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Diffstat (limited to 'zlib/gzio.c')
| -rw-r--r-- | zlib/gzio.c | 1026 |
1 files changed, 1026 insertions, 0 deletions
diff --git a/zlib/gzio.c b/zlib/gzio.c new file mode 100644 index 000000000..7e90f4928 --- /dev/null +++ b/zlib/gzio.c @@ -0,0 +1,1026 @@ +/* gzio.c -- IO on .gz files + * Copyright (C) 1995-2005 Jean-loup Gailly. + * For conditions of distribution and use, see copyright notice in zlib.h + * + * Compile this file with -DNO_GZCOMPRESS to avoid the compression code. + */ + +/* @(#) $Id$ */ + +#include <stdio.h> + +#include "zutil.h" + +#ifdef NO_DEFLATE /* for compatibility with old definition */ +# define NO_GZCOMPRESS +#endif + +#ifndef NO_DUMMY_DECL +struct internal_state {int dummy;}; /* for buggy compilers */ +#endif + +#ifndef Z_BUFSIZE +# ifdef MAXSEG_64K +# define Z_BUFSIZE 4096 /* minimize memory usage for 16-bit DOS */ +# else +# define Z_BUFSIZE 16384 +# endif +#endif +#ifndef Z_PRINTF_BUFSIZE +# define Z_PRINTF_BUFSIZE 4096 +#endif + +#ifdef __MVS__ +# pragma map (fdopen , "\174\174FDOPEN") + FILE *fdopen(int, const char *); +#endif + +#ifndef STDC +extern voidp malloc OF((uInt size)); +extern void free OF((voidpf ptr)); +#endif + +#define ALLOC(size) malloc(size) +#define TRYFREE(p) {if (p) free(p);} + +static int const gz_magic[2] = {0x1f, 0x8b}; /* gzip magic header */ + +/* gzip flag byte */ +#define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */ +#define HEAD_CRC 0x02 /* bit 1 set: header CRC present */ +#define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */ +#define ORIG_NAME 0x08 /* bit 3 set: original file name present */ +#define COMMENT 0x10 /* bit 4 set: file comment present */ +#define RESERVED 0xE0 /* bits 5..7: reserved */ + +typedef struct gz_stream { + z_stream stream; + int z_err; /* error code for last stream operation */ + int z_eof; /* set if end of input file */ + FILE *file; /* .gz file */ + Byte *inbuf; /* input buffer */ + Byte *outbuf; /* output buffer */ + uLong crc; /* crc32 of uncompressed data */ + char *msg; /* error message */ + char *path; /* path name for debugging only */ + int transparent; /* 1 if input file is not a .gz file */ + char mode; /* 'w' or 'r' */ + z_off_t start; /* start of compressed data in file (header skipped) */ + z_off_t in; /* bytes into deflate or inflate */ + z_off_t out; /* bytes out of deflate or inflate */ + int back; /* one character push-back */ + int last; /* true if push-back is last character */ +} gz_stream; + + +local gzFile gz_open OF((const char *path, const char *mode, int fd)); +local int do_flush OF((gzFile file, int flush)); +local int get_byte OF((gz_stream *s)); +local void check_header OF((gz_stream *s)); +local int destroy OF((gz_stream *s)); +local void putLong OF((FILE *file, uLong x)); +local uLong getLong OF((gz_stream *s)); + +/* =========================================================================== + Opens a gzip (.gz) file for reading or writing. The mode parameter + is as in fopen ("rb" or "wb"). The file is given either by file descriptor + or path name (if fd == -1). + gz_open returns NULL if the file could not be opened or if there was + insufficient memory to allocate the (de)compression state; errno + can be checked to distinguish the two cases (if errno is zero, the + zlib error is Z_MEM_ERROR). +*/ +local gzFile gz_open (path, mode, fd) + const char *path; + const char *mode; + int fd; +{ + int err; + int level = Z_DEFAULT_COMPRESSION; /* compression level */ + int strategy = Z_DEFAULT_STRATEGY; /* compression strategy */ + char *p = (char*)mode; + gz_stream *s; + char fmode[80]; /* copy of mode, without the compression level */ + char *m = fmode; + + if (!path || !mode) return Z_NULL; + + s = (gz_stream *)ALLOC(sizeof(gz_stream)); + if (!s) return Z_NULL; + + s->stream.zalloc = (alloc_func)0; + s->stream.zfree = (free_func)0; + s->stream.opaque = (voidpf)0; + s->stream.next_in = s->inbuf = Z_NULL; + s->stream.next_out = s->outbuf = Z_NULL; + s->stream.avail_in = s->stream.avail_out = 0; + s->file = NULL; + s->z_err = Z_OK; + s->z_eof = 0; + s->in = 0; + s->out = 0; + s->back = EOF; + s->crc = crc32(0L, Z_NULL, 0); + s->msg = NULL; + s->transparent = 0; + + s->path = (char*)ALLOC(strlen(path)+1); + if (s->path == NULL) { + return destroy(s), (gzFile)Z_NULL; + } + strcpy(s->path, path); /* do this early for debugging */ + + s->mode = '\0'; + do { + if (*p == 'r') s->mode = 'r'; + if (*p == 'w' || *p == 'a') s->mode = 'w'; + if (*p >= '0' && *p <= '9') { + level = *p - '0'; + } else if (*p == 'f') { + strategy = Z_FILTERED; + } else if (*p == 'h') { + strategy = Z_HUFFMAN_ONLY; + } else if (*p == 'R') { + strategy = Z_RLE; + } else { + *m++ = *p; /* copy the mode */ + } + } while (*p++ && m != fmode + sizeof(fmode)); + if (s->mode == '\0') return destroy(s), (gzFile)Z_NULL; + + if (s->mode == 'w') { +#ifdef NO_GZCOMPRESS + err = Z_STREAM_ERROR; +#else + err = deflateInit2(&(s->stream), level, + Z_DEFLATED, -MAX_WBITS, DEF_MEM_LEVEL, strategy); + /* windowBits is passed < 0 to suppress zlib header */ + + s->stream.next_out = s->outbuf = (Byte*)ALLOC(Z_BUFSIZE); +#endif + if (err != Z_OK || s->outbuf == Z_NULL) { + return destroy(s), (gzFile)Z_NULL; + } + } else { + s->stream.next_in = s->inbuf = (Byte*)ALLOC(Z_BUFSIZE); + + err = inflateInit2(&(s->stream), -MAX_WBITS); + /* windowBits is passed < 0 to tell that there is no zlib header. + * Note that in this case inflate *requires* an extra "dummy" byte + * after the compressed stream in order to complete decompression and + * return Z_STREAM_END. Here the gzip CRC32 ensures that 4 bytes are + * present after the compressed stream. + */ + if (err != Z_OK || s->inbuf == Z_NULL) { + return destroy(s), (gzFile)Z_NULL; + } + } + s->stream.avail_out = Z_BUFSIZE; + + errno = 0; + s->file = fd < 0 ? F_OPEN(path, fmode) : (FILE*)fdopen(fd, fmode); + + if (s->file == NULL) { + return destroy(s), (gzFile)Z_NULL; + } + if (s->mode == 'w') { + /* Write a very simple .gz header: + */ + fprintf(s->file, "%c%c%c%c%c%c%c%c%c%c", gz_magic[0], gz_magic[1], + Z_DEFLATED, 0 /*flags*/, 0,0,0,0 /*time*/, 0 /*xflags*/, OS_CODE); + s->start = 10L; + /* We use 10L instead of ftell(s->file) to because ftell causes an + * fflush on some systems. This version of the library doesn't use + * start anyway in write mode, so this initialization is not + * necessary. + */ + } else { + check_header(s); /* skip the .gz header */ + s->start = ftell(s->file) - s->stream.avail_in; + } + + return (gzFile)s; +} + +/* =========================================================================== + Opens a gzip (.gz) file for reading or writing. +*/ +gzFile ZEXPORT gzopen (path, mode) + const char *path; + const char *mode; +{ + return gz_open (path, mode, -1); +} + +/* =========================================================================== + Associate a gzFile with the file descriptor fd. fd is not dup'ed here + to mimic the behavio(u)r of fdopen. +*/ +gzFile ZEXPORT gzdopen (fd, mode) + int fd; + const char *mode; +{ + char name[46]; /* allow for up to 128-bit integers */ + + if (fd < 0) return (gzFile)Z_NULL; + sprintf(name, "<fd:%d>", fd); /* for debugging */ + + return gz_open (name, mode, fd); +} + +/* =========================================================================== + * Update the compression level and strategy + */ +int ZEXPORT gzsetparams (file, level, strategy) + gzFile file; + int level; + int strategy; +{ + gz_stream *s = (gz_stream*)file; + + if (s == NULL || s->mode != 'w') return Z_STREAM_ERROR; + + /* Make room to allow flushing */ + if (s->stream.avail_out == 0) { + + s->stream.next_out = s->outbuf; + if (fwrite(s->outbuf, 1, Z_BUFSIZE, s->file) != Z_BUFSIZE) { + s->z_err = Z_ERRNO; + } + s->stream.avail_out = Z_BUFSIZE; + } + + return deflateParams (&(s->stream), level, strategy); +} + +/* =========================================================================== + Read a byte from a gz_stream; update next_in and avail_in. Return EOF + for end of file. + IN assertion: the stream s has been sucessfully opened for reading. +*/ +local int get_byte(s) + gz_stream *s; +{ + if (s->z_eof) return EOF; + if (s->stream.avail_in == 0) { + errno = 0; + s->stream.avail_in = (uInt)fread(s->inbuf, 1, Z_BUFSIZE, s->file); + if (s->stream.avail_in == 0) { + s->z_eof = 1; + if (ferror(s->file)) s->z_err = Z_ERRNO; + return EOF; + } + s->stream.next_in = s->inbuf; + } + s->stream.avail_in--; + return *(s->stream.next_in)++; +} + +/* =========================================================================== + Check the gzip header of a gz_stream opened for reading. Set the stream + mode to transparent if the gzip magic header is not present; set s->err + to Z_DATA_ERROR if the magic header is present but the rest of the header + is incorrect. + IN assertion: the stream s has already been created sucessfully; + s->stream.avail_in is zero for the first time, but may be non-zero + for concatenated .gz files. +*/ +local void check_header(s) + gz_stream *s; +{ + int method; /* method byte */ + int flags; /* flags byte */ + uInt len; + int c; + + /* Assure two bytes in the buffer so we can peek ahead -- handle case + where first byte of header is at the end of the buffer after the last + gzip segment */ + len = s->stream.avail_in; + if (len < 2) { + if (len) s->inbuf[0] = s->stream.next_in[0]; + errno = 0; + len = (uInt)fread(s->inbuf + len, 1, Z_BUFSIZE >> len, s->file); + if (len == 0 && ferror(s->file)) s->z_err = Z_ERRNO; + s->stream.avail_in += len; + s->stream.next_in = s->inbuf; + if (s->stream.avail_in < 2) { + s->transparent = s->stream.avail_in; + return; + } + } + + /* Peek ahead to check the gzip magic header */ + if (s->stream.next_in[0] != gz_magic[0] || + s->stream.next_in[1] != gz_magic[1]) { + s->transparent = 1; + return; + } + s->stream.avail_in -= 2; + s->stream.next_in += 2; + + /* Check the rest of the gzip header */ + method = get_byte(s); + flags = get_byte(s); + if (method != Z_DEFLATED || (flags & RESERVED) != 0) { + s->z_err = Z_DATA_ERROR; + return; + } + + /* Discard time, xflags and OS code: */ + for (len = 0; len < 6; len++) (void)get_byte(s); + + if ((flags & EXTRA_FIELD) != 0) { /* skip the extra field */ + len = (uInt)get_byte(s); + len += ((uInt)get_byte(s))<<8; + /* len is garbage if EOF but the loop below will quit anyway */ + while (len-- != 0 && get_byte(s) != EOF) ; + } + if ((flags & ORIG_NAME) != 0) { /* skip the original file name */ + while ((c = get_byte(s)) != 0 && c != EOF) ; + } + if ((flags & COMMENT) != 0) { /* skip the .gz file comment */ + while ((c = get_byte(s)) != 0 && c != EOF) ; + } + if ((flags & HEAD_CRC) != 0) { /* skip the header crc */ + for (len = 0; len < 2; len++) (void)get_byte(s); + } + s->z_err = s->z_eof ? Z_DATA_ERROR : Z_OK; +} + + /* =========================================================================== + * Cleanup then free the given gz_stream. Return a zlib error code. + Try freeing in the reverse order of allocations. + */ +local int destroy (s) + gz_stream *s; +{ + int err = Z_OK; + + if (!s) return Z_STREAM_ERROR; + + TRYFREE(s->msg); + + if (s->stream.state != NULL) { + if (s->mode == 'w') { +#ifdef NO_GZCOMPRESS + err = Z_STREAM_ERROR; +#else + err = deflateEnd(&(s->stream)); +#endif + } else if (s->mode == 'r') { + err = inflateEnd(&(s->stream)); + } + } + if (s->file != NULL && fclose(s->file)) { +#ifdef ESPIPE + if (errno != ESPIPE) /* fclose is broken for pipes in HP/UX */ +#endif + err = Z_ERRNO; + } + if (s->z_err < 0) err = s->z_err; + + TRYFREE(s->inbuf); + TRYFREE(s->outbuf); + TRYFREE(s->path); + TRYFREE(s); + return err; +} + +/* =========================================================================== + Reads the given number of uncompressed bytes from the compressed file. + gzread returns the number of bytes actually read (0 for end of file). +*/ +int ZEXPORT gzread (file, buf, len) + gzFile file; + voidp buf; + unsigned len; +{ + gz_stream *s = (gz_stream*)file; + Bytef *start = (Bytef*)buf; /* starting point for crc computation */ + Byte *next_out; /* == stream.next_out but not forced far (for MSDOS) */ + + if (s == NULL || s->mode != 'r') return Z_STREAM_ERROR; + + if (s->z_err == Z_DATA_ERROR || s->z_err == Z_ERRNO) return -1; + if (s->z_err == Z_STREAM_END) return 0; /* EOF */ + + next_out = (Byte*)buf; + s->stream.next_out = (Bytef*)buf; + s->stream.avail_out = len; + + if (s->stream.avail_out && s->back != EOF) { + *next_out++ = s->back; + s->stream.next_out++; + s->stream.avail_out--; + s->back = EOF; + s->out++; + start++; + if (s->last) { + s->z_err = Z_STREAM_END; + return 1; + } + } + + while (s->stream.avail_out != 0) { + + if (s->transparent) { + /* Copy first the lookahead bytes: */ + uInt n = s->stream.avail_in; + if (n > s->stream.avail_out) n = s->stream.avail_out; + if (n > 0) { + zmemcpy(s->stream.next_out, s->stream.next_in, n); + next_out += n; + s->stream.next_out = next_out; + s->stream.next_in += n; + s->stream.avail_out -= n; + s->stream.avail_in -= n; + } + if (s->stream.avail_out > 0) { + s->stream.avail_out -= + (uInt)fread(next_out, 1, s->stream.avail_out, s->file); + } + len -= s->stream.avail_out; + s->in += len; + s->out += len; + if (len == 0) s->z_eof = 1; + return (int)len; + } + if (s->stream.avail_in == 0 && !s->z_eof) { + + errno = 0; + s->stream.avail_in = (uInt)fread(s->inbuf, 1, Z_BUFSIZE, s->file); + if (s->stream.avail_in == 0) { + s->z_eof = 1; + if (ferror(s->file)) { + s->z_err = Z_ERRNO; + break; + } + } + s->stream.next_in = s->inbuf; + } + s->in += s->stream.avail_in; + s->out += s->stream.avail_out; + s->z_err = inflate(&(s->stream), Z_NO_FLUSH); + s->in -= s->stream.avail_in; + s->out -= s->stream.avail_out; + + if (s->z_err == Z_STREAM_END) { + /* Check CRC and original size */ + s->crc = crc32(s->crc, start, (uInt)(s->stream.next_out - start)); + start = s->stream.next_out; + + if (getLong(s) != s->crc) { + s->z_err = Z_DATA_ERROR; + } else { + (void)getLong(s); + /* The uncompressed length returned by above getlong() may be + * different from s->out in case of concatenated .gz files. + * Check for such files: + */ + check_header(s); + if (s->z_err == Z_OK) { + inflateReset(&(s->stream)); + s->crc = crc32(0L, Z_NULL, 0); + } + } + } + if (s->z_err != Z_OK || s->z_eof) break; + } + s->crc = crc32(s->crc, start, (uInt)(s->stream.next_out - start)); + + if (len == s->stream.avail_out && + (s->z_err == Z_DATA_ERROR || s->z_err == Z_ERRNO)) + return -1; + return (int)(len - s->stream.avail_out); +} + + +/* =========================================================================== + Reads one byte from the compressed file. gzgetc returns this byte + or -1 in case of end of file or error. +*/ +int ZEXPORT gzgetc(file) + gzFile file; +{ + unsigned char c; + + return gzread(file, &c, 1) == 1 ? c : -1; +} + + +/* =========================================================================== + Push one byte back onto the stream. +*/ +int ZEXPORT gzungetc(c, file) + int c; + gzFile file; +{ + gz_stream *s = (gz_stream*)file; + + if (s == NULL || s->mode != 'r' || c == EOF || s->back != EOF) return EOF; + s->back = c; + s->out--; + s->last = (s->z_err == Z_STREAM_END); + if (s->last) s->z_err = Z_OK; + s->z_eof = 0; + return c; +} + + +/* =========================================================================== + Reads bytes from the compressed file until len-1 characters are + read, or a newline character is read and transferred to buf, or an + end-of-file condition is encountered. The string is then terminated + with a null character. + gzgets returns buf, or Z_NULL in case of error. + + The current implementation is not optimized at all. +*/ +char * ZEXPORT gzgets(file, buf, len) + gzFile file; + char *buf; + int len; +{ + char *b = buf; + if (buf == Z_NULL || len <= 0) return Z_NULL; + + while (--len > 0 && gzread(file, buf, 1) == 1 && *buf++ != '\n') ; + *buf = '\0'; + return b == buf && len > 0 ? Z_NULL : b; +} + + +#ifndef NO_GZCOMPRESS +/* =========================================================================== + Writes the given number of uncompressed bytes into the compressed file. + gzwrite returns the number of bytes actually written (0 in case of error). +*/ +int ZEXPORT gzwrite (file, buf, len) + gzFile file; + voidpc buf; + unsigned len; +{ + gz_stream *s = (gz_stream*)file; + + if (s == NULL || s->mode != 'w') return Z_STREAM_ERROR; + + s->stream.next_in = (Bytef*)buf; + s->stream.avail_in = len; + + 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->in += s->stream.avail_in; + s->out += s->stream.avail_out; + s->z_err = deflate(&(s->stream), Z_NO_FLUSH); + s->in -= s->stream.avail_in; + s->out -= s->stream.avail_out; + 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; + + buf[sizeof(buf) - 1] = 0; + va_start(va, format); +#ifdef NO_vsnprintf +# ifdef HAS_vsprintf_void + (void)vsprintf(buf, format, va); + va_end(va); + for (len = 0; len < sizeof(buf); len++) + if (buf[len] == 0) break; +# else + len = vsprintf(buf, format, va); + va_end(va); +# endif +#else +# ifdef HAS_vsnprintf_void + (void)vsnprintf(buf, sizeof(buf), format, va); + va_end(va); + len = strlen(buf); +# else + len = vsnprintf(buf, sizeof(buf), format, va); + va_end(va); +# endif +#endif + if (len <= 0 || len >= (int)sizeof(buf) || buf[sizeof(buf) - 1] != 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; + + buf[sizeof(buf) - 1] = 0; +#ifdef NO_snprintf +# ifdef HAS_sprintf_void + sprintf(buf, format, a1, a2, a3, a4, a5, a6, a7, a8, + a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20); + for (len = 0; len < sizeof(buf); len++) + if (buf[len] == 0) break; +# else + len = sprintf(buf, format, a1, a2, a3, a4, a5, a6, a7, a8, + a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20); +# endif +#else +# ifdef HAS_snprintf_void + 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); + len = strlen(buf); +# else + len = 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); +# endif +#endif + if (len <= 0 || len >= sizeof(buf) || buf[sizeof(buf) - 1] != 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->out += s->stream.avail_out; + s->z_err = deflate(&(s->stream), flush); + s->out -= s->stream.avail_out; + + /* 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_GZCOMPRESS */ + +/* =========================================================================== + 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_GZCOMPRESS + return -1L; +#else + if (whence == SEEK_SET) { + offset -= s->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 */ + if (s->inbuf == Z_NULL) return -1L; + 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 s->in; +#endif + } + /* Rest of function is for reading only */ + + /* compute absolute position */ + if (whence == SEEK_CUR) { + offset += s->out; + } + if (offset < 0) return -1L; + + if (s->transparent) { + /* map to fseek */ + s->back = EOF; + s->stream.avail_in = 0; + s->stream.next_in = s->inbuf; + if (fseek(s->file, offset, SEEK_SET) < 0) return -1L; + + s->in = s->out = offset; + return offset; + } + + /* For a negative seek, rewind and use positive seek */ + if (offset >= s->out) { + offset -= s->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); + if (s->outbuf == Z_NULL) return -1L; + } + if (offset && s->back != EOF) { + s->back = EOF; + s->out++; + offset--; + if (s->last) s->z_err = Z_STREAM_END; + } + 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 s->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->back = EOF; + s->stream.avail_in = 0; + s->stream.next_in = s->inbuf; + s->crc = crc32(0L, Z_NULL, 0); + if (!s->transparent) (void)inflateReset(&s->stream); + s->in = 0; + s->out = 0; + return fseek(s->file, s->start, 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; + + /* With concatenated compressed files that can have embedded + * crc trailers, z_eof is no longer the only/best indicator of EOF + * on a gz_stream. Handle end-of-stream error explicitly here. + */ + if (s == NULL || s->mode != 'r') return 0; + if (s->z_eof) return 1; + return s->z_err == Z_STREAM_END; +} + +/* =========================================================================== + Returns 1 if reading and doing so transparently, otherwise zero. +*/ +int ZEXPORT gzdirect (file) + gzFile file; +{ + gz_stream *s = (gz_stream*)file; + + if (s == NULL || s->mode != 'r') return 0; + return s->transparent; +} + +/* =========================================================================== + 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; +{ + gz_stream *s = (gz_stream*)file; + + if (s == NULL) return Z_STREAM_ERROR; + + if (s->mode == 'w') { +#ifdef NO_GZCOMPRESS + return Z_STREAM_ERROR; +#else + if (do_flush (file, Z_FINISH) != Z_OK) + return destroy((gz_stream*)file); + + putLong (s->file, s->crc); + putLong (s->file, (uLong)(s->in & 0xffffffff)); +#endif + } + return destroy((gz_stream*)file); +} + +#ifdef STDC +# define zstrerror(errnum) strerror(errnum) +#else +# define zstrerror(errnum) "" +#endif + +/* =========================================================================== + Returns the error message for the last error which occurred on the + given compressed file. errnum is set to zlib error number. If an + error occurred 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); + if (s->msg == Z_NULL) return (const char*)ERR_MSG(Z_MEM_ERROR); + strcpy(s->msg, s->path); + strcat(s->msg, ": "); + strcat(s->msg, m); + return (const char*)s->msg; +} + +/* =========================================================================== + Clear the error and end-of-file flags, and do the same for the real file. +*/ +void ZEXPORT gzclearerr (file) + gzFile file; +{ + gz_stream *s = (gz_stream*)file; + + if (s == NULL) return; + if (s->z_err != Z_STREAM_END) s->z_err = Z_OK; + s->z_eof = 0; + clearerr(s->file); +} |