1
/* gzio.c -- IO on .gz files
2
* Copyright (C) 1995-2005 Jean-loup Gailly.
3
* For conditions of distribution and use, see copyright notice in zlib.h
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* Compile this file with -DNO_GZCOMPRESS to avoid the compression code.
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/* Need to be included "early" to control other headers */
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#ifdef NO_DEFLATE /* for compatibility with old definition */
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# define NO_GZCOMPRESS
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struct internal_state {int dummy;}; /* for buggy compilers */
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# define Z_BUFSIZE 4096 /* minimize memory usage for 16-bit DOS */
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# define Z_BUFSIZE 16384
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#ifndef Z_PRINTF_BUFSIZE
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# define Z_PRINTF_BUFSIZE 4096
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# pragma map (fdopen , "\174\174FDOPEN")
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FILE *fdopen(int, const char *);
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extern voidp malloc OF((uInt size));
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extern void free OF((voidpf ptr));
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#define ALLOC(size) malloc(size)
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#define TRYFREE(p) {if (p) free(p);}
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static int const gz_magic[2] = {0x1f, 0x8b}; /* gzip magic header */
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#define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */
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#define HEAD_CRC 0x02 /* bit 1 set: header CRC present */
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#define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */
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#define ORIG_NAME 0x08 /* bit 3 set: original file name present */
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#define COMMENT 0x10 /* bit 4 set: file comment present */
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#define RESERVED 0xE0 /* bits 5..7: reserved */
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typedef struct gz_stream {
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int z_err; /* error code for last stream operation */
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int z_eof; /* set if end of input file */
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FILE *file; /* .gz file */
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Byte *inbuf; /* input buffer */
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Byte *outbuf; /* output buffer */
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uLong crc; /* crc32 of uncompressed data */
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char *msg; /* error message */
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char *path; /* path name for debugging only */
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int transparent; /* 1 if input file is not a .gz file */
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char mode; /* 'w' or 'r' */
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z_off_t start; /* start of compressed data in file (header skipped) */
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z_off_t in; /* bytes into deflate or inflate */
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z_off_t out; /* bytes out of deflate or inflate */
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int back; /* one character push-back */
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int last; /* true if push-back is last character */
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local gzFile gz_open OF((const char *path, const char *mode, int fd));
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local int do_flush OF((gzFile file, int flush));
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local int get_byte OF((gz_stream *s));
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local void check_header OF((gz_stream *s));
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local int destroy OF((gz_stream *s));
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local void putLong OF((FILE *file, uLong x));
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local uLong getLong OF((gz_stream *s));
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/* ===========================================================================
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Opens a gzip (.gz) file for reading or writing. The mode parameter
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is as in fopen ("rb" or "wb"). The file is given either by file descriptor
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or path name (if fd == -1).
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gz_open returns NULL if the file could not be opened or if there was
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insufficient memory to allocate the (de)compression state; errno
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can be checked to distinguish the two cases (if errno is zero, the
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zlib error is Z_MEM_ERROR).
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local gzFile gz_open (path, mode, fd)
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int level = Z_DEFAULT_COMPRESSION; /* compression level */
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int strategy = Z_DEFAULT_STRATEGY; /* compression strategy */
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char *p = (char*)mode;
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char fmode[80]; /* copy of mode, without the compression level */
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if (!path || !mode) return Z_NULL;
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s = (gz_stream *)ALLOC(sizeof(gz_stream));
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if (!s) return Z_NULL;
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s->stream.zalloc = (alloc_func)0;
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s->stream.zfree = (free_func)0;
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s->stream.opaque = (voidpf)0;
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s->stream.next_in = s->inbuf = Z_NULL;
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s->stream.next_out = s->outbuf = Z_NULL;
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s->stream.avail_in = s->stream.avail_out = 0;
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s->crc = crc32(0L, Z_NULL, 0);
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s->path = (char*)ALLOC(strlen(path)+1);
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if (s->path == NULL) {
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return destroy(s), (gzFile)Z_NULL;
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strcpy(s->path, path); /* do this early for debugging */
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if (*p == 'r') s->mode = 'r';
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if (*p == 'w' || *p == 'a') s->mode = 'w';
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if (*p >= '0' && *p <= '9') {
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} else if (*p == 'f') {
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strategy = Z_FILTERED;
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} else if (*p == 'h') {
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strategy = Z_HUFFMAN_ONLY;
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} else if (*p == 'R') {
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*m++ = *p; /* copy the mode */
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} while (*p++ && m != fmode + sizeof(fmode));
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if (s->mode == '\0') return destroy(s), (gzFile)Z_NULL;
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if (s->mode == 'w') {
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err = Z_STREAM_ERROR;
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err = deflateInit2(&(s->stream), level,
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Z_DEFLATED, -MAX_WBITS, DEF_MEM_LEVEL, strategy);
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/* windowBits is passed < 0 to suppress zlib header */
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s->stream.next_out = s->outbuf = (Byte*)ALLOC(Z_BUFSIZE);
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if (err != Z_OK || s->outbuf == Z_NULL) {
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return destroy(s), (gzFile)Z_NULL;
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s->stream.next_in = s->inbuf = (Byte*)ALLOC(Z_BUFSIZE);
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err = inflateInit2(&(s->stream), -MAX_WBITS);
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/* windowBits is passed < 0 to tell that there is no zlib header.
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* Note that in this case inflate *requires* an extra "dummy" byte
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* after the compressed stream in order to complete decompression and
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* return Z_STREAM_END. Here the gzip CRC32 ensures that 4 bytes are
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* present after the compressed stream.
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if (err != Z_OK || s->inbuf == Z_NULL) {
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return destroy(s), (gzFile)Z_NULL;
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s->stream.avail_out = Z_BUFSIZE;
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s->file = fd < 0 ? F_OPEN(path, fmode) : (FILE*)fdopen(fd, fmode);
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if (s->file == NULL) {
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return destroy(s), (gzFile)Z_NULL;
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if (s->mode == 'w') {
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/* Write a very simple .gz header:
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fprintf(s->file, "%c%c%c%c%c%c%c%c%c%c", gz_magic[0], gz_magic[1],
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Z_DEFLATED, 0 /*flags*/, 0,0,0,0 /*time*/, 0 /*xflags*/, OS_CODE);
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/* We use 10L instead of ftell(s->file) to because ftell causes an
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* fflush on some systems. This version of the library doesn't use
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* start anyway in write mode, so this initialization is not
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check_header(s); /* skip the .gz header */
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s->start = ftell(s->file) - s->stream.avail_in;
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/* ===========================================================================
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Opens a gzip (.gz) file for reading or writing.
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gzFile ZEXPORT gzopen (path, mode)
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return gz_open (path, mode, -1);
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/* ===========================================================================
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Associate a gzFile with the file descriptor fd. fd is not dup'ed here
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to mimic the behavio(u)r of fdopen.
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gzFile ZEXPORT gzdopen (fd, mode)
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char name[46]; /* allow for up to 128-bit integers */
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if (fd < 0) return (gzFile)Z_NULL;
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sprintf(name, "<fd:%d>", fd); /* for debugging */
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return gz_open (name, mode, fd);
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/* ===========================================================================
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* Update the compression level and strategy
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int ZEXPORT gzsetparams (file, level, strategy)
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gz_stream *s = (gz_stream*)file;
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if (s == NULL || s->mode != 'w') return Z_STREAM_ERROR;
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/* Make room to allow flushing */
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if (s->stream.avail_out == 0) {
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s->stream.next_out = s->outbuf;
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if (fwrite(s->outbuf, 1, Z_BUFSIZE, s->file) != Z_BUFSIZE) {
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s->stream.avail_out = Z_BUFSIZE;
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return deflateParams (&(s->stream), level, strategy);
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/* ===========================================================================
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Read a byte from a gz_stream; update next_in and avail_in. Return EOF
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IN assertion: the stream s has been sucessfully opened for reading.
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local int get_byte(s)
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if (s->z_eof) return EOF;
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if (s->stream.avail_in == 0) {
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s->stream.avail_in = (uInt)fread(s->inbuf, 1, Z_BUFSIZE, s->file);
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if (s->stream.avail_in == 0) {
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if (ferror(s->file)) s->z_err = Z_ERRNO;
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s->stream.next_in = s->inbuf;
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s->stream.avail_in--;
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return *(s->stream.next_in)++;
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/* ===========================================================================
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Check the gzip header of a gz_stream opened for reading. Set the stream
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mode to transparent if the gzip magic header is not present; set s->err
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to Z_DATA_ERROR if the magic header is present but the rest of the header
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IN assertion: the stream s has already been created sucessfully;
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s->stream.avail_in is zero for the first time, but may be non-zero
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for concatenated .gz files.
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local void check_header(s)
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int method; /* method byte */
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int flags; /* flags byte */
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/* Assure two bytes in the buffer so we can peek ahead -- handle case
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where first byte of header is at the end of the buffer after the last
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len = s->stream.avail_in;
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if (len) s->inbuf[0] = s->stream.next_in[0];
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len = (uInt)fread(s->inbuf + len, 1, Z_BUFSIZE >> len, s->file);
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if (len == 0 && ferror(s->file)) s->z_err = Z_ERRNO;
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s->stream.avail_in += len;
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s->stream.next_in = s->inbuf;
312
if (s->stream.avail_in < 2) {
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s->transparent = s->stream.avail_in;
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/* Peek ahead to check the gzip magic header */
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if (s->stream.next_in[0] != gz_magic[0] ||
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s->stream.next_in[1] != gz_magic[1]) {
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s->stream.avail_in -= 2;
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s->stream.next_in += 2;
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/* Check the rest of the gzip header */
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method = get_byte(s);
330
if (method != Z_DEFLATED || (flags & RESERVED) != 0) {
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s->z_err = Z_DATA_ERROR;
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/* Discard time, xflags and OS code: */
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for (len = 0; len < 6; len++) (void)get_byte(s);
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if ((flags & EXTRA_FIELD) != 0) { /* skip the extra field */
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len = (uInt)get_byte(s);
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len += ((uInt)get_byte(s))<<8;
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/* len is garbage if EOF but the loop below will quit anyway */
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while (len-- != 0 && get_byte(s) != EOF) ;
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if ((flags & ORIG_NAME) != 0) { /* skip the original file name */
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while ((c = get_byte(s)) != 0 && c != EOF) ;
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if ((flags & COMMENT) != 0) { /* skip the .gz file comment */
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while ((c = get_byte(s)) != 0 && c != EOF) ;
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if ((flags & HEAD_CRC) != 0) { /* skip the header crc */
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for (len = 0; len < 2; len++) (void)get_byte(s);
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s->z_err = s->z_eof ? Z_DATA_ERROR : Z_OK;
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/* ===========================================================================
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* Cleanup then free the given gz_stream. Return a zlib error code.
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Try freeing in the reverse order of allocations.
360
local int destroy (s)
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if (!s) return Z_STREAM_ERROR;
369
if (s->stream.state != NULL) {
370
if (s->mode == 'w') {
372
err = Z_STREAM_ERROR;
374
err = deflateEnd(&(s->stream));
376
} else if (s->mode == 'r') {
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err = inflateEnd(&(s->stream));
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if (s->file != NULL && fclose(s->file)) {
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if (errno != ESPIPE) /* fclose is broken for pipes in HP/UX */
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if (s->z_err < 0) err = s->z_err;
395
/* ===========================================================================
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Reads the given number of uncompressed bytes from the compressed file.
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gzread returns the number of bytes actually read (0 for end of file).
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int ZEXPORT gzread (file, buf, len)
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gz_stream *s = (gz_stream*)file;
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Bytef *start = (Bytef*)buf; /* starting point for crc computation */
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Byte *next_out; /* == stream.next_out but not forced far (for MSDOS) */
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if (s == NULL || s->mode != 'r') return Z_STREAM_ERROR;
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if (s->z_err == Z_DATA_ERROR || s->z_err == Z_ERRNO) return -1;
411
if (s->z_err == Z_STREAM_END) return 0; /* EOF */
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next_out = (Byte*)buf;
414
s->stream.next_out = (Bytef*)buf;
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s->stream.avail_out = len;
417
if (s->stream.avail_out && s->back != EOF) {
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*next_out++ = s->back;
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s->stream.next_out++;
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s->stream.avail_out--;
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s->z_err = Z_STREAM_END;
430
while (s->stream.avail_out != 0) {
432
if (s->transparent) {
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/* Copy first the lookahead bytes: */
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uInt n = s->stream.avail_in;
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if (n > s->stream.avail_out) n = s->stream.avail_out;
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zmemcpy(s->stream.next_out, s->stream.next_in, n);
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s->stream.next_out = next_out;
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s->stream.next_in += n;
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s->stream.avail_out -= n;
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s->stream.avail_in -= n;
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if (s->stream.avail_out > 0) {
445
s->stream.avail_out -=
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(uInt)fread(next_out, 1, s->stream.avail_out, s->file);
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len -= s->stream.avail_out;
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if (len == 0) s->z_eof = 1;
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if (s->stream.avail_in == 0 && !s->z_eof) {
457
s->stream.avail_in = (uInt)fread(s->inbuf, 1, Z_BUFSIZE, s->file);
458
if (s->stream.avail_in == 0) {
460
if (ferror(s->file)) {
465
s->stream.next_in = s->inbuf;
467
s->in += s->stream.avail_in;
468
s->out += s->stream.avail_out;
469
s->z_err = inflate(&(s->stream), Z_NO_FLUSH);
470
s->in -= s->stream.avail_in;
471
s->out -= s->stream.avail_out;
473
if (s->z_err == Z_STREAM_END) {
474
/* Check CRC and original size */
475
s->crc = crc32(s->crc, start, (uInt)(s->stream.next_out - start));
476
start = s->stream.next_out;
478
if (getLong(s) != s->crc) {
479
s->z_err = Z_DATA_ERROR;
482
/* The uncompressed length returned by above getlong() may be
483
* different from s->out in case of concatenated .gz files.
484
* Check for such files:
487
if (s->z_err == Z_OK) {
488
inflateReset(&(s->stream));
489
s->crc = crc32(0L, Z_NULL, 0);
493
if (s->z_err != Z_OK || s->z_eof) break;
495
s->crc = crc32(s->crc, start, (uInt)(s->stream.next_out - start));
497
if (len == s->stream.avail_out &&
498
(s->z_err == Z_DATA_ERROR || s->z_err == Z_ERRNO))
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return (int)(len - s->stream.avail_out);
504
/* ===========================================================================
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Reads one byte from the compressed file. gzgetc returns this byte
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or -1 in case of end of file or error.
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int ZEXPORT gzgetc(file)
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return gzread(file, &c, 1) == 1 ? c : -1;
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/* ===========================================================================
518
Push one byte back onto the stream.
520
int ZEXPORT gzungetc(c, file)
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gz_stream *s = (gz_stream*)file;
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if (s == NULL || s->mode != 'r' || c == EOF || s->back != EOF) return EOF;
529
s->last = (s->z_err == Z_STREAM_END);
530
if (s->last) s->z_err = Z_OK;
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/* ===========================================================================
537
Reads bytes from the compressed file until len-1 characters are
538
read, or a newline character is read and transferred to buf, or an
539
end-of-file condition is encountered. The string is then terminated
540
with a null character.
541
gzgets returns buf, or Z_NULL in case of error.
543
The current implementation is not optimized at all.
545
char * ZEXPORT gzgets(file, buf, len)
551
if (buf == Z_NULL || len <= 0) return Z_NULL;
553
while (--len > 0 && gzread(file, buf, 1) == 1 && *buf++ != '\n') ;
555
return b == buf && len > 0 ? Z_NULL : b;
559
#ifndef NO_GZCOMPRESS
560
/* ===========================================================================
561
Writes the given number of uncompressed bytes into the compressed file.
562
gzwrite returns the number of bytes actually written (0 in case of error).
564
int ZEXPORT gzwrite (file, buf, len)
569
gz_stream *s = (gz_stream*)file;
571
if (s == NULL || s->mode != 'w') return Z_STREAM_ERROR;
573
s->stream.next_in = (Bytef*)buf;
574
s->stream.avail_in = len;
576
while (s->stream.avail_in != 0) {
578
if (s->stream.avail_out == 0) {
580
s->stream.next_out = s->outbuf;
581
if (fwrite(s->outbuf, 1, Z_BUFSIZE, s->file) != Z_BUFSIZE) {
585
s->stream.avail_out = Z_BUFSIZE;
587
s->in += s->stream.avail_in;
588
s->out += s->stream.avail_out;
589
s->z_err = deflate(&(s->stream), Z_NO_FLUSH);
590
s->in -= s->stream.avail_in;
591
s->out -= s->stream.avail_out;
592
if (s->z_err != Z_OK) break;
594
s->crc = crc32(s->crc, (const Bytef *)buf, len);
596
return (int)(len - s->stream.avail_in);
600
/* ===========================================================================
601
Converts, formats, and writes the args to the compressed file under
602
control of the format string, as in fprintf. gzprintf returns the number of
603
uncompressed bytes actually written (0 in case of error).
608
int ZEXPORTVA gzprintf (gzFile file, const char *format, /* args */ ...)
610
char buf[Z_PRINTF_BUFSIZE];
614
buf[sizeof(buf) - 1] = 0;
615
va_start(va, format);
617
# ifdef HAS_vsprintf_void
618
(void)vsprintf(buf, format, va);
620
for (len = 0; len < sizeof(buf); len++)
621
if (buf[len] == 0) break;
623
len = vsprintf(buf, format, va);
627
# ifdef HAS_vsnprintf_void
628
(void)vsnprintf(buf, sizeof(buf), format, va);
632
len = vsnprintf(buf, sizeof(buf), format, va);
636
if (len <= 0 || len >= (int)sizeof(buf) || buf[sizeof(buf) - 1] != 0)
638
return gzwrite(file, buf, (unsigned)len);
640
#else /* not ANSI C */
642
int ZEXPORTVA gzprintf (file, format, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10,
643
a11, a12, a13, a14, a15, a16, a17, a18, a19, a20)
646
int a1, a2, a3, a4, a5, a6, a7, a8, a9, a10,
647
a11, a12, a13, a14, a15, a16, a17, a18, a19, a20;
649
char buf[Z_PRINTF_BUFSIZE];
652
buf[sizeof(buf) - 1] = 0;
654
# ifdef HAS_sprintf_void
655
sprintf(buf, format, a1, a2, a3, a4, a5, a6, a7, a8,
656
a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20);
657
for (len = 0; len < sizeof(buf); len++)
658
if (buf[len] == 0) break;
660
len = sprintf(buf, format, a1, a2, a3, a4, a5, a6, a7, a8,
661
a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20);
664
# ifdef HAS_snprintf_void
665
snprintf(buf, sizeof(buf), format, a1, a2, a3, a4, a5, a6, a7, a8,
666
a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20);
669
len = snprintf(buf, sizeof(buf), format, a1, a2, a3, a4, a5, a6, a7, a8,
670
a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20);
673
if (len <= 0 || len >= sizeof(buf) || buf[sizeof(buf) - 1] != 0)
675
return gzwrite(file, buf, len);
679
/* ===========================================================================
680
Writes c, converted to an unsigned char, into the compressed file.
681
gzputc returns the value that was written, or -1 in case of error.
683
int ZEXPORT gzputc(file, c)
687
unsigned char cc = (unsigned char) c; /* required for big endian systems */
689
return gzwrite(file, &cc, 1) == 1 ? (int)cc : -1;
693
/* ===========================================================================
694
Writes the given null-terminated string to the compressed file, excluding
695
the terminating null character.
696
gzputs returns the number of characters written, or -1 in case of error.
698
int ZEXPORT gzputs(file, s)
702
return gzwrite(file, (char*)s, (unsigned)strlen(s));
706
/* ===========================================================================
707
Flushes all pending output into the compressed file. The parameter
708
flush is as in the deflate() function.
710
local int do_flush (file, flush)
716
gz_stream *s = (gz_stream*)file;
718
if (s == NULL || s->mode != 'w') return Z_STREAM_ERROR;
720
s->stream.avail_in = 0; /* should be zero already anyway */
723
len = Z_BUFSIZE - s->stream.avail_out;
726
if ((uInt)fwrite(s->outbuf, 1, len, s->file) != len) {
730
s->stream.next_out = s->outbuf;
731
s->stream.avail_out = Z_BUFSIZE;
734
s->out += s->stream.avail_out;
735
s->z_err = deflate(&(s->stream), flush);
736
s->out -= s->stream.avail_out;
738
/* Ignore the second of two consecutive flushes: */
739
if (len == 0 && s->z_err == Z_BUF_ERROR) s->z_err = Z_OK;
741
/* deflate has finished flushing only when it hasn't used up
742
* all the available space in the output buffer:
744
done = (s->stream.avail_out != 0 || s->z_err == Z_STREAM_END);
746
if (s->z_err != Z_OK && s->z_err != Z_STREAM_END) break;
748
return s->z_err == Z_STREAM_END ? Z_OK : s->z_err;
751
int ZEXPORT gzflush (file, flush)
755
gz_stream *s = (gz_stream*)file;
756
int err = do_flush (file, flush);
760
return s->z_err == Z_STREAM_END ? Z_OK : s->z_err;
762
#endif /* NO_GZCOMPRESS */
764
/* ===========================================================================
765
Sets the starting position for the next gzread or gzwrite on the given
766
compressed file. The offset represents a number of bytes in the
767
gzseek returns the resulting offset location as measured in bytes from
768
the beginning of the uncompressed stream, or -1 in case of error.
769
SEEK_END is not implemented, returns error.
770
In this version of the library, gzseek can be extremely slow.
772
z_off_t ZEXPORT gzseek (file, offset, whence)
777
gz_stream *s = (gz_stream*)file;
779
if (s == NULL || whence == SEEK_END ||
780
s->z_err == Z_ERRNO || s->z_err == Z_DATA_ERROR) {
784
if (s->mode == 'w') {
788
if (whence == SEEK_SET) {
791
if (offset < 0) return -1L;
793
/* At this point, offset is the number of zero bytes to write. */
794
if (s->inbuf == Z_NULL) {
795
s->inbuf = (Byte*)ALLOC(Z_BUFSIZE); /* for seeking */
796
if (s->inbuf == Z_NULL) return -1L;
797
zmemzero(s->inbuf, Z_BUFSIZE);
800
uInt size = Z_BUFSIZE;
801
if (offset < Z_BUFSIZE) size = (uInt)offset;
803
size = gzwrite(file, s->inbuf, size);
804
if (size == 0) return -1L;
811
/* Rest of function is for reading only */
813
/* compute absolute position */
814
if (whence == SEEK_CUR) {
817
if (offset < 0) return -1L;
819
if (s->transparent) {
822
s->stream.avail_in = 0;
823
s->stream.next_in = s->inbuf;
824
if (fseek(s->file, offset, SEEK_SET) < 0) return -1L;
826
s->in = s->out = offset;
830
/* For a negative seek, rewind and use positive seek */
831
if (offset >= s->out) {
833
} else if (gzrewind(file) < 0) {
836
/* offset is now the number of bytes to skip. */
838
if (offset != 0 && s->outbuf == Z_NULL) {
839
s->outbuf = (Byte*)ALLOC(Z_BUFSIZE);
840
if (s->outbuf == Z_NULL) return -1L;
842
if (offset && s->back != EOF) {
846
if (s->last) s->z_err = Z_STREAM_END;
849
int size = Z_BUFSIZE;
850
if (offset < Z_BUFSIZE) size = (int)offset;
852
size = gzread(file, s->outbuf, (uInt)size);
853
if (size <= 0) return -1L;
859
/* ===========================================================================
862
int ZEXPORT gzrewind (file)
865
gz_stream *s = (gz_stream*)file;
867
if (s == NULL || s->mode != 'r') return -1;
872
s->stream.avail_in = 0;
873
s->stream.next_in = s->inbuf;
874
s->crc = crc32(0L, Z_NULL, 0);
875
if (!s->transparent) (void)inflateReset(&s->stream);
878
return fseek(s->file, s->start, SEEK_SET);
881
/* ===========================================================================
882
Returns the starting position for the next gzread or gzwrite on the
883
given compressed file. This position represents a number of bytes in the
884
uncompressed data stream.
886
z_off_t ZEXPORT gztell (file)
889
return gzseek(file, 0L, SEEK_CUR);
892
/* ===========================================================================
893
Returns 1 when EOF has previously been detected reading the given
894
input stream, otherwise zero.
896
int ZEXPORT gzeof (file)
899
gz_stream *s = (gz_stream*)file;
901
/* With concatenated compressed files that can have embedded
902
* crc trailers, z_eof is no longer the only/best indicator of EOF
903
* on a gz_stream. Handle end-of-stream error explicitly here.
905
if (s == NULL || s->mode != 'r') return 0;
906
if (s->z_eof) return 1;
907
return s->z_err == Z_STREAM_END;
910
/* ===========================================================================
911
Returns 1 if reading and doing so transparently, otherwise zero.
913
int ZEXPORT gzdirect (file)
916
gz_stream *s = (gz_stream*)file;
918
if (s == NULL || s->mode != 'r') return 0;
919
return s->transparent;
922
/* ===========================================================================
923
Outputs a long in LSB order to the given file
925
local void putLong (file, x)
930
for (n = 0; n < 4; n++) {
931
fputc((int)(x & 0xff), file);
936
/* ===========================================================================
937
Reads a long in LSB order from the given gz_stream. Sets z_err in case
940
local uLong getLong (s)
943
uLong x = (uLong)get_byte(s);
946
x += ((uLong)get_byte(s))<<8;
947
x += ((uLong)get_byte(s))<<16;
949
if (c == EOF) s->z_err = Z_DATA_ERROR;
954
/* ===========================================================================
955
Flushes all pending output if necessary, closes the compressed file
956
and deallocates all the (de)compression state.
958
int ZEXPORT gzclose (file)
961
gz_stream *s = (gz_stream*)file;
963
if (s == NULL) return Z_STREAM_ERROR;
965
if (s->mode == 'w') {
967
return Z_STREAM_ERROR;
969
if (do_flush (file, Z_FINISH) != Z_OK)
970
return destroy((gz_stream*)file);
972
putLong (s->file, s->crc);
973
putLong (s->file, (uLong)(s->in & 0xffffffff));
976
return destroy((gz_stream*)file);
980
# define zstrerror(errnum) strerror(errnum)
982
# define zstrerror(errnum) ""
985
/* ===========================================================================
986
Returns the error message for the last error which occurred on the
987
given compressed file. errnum is set to zlib error number. If an
988
error occurred in the file system and not in the compression library,
989
errnum is set to Z_ERRNO and the application may consult errno
990
to get the exact error code.
992
const char * ZEXPORT gzerror (file, errnum)
997
gz_stream *s = (gz_stream*)file;
1000
*errnum = Z_STREAM_ERROR;
1001
return (const char*)ERR_MSG(Z_STREAM_ERROR);
1004
if (*errnum == Z_OK) return (const char*)"";
1006
m = (char*)(*errnum == Z_ERRNO ? zstrerror(errno) : s->stream.msg);
1008
if (m == NULL || *m == '\0') m = (char*)ERR_MSG(s->z_err);
1011
s->msg = (char*)ALLOC(strlen(s->path) + strlen(m) + 3);
1012
if (s->msg == Z_NULL) return (const char*)ERR_MSG(Z_MEM_ERROR);
1013
strcpy(s->msg, s->path);
1014
strcat(s->msg, ": ");
1016
return (const char*)s->msg;
1019
/* ===========================================================================
1020
Clear the error and end-of-file flags, and do the same for the real file.
1022
void ZEXPORT gzclearerr (file)
1025
gz_stream *s = (gz_stream*)file;
1027
if (s == NULL) return;
1028
if (s->z_err != Z_STREAM_END) s->z_err = Z_OK;