/* gzio.c -- IO on .gz files * Copyright (C) 1995-2002 Jean-loup Gailly. * For conditions of distribution and use, see copyright notice in zlib.h * * Compile this file with -DNO_DEFLATE to avoid the compression code. */ /* @(#) $Id: gzio.c,v 1.9 2002/03/17 15:46:23 jbj Exp $ */ #include #include "zutil.h" struct internal_state {int dummy;}; /* for buggy compilers */ #ifndef Z_BUFSIZE # ifdef MAXSEG_64K # define Z_BUFSIZE 4096 /* minimize memory usage for 16-bit DOS */ # else # define Z_BUFSIZE 16384 # endif #endif #ifndef Z_PRINTF_BUFSIZE # define Z_PRINTF_BUFSIZE 4096 #endif #define ALLOC(size) malloc(size) #define TRYFREE(p) {if (p) free(p);} /*@observer@*/ /*@unchecked@*/ 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' */ long startpos; /*!< start of compressed data in file (header skipped) */ } gz_stream; local gzFile gz_open OF((const char *path, const char *mode, int fd)) /*@globals errno, fileSystem @*/ /*@modifies errno, fileSystem @*/; local int do_flush OF((gzFile file, int flush)) /*@globals fileSystem @*/ /*@modifies fileSystem @*/; local int get_byte OF((gz_stream *s)) /*@globals errno, fileSystem @*/ /*@modifies s, errno, fileSystem @*/; local void check_header OF((gz_stream *s)) /*@globals fileSystem @*/ /*@modifies s, fileSystem @*/; local int destroy OF((gz_stream *s)) /*@globals fileSystem @*/ /*@modifies s, fileSystem @*/; local void putLong OF((FILE *file, uLong x)) /*@globals fileSystem @*/ /*@modifies file, fileSystem @*/; local uLong getLong OF((gz_stream *s)) /*@globals fileSystem @*/ /*@modifies s, fileSystem @*/; /* ========================================================================= */ /** * 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 (const char * path, const char * mode, int fd) { int err; int level = Z_DEFAULT_COMPRESSION; /* compression level */ int strategy = Z_DEFAULT_STRATEGY; /* compression strategy */ 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 if (*p == 'f') { strategy = Z_FILTERED; } else if (*p == 'h') { strategy = Z_HUFFMAN_ONLY; } 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') { #ifdef NO_DEFLATE err = Z_STREAM_ERROR; #else err = deflateInit2(&(s->stream), level, Z_DEFLATED, -MAX_WBITS, DEF_MEM_LEVEL, strategy); /* windowBits is passed < 0 to suppress zlib header */ s->stream.next_out = s->outbuf = (Byte*)ALLOC(Z_BUFSIZE); #endif if (err != Z_OK || s->outbuf == Z_NULL) { return destroy(s), (gzFile)Z_NULL; } } else { s->stream.next_in = s->inbuf = (Byte*)ALLOC(Z_BUFSIZE); err = inflateInit2(&(s->stream), -MAX_WBITS); /* windowBits is passed < 0 to tell that there is no zlib header. * Note that in this case inflate *requires* an extra "dummy" byte * after the compressed stream in order to complete decompression and * return Z_STREAM_END. Here the gzip CRC32 ensures that 4 bytes are * present after the compressed stream. */ 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 ? F_OPEN(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); s->startpos = 10L; /* We use 10L instead of ftell(s->file) to because ftell causes an * fflush on some systems. This version of the library doesn't use * startpos anyway in write mode, so this initialization is not * necessary. */ } else { check_header(s); /* skip the .gz header */ s->startpos = (ftell(s->file) - s->stream.avail_in); } return (gzFile)s; } /* ========================================================================= */ /** * Opens a gzip (.gz) file for reading or writing. */ gzFile ZEXPORT gzopen (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 ZEXPORT gzdopen (int fd, const char * mode) { char name[20]; if (fd < 0) return (gzFile)Z_NULL; sprintf(name, "", fd); /* for debugging */ return gz_open (name, mode, fd); } /* ========================================================================= */ /** * Update the compression level and strategy. */ int ZEXPORT gzsetparams (gzFile file, int level, int strategy) { gz_stream *s = (gz_stream*)file; if (s == NULL || s->mode != 'w') return Z_STREAM_ERROR; /* Make room to allow flushing */ 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; } s->stream.avail_out = Z_BUFSIZE; } return deflateParams (&(s->stream), level, strategy); } /* ========================================================================= */ /** * 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(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(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]) { if (len != 0) s->stream.avail_in++, s->stream.next_in--; if (c != EOF) { s->stream.avail_in++, s->stream.next_in--; s->transparent = 1; } 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 (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') { #ifdef NO_DEFLATE err = Z_STREAM_ERROR; #else err = deflateEnd(&(s->stream)); #endif } else if (s->mode == 'r') { err = inflateEnd(&(s->stream)); } } if (s->file != NULL && fclose(s->file)) { #ifdef ESPIPE if (errno != ESPIPE) /* fclose is broken for pipes in HP/UX */ #endif 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 ZEXPORT gzread (gzFile file, voidp buf, unsigned len) { gz_stream *s = (gz_stream*)file; Bytef *start = (Bytef*)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 */ next_out = (Byte*)buf; s->stream.next_out = (Bytef*)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); } len -= s->stream.avail_out; s->stream.total_in += (uLong)len; s->stream.total_out += (uLong)len; if (len == 0) s->z_eof = 1; return (int)len; } 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) { s->z_err = Z_DATA_ERROR; } else { (void)getLong(s); /* The uncompressed length returned by above getlong() may * be different from s->stream.total_out) in case of * concatenated .gz files. Check for such files: */ check_header(s); if (s->z_err == Z_OK) { uLong total_in = s->stream.total_in; uLong total_out = s->stream.total_out; inflateReset(&(s->stream)); s->stream.total_in = total_in; s->stream.total_out = total_out; 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); } /* ========================================================================= */ /** * Reads one byte from the compressed file. gzgetc returns this byte * or -1 in case of end of file or error. */ int ZEXPORT gzgetc(gzFile file) { unsigned char c; return gzread(file, &c, 1) == 1 ? c : -1; } /* ========================================================================= */ /** * Reads bytes from the compressed file until len-1 characters are * read, or a newline character is read and transferred to buf, or an * end-of-file condition is encountered. The string is then terminated * with a null character. * gzgets returns buf, or Z_NULL in case of error. * * The current implementation is not optimized at all. */ char * ZEXPORT gzgets(gzFile file, char * buf, int len) { char *b = buf; if (buf == Z_NULL || len <= 0) return Z_NULL; while (--len > 0 && gzread(file, buf, 1) == 1 && *buf++ != '\n') ; *buf = '\0'; return b == buf && len > 0 ? Z_NULL : b; } #ifndef NO_DEFLATE /* ========================================================================= */ /** * 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 ZEXPORT gzwrite (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 = (Bytef*)buf; s->stream.avail_in = len; /*@-infloops@*/ 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; } /*@=infloops@*/ s->crc = crc32(s->crc, (const Bytef *)buf, len); return (int)(len - s->stream.avail_in); } /* ========================================================================= */ /** * Converts, formats, and writes the args to the compressed file under * control of the format string, as in fprintf. gzprintf returns the number of * uncompressed bytes actually written (0 in case of error). */ #ifdef STDC #include int ZEXPORTVA gzprintf (gzFile file, const char *format, /* args */ ...) { char buf[Z_PRINTF_BUFSIZE]; va_list va; int len; va_start(va, format); #ifdef HAS_vsnprintf (void)vsnprintf(buf, sizeof(buf), format, va); #else (void)vsprintf(buf, format, va); #endif va_end(va); len = strlen(buf); /* some *sprintf don't return the nb of bytes written */ if (len <= 0) return 0; return gzwrite(file, buf, (unsigned)len); } #else /* not ANSI C */ int ZEXPORTVA gzprintf (file, format, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20) gzFile file; const char *format; int a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20; { char buf[Z_PRINTF_BUFSIZE]; int len; #ifdef HAS_snprintf snprintf(buf, sizeof(buf), format, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20); #else sprintf(buf, format, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20); #endif len = strlen(buf); /* old sprintf doesn't return the nb of bytes written */ if (len <= 0) return 0; return gzwrite(file, buf, len); } #endif /* ========================================================================= */ /** * Writes c, converted to an unsigned char, into the compressed file. * gzputc returns the value that was written, or -1 in case of error. */ int ZEXPORT gzputc(gzFile file, int c) { unsigned char cc = (unsigned char) c; /* required for big endian systems */ return gzwrite(file, &cc, 1) == 1 ? (int)cc : -1; } /* ========================================================================= */ /** * Writes the given null-terminated string to the compressed file, excluding * the terminating null character. * gzputs returns the number of characters written, or -1 in case of error. */ int ZEXPORT gzputs(gzFile file, const char * s) { return gzwrite(file, (char*)s, (unsigned)strlen(s)); } /* ========================================================================= */ /** * Flushes all pending output into the compressed file. The parameter * flush is as in the deflate() function. */ local int do_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); /* Ignore the second of two consecutive flushes: */ if (len == 0 && s->z_err == Z_BUF_ERROR) s->z_err = Z_OK; /* 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; } return s->z_err == Z_STREAM_END ? Z_OK : s->z_err; } int ZEXPORT gzflush (gzFile file, int flush) { gz_stream *s = (gz_stream*)file; int err = do_flush (file, flush); if (err) return err; fflush(s->file); return s->z_err == Z_STREAM_END ? Z_OK : s->z_err; } #endif /* NO_DEFLATE */ /* ========================================================================= */ /** * Sets the starting position for the next gzread or gzwrite on the given * compressed file. The offset represents a number of bytes in the * gzseek returns the resulting offset location as measured in bytes from * the beginning of the uncompressed stream, or -1 in case of error. * SEEK_END is not implemented, returns error. * In this version of the library, gzseek can be extremely slow. */ z_off_t ZEXPORT gzseek (gzFile file, z_off_t offset, int whence) { gz_stream *s = (gz_stream*)file; if (s == NULL || whence == SEEK_END || s->z_err == Z_ERRNO || s->z_err == Z_DATA_ERROR) { return -1L; } if (s->mode == 'w') { #ifdef NO_DEFLATE return -1L; #else if (whence == SEEK_SET) { offset -= s->stream.total_in; } if (offset < 0) return -1L; /* At this point, offset is the number of zero bytes to write. */ if (s->inbuf == Z_NULL) { s->inbuf = (Byte*)ALLOC(Z_BUFSIZE); /* for seeking */ zmemzero(s->inbuf, Z_BUFSIZE); } while (offset > 0) { uInt size = Z_BUFSIZE; if (offset < Z_BUFSIZE) size = (uInt)offset; size = gzwrite(file, s->inbuf, size); if (size == 0) return -1L; offset -= size; } return (z_off_t)s->stream.total_in; #endif } /* Rest of function is for reading only */ /* compute absolute position */ if (whence == SEEK_CUR) { offset += s->stream.total_out; } if (offset < 0) return -1L; if (s->transparent) { /* map to fseek */ s->stream.avail_in = 0; s->stream.next_in = s->inbuf; if (fseek(s->file, offset, SEEK_SET) < 0) return -1L; s->stream.total_in = s->stream.total_out = (uLong)offset; return offset; } /* For a negative seek, rewind and use positive seek */ if ((uLong)offset >= s->stream.total_out) { offset -= s->stream.total_out; } else if (gzrewind(file) < 0) { return -1L; } /* offset is now the number of bytes to skip. */ if (offset != 0 && s->outbuf == Z_NULL) { s->outbuf = (Byte*)ALLOC(Z_BUFSIZE); } while (offset > 0) { int size = Z_BUFSIZE; if (offset < Z_BUFSIZE) size = (int)offset; size = gzread(file, s->outbuf, (uInt)size); if (size <= 0) return -1L; offset -= size; } return (z_off_t)s->stream.total_out; } /* ========================================================================= */ /** * Rewinds input file. */ int ZEXPORT gzrewind (gzFile file) { gz_stream *s = (gz_stream*)file; if (s == NULL || s->mode != 'r') return -1; s->z_err = Z_OK; s->z_eof = 0; s->stream.avail_in = 0; s->stream.next_in = s->inbuf; s->crc = crc32(0L, Z_NULL, 0); if (s->startpos == 0) { /* not a compressed file */ rewind(s->file); return 0; } (void) inflateReset(&s->stream); return fseek(s->file, s->startpos, SEEK_SET); } /* ========================================================================= */ /** * Returns the starting position for the next gzread or gzwrite on the * given compressed file. This position represents a number of bytes in the * uncompressed data stream. */ z_off_t ZEXPORT gztell (gzFile file) { return gzseek(file, 0L, SEEK_CUR); } /* ========================================================================= */ /** * Returns 1 when EOF has previously been detected reading the given * input stream, otherwise zero. */ int ZEXPORT gzeof (gzFile file) { gz_stream *s = (gz_stream*)file; return (s == NULL || s->mode != 'r') ? 0 : s->z_eof; } /* ========================================================================= */ /** * Outputs a long in LSB order to the given file */ local void putLong (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 z_err in case * of error. */ local uLong getLong (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 ZEXPORT gzclose (gzFile file) { int err; gz_stream *s = (gz_stream*)file; if (s == NULL) return Z_STREAM_ERROR; if (s->mode == 'w') { #ifdef NO_DEFLATE return Z_STREAM_ERROR; #else err = do_flush (file, Z_FINISH); if (err != Z_OK) return destroy((gz_stream*)file); putLong (s->file, s->crc); putLong (s->file, s->stream.total_in); #endif } return destroy((gz_stream*)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* ZEXPORT gzerror (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; }