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875 lines
26 KiB
875 lines
26 KiB
/* 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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|
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/* @(#) $Id$ */ |
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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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|
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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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{ |
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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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s->stream.next_in = (Bytef*)buf; |
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s->stream.avail_in = len; |
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while (s->stream.avail_in != 0) { |
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|
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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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break; |
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} |
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s->stream.avail_out = Z_BUFSIZE; |
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} |
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s->z_err = deflate(&(s->stream), Z_NO_FLUSH); |
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if (s->z_err != Z_OK) break; |
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} |
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s->crc = crc32(s->crc, (const Bytef *)buf, len); |
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|
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return (int)(len - s->stream.avail_in); |
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} |
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|
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/* =========================================================================== |
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Converts, formats, and writes the args to the compressed file under |
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control of the format string, as in fprintf. gzprintf returns the number of |
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uncompressed bytes actually written (0 in case of error). |
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*/ |
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#ifdef STDC |
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#include <stdarg.h> |
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|
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int ZEXPORTVA gzprintf (gzFile file, const char *format, /* args */ ...) |
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{ |
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char buf[Z_PRINTF_BUFSIZE]; |
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va_list va; |
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int len; |
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|
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va_start(va, format); |
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#ifdef HAS_vsnprintf |
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(void)vsnprintf(buf, sizeof(buf), format, va); |
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#else |
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(void)vsprintf(buf, format, va); |
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#endif |
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va_end(va); |
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len = strlen(buf); /* some *sprintf don't return the nb of bytes written */ |
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if (len <= 0) return 0; |
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|
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return gzwrite(file, buf, (unsigned)len); |
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} |
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#else /* not ANSI C */ |
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|
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int ZEXPORTVA gzprintf (file, format, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, |
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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; |
|
}
|
|
|