revi-archive/xz-archive
1
0
Fork 0
mirror of https://git.tukaani.org/xz.git synced 2024-04-04 12:36:23 +02:00
Code Activity

Remove uncompressed size tracking from the filter encoders.

Browse source 
It's not strictly needed there, and just complicates the
code. LZ encoder never even had this feature.

The primary reason to have uncompressed size tracking in
filter encoders was validating that the application
doesn't give different amount of input that it had
promised. A side effect was to validate internal workings
of liblzma.

Uncompressed size tracking is still present in the Block
encoder. Maybe it should be added to LZMA_Alone and raw
encoders too. It's simpler to have one coder just to
validate the uncompressed size instead of having it
in every filter.
This commit is contained in:
Lasse Collin 2007-12-11 16:49:19 +02:00
parent 5286723e0d
commit 3e16d51dd6
3 changed files with 12 additions and 80 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

25
src/liblzma/common/copy_coder.c
View file

@ -42,33 +42,12 @@ copy_encode(lzma_coder *coder, lzma_allocator *allocator,
in, in_pos, in_size, out, out_pos, out_size,
action);
// If we get here, we are the last filter in the chain.
assert(coder->uncompressed_size <= LZMA_VLI_VALUE_MAX);
const size_t in_avail = in_size - *in_pos;
// Check that we don't have too much input.
if ((lzma_vli)(in_avail) > coder->uncompressed_size)
return LZMA_DATA_ERROR;
// Check that once LZMA_FINISH has been given, the amount of input
// matches uncompressed_size, which is always known.
if (action == LZMA_FINISH
&& coder->uncompressed_size != (lzma_vli)(in_avail))
return LZMA_DATA_ERROR;
// We are the last coder in the chain.
// Just copy as much data as possible.
const size_t in_used = bufcpy(
in, in_pos, in_size, out, out_pos, out_size);
// Update uncompressed_size if it is known.
if (coder->uncompressed_size != LZMA_VLI_VALUE_UNKNOWN)
coder->uncompressed_size -= in_used;
bufcpy(in, in_pos, in_size, out, out_pos, out_size);
// LZMA_SYNC_FLUSH and LZMA_FINISH are the same thing for us.
if ((action != LZMA_RUN && *in_pos == in_size)
|| coder->uncompressed_size == 0)
if (action != LZMA_RUN && *in_pos == in_size)
return LZMA_STREAM_END;
return LZMA_OK;

29
src/liblzma/simple/simple_coder.c
View file

@ -39,44 +39,23 @@ copy_or_code(lzma_coder *coder, lzma_allocator *allocator,
if (coder->next.code == NULL) {
const size_t in_avail = in_size - *in_pos;
if (coder->is_encoder) {
if (action == LZMA_FINISH) {
// If uncompressed size is known and the
// amount of available input doesn't match
// the uncompressed size, return an error.
if (coder->uncompressed_size
!= LZMA_VLI_VALUE_UNKNOWN
&& coder->uncompressed_size
!= in_avail)
return LZMA_DATA_ERROR;
} else if (coder->uncompressed_size
< (lzma_vli)(in_avail)) {
// There is too much input available.
return LZMA_DATA_ERROR;
}
} else {
if (!coder->is_encoder) {
// Limit in_size so that we don't copy too much.
if ((lzma_vli)(in_avail) > coder->uncompressed_size)
in_size = *in_pos + (size_t)(
coder->uncompressed_size);
}
// Store the old position so we can update uncompressed_size.
const size_t out_start = *out_pos;
// Copy the data
bufcpy(in, in_pos, in_size, out, out_pos, out_size);
// Update uncompressed_size.
if (coder->uncompressed_size != LZMA_VLI_VALUE_UNKNOWN)
coder->uncompressed_size -= *out_pos - out_start;
// Check if end of stream was reached.
if (coder->is_encoder) {
if (action == LZMA_FINISH && *in_pos == in_size)
coder->end_was_reached = true;
} else {
} else if (coder->uncompressed_size
!= LZMA_VLI_VALUE_UNKNOWN) {
coder->uncompressed_size -= *out_pos - out_start;
if (coder->uncompressed_size == 0)
coder->end_was_reached = true;
}

38
src/liblzma/subblock/subblock_encoder.c
View file

@ -41,6 +41,7 @@ do { \
struct lzma_coder_s {
lzma_next_coder next;
bool next_finished;
bool use_eopm;
enum {
SEQ_FILL,
@ -62,8 +63,6 @@ struct lzma_coder_s {
lzma_options_subblock *options;
lzma_vli uncompressed_size;
size_t pos;
uint32_t tmp;
@ -235,18 +234,6 @@ subblock_buffer(lzma_coder *coder, lzma_allocator *allocator,
size_t in_size, uint8_t *restrict out,
size_t *restrict out_pos, size_t out_size, lzma_action action)
{
// Verify that there is a sane amount of input.
if (coder->uncompressed_size != LZMA_VLI_VALUE_UNKNOWN) {
const lzma_vli in_avail = in_size - *in_pos;
if (action == LZMA_FINISH) {
if (in_avail != coder->uncompressed_size)
return LZMA_DATA_ERROR;
} else {
if (in_avail > coder->uncompressed_size)
return LZMA_DATA_ERROR;
}
}
// Check if we need to do something special with the Subfilter.
if (coder->options != NULL && coder->options->allow_subfilters) {
switch (coder->options->subfilter_mode) {
@ -304,18 +291,12 @@ subblock_buffer(lzma_coder *coder, lzma_allocator *allocator,
assert(coder->subfilter.subcoder.code == NULL);
// No Subfilter is enabled, just copy the data as is.
// NOTE: uncompressed_size cannot overflow because we
// have checked/ it in the beginning of this function.
const size_t in_used = bufcpy(in, in_pos, in_size,
coder->alignment.in_pending += bufcpy(
in, in_pos, in_size,
coder->subblock.data,
&coder->subblock.size,
coder->subblock.limit);
if (coder->uncompressed_size != LZMA_VLI_VALUE_UNKNOWN)
coder->uncompressed_size -= in_used;
coder->alignment.in_pending += in_used;
} else {
const size_t in_start = *in_pos;
lzma_ret ret;
@ -351,11 +332,6 @@ subblock_buffer(lzma_coder *coder, lzma_allocator *allocator,
if (in_used > 0)
coder->subfilter.got_input = true;
// NOTE: uncompressed_size cannot overflow because we
// have checked it in the beginning of this function.
if (coder->uncompressed_size != LZMA_VLI_VALUE_UNKNOWN)
coder->uncompressed_size -= *in_pos - in_start;
coder->alignment.in_pending += in_used;
if (ret == LZMA_STREAM_END) {
@ -509,14 +485,11 @@ subblock_buffer(lzma_coder *coder, lzma_allocator *allocator,
break;
}
if (coder->uncompressed_size
== LZMA_VLI_VALUE_UNKNOWN) {
if (coder->use_eopm) {
// NOTE: No need to use write_byte() here
// since we are finishing.
out[*out_pos] = 0x10;
++*out_pos;
} else if (coder->uncompressed_size != 0) {
return LZMA_DATA_ERROR;
}
return LZMA_STREAM_END;
@ -782,7 +755,8 @@ lzma_subblock_encoder_init(lzma_next_coder *next, lzma_allocator *allocator,
next->coder->next_finished = false;
next->coder->sequence = SEQ_FILL;
next->coder->options = filters[0].options;
next->coder->uncompressed_size = filters[0].uncompressed_size;
next->coder->use_eopm = filters[0].uncompressed_size
== LZMA_VLI_VALUE_UNKNOWN;
next->coder->pos = 0;
next->coder->alignment.in_pending = 0;