/* gzread.c -- zlib functions for reading gzip files | |
* Copyright (C) 2004, 2005, 2010 Mark Adler | |
* For conditions of distribution and use, see copyright notice in zlib.h | |
*/ | |
#include "gzguts.h" | |
/* Local functions */ | |
local int gz_load OF((gz_statep, unsigned char *, unsigned, unsigned *)); | |
local int gz_avail OF((gz_statep)); | |
local int gz_next4 OF((gz_statep, unsigned long *)); | |
local int gz_head OF((gz_statep)); | |
local int gz_decomp OF((gz_statep)); | |
local int gz_make OF((gz_statep)); | |
local int gz_skip OF((gz_statep, z_off64_t)); | |
/* Use read() to load a buffer -- return -1 on error, otherwise 0. Read from | |
state->fd, and update state->eof, state->err, and state->msg as appropriate. | |
This function needs to loop on read(), since read() is not guaranteed to | |
read the number of bytes requested, depending on the type of descriptor. */ | |
local int gz_load(state, buf, len, have) | |
gz_statep state; | |
unsigned char *buf; | |
unsigned len; | |
unsigned *have; | |
{ | |
int ret; | |
*have = 0; | |
do { | |
ret = read(state->fd, buf + *have, len - *have); | |
if (ret <= 0) | |
break; | |
*have += ret; | |
} while (*have < len); | |
if (ret < 0) { | |
gz_error(state, Z_ERRNO, zstrerror()); | |
return -1; | |
} | |
if (ret == 0) | |
state->eof = 1; | |
return 0; | |
} | |
/* Load up input buffer and set eof flag if last data loaded -- return -1 on | |
error, 0 otherwise. Note that the eof flag is set when the end of the input | |
file is reached, even though there may be unused data in the buffer. Once | |
that data has been used, no more attempts will be made to read the file. | |
gz_avail() assumes that strm->avail_in == 0. */ | |
local int gz_avail(state) | |
gz_statep state; | |
{ | |
z_streamp strm = &(state->strm); | |
if (state->err != Z_OK) | |
return -1; | |
if (state->eof == 0) { | |
if (gz_load(state, state->in, state->size, | |
(unsigned *)&(strm->avail_in)) == -1) | |
return -1; | |
strm->next_in = state->in; | |
} | |
return 0; | |
} | |
/* Get next byte from input, or -1 if end or error. */ | |
#define NEXT() ((strm->avail_in == 0 && gz_avail(state) == -1) ? -1 : \ | |
(strm->avail_in == 0 ? -1 : \ | |
(strm->avail_in--, *(strm->next_in)++))) | |
/* Get a four-byte little-endian integer and return 0 on success and the value | |
in *ret. Otherwise -1 is returned and *ret is not modified. */ | |
local int gz_next4(state, ret) | |
gz_statep state; | |
unsigned long *ret; | |
{ | |
int ch; | |
unsigned long val; | |
z_streamp strm = &(state->strm); | |
val = NEXT(); | |
val += (unsigned)NEXT() << 8; | |
val += (unsigned long)NEXT() << 16; | |
ch = NEXT(); | |
if (ch == -1) | |
return -1; | |
val += (unsigned long)ch << 24; | |
*ret = val; | |
return 0; | |
} | |
/* Look for gzip header, set up for inflate or copy. state->have must be zero. | |
If this is the first time in, allocate required memory. state->how will be | |
left unchanged if there is no more input data available, will be set to COPY | |
if there is no gzip header and direct copying will be performed, or it will | |
be set to GZIP for decompression, and the gzip header will be skipped so | |
that the next available input data is the raw deflate stream. If direct | |
copying, then leftover input data from the input buffer will be copied to | |
the output buffer. In that case, all further file reads will be directly to | |
either the output buffer or a user buffer. If decompressing, the inflate | |
state and the check value will be initialized. gz_head() will return 0 on | |
success or -1 on failure. Failures may include read errors or gzip header | |
errors. */ | |
local int gz_head(state) | |
gz_statep state; | |
{ | |
z_streamp strm = &(state->strm); | |
int flags; | |
unsigned len; | |
/* allocate read buffers and inflate memory */ | |
if (state->size == 0) { | |
/* allocate buffers */ | |
state->in = malloc(state->want); | |
state->out = malloc(state->want << 1); | |
if (state->in == NULL || state->out == NULL) { | |
if (state->out != NULL) | |
free(state->out); | |
if (state->in != NULL) | |
free(state->in); | |
gz_error(state, Z_MEM_ERROR, "out of memory"); | |
return -1; | |
} | |
state->size = state->want; | |
/* allocate inflate memory */ | |
state->strm.zalloc = Z_NULL; | |
state->strm.zfree = Z_NULL; | |
state->strm.opaque = Z_NULL; | |
state->strm.avail_in = 0; | |
state->strm.next_in = Z_NULL; | |
if (inflateInit2(&(state->strm), -15) != Z_OK) { /* raw inflate */ | |
free(state->out); | |
free(state->in); | |
state->size = 0; | |
gz_error(state, Z_MEM_ERROR, "out of memory"); | |
return -1; | |
} | |
} | |
/* get some data in the input buffer */ | |
if (strm->avail_in == 0) { | |
if (gz_avail(state) == -1) | |
return -1; | |
if (strm->avail_in == 0) | |
return 0; | |
} | |
/* look for the gzip magic header bytes 31 and 139 */ | |
if (strm->next_in[0] == 31) { | |
strm->avail_in--; | |
strm->next_in++; | |
if (strm->avail_in == 0 && gz_avail(state) == -1) | |
return -1; | |
if (strm->avail_in && strm->next_in[0] == 139) { | |
/* we have a gzip header, woo hoo! */ | |
strm->avail_in--; | |
strm->next_in++; | |
/* skip rest of header */ | |
if (NEXT() != 8) { /* compression method */ | |
gz_error(state, Z_DATA_ERROR, "unknown compression method"); | |
return -1; | |
} | |
flags = NEXT(); | |
if (flags & 0xe0) { /* reserved flag bits */ | |
gz_error(state, Z_DATA_ERROR, "unknown header flags set"); | |
return -1; | |
} | |
NEXT(); /* modification time */ | |
NEXT(); | |
NEXT(); | |
NEXT(); | |
NEXT(); /* extra flags */ | |
NEXT(); /* operating system */ | |
if (flags & 4) { /* extra field */ | |
len = (unsigned)NEXT(); | |
len += (unsigned)NEXT() << 8; | |
while (len--) | |
if (NEXT() < 0) | |
break; | |
} | |
if (flags & 8) /* file name */ | |
while (NEXT() > 0) | |
; | |
if (flags & 16) /* comment */ | |
while (NEXT() > 0) | |
; | |
if (flags & 2) { /* header crc */ | |
NEXT(); | |
NEXT(); | |
} | |
/* an unexpected end of file is not checked for here -- it will be | |
noticed on the first request for uncompressed data */ | |
/* set up for decompression */ | |
inflateReset(strm); | |
strm->adler = crc32(0L, Z_NULL, 0); | |
state->how = GZIP; | |
state->direct = 0; | |
return 0; | |
} | |
else { | |
/* not a gzip file -- save first byte (31) and fall to raw i/o */ | |
state->out[0] = 31; | |
state->have = 1; | |
} | |
} | |
/* doing raw i/o, save start of raw data for seeking, copy any leftover | |
input to output -- this assumes that the output buffer is larger than | |
the input buffer, which also assures space for gzungetc() */ | |
state->raw = state->pos; | |
state->next = state->out; | |
if (strm->avail_in) { | |
memcpy(state->next + state->have, strm->next_in, strm->avail_in); | |
state->have += strm->avail_in; | |
strm->avail_in = 0; | |
} | |
state->how = COPY; | |
state->direct = 1; | |
return 0; | |
} | |
/* Decompress from input to the provided next_out and avail_out in the state. | |
If the end of the compressed data is reached, then verify the gzip trailer | |
check value and length (modulo 2^32). state->have and state->next are set | |
to point to the just decompressed data, and the crc is updated. If the | |
trailer is verified, state->how is reset to LOOK to look for the next gzip | |
stream or raw data, once state->have is depleted. Returns 0 on success, -1 | |
on failure. Failures may include invalid compressed data or a failed gzip | |
trailer verification. */ | |
local int gz_decomp(state) | |
gz_statep state; | |
{ | |
int ret; | |
unsigned had; | |
unsigned long crc, len; | |
z_streamp strm = &(state->strm); | |
/* fill output buffer up to end of deflate stream */ | |
had = strm->avail_out; | |
do { | |
/* get more input for inflate() */ | |
if (strm->avail_in == 0 && gz_avail(state) == -1) | |
return -1; | |
if (strm->avail_in == 0) { | |
gz_error(state, Z_DATA_ERROR, "unexpected end of file"); | |
return -1; | |
} | |
/* decompress and handle errors */ | |
ret = inflate(strm, Z_NO_FLUSH); | |
if (ret == Z_STREAM_ERROR || ret == Z_NEED_DICT) { | |
gz_error(state, Z_STREAM_ERROR, | |
"internal error: inflate stream corrupt"); | |
return -1; | |
} | |
if (ret == Z_MEM_ERROR) { | |
gz_error(state, Z_MEM_ERROR, "out of memory"); | |
return -1; | |
} | |
if (ret == Z_DATA_ERROR) { /* deflate stream invalid */ | |
gz_error(state, Z_DATA_ERROR, | |
strm->msg == NULL ? "compressed data error" : strm->msg); | |
return -1; | |
} | |
} while (strm->avail_out && ret != Z_STREAM_END); | |
/* update available output and crc check value */ | |
state->have = had - strm->avail_out; | |
state->next = strm->next_out - state->have; | |
strm->adler = crc32(strm->adler, state->next, state->have); | |
/* check gzip trailer if at end of deflate stream */ | |
if (ret == Z_STREAM_END) { | |
if (gz_next4(state, &crc) == -1 || gz_next4(state, &len) == -1) { | |
gz_error(state, Z_DATA_ERROR, "unexpected end of file"); | |
return -1; | |
} | |
if (crc != strm->adler) { | |
gz_error(state, Z_DATA_ERROR, "incorrect data check"); | |
return -1; | |
} | |
if (len != (strm->total_out & 0xffffffffL)) { | |
gz_error(state, Z_DATA_ERROR, "incorrect length check"); | |
return -1; | |
} | |
state->how = LOOK; /* ready for next stream, once have is 0 (leave | |
state->direct unchanged to remember how) */ | |
} | |
/* good decompression */ | |
return 0; | |
} | |
/* Make data and put in the output buffer. Assumes that state->have == 0. | |
Data is either copied from the input file or decompressed from the input | |
file depending on state->how. If state->how is LOOK, then a gzip header is | |
looked for (and skipped if found) to determine wither to copy or decompress. | |
Returns -1 on error, otherwise 0. gz_make() will leave state->have as COPY | |
or GZIP unless the end of the input file has been reached and all data has | |
been processed. */ | |
local int gz_make(state) | |
gz_statep state; | |
{ | |
z_streamp strm = &(state->strm); | |
if (state->how == LOOK) { /* look for gzip header */ | |
if (gz_head(state) == -1) | |
return -1; | |
if (state->have) /* got some data from gz_head() */ | |
return 0; | |
} | |
if (state->how == COPY) { /* straight copy */ | |
if (gz_load(state, state->out, state->size << 1, &(state->have)) == -1) | |
return -1; | |
state->next = state->out; | |
} | |
else if (state->how == GZIP) { /* decompress */ | |
strm->avail_out = state->size << 1; | |
strm->next_out = state->out; | |
if (gz_decomp(state) == -1) | |
return -1; | |
} | |
return 0; | |
} | |
/* Skip len uncompressed bytes of output. Return -1 on error, 0 on success. */ | |
local int gz_skip(state, len) | |
gz_statep state; | |
z_off64_t len; | |
{ | |
unsigned n; | |
/* skip over len bytes or reach end-of-file, whichever comes first */ | |
while (len) | |
/* skip over whatever is in output buffer */ | |
if (state->have) { | |
n = GT_OFF(state->have) || (z_off64_t)state->have > len ? | |
(unsigned)len : state->have; | |
state->have -= n; | |
state->next += n; | |
state->pos += n; | |
len -= n; | |
} | |
/* output buffer empty -- return if we're at the end of the input */ | |
else if (state->eof && state->strm.avail_in == 0) | |
break; | |
/* need more data to skip -- load up output buffer */ | |
else { | |
/* get more output, looking for header if required */ | |
if (gz_make(state) == -1) | |
return -1; | |
} | |
return 0; | |
} | |
/* -- see zlib.h -- */ | |
int ZEXPORT gzread(file, buf, len) | |
gzFile file; | |
voidp buf; | |
unsigned len; | |
{ | |
unsigned got, n; | |
gz_statep state; | |
z_streamp strm; | |
/* get internal structure */ | |
if (file == NULL) | |
return -1; | |
state = (gz_statep)file; | |
strm = &(state->strm); | |
/* check that we're reading and that there's no error */ | |
if (state->mode != GZ_READ || state->err != Z_OK) | |
return -1; | |
/* since an int is returned, make sure len fits in one, otherwise return | |
with an error (this avoids the flaw in the interface) */ | |
if ((int)len < 0) { | |
gz_error(state, Z_BUF_ERROR, "requested length does not fit in int"); | |
return -1; | |
} | |
/* if len is zero, avoid unnecessary operations */ | |
if (len == 0) | |
return 0; | |
/* process a skip request */ | |
if (state->seek) { | |
state->seek = 0; | |
if (gz_skip(state, state->skip) == -1) | |
return -1; | |
} | |
/* get len bytes to buf, or less than len if at the end */ | |
got = 0; | |
do { | |
/* first just try copying data from the output buffer */ | |
if (state->have) { | |
n = state->have > len ? len : state->have; | |
memcpy(buf, state->next, n); | |
state->next += n; | |
state->have -= n; | |
} | |
/* output buffer empty -- return if we're at the end of the input */ | |
else if (state->eof && strm->avail_in == 0) | |
break; | |
/* need output data -- for small len or new stream load up our output | |
buffer */ | |
else if (state->how == LOOK || len < (state->size << 1)) { | |
/* get more output, looking for header if required */ | |
if (gz_make(state) == -1) | |
return -1; | |
continue; /* no progress yet -- go back to memcpy() above */ | |
/* the copy above assures that we will leave with space in the | |
output buffer, allowing at least one gzungetc() to succeed */ | |
} | |
/* large len -- read directly into user buffer */ | |
else if (state->how == COPY) { /* read directly */ | |
if (gz_load(state, buf, len, &n) == -1) | |
return -1; | |
} | |
/* large len -- decompress directly into user buffer */ | |
else { /* state->how == GZIP */ | |
strm->avail_out = len; | |
strm->next_out = buf; | |
if (gz_decomp(state) == -1) | |
return -1; | |
n = state->have; | |
state->have = 0; | |
} | |
/* update progress */ | |
len -= n; | |
buf = (char *)buf + n; | |
got += n; | |
state->pos += n; | |
} while (len); | |
/* return number of bytes read into user buffer (will fit in int) */ | |
return (int)got; | |
} | |
/* -- see zlib.h -- */ | |
int ZEXPORT gzgetc(file) | |
gzFile file; | |
{ | |
int ret; | |
unsigned char buf[1]; | |
gz_statep state; | |
/* get internal structure */ | |
if (file == NULL) | |
return -1; | |
state = (gz_statep)file; | |
/* check that we're reading and that there's no error */ | |
if (state->mode != GZ_READ || state->err != Z_OK) | |
return -1; | |
/* try output buffer (no need to check for skip request) */ | |
if (state->have) { | |
state->have--; | |
state->pos++; | |
return *(state->next)++; | |
} | |
/* nothing there -- try gzread() */ | |
ret = gzread(file, buf, 1); | |
return ret < 1 ? -1 : buf[0]; | |
} | |
/* -- see zlib.h -- */ | |
int ZEXPORT gzungetc(c, file) | |
int c; | |
gzFile file; | |
{ | |
gz_statep state; | |
/* get internal structure */ | |
if (file == NULL) | |
return -1; | |
state = (gz_statep)file; | |
/* check that we're reading and that there's no error */ | |
if (state->mode != GZ_READ || state->err != Z_OK) | |
return -1; | |
/* process a skip request */ | |
if (state->seek) { | |
state->seek = 0; | |
if (gz_skip(state, state->skip) == -1) | |
return -1; | |
} | |
/* can't push EOF */ | |
if (c < 0) | |
return -1; | |
/* if output buffer empty, put byte at end (allows more pushing) */ | |
if (state->have == 0) { | |
state->have = 1; | |
state->next = state->out + (state->size << 1) - 1; | |
state->next[0] = c; | |
state->pos--; | |
return c; | |
} | |
/* if no room, give up (must have already done a gzungetc()) */ | |
if (state->have == (state->size << 1)) { | |
gz_error(state, Z_BUF_ERROR, "out of room to push characters"); | |
return -1; | |
} | |
/* slide output data if needed and insert byte before existing data */ | |
if (state->next == state->out) { | |
unsigned char *src = state->out + state->have; | |
unsigned char *dest = state->out + (state->size << 1); | |
while (src > state->out) | |
*--dest = *--src; | |
state->next = dest; | |
} | |
state->have++; | |
state->next--; | |
state->next[0] = c; | |
state->pos--; | |
return c; | |
} | |
/* -- see zlib.h -- */ | |
char * ZEXPORT gzgets(file, buf, len) | |
gzFile file; | |
char *buf; | |
int len; | |
{ | |
unsigned left, n; | |
char *str; | |
unsigned char *eol; | |
gz_statep state; | |
/* check parameters and get internal structure */ | |
if (file == NULL || buf == NULL || len < 1) | |
return NULL; | |
state = (gz_statep)file; | |
/* check that we're reading and that there's no error */ | |
if (state->mode != GZ_READ || state->err != Z_OK) | |
return NULL; | |
/* process a skip request */ | |
if (state->seek) { | |
state->seek = 0; | |
if (gz_skip(state, state->skip) == -1) | |
return NULL; | |
} | |
/* copy output bytes up to new line or len - 1, whichever comes first -- | |
append a terminating zero to the string (we don't check for a zero in | |
the contents, let the user worry about that) */ | |
str = buf; | |
left = (unsigned)len - 1; | |
if (left) do { | |
/* assure that something is in the output buffer */ | |
if (state->have == 0) { | |
if (gz_make(state) == -1) | |
return NULL; /* error */ | |
if (state->have == 0) { /* end of file */ | |
if (buf == str) /* got bupkus */ | |
return NULL; | |
break; /* got something -- return it */ | |
} | |
} | |
/* look for end-of-line in current output buffer */ | |
n = state->have > left ? left : state->have; | |
eol = memchr(state->next, '\n', n); | |
if (eol != NULL) | |
n = (unsigned)(eol - state->next) + 1; | |
/* copy through end-of-line, or remainder if not found */ | |
memcpy(buf, state->next, n); | |
state->have -= n; | |
state->next += n; | |
state->pos += n; | |
left -= n; | |
buf += n; | |
} while (left && eol == NULL); | |
/* found end-of-line or out of space -- terminate string and return it */ | |
buf[0] = 0; | |
return str; | |
} | |
/* -- see zlib.h -- */ | |
int ZEXPORT gzdirect(file) | |
gzFile file; | |
{ | |
gz_statep state; | |
/* get internal structure */ | |
if (file == NULL) | |
return 0; | |
state = (gz_statep)file; | |
/* check that we're reading */ | |
if (state->mode != GZ_READ) | |
return 0; | |
/* if the state is not known, but we can find out, then do so (this is | |
mainly for right after a gzopen() or gzdopen()) */ | |
if (state->how == LOOK && state->have == 0) | |
(void)gz_head(state); | |
/* return 1 if reading direct, 0 if decompressing a gzip stream */ | |
return state->direct; | |
} | |
/* -- see zlib.h -- */ | |
int ZEXPORT gzclose_r(file) | |
gzFile file; | |
{ | |
int ret; | |
gz_statep state; | |
/* get internal structure */ | |
if (file == NULL) | |
return Z_STREAM_ERROR; | |
state = (gz_statep)file; | |
/* check that we're reading */ | |
if (state->mode != GZ_READ) | |
return Z_STREAM_ERROR; | |
/* free memory and close file */ | |
if (state->size) { | |
inflateEnd(&(state->strm)); | |
free(state->out); | |
free(state->in); | |
} | |
gz_error(state, Z_OK, NULL); | |
free(state->path); | |
ret = close(state->fd); | |
free(state); | |
return ret ? Z_ERRNO : Z_OK; | |
} |