char * ZEXPORT gzgets(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 gzungetc(
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] = 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] = c;
state->x.pos--;
state->past = 0;
return c;
}
/* -- see zlib.h -- */
int ZEXPORT
gzread (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 (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 the flaw in the interface) */
if ((int) len < 0)
{
gz_error (state, Z_DATA_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->x.have)
{
n = state->x.have > len ? len : 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 && 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 || len < (state->size << 1))
{
/* get more output, looking for header if required */
if (gz_fetch (state) == -1)
return -1;
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, len, &n) == -1)
return -1;
}
/* large len -- decompress directly into user buffer */
else
{ /* state->how == GZIP */
strm->avail_out = len;
strm->next_out = (unsigned char *) buf;
if (gz_decomp (state) == -1)
return -1;
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 (will fit in int) */
return (int) got;
}
