inbuf, 1, 2, s->file); |
| if (s->stream.avail_in != 2 || s->inbuf[0] != GZ_MAGIC_1 |
| || s->inbuf[1] != GZ_MAGIC_2) { |
| s->transparent = 1; |
| return (gzFile)s; |
| } |
| s->stream.avail_in = 0; |
| fscanf(s->file,"%c%c%4c%c%c", &method, &flags, time, &xflags, &osCode); |
| |
| if (method != Z_DEFLATED || feof(s->file) || (flags & RESERVED) != 0) { |
| s->z_err = Z_DATA_ERROR; |
| return (gzFile)s; |
| } |
| if ((flags & EXTRA_FIELD) != 0) { /* skip the extra field */ |
| long len; |
| fscanf(s->file, "%c%c", &c1, &c2); |
| len = c1 + ((long)c2<<8); |
| fseek(s->file, len, SEEK_CUR); |
| } |
| if ((flags & ORIG_NAME) != 0) { /* skip the original file name */ |
| while ((c = getc(s->file)) != 0 && c != EOF) ; |
| } |
| if ((flags & COMMENT) != 0) { /* skip the .gz file comment */ |
| while ((c = getc(s->file)) != 0 && c != EOF) ; |
| } |
| if ((flags & HEAD_CRC) != 0) { /* skip the header crc */ |
| fscanf(s->file, "%c%c", &c1, &c2); |
| } |
| if (feof(s->file)) { |
| s->z_err = Z_DATA_ERROR; |
| } |
| } |
| return (gzFile)s; |
| } |
| |
| /* =========================================================================== |
| Opens a gzip (.gz) file for reading or writing. |
| */ |
| gzFile gzopen (path, mode) |
| char *path; |
| char *mode; |
| { |
| return gz_open (path, mode, -1); |
| } |
| |
| /* =========================================================================== |
| Associate a gzFile with the file descriptor fd. |
| */ |
| gzFile gzdopen (fd, mode) |
| int fd; |
| char *mode; |
| { |
| char name[20]; |
| sprintf(name, "<fd:%d>", fd); /* for debugging */ |
| |
| return gz_open (name, mode, fd); |
| } |
| |
| /* =========================================================================== |
| 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; |
| |
| if (s == NULL || s->mode != 'r') return Z_STREAM_ERROR; |
| |
| if (s->transparent) { |
| int n = 0; |
| Byte *b = (Byte*)buf; |
| /* Copy the first two (non-magic) bytes if not done already */ |
| while (s->stream.avail_in > 0 && len > 0) { |
| *b++ = *s->stream.next_in++; |
| s->stream.avail_in--; |
| len--; n++; |
| } |
| if (len == 0) return n; |
| return n + fread(b, 1, len, s->file); |
| } |
| if (s->z_err == Z_DATA_ERROR) return -1; /* bad .gz file */ |
| if (s->z_err == Z_STREAM_END) return 0; /* don't read crc as data */ |
| |
| s->stream.next_out = buf; |
| s->stream.avail_out = len; |
| |
| while (s->stream.avail_out != 0) { |
| |
| 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; |
| } else if (s->stream.avail_in == (uInt)EOF) { |
| s->stream.avail_in = 0; |
| s->z_eof = 1; |
| 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 || |
| s->z_err != Z_OK || s->z_eof) break; |
| } |
| len -= s->stream.avail_out; |
| s->crc = crc32(s->crc, buf, len); |
| return (int)len; |
| } |
| |
| /* =========================================================================== |
| 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; |
| 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 (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 buffer |
| */ |
| local uLong getLong (buf) |
| Bytef *buf; |
| { |
| uLong x = 0; |
| Bytef *p = buf+4; |
| |
| do { |
| x <<= 8; |
| x |= *--p; |
| } while (p != buf); |
| return x; |
| } |
| |
| /* =========================================================================== |
| Flushes all pending output if necessary, closes the compressed file |
| and deallocates all the (de)compression state. |
| */ |
| int gzclose (file) |
| gzFile file; |
| { |
| uInt n; |
| 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); |
| |
| } else if (s->mode == 'r' && s->z_err == Z_STREAM_END) { |
| |
| /* slide CRC and original size if they are at the end of inbuf */ |
| if ((n = s->stream.avail_in) < 8 && !s->z_eof) { |
| Byte *p = s->inbuf; |
| Bytef *q = s->stream.next_in; |
| while (n--) { *p++ = *q++; }; |
| |
| n = s->stream.avail_in; |
| n += fread(p, 1, 8, s->file); |
| s->stream.next_in = s->inbuf; |
| } |
| /* check CRC and original size */ |
| if (n < 8 || |
| getLong(s->stream.next_in) != s->crc || |
| getLong(s->stream.next_in + 4) != s->stream.total_out) { |
| |
| s->z_err = Z_DATA_ERROR; |
| } |
| } |
| 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. |
| */ |
| char* gzerror (file, errnum) |
| gzFile file; |
| int *errnum; |
| { |
| char *m; |
| gz_stream *s = (gz_stream*)file; |
| |
| if (s == NULL) { |
| *errnum = Z_STREAM_ERROR; |
| return z_errmsg[1-Z_STREAM_ERROR]; |
| } |
| *errnum = s->z_err; |
| if (*errnum == Z_OK) return ""; |
| |
| m = *errnum == Z_ERRNO ? zstrerror(errno) : s->stream.msg; |
| |
| if (m == NULL || *m == '\0') m = z_errmsg[1-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 s->msg; |
| } |