876 lines
26 KiB
C
876 lines
26 KiB
C
/* gzio.c -- IO on .gz files
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* Copyright (C) 1995-2002 Jean-loup Gailly.
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* For conditions of distribution and use, see copyright notice in zlib.h
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*
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* Compile this file with -DNO_DEFLATE to avoid the compression code.
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*/
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/* @(#) $Id: gzio.c 3351 2006-01-08 23:25:19Z mmiller $ */
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#include <stdio.h>
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#include "zutil.h"
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struct internal_state {int dummy;}; /* for buggy compilers */
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#ifndef Z_BUFSIZE
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# ifdef MAXSEG_64K
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# define Z_BUFSIZE 4096 /* minimize memory usage for 16-bit DOS */
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# else
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# define Z_BUFSIZE 16384
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# endif
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#endif
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#ifndef Z_PRINTF_BUFSIZE
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# define Z_PRINTF_BUFSIZE 4096
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#endif
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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 gz_magic[2] = {0x1f, 0x8b}; /* gzip magic header */
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/* gzip flag byte */
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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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z_stream 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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long startpos; /* start of compressed data in file (header skipped) */
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} gz_stream;
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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 return 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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*/
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local gzFile gz_open (path, mode, fd)
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const char *path;
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const char *mode;
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int fd;
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{
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int err;
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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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gz_stream *s;
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char fmode[80]; /* copy of mode, without the compression level */
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char *m = fmode;
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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->file = NULL;
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s->z_err = Z_OK;
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s->z_eof = 0;
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s->crc = crc32(0L, Z_NULL, 0);
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s->msg = NULL;
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s->transparent = 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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}
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strcpy(s->path, path); /* do this early for debugging */
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s->mode = '\0';
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do {
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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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level = *p - '0';
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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 {
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*m++ = *p; /* copy the mode */
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}
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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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#ifdef NO_DEFLATE
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err = Z_STREAM_ERROR;
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#else
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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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#endif
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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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}
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} else {
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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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*/
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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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}
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}
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s->stream.avail_out = Z_BUFSIZE;
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errno = 0;
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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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}
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if (s->mode == 'w') {
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/* Write a very simple .gz header:
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*/
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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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s->startpos = 10L;
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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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* startpos anyway in write mode, so this initialization is not
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* necessary.
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*/
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} else {
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check_header(s); /* skip the .gz header */
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s->startpos = (ftell(s->file) - s->stream.avail_in);
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}
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return (gzFile)s;
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}
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/* ===========================================================================
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Opens a gzip (.gz) file for reading or writing.
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*/
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gzFile ZEXPORT gzopen (path, mode)
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const char *path;
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const char *mode;
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{
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return gz_open (path, mode, -1);
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}
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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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*/
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gzFile ZEXPORT gzdopen (fd, mode)
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int fd;
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const char *mode;
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{
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char name[20];
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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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/* ===========================================================================
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* Update the compression level and strategy
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*/
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int ZEXPORT gzsetparams (file, level, strategy)
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gzFile file;
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int level;
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int strategy;
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{
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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->z_err = Z_ERRNO;
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}
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s->stream.avail_out = Z_BUFSIZE;
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}
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return deflateParams (&(s->stream), level, strategy);
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}
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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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for end of file.
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IN assertion: the stream s has been sucessfully opened for reading.
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*/
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local int get_byte(s)
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gz_stream *s;
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{
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if (s->z_eof) return EOF;
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if (s->stream.avail_in == 0) {
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errno = 0;
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s->stream.avail_in = fread(s->inbuf, 1, Z_BUFSIZE, s->file);
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if (s->stream.avail_in == 0) {
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s->z_eof = 1;
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if (ferror(s->file)) s->z_err = Z_ERRNO;
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return EOF;
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}
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s->stream.next_in = s->inbuf;
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}
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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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/* ===========================================================================
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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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is incorrect.
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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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*/
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local void check_header(s)
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gz_stream *s;
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{
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int method; /* method byte */
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int flags; /* flags byte */
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uInt len;
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int c;
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/* Check the gzip magic header */
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for (len = 0; len < 2; len++) {
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c = get_byte(s);
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if (c != gz_magic[len]) {
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if (len != 0) s->stream.avail_in++, s->stream.next_in--;
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if (c != EOF) {
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s->stream.avail_in++, s->stream.next_in--;
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s->transparent = 1;
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}
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s->z_err = s->stream.avail_in != 0 ? Z_OK : Z_STREAM_END;
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return;
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}
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}
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method = get_byte(s);
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flags = get_byte(s);
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if (method != Z_DEFLATED || (flags & RESERVED) != 0) {
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s->z_err = Z_DATA_ERROR;
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return;
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}
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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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}
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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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}
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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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}
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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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}
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s->z_err = s->z_eof ? Z_DATA_ERROR : Z_OK;
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}
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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.
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*/
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local int destroy (s)
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gz_stream *s;
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{
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int err = Z_OK;
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if (!s) return Z_STREAM_ERROR;
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TRYFREE(s->msg);
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if (s->stream.state != NULL) {
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if (s->mode == 'w') {
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#ifdef NO_DEFLATE
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err = Z_STREAM_ERROR;
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#else
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err = deflateEnd(&(s->stream));
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#endif
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} else if (s->mode == 'r') {
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err = inflateEnd(&(s->stream));
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}
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}
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if (s->file != NULL && fclose(s->file)) {
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#ifdef ESPIPE
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if (errno != ESPIPE) /* fclose is broken for pipes in HP/UX */
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#endif
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err = Z_ERRNO;
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}
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if (s->z_err < 0) err = s->z_err;
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TRYFREE(s->inbuf);
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TRYFREE(s->outbuf);
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TRYFREE(s->path);
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TRYFREE(s);
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return err;
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}
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/* ===========================================================================
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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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*/
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int ZEXPORT gzread (file, buf, len)
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gzFile file;
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voidp buf;
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unsigned len;
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{
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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;
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if (s->z_err == Z_STREAM_END) return 0; /* EOF */
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next_out = (Byte*)buf;
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s->stream.next_out = (Bytef*)buf;
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s->stream.avail_out = len;
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while (s->stream.avail_out != 0) {
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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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if (n > 0) {
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zmemcpy(s->stream.next_out, s->stream.next_in, n);
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next_out += 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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}
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if (s->stream.avail_out > 0) {
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s->stream.avail_out -= fread(next_out, 1, s->stream.avail_out,
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s->file);
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}
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len -= s->stream.avail_out;
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s->stream.total_in += (uLong)len;
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s->stream.total_out += (uLong)len;
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if (len == 0) s->z_eof = 1;
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return (int)len;
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}
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if (s->stream.avail_in == 0 && !s->z_eof) {
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errno = 0;
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s->stream.avail_in = fread(s->inbuf, 1, Z_BUFSIZE, s->file);
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if (s->stream.avail_in == 0) {
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s->z_eof = 1;
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if (ferror(s->file)) {
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s->z_err = Z_ERRNO;
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break;
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}
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}
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s->stream.next_in = s->inbuf;
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}
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s->z_err = inflate(&(s->stream), Z_NO_FLUSH);
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if (s->z_err == Z_STREAM_END) {
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/* Check CRC and original size */
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s->crc = crc32(s->crc, start, (uInt)(s->stream.next_out - start));
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start = s->stream.next_out;
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if (getLong(s) != s->crc) {
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s->z_err = Z_DATA_ERROR;
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} else {
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(void)getLong(s);
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/* The uncompressed length returned by above getlong() may
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* be different from s->stream.total_out) in case of
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* concatenated .gz files. Check for such files:
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*/
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check_header(s);
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if (s->z_err == Z_OK) {
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uLong total_in = s->stream.total_in;
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uLong total_out = s->stream.total_out;
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inflateReset(&(s->stream));
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s->stream.total_in = total_in;
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s->stream.total_out = total_out;
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s->crc = crc32(0L, Z_NULL, 0);
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}
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}
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}
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if (s->z_err != Z_OK || s->z_eof) break;
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}
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s->crc = crc32(s->crc, start, (uInt)(s->stream.next_out - start));
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return (int)(len - s->stream.avail_out);
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}
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/* ===========================================================================
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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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*/
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int ZEXPORT gzgetc(file)
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gzFile file;
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{
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unsigned char c;
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return gzread(file, &c, 1) == 1 ? c : -1;
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}
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/* ===========================================================================
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Reads bytes from the compressed file until len-1 characters are
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read, or a newline character is read and transferred to buf, or an
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end-of-file condition is encountered. The string is then terminated
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with a null character.
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gzgets returns buf, or Z_NULL in case of error.
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The current implementation is not optimized at all.
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*/
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char * ZEXPORT gzgets(file, buf, len)
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gzFile file;
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char *buf;
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int len;
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{
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char *b = buf;
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if (buf == Z_NULL || len <= 0) return Z_NULL;
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while (--len > 0 && gzread(file, buf, 1) == 1 && *buf++ != '\n') ;
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*buf = '\0';
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return b == buf && len > 0 ? Z_NULL : b;
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}
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#ifndef NO_DEFLATE
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/* ===========================================================================
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Writes the given number of uncompressed bytes into the compressed file.
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gzwrite returns the number of bytes actually written (0 in case of error).
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*/
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int ZEXPORT gzwrite (file, buf, len)
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gzFile file;
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const voidp buf;
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unsigned len;
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{
|
|
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;
|
|
|
|
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, (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 <stdarg.h>
|
|
|
|
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(file, c)
|
|
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(file, s)
|
|
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 (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);
|
|
|
|
/* 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 (file, flush)
|
|
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 (file, offset, whence)
|
|
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 (file)
|
|
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 (file)
|
|
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 (file)
|
|
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, 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 z_err in case
|
|
of error.
|
|
*/
|
|
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 ZEXPORT gzclose (file)
|
|
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 (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;
|
|
}
|