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/* SPDX-License-Identifier: GPL-3.0-or-later */
/*
* istream.c
*
* Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
*/
#include "../internal.h"
#include "sqfs/io.h"
#include "sqfs/error.h"
typedef struct istream_xfrm_t {
sqfs_istream_t base;
sqfs_istream_t *wrapped;
xfrm_stream_t *xfrm;
size_t buffer_offset;
size_t buffer_used;
sqfs_u8 uncompressed[BUFSZ];
} istream_xfrm_t;
static int precache(sqfs_istream_t *base)
{
istream_xfrm_t *xfrm = (istream_xfrm_t *)base;
int ret;
if (xfrm->buffer_offset > 0 &&
xfrm->buffer_offset < xfrm->buffer_used) {
memmove(xfrm->uncompressed,
xfrm->uncompressed + xfrm->buffer_offset,
xfrm->buffer_used - xfrm->buffer_offset);
}
xfrm->buffer_used -= xfrm->buffer_offset;
xfrm->buffer_offset = 0;
for (;;) {
sqfs_u32 in_off = 0, out_off = xfrm->buffer_used;
int mode = XFRM_STREAM_FLUSH_NONE;
const sqfs_u8 *ptr;
size_t avail;
ret = xfrm->wrapped->get_buffered_data(xfrm->wrapped, &ptr,
&avail, BUFSZ);
if (ret < 0)
return ret;
if (ret > 0)
mode = XFRM_STREAM_FLUSH_FULL;
ret = xfrm->xfrm->process_data(xfrm->xfrm,
ptr, avail,
xfrm->uncompressed + out_off,
BUFSZ - out_off,
&in_off, &out_off, mode);
if (ret == XFRM_STREAM_ERROR)
return SQFS_ERROR_COMPRESSOR;
xfrm->buffer_used = out_off;
xfrm->wrapped->advance_buffer(xfrm->wrapped, in_off);
if (ret == XFRM_STREAM_BUFFER_FULL || out_off >= BUFSZ)
break;
if (mode == XFRM_STREAM_FLUSH_FULL)
break;
}
return 0;
}
static int xfrm_get_buffered_data(sqfs_istream_t *strm, const sqfs_u8 **out,
size_t *size, size_t want)
{
istream_xfrm_t *xfrm = (istream_xfrm_t *)strm;
if (want > BUFSZ)
want = BUFSZ;
if (xfrm->buffer_used == 0 ||
(xfrm->buffer_used - xfrm->buffer_offset) < want) {
int ret = precache(strm);
if (ret)
return ret;
}
*out = xfrm->uncompressed + xfrm->buffer_offset;
*size = xfrm->buffer_used - xfrm->buffer_offset;
return (*size == 0) ? 1 : 0;
}
static void xfrm_advance_buffer(sqfs_istream_t *strm, size_t count)
{
istream_xfrm_t *xfrm = (istream_xfrm_t *)strm;
assert(count <= xfrm->buffer_used);
xfrm->buffer_offset += count;
assert(xfrm->buffer_offset <= xfrm->buffer_used);
}
static const char *xfrm_get_filename(sqfs_istream_t *strm)
{
istream_xfrm_t *xfrm = (istream_xfrm_t *)strm;
return xfrm->wrapped->get_filename(xfrm->wrapped);
}
static void xfrm_destroy(sqfs_object_t *obj)
{
istream_xfrm_t *xfrm = (istream_xfrm_t *)obj;
sqfs_drop(xfrm->xfrm);
sqfs_drop(xfrm->wrapped);
free(xfrm);
}
sqfs_istream_t *istream_xfrm_create(sqfs_istream_t *strm, xfrm_stream_t *xfrm)
{
istream_xfrm_t *stream = calloc(1, sizeof(*stream));
sqfs_istream_t *base = (sqfs_istream_t *)stream;
if (stream == NULL)
goto fail;
sqfs_object_init(stream, xfrm_destroy, NULL);
stream->wrapped = sqfs_grab(strm);
stream->xfrm = sqfs_grab(xfrm);
base->get_buffered_data = xfrm_get_buffered_data;
base->advance_buffer = xfrm_advance_buffer;
base->get_filename = xfrm_get_filename;
return base;
fail:
fprintf(stderr, "%s: error initializing decompressor stream.\n",
strm->get_filename(strm));
return NULL;
}
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