if (coder->mf.read_pos >= coder->mf.size - coder->mf.keep_size_after)
move_window(&coder->mf);
+ // Maybe this is ugly, but lzma_mf uses uint32_t for most things
+ // (which I find cleanest), but we need size_t here when filling
+ // the history window.
+ size_t write_pos = coder->mf.write_pos;
size_t in_used;
lzma_ret ret;
if (coder->next.code == NULL) {
// Not using a filter, simply memcpy() as much as possible.
in_used = lzma_bufcpy(in, in_pos, in_size, coder->mf.buffer,
- &coder->mf.write_pos, coder->mf.size);
+ &write_pos, coder->mf.size);
ret = action != LZMA_RUN && *in_pos == in_size
? LZMA_STREAM_END : LZMA_OK;
const size_t in_start = *in_pos;
ret = coder->next.code(coder->next.coder, allocator,
in, in_pos, in_size,
- coder->mf.buffer, &coder->mf.write_pos,
+ coder->mf.buffer, &write_pos,
coder->mf.size, action);
in_used = *in_pos - in_start;
}
+ coder->mf.write_pos = write_pos;
+
// If end of stream has been reached or flushing completed, we allow
// the encoder to process all the input (that is, read_pos is allowed
// to reach write_pos). Otherwise we keep keep_size_after bytes
lz_encoder_prepare(lzma_mf *mf, lzma_allocator *allocator,
const lzma_lz_options *lz_options)
{
+ // For now, the dictionary size is limited to 1.5 GiB. This may grow
+ // in the future if needed, but it needs a little more work than just
+ // changing this check.
if (lz_options->dictionary_size < LZMA_DICTIONARY_SIZE_MIN
|| lz_options->dictionary_size
- > LZMA_DICTIONARY_SIZE_MAX
+ > (UINT32_C(1) << 30) + (UINT32_C(1) << 29)
|| lz_options->find_len_max
> lz_options->match_len_max)
return true;
// memmove()s become more expensive when the size of the buffer
// increases, we reserve more space when a large dictionary is
// used to make the memmove() calls rarer.
+ //
+ // This works with dictionaries up to about 3 GiB. If bigger
+ // dictionary is wanted, some extra work is needed:
+ // - Several variables in lzma_mf have to be changed from uint32_t
+ // to size_t.
+ // - Memory usage calculation needs something too, e.g. use uint64_t
+ // for mf->size.
uint32_t reserve = lz_options->dictionary_size / 2;
if (reserve > (UINT32_C(1) << 30))
reserve /= 2;
const uint32_t old_size = mf->size;
mf->size = mf->keep_size_before + reserve + mf->keep_size_after;
- // FIXME Integer overflows
-
// Deallocate the old history buffer if it exists but has different
// size than what is needed now.
if (mf->buffer != NULL && old_size != mf->size) {
// Match finder options
mf->match_len_max = lz_options->match_len_max;
mf->find_len_max = lz_options->find_len_max;
- mf->cyclic_buffer_size = lz_options->dictionary_size + 1;
+
+ // cyclic_size has to stay smaller than 2 Gi. Note that this doesn't
+ // mean limitting dictionary size to less than 2 GiB. With a match
+ // finder that uses multibyte resolution (hashes start at e.g. every
+ // fourth byte), cyclic_size would stay below 2 Gi even when
+ // dictionary size is greater than 2 GiB.
+ //
+ // It would be possible to allow cyclic_size >= 2 Gi, but then we
+ // would need to be careful to use 64-bit types in various places
+ // (size_t could do since we would need bigger than 32-bit address
+ // space anyway). It would also require either zeroing a multigigabyte
+ // buffer at initialization (waste of time and RAM) or allow
+ // normalization in lz_encoder_mf.c to access uninitialized
+ // memory to keep the code simpler. The current way is simple and
+ // still allows pretty big dictionaries, so I don't expect these
+ // limits to change.
+ mf->cyclic_size = lz_options->dictionary_size + 1;
// Validate the match finder ID and setup the function pointers.
switch (lz_options->match_finder) {
hs += HASH_4_SIZE;
*/
+ // If the above code calculating hs is modified, make sure that
+ // this assertion stays valid (UINT32_MAX / 5 is not strictly the
+ // exact limit). If it doesn't, you need to calculate that
+ // hash_size_sum + sons_count cannot overflow.
+ assert(hs < UINT32_MAX / 5);
+
const uint32_t old_count = mf->hash_size_sum + mf->sons_count;
mf->hash_size_sum = hs;
- mf->sons_count = mf->cyclic_buffer_size;
+ mf->sons_count = mf->cyclic_size;
if (is_bt)
mf->sons_count *= 2;
return true;
}
- // Use cyclic_buffer_size as initial mf->offset. This allows
+ // Use cyclic_size as initial mf->offset. This allows
// avoiding a few branches in the match finders. The downside is
// that match finder needs to be normalized more often, which may
// hurt performance with huge dictionaries.
- mf->offset = mf->cyclic_buffer_size;
+ mf->offset = mf->cyclic_size;
mf->read_pos = 0;
mf->read_ahead = 0;
mf->read_limit = 0;
}
mf->son = mf->hash + mf->hash_size_sum;
- mf->cyclic_buffer_pos = 0;
+ mf->cyclic_pos = 0;
// Initialize the hash table. Since EMPTY_HASH_VALUE is zero, we
// can use memset().
/// Number of bytes that must be kept in buffer after read_pos.
/// That is, read_pos <= write_pos - keep_size_after as long as
- /// stream_end_was_reached is false (once it is true, read_pos
- /// is allowed to reach write_pos).
+ /// action is LZMA_RUN; when action != LZMA_RUN, read_pos is allowed
+ /// to reach write_pos so that the last bytes get encoded too.
uint32_t keep_size_after;
/// Match finders store locations of matches using 32-bit integers.
/// To avoid adjusting several megabytes of integers every time the
- /// input window is moved with move_window(), we only adjust the
- /// offset of the buffer. Thus, buffer[match_finder_pos - offset]
- /// is the byte pointed by match_finder_pos.
+ /// input window is moved with move_window, we only adjust the
+ /// offset of the buffer. Thus, buffer[value_in_hash_table - offset]
+ /// is the byte pointed by value_in_hash_table.
uint32_t offset;
- /// buffer[read_pos] is the current byte.
+ /// buffer[read_pos] is the next byte to run through the match
+ /// finder. This is incremented in the match finder once the byte
+ /// has been processed.
uint32_t read_pos;
/// Number of bytes that have been ran through the match finder, but
uint32_t *hash;
uint32_t *son;
- uint32_t cyclic_buffer_pos;
- uint32_t cyclic_buffer_size; // Must be dictionary_size + 1.
+ uint32_t cyclic_pos;
+ uint32_t cyclic_size; // Must be dictionary size + 1.
uint32_t hash_mask;
/// Maximum number of loops in the match finder
// In future we may not want to touch the lowest bits, because there
// may be match finders that use larger resolution than one byte.
const uint32_t subvalue
- = (MUST_NORMALIZE_POS - mf->cyclic_buffer_size);
+ = (MUST_NORMALIZE_POS - mf->cyclic_size);
// & (~(UINT32_C(1) << 10) - 1);
const uint32_t count = mf->hash_size_sum + mf->sons_count;
static void
move_pos(lzma_mf *mf)
{
- if (++mf->cyclic_buffer_pos == mf->cyclic_buffer_size)
- mf->cyclic_buffer_pos = 0;
+ if (++mf->cyclic_pos == mf->cyclic_size)
+ mf->cyclic_pos = 0;
++mf->read_pos;
assert(mf->read_pos <= mf->write_pos);
/// function (with small amount of input, it may start using mf->pending
/// again if flushing).
///
-/// Due to this rewinding, we don't touch cyclic_buffer_pos or test for
+/// Due to this rewinding, we don't touch cyclic_pos or test for
/// normalization. It will be done when the match finder's skip function
/// catches up after a flush.
static void
#define call_find(func, len_best) \
do { \
matches_count = func(len_limit, pos, cur, cur_match, mf->loops, \
- mf->son, mf->cyclic_buffer_pos, \
- mf->cyclic_buffer_size, \
+ mf->son, mf->cyclic_pos, mf->cyclic_size, \
matches + matches_count, len_best) \
- matches; \
move_pos(mf); \
/// \param cur_match Start position of the current match candidate
/// \param loops Maximum length of the hash chain
/// \param son lzma_mf.son (contains the hash chain)
-/// \param cyclic_buffer_pos
-/// \param cyclic_buffer_size
+/// \param cyclic_pos
+/// \param cyclic_size
/// \param matches Array to hold the matches.
/// \param len_best The length of the longest match found so far.
static lzma_match *
uint32_t cur_match,
uint32_t loops,
uint32_t *const son,
- const uint32_t cyclic_buffer_pos,
- const uint32_t cyclic_buffer_size,
+ const uint32_t cyclic_pos,
+ const uint32_t cyclic_size,
lzma_match *matches,
uint32_t len_best)
{
- son[cyclic_buffer_pos] = cur_match;
+ son[cyclic_pos] = cur_match;
while (true) {
const uint32_t delta = pos - cur_match;
- if (loops-- == 0 || delta >= cyclic_buffer_size)
+ if (loops-- == 0 || delta >= cyclic_size)
return matches;
const uint8_t *const pb = cur - delta;
- cur_match = son[cyclic_buffer_pos - delta
- + (delta > cyclic_buffer_pos
- ? cyclic_buffer_size : 0)];
+ cur_match = son[cyclic_pos - delta
+ + (delta > cyclic_pos ? cyclic_size : 0)];
if (pb[len_best] == cur[len_best] && pb[0] == cur[0]) {
uint32_t len = 0;
}
}
-/*
-#define hc_header_find(len_min, ret_op) \
- uint32_t len_limit = mf_avail(mf); \
- if (mf->find_len_max <= len_limit) { \
- len_limit = mf->find_len_max; \
- } else if (len_limit < (len_min)) { \
- move_pending(mf); \
- ret_op; \
- } \
-#define header_hc(len_min, ret_op) \
-do { \
- if (mf_avail(mf) < (len_min)) { \
- move_pending(mf); \
- ret_op; \
- } \
-} while (0)
-*/
#define hc_find(len_best) \
call_find(hc_find_func, len_best)
#define hc_skip() \
do { \
- mf->son[mf->cyclic_buffer_pos] = cur_match; \
+ mf->son[mf->cyclic_pos] = cur_match; \
move_pos(mf); \
} while (0)
uint32_t len_best = 2;
- if (delta2 < mf->cyclic_buffer_size && *(cur - delta2) == *cur) {
+ if (delta2 < mf->cyclic_size && *(cur - delta2) == *cur) {
for ( ; len_best != len_limit; ++len_best)
if (*(cur + len_best - delta2) != cur[len_best])
break;
uint32_t len_best = 1;
- if (delta2 < mf->cyclic_buffer_size && *(cur - delta2) == *cur) {
+ if (delta2 < mf->cyclic_size && *(cur - delta2) == *cur) {
len_best = 2;
matches[0].len = 2;
matches[0].dist = delta2 - 1;
matches_count = 1;
}
- if (delta2 != delta3 && delta3 < mf->cyclic_buffer_size
+ if (delta2 != delta3 && delta3 < mf->cyclic_size
&& *(cur - delta3) == *cur) {
len_best = 3;
matches[matches_count++].dist = delta3 - 1;
uint32_t cur_match,
uint32_t loops,
uint32_t *const son,
- const uint32_t cyclic_buffer_pos,
- const uint32_t cyclic_buffer_size,
+ const uint32_t cyclic_pos,
+ const uint32_t cyclic_size,
lzma_match *matches,
uint32_t len_best)
{
- uint32_t *ptr0 = son + (cyclic_buffer_pos << 1) + 1;
- uint32_t *ptr1 = son + (cyclic_buffer_pos << 1);
+ uint32_t *ptr0 = son + (cyclic_pos << 1) + 1;
+ uint32_t *ptr1 = son + (cyclic_pos << 1);
uint32_t len0 = 0;
uint32_t len1 = 0;
while (true) {
const uint32_t delta = pos - cur_match;
- if (loops-- == 0 || delta >= cyclic_buffer_size) {
+ if (loops-- == 0 || delta >= cyclic_size) {
*ptr0 = EMPTY_HASH_VALUE;
*ptr1 = EMPTY_HASH_VALUE;
return matches;
}
- uint32_t *const pair = son + ((cyclic_buffer_pos - delta
- + (delta > cyclic_buffer_pos
- ? cyclic_buffer_size : 0)) << 1);
+ uint32_t *const pair = son + ((cyclic_pos - delta
+ + (delta > cyclic_pos ? cyclic_size : 0))
+ << 1);
const uint8_t *const pb = cur - delta;
uint32_t len = MIN(len0, len1);
uint32_t cur_match,
uint32_t loops,
uint32_t *const son,
- const uint32_t cyclic_buffer_pos,
- const uint32_t cyclic_buffer_size)
+ const uint32_t cyclic_pos,
+ const uint32_t cyclic_size)
{
- uint32_t *ptr0 = son + (cyclic_buffer_pos << 1) + 1;
- uint32_t *ptr1 = son + (cyclic_buffer_pos << 1);
+ uint32_t *ptr0 = son + (cyclic_pos << 1) + 1;
+ uint32_t *ptr1 = son + (cyclic_pos << 1);
uint32_t len0 = 0;
uint32_t len1 = 0;
while (true) {
const uint32_t delta = pos - cur_match;
- if (loops-- == 0 || delta >= cyclic_buffer_size) {
+ if (loops-- == 0 || delta >= cyclic_size) {
*ptr0 = EMPTY_HASH_VALUE;
*ptr1 = EMPTY_HASH_VALUE;
return;
}
- uint32_t *pair = son + ((cyclic_buffer_pos - delta
- + (delta > cyclic_buffer_pos
- ? cyclic_buffer_size : 0)) << 1);
+ uint32_t *pair = son + ((cyclic_pos - delta
+ + (delta > cyclic_pos ? cyclic_size : 0))
+ << 1);
const uint8_t *pb = cur - delta;
uint32_t len = MIN(len0, len1);
#define bt_skip() \
do { \
bt_skip_func(len_limit, pos, cur, cur_match, mf->loops, \
- mf->son, mf->cyclic_buffer_pos, \
- mf->cyclic_buffer_size); \
+ mf->son, mf->cyclic_pos, \
+ mf->cyclic_size); \
move_pos(mf); \
} while (0)
uint32_t len_best = 2;
- if (delta2 < mf->cyclic_buffer_size && *(cur - delta2) == *cur) {
+ if (delta2 < mf->cyclic_size && *(cur - delta2) == *cur) {
for ( ; len_best != len_limit; ++len_best)
if (*(cur + len_best - delta2) != cur[len_best])
break;
uint32_t len_best = 1;
- if (delta2 < mf->cyclic_buffer_size && *(cur - delta2) == *cur) {
+ if (delta2 < mf->cyclic_size && *(cur - delta2) == *cur) {
len_best = 2;
matches[0].len = 2;
matches[0].dist = delta2 - 1;
matches_count = 1;
}
- if (delta2 != delta3 && delta3 < mf->cyclic_buffer_size
+ if (delta2 != delta3 && delta3 < mf->cyclic_size
&& *(cur - delta3) == *cur) {
len_best = 3;
matches[matches_count++].dist = delta3 - 1;
projects / platform / upstream / xz.git / commitdiff