gzread.c
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/* gzread.c -- zlib functions for reading gzip files
* Copyright (C) 2004, 2005, 2010, 2011, 2012, 2013, 2016 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_look OF((gz_statep));
local int gz_decomp OF((gz_statep));
local int gz_fetch OF((gz_statep));
local int gz_skip OF((gz_statep, z_off64_t));
local z_size_t gz_read OF((gz_statep, voidp, z_size_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;
unsigned get, max = ((unsigned)-1 >> 2) + 1;
*have = 0;
do {
get = len - *have;
if (get > max)
get = max;
ret = read(state->fd, buf + *have, get);
if (ret <= 0)
break;
*have += (unsigned)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.
If strm->avail_in != 0, then the current data is moved to the beginning of
the input buffer, and then the remainder of the buffer is loaded with the
available data from the input file. */
local int gz_avail(state)
gz_statep state;
{
unsigned got;
z_streamp strm = &(state->strm);
if (state->err != Z_OK && state->err != Z_BUF_ERROR)
return -1;
if (state->eof == 0) {
if (strm->avail_in) { /* copy what's there to the start */
unsigned char *p = state->in;
unsigned const char *q = strm->next_in;
unsigned n = strm->avail_in;
do {
*p++ = *q++;
} while (--n);
}
if (gz_load(state, state->in + strm->avail_in,
state->size - strm->avail_in, &got) == -1)
return -1;
strm->avail_in += got;
strm->next_in = state->in;
}
return 0;
}
/* Look for gzip header, set up for inflate or copy. state->x.have must be 0.
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. 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 will be initialized.
gz_look() will return 0 on success or -1 on failure. */
local int gz_look(state)
gz_statep state;
{
z_streamp strm = &(state->strm);
/* allocate read buffers and inflate memory */
if (state->size == 0) {
/* allocate buffers */
state->in = (unsigned char *)malloc(state->want);
state->out = (unsigned char *)malloc(state->want << 1);
if (state->in == NULL || state->out == NULL) {
free(state->out);
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 + 16) != Z_OK) { /* gunzip */
free(state->out);
free(state->in);
state->size = 0;
gz_error(state, Z_MEM_ERROR, "out of memory");
return -1;
}
}
/* get at least the magic bytes in the input buffer */
if (strm->avail_in < 2) {
if (gz_avail(state) == -1)
return -1;
if (strm->avail_in == 0)
return 0;
}
/* look for gzip magic bytes -- if there, do gzip decoding (note: there is
a logical dilemma here when considering the case of a partially written
gzip file, to wit, if a single 31 byte is written, then we cannot tell
whether this is a single-byte file, or just a partially written gzip
file -- for here we assume that if a gzip file is being written, then
the header will be written in a single operation, so that reading a
single byte is sufficient indication that it is not a gzip file) */
if (strm->avail_in > 1 &&
strm->next_in[0] == 31 && strm->next_in[1] == 139) {
inflateReset(strm);
state->how = GZIP;
state->direct = 0;
return 0;
}
/* no gzip header -- if we were decoding gzip before, then this is trailing
garbage. Ignore the trailing garbage and finish. */
if (state->direct == 0) {
strm->avail_in = 0;
state->eof = 1;
state->x.have = 0;
return 0;
}
/* doing raw i/o, 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->x.next = state->out;
if (strm->avail_in) {
memcpy(state->x.next, strm->next_in, strm->avail_in);
state->x.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.
On return, state->x.have and state->x.next point to the just decompressed
data. If the gzip stream completes, state->how is reset to LOOK to look for
the next gzip stream or raw data, once state->x.have is depleted. Returns 0
on success, -1 on failure. */
local int gz_decomp(state)
gz_statep state;
{
int ret = Z_OK;
unsigned had;
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_BUF_ERROR, "unexpected end of file");
break;
}
/* 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 */
state->x.have = had - strm->avail_out;
state->x.next = strm->next_out - state->x.have;
/* if the gzip stream completed successfully, look for another */
if (ret == Z_STREAM_END)
state->how = LOOK;
/* good decompression */
return 0;
}
/* Fetch data and put it in the output buffer. Assumes state->x.have is 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 to determine whether to copy or decompress. Returns -1 on error,
otherwise 0. gz_fetch() will leave state->how as COPY or GZIP unless the
end of the input file has been reached and all data has been processed. */
local int gz_fetch(state)
gz_statep state;
{
z_streamp strm = &(state->strm);
do {
switch(state->how) {
case LOOK: /* -> LOOK, COPY (only if never GZIP), or GZIP */
if (gz_look(state) == -1)
return -1;
if (state->how == LOOK)
return 0;
break;
case COPY: /* -> COPY */
if (gz_load(state, state->out, state->size << 1, &(state->x.have))
== -1)
return -1;
state->x.next = state->out;
return 0;
case GZIP: /* -> GZIP or LOOK (if end of gzip stream) */
strm->avail_out = state->size << 1;
strm->next_out = state->out;
if (gz_decomp(state) == -1)
return -1;
}
} while (state->x.have == 0 && (!state->eof || strm->avail_in));
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->x.have) {
n = GT_OFF(state->x.have) || (z_off64_t)state->x.have > len ?
(unsigned)len : state->x.have;
state->x.have -= n;
state->x.next += n;
state->x.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_fetch(state) == -1)
return -1;
}
return 0;
}
/* Read len bytes into buf from file, or less than len up to the end of the
input. Return the number of bytes read. If zero is returned, either the
end of file was reached, or there was an error. state->err must be
consulted in that case to determine which. */
local z_size_t gz_read(state, buf, len)
gz_statep state;
voidp buf;
z_size_t len;
{
z_size_t got;
unsigned n;
/* 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 0;
}
/* get len bytes to buf, or less than len if at the end */
got = 0;
do {
/* set n to the maximum amount of len that fits in an unsigned int */
n = -1;
if (n > len)
n = len;
/* first just try copying data from the output buffer */
if (state->x.have) {
if (state->x.have < n)
n = state->x.have;
memcpy(buf, state->x.next, n);
state->x.next += n;
state->x.have -= n;
}
/* output buffer empty -- return if we're at the end of the input */
else if (state->eof && state->strm.avail_in == 0) {
state->past = 1; /* tried to read past end */
break;
}
/* need output data -- for small len or new stream load up our output
buffer */
else if (state->how == LOOK || n < (state->size << 1)) {
/* get more output, looking for header if required */
if (gz_fetch(state) == -1)
return 0;
continue; /* no progress yet -- go back to copy 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, (unsigned char *)buf, n, &n) == -1)
return 0;
}
/* large len -- decompress directly into user buffer */
else { /* state->how == GZIP */
state->strm.avail_out = n;
state->strm.next_out = (unsigned char *)buf;
if (gz_decomp(state) == -1)
return 0;
n = state->x.have;
state->x.have = 0;
}
/* update progress */
len -= n;
buf = (char *)buf + n;
got += n;
state->x.pos += n;
} while (len);
/* return number of bytes read into user buffer */
return got;
}
/* -- see zlib.h -- */
int ZEXPORT gzread(file, buf, len)
gzFile file;
voidp buf;
unsigned len;
{
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 (serious) error */
if (state->mode != GZ_READ ||
(state->err != Z_OK && state->err != Z_BUF_ERROR))
return -1;
/* since an int is returned, make sure len fits in one, otherwise return
with an error (this avoids a flaw in the interface) */
if ((int)len < 0) {
gz_error(state, Z_STREAM_ERROR, "request does not fit in an int");
return -1;
}
/* read len or fewer bytes to buf */
len = gz_read(state, buf, len);
/* check for an error */
if (len == 0 && state->err != Z_OK && state->err != Z_BUF_ERROR)
return -1;
/* return the number of bytes read (this is assured to fit in an int) */
return (int)len;
}
/* -- see zlib.h -- */
z_size_t ZEXPORT gzfread(buf, size, nitems, file)
voidp buf;
z_size_t size;
z_size_t nitems;
gzFile file;
{
z_size_t len;
gz_statep state;
/* get internal structure */
if (file == NULL)
return 0;
state = (gz_statep)file;
/* check that we're reading and that there's no (serious) error */
if (state->mode != GZ_READ ||
(state->err != Z_OK && state->err != Z_BUF_ERROR))
return 0;
/* compute bytes to read -- error on overflow */
len = nitems * size;
if (size && len / size != nitems) {
gz_error(state, Z_STREAM_ERROR, "request does not fit in a size_t");
return 0;
}
/* read len or fewer bytes to buf, return the number of full items read */
return len ? gz_read(state, buf, len) / size : 0;
}
/* -- see zlib.h -- */
#ifdef Z_PREFIX_SET
# undef z_gzgetc
#else
# undef gzgetc
#endif
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 (serious) error */
if (state->mode != GZ_READ ||
(state->err != Z_OK && state->err != Z_BUF_ERROR))
return -1;
/* try output buffer (no need to check for skip request) */
if (state->x.have) {
state->x.have--;
state->x.pos++;
return *(state->x.next)++;
}
/* nothing there -- try gz_read() */
ret = gz_read(state, buf, 1);
return ret < 1 ? -1 : buf[0];
}
int ZEXPORT gzgetc_(file)
gzFile file;
{
return gzgetc(file);
}
/* -- 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 (serious) error */
if (state->mode != GZ_READ ||
(state->err != Z_OK && state->err != Z_BUF_ERROR))
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->x.have == 0) {
state->x.have = 1;
state->x.next = state->out + (state->size << 1) - 1;
state->x.next[0] = (unsigned char)c;
state->x.pos--;
state->past = 0;
return c;
}
/* if no room, give up (must have already done a gzungetc()) */
if (state->x.have == (state->size << 1)) {
gz_error(state, Z_DATA_ERROR, "out of room to push characters");
return -1;
}
/* slide output data if needed and insert byte before existing data */
if (state->x.next == state->out) {
unsigned char *src = state->out + state->x.have;
unsigned char *dest = state->out + (state->size << 1);
while (src > state->out)
*--dest = *--src;
state->x.next = dest;
}
state->x.have++;
state->x.next--;
state->x.next[0] = (unsigned char)c;
state->x.pos--;
state->past = 0;
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 (serious) error */
if (state->mode != GZ_READ ||
(state->err != Z_OK && state->err != Z_BUF_ERROR))
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->x.have == 0 && gz_fetch(state) == -1)
return NULL; /* error */
if (state->x.have == 0) { /* end of file */
state->past = 1; /* read past end */
break; /* return what we have */
}
/* look for end-of-line in current output buffer */
n = state->x.have > left ? left : state->x.have;
eol = (unsigned char *)memchr(state->x.next, '\n', n);
if (eol != NULL)
n = (unsigned)(eol - state->x.next) + 1;
/* copy through end-of-line, or remainder if not found */
memcpy(buf, state->x.next, n);
state->x.have -= n;
state->x.next += n;
state->x.pos += n;
left -= n;
buf += n;
} while (left && eol == NULL);
/* return terminated string, or if nothing, end of file */
if (buf == str)
return NULL;
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;
/* 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->mode == GZ_READ && state->how == LOOK && state->x.have == 0)
(void)gz_look(state);
/* return 1 if transparent, 0 if processing a gzip stream */
return state->direct;
}
/* -- see zlib.h -- */
int ZEXPORT gzclose_r(file)
gzFile file;
{
int ret, err;
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);
}
err = state->err == Z_BUF_ERROR ? Z_BUF_ERROR : Z_OK;
gz_error(state, Z_OK, NULL);
free(state->path);
ret = close(state->fd);
free(state);
return ret ? Z_ERRNO : err;
}
GZIP
#define GZIP
Definition: deflate.h:23
gzguts.h
local
#define local
Definition: gzguts.h:114
gz_statep
gz_state FAR * gz_statep
Definition: gzguts.h:202
LOOK
#define LOOK
Definition: gzguts.h:165
GT_OFF
#define GT_OFF(x)
Definition: gzguts.h:217
GZ_READ
#define GZ_READ
Definition: gzguts.h:160
zstrerror
#define zstrerror()
Definition: gzguts.h:133
gz_error
void ZLIB_INTERNAL gz_error(gz_statep state, int err, const char *msg)
Definition: gzlib.c:579
gzungetc
int ZEXPORT gzungetc(int c, gzFile file)
Definition: gzread.c:483
OF
int gz_load OF((gz_statep, unsigned char *, unsigned, unsigned *))
gzgetc
int ZEXPORT gzgetc(gzFile file)
Definition: gzread.c:447
gzdirect
int ZEXPORT gzdirect(gzFile file)
Definition: gzread.c:607
gz_skip
int gz_skip(gz_statep state, z_off64_t len)
Definition: gzread.c:259
gzread
int ZEXPORT gzread(gzFile file, voidp buf, unsigned len)
Definition: gzread.c:375
gzgetc_
int ZEXPORT gzgetc_(gzFile file)
Definition: gzread.c:476
gz_fetch
int gz_fetch(gz_statep state)
Definition: gzread.c:229
gz_read
z_size_t gz_read(gz_statep state, voidp buf, z_size_t len)
Definition: gzread.c:294
gz_decomp
int gz_decomp(gz_statep state)
Definition: gzread.c:175
gz_avail
int gz_avail(gz_statep state)
Definition: gzread.c:56
gzclose_r
int ZEXPORT gzclose_r(gzFile file)
Definition: gzread.c:627
gzgets
char *ZEXPORT gzgets(gzFile file, char *buf, int len)
Definition: gzread.c:543
gz_load
int gz_load(gz_statep state, unsigned char *buf, unsigned len, unsigned *have)
Definition: gzread.c:21
gz_look
int gz_look(gz_statep state)
Definition: gzread.c:91
gzfread
z_size_t ZEXPORT gzfread(voidp buf, z_size_t size, z_size_t nitems, gzFile file)
Definition: gzread.c:411
inflate
int ZEXPORT inflate(z_streamp strm, int flush)
Definition: inflate.c:622
inflateReset
int ZEXPORT inflateReset(z_streamp strm)
Definition: inflate.c:144
inflateEnd
int ZEXPORT inflateEnd(z_streamp strm)
Definition: inflate.c:1277
COPY
@ COPY
Definition: inflate.h:36
restinio::get
Value_Type get(const router::route_params_t &params, string_view_t key)
Cast named parameter value to a given type.
Definition: express.hpp:850
gzFile_s
Definition: zlib.h:1817
gzFile_s::have
unsigned have
Definition: zlib.h:1818
ZEXPORT
#define ZEXPORT
Definition: zconf.h:380
voidp
Byte * voidp
Definition: zconf.h:414
z_off64_t
#define z_off64_t
Definition: zconf.h:513
z_size_t
unsigned long z_size_t
Definition: zconf.h:250
Z_NEED_DICT
#define Z_NEED_DICT
Definition: zlib.h:179
Z_ERRNO
#define Z_ERRNO
Definition: zlib.h:180
Z_BUF_ERROR
#define Z_BUF_ERROR
Definition: zlib.h:184
inflateInit2
#define inflateInit2(strm, windowBits)
Definition: zlib.h:1800
z_streamp
z_stream FAR * z_streamp
Definition: zlib.h:108
Z_STREAM_END
#define Z_STREAM_END
Definition: zlib.h:178
Z_OK
#define Z_OK
Definition: zlib.h:177
Z_DATA_ERROR
#define Z_DATA_ERROR
Definition: zlib.h:182
Z_STREAM_ERROR
#define Z_STREAM_ERROR
Definition: zlib.h:181
Z_NO_FLUSH
#define Z_NO_FLUSH
Definition: zlib.h:168
Z_NULL
#define Z_NULL
Definition: zlib.h:212
Z_MEM_ERROR
#define Z_MEM_ERROR
Definition: zlib.h:183