mirror of https://github.com/madler/zlib.git
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
523 lines
15 KiB
523 lines
15 KiB
/* gzio.c -- IO on .gz files |
|
* Copyright (C) 1995-1996 Jean-loup Gailly. |
|
* For conditions of distribution and use, see copyright notice in zlib.h |
|
*/ |
|
|
|
/* $Id: gzio.c,v 1.14 1996/07/24 13:41:01 me Exp $ */ |
|
|
|
#include <stdio.h> |
|
|
|
#include "zutil.h" |
|
|
|
struct internal_state {int dummy;}; /* for buggy compilers */ |
|
|
|
#define Z_BUFSIZE 4096 |
|
|
|
#define ALLOC(size) malloc(size) |
|
#define TRYFREE(p) {if (p) free(p);} |
|
|
|
static int gz_magic[2] = {0x1f, 0x8b}; /* gzip magic header */ |
|
|
|
/* gzip flag byte */ |
|
#define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */ |
|
#define HEAD_CRC 0x02 /* bit 1 set: header CRC present */ |
|
#define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */ |
|
#define ORIG_NAME 0x08 /* bit 3 set: original file name present */ |
|
#define COMMENT 0x10 /* bit 4 set: file comment present */ |
|
#define RESERVED 0xE0 /* bits 5..7: reserved */ |
|
|
|
typedef struct gz_stream { |
|
z_stream stream; |
|
int z_err; /* error code for last stream operation */ |
|
int z_eof; /* set if end of input file */ |
|
FILE *file; /* .gz file */ |
|
Byte *inbuf; /* input buffer */ |
|
Byte *outbuf; /* output buffer */ |
|
uLong crc; /* crc32 of uncompressed data */ |
|
char *msg; /* error message */ |
|
char *path; /* path name for debugging only */ |
|
int transparent; /* 1 if input file is not a .gz file */ |
|
char mode; /* 'w' or 'r' */ |
|
} gz_stream; |
|
|
|
|
|
local gzFile gz_open OF((const char *path, const char *mode, int fd)); |
|
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 return NULL if the file could not be opened or if there was |
|
insufficient memory to allocate the (de)compression state; errno |
|
can be checked to distinguish the two cases (if errno is zero, the |
|
zlib error is Z_MEM_ERROR). |
|
*/ |
|
local gzFile gz_open (path, mode, fd) |
|
const char *path; |
|
const char *mode; |
|
int fd; |
|
{ |
|
int err; |
|
int level = Z_DEFAULT_COMPRESSION; /* compression level */ |
|
char *p = (char*)mode; |
|
gz_stream *s; |
|
char fmode[80]; /* copy of mode, without the compression level */ |
|
char *m = fmode; |
|
|
|
if (!path || !mode) return Z_NULL; |
|
|
|
s = (gz_stream *)ALLOC(sizeof(gz_stream)); |
|
if (!s) return Z_NULL; |
|
|
|
s->stream.zalloc = (alloc_func)0; |
|
s->stream.zfree = (free_func)0; |
|
s->stream.opaque = (voidpf)0; |
|
s->stream.next_in = s->inbuf = Z_NULL; |
|
s->stream.next_out = s->outbuf = Z_NULL; |
|
s->stream.avail_in = s->stream.avail_out = 0; |
|
s->file = NULL; |
|
s->z_err = Z_OK; |
|
s->z_eof = 0; |
|
s->crc = crc32(0L, Z_NULL, 0); |
|
s->msg = NULL; |
|
s->transparent = 0; |
|
|
|
s->path = (char*)ALLOC(strlen(path)+1); |
|
if (s->path == NULL) { |
|
return destroy(s), (gzFile)Z_NULL; |
|
} |
|
strcpy(s->path, path); /* do this early for debugging */ |
|
|
|
s->mode = '\0'; |
|
do { |
|
if (*p == 'r') s->mode = 'r'; |
|
if (*p == 'w' || *p == 'a') s->mode = 'w'; |
|
if (*p >= '0' && *p <= '9') { |
|
level = *p - '0'; |
|
} else { |
|
*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') { |
|
err = deflateInit2(&(s->stream), level, |
|
Z_DEFLATED, -MAX_WBITS, DEF_MEM_LEVEL, 0); |
|
/* windowBits is passed < 0 to suppress zlib header */ |
|
|
|
s->stream.next_out = s->outbuf = (Byte*)ALLOC(Z_BUFSIZE); |
|
|
|
if (err != Z_OK || s->outbuf == Z_NULL) { |
|
return destroy(s), (gzFile)Z_NULL; |
|
} |
|
} else { |
|
err = inflateInit2(&(s->stream), -MAX_WBITS); |
|
s->stream.next_in = s->inbuf = (Byte*)ALLOC(Z_BUFSIZE); |
|
|
|
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 ? FOPEN(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); |
|
} else { |
|
check_header(s); /* skip the .gz header */ |
|
} |
|
return (gzFile)s; |
|
} |
|
|
|
/* =========================================================================== |
|
Opens a gzip (.gz) file for reading or writing. |
|
*/ |
|
gzFile 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 gzdopen (fd, mode) |
|
int fd; |
|
const char *mode; |
|
{ |
|
char name[20]; |
|
|
|
if (fd < 0) return (gzFile)Z_NULL; |
|
sprintf(name, "<fd:%d>", fd); /* for debugging */ |
|
|
|
return gz_open (name, mode, fd); |
|
} |
|
|
|
/* =========================================================================== |
|
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 = 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; |
|
|
|
/* Check the gzip magic header */ |
|
for (len = 0; len < 2; len++) { |
|
c = get_byte(s); |
|
if (c != gz_magic[len]) { |
|
s->transparent = 1; |
|
if (c != EOF) s->stream.avail_in++, s->stream.next_in--; |
|
s->z_err = s->stream.avail_in != 0 ? Z_OK : Z_STREAM_END; |
|
return; |
|
} |
|
} |
|
method = get_byte(s); |
|
flags = get_byte(s); |
|
if (method != Z_DEFLATED || (flags & RESERVED) != 0) { |
|
s->z_err = Z_DATA_ERROR; |
|
return; |
|
} |
|
|
|
/* Discard time, xflags and OS code: */ |
|
for (len = 0; len < 6; len++) (void)get_byte(s); |
|
|
|
if ((flags & EXTRA_FIELD) != 0) { /* skip the extra field */ |
|
len = (uInt)get_byte(s); |
|
len += ((uInt)get_byte(s))<<8; |
|
/* len is garbage if EOF but the loop below will quit anyway */ |
|
while (len-- != 0 && get_byte(s) != EOF) ; |
|
} |
|
if ((flags & ORIG_NAME) != 0) { /* skip the original file name */ |
|
while ((c = get_byte(s)) != 0 && c != EOF) ; |
|
} |
|
if ((flags & COMMENT) != 0) { /* skip the .gz file comment */ |
|
while ((c = get_byte(s)) != 0 && c != EOF) ; |
|
} |
|
if ((flags & HEAD_CRC) != 0) { /* skip the header crc */ |
|
for (len = 0; len < 2; len++) (void)get_byte(s); |
|
} |
|
s->z_err = s->z_eof ? Z_DATA_ERROR : Z_OK; |
|
} |
|
|
|
/* =========================================================================== |
|
* Cleanup then free the given gz_stream. Return a zlib error code. |
|
Try freeing in the reverse order of allocations. |
|
*/ |
|
local int destroy (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') { |
|
err = deflateEnd(&(s->stream)); |
|
} else if (s->mode == 'r') { |
|
err = inflateEnd(&(s->stream)); |
|
} |
|
} |
|
if (s->file != NULL && fclose(s->file)) { |
|
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 gzread (file, buf, len) |
|
gzFile file; |
|
voidp buf; |
|
unsigned len; |
|
{ |
|
gz_stream *s = (gz_stream*)file; |
|
Bytef *start = 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 */ |
|
|
|
s->stream.next_out = next_out = buf; |
|
s->stream.avail_out = len; |
|
|
|
while (s->stream.avail_out != 0) { |
|
|
|
if (s->transparent) { |
|
/* Copy first the lookahead bytes: */ |
|
uInt n = s->stream.avail_in; |
|
if (n > s->stream.avail_out) n = s->stream.avail_out; |
|
if (n > 0) { |
|
zmemcpy(s->stream.next_out, s->stream.next_in, n); |
|
next_out += n; |
|
s->stream.next_out = next_out; |
|
s->stream.next_in += n; |
|
s->stream.avail_out -= n; |
|
s->stream.avail_in -= n; |
|
} |
|
if (s->stream.avail_out > 0) { |
|
s->stream.avail_out -= fread(next_out, 1, s->stream.avail_out, |
|
s->file); |
|
} |
|
return (int)(len - s->stream.avail_out); |
|
} |
|
if (s->stream.avail_in == 0 && !s->z_eof) { |
|
|
|
errno = 0; |
|
s->stream.avail_in = fread(s->inbuf, 1, Z_BUFSIZE, s->file); |
|
if (s->stream.avail_in == 0) { |
|
s->z_eof = 1; |
|
if (ferror(s->file)) { |
|
s->z_err = Z_ERRNO; |
|
break; |
|
} |
|
} |
|
s->stream.next_in = s->inbuf; |
|
} |
|
s->z_err = inflate(&(s->stream), Z_NO_FLUSH); |
|
|
|
if (s->z_err == Z_STREAM_END) { |
|
/* Check CRC and original size */ |
|
s->crc = crc32(s->crc, start, (uInt)(s->stream.next_out - start)); |
|
start = s->stream.next_out; |
|
|
|
if (getLong(s) != s->crc || getLong(s) != s->stream.total_out) { |
|
s->z_err = Z_DATA_ERROR; |
|
} else { |
|
/* Check for concatenated .gz 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)); |
|
|
|
return (int)(len - s->stream.avail_out); |
|
} |
|
|
|
/* =========================================================================== |
|
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 gzwrite (file, buf, len) |
|
gzFile file; |
|
const voidp buf; |
|
unsigned len; |
|
{ |
|
gz_stream *s = (gz_stream*)file; |
|
|
|
if (s == NULL || s->mode != 'w') return Z_STREAM_ERROR; |
|
|
|
s->stream.next_in = 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, buf, len); |
|
|
|
return (int)(len - s->stream.avail_in); |
|
} |
|
|
|
/* =========================================================================== |
|
Flushes all pending output into the compressed file. The parameter |
|
flush is as in the deflate() function. |
|
gzflush should be called only when strictly necessary because it can |
|
degrade compression. |
|
*/ |
|
int gzflush (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); |
|
|
|
/* 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; |
|
} |
|
fflush(s->file); |
|
return s->z_err == Z_STREAM_END ? Z_OK : s->z_err; |
|
} |
|
|
|
/* =========================================================================== |
|
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 |
|
*/ |
|
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 gzclose (file) |
|
gzFile file; |
|
{ |
|
int err; |
|
gz_stream *s = (gz_stream*)file; |
|
|
|
if (s == NULL) return Z_STREAM_ERROR; |
|
|
|
if (s->mode == 'w') { |
|
err = gzflush (file, Z_FINISH); |
|
if (err != Z_OK) return destroy(file); |
|
|
|
putLong (s->file, s->crc); |
|
putLong (s->file, s->stream.total_in); |
|
|
|
} |
|
return destroy(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* 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; |
|
}
|
|
|