int fz_tell(fz_stream *stm)
{
if (stm->mode == FZ_SREAD)
return fz_rtell(stm);
return fz_wtell(stm);
}
fz_error *
fz_rseek(fz_stream *stm, int offset, int whence)
{
fz_error *error;
fz_buffer *buf = stm->buffer;
int t, c;
if (stm->dead)
return fz_throw("assert: seek in dead stream");
if (stm->mode != FZ_SREAD)
return fz_throw("assert: read operation on writing stream");
if (whence == 1)
{
int cur = fz_rtell(stm);
if (cur < 0)
return fz_throw("cannot tell current position");
offset = cur + offset;
whence = 0;
}
buf->eof = 0;
switch (stm->kind)
{
case FZ_SFILE:
t = lseek(stm->file, offset, whence);
if (t < 0)
{
stm->dead = 1;
return fz_throw("syserr: lseek: %s", strerror(errno));
}
buf->rp = buf->bp;
buf->wp = buf->bp;
return fz_okay;
case FZ_SFILTER:
if (whence == 0)
{
if (offset < fz_rtell(stm))
{
stm->dead = 1;
return fz_throw("assert: seek backwards in filter");
}
while (fz_rtell(stm) < offset)
{
c = fz_readbyte(stm);
if (c == EOF)
{
error = fz_readerror(stm);
if (error)
return fz_rethrow(error, "cannot seek forward in filter");
break;
}
}
return fz_okay;
}
stm->dead = 1;
return fz_throw("assert: relative seek in filter");
case FZ_SBUFFER:
if (whence == 0)
buf->rp = CLAMP(buf->bp + offset, buf->bp, buf->ep);
else
buf->rp = CLAMP(buf->ep + offset, buf->bp, buf->ep);
return fz_okay;
default:
return fz_throw("unknown stream type");
}
}
