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fix(?) a huge concurrency issue

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(why the fuck did i think having any sort of global state in a
compression routine was a good idea?)
This commit is contained in:
devinacker 2014-09-28 23:45:48 -04:00
parent e45f993eed
commit ab1823487b
1 changed files with 13 additions and 13 deletions
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26
compress.c
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@ -71,14 +71,11 @@ typedef struct {
uint8_t rotate (uint8_t);
rle_t rle_check (uint8_t*, uint8_t*, uint32_t, int);
backref_t ref_search (uint8_t*, uint8_t*, uint32_t, int);
backref_t ref_search (uint8_t*, uint8_t*, uint32_t, tuple_t*, int);
uint16_t write_backref (uint8_t*, uint16_t, backref_t);
uint16_t write_rle (uint8_t*, uint16_t, rle_t);
uint16_t write_raw (uint8_t*, uint16_t, uint8_t*, uint16_t);
void free_offsets();
// index of first locations of byte-tuples used to speed up LZ string search (unfinished)
tuple_t *offsets = NULL;
void free_offsets(tuple_t*);
// Compresses a file of up to 64 kb.
// unpacked/packed are 65536 byte buffers to read/from write to,
@ -98,6 +95,9 @@ size_t pack(uint8_t *unpacked, size_t inputsize, uint8_t *packed, int fast) {
// used to collect data which should be written uncompressed
uint8_t dontpack[LONG_RUN_SIZE];
uint16_t dontpacksize = 0;
// index of first locations of byte-tuples used to speed up LZ string search
tuple_t *offsets = NULL;
debug("inputsize = %d\n", inputsize);
@ -120,13 +120,13 @@ size_t pack(uint8_t *unpacked, size_t inputsize, uint8_t *packed, int fast) {
rle = rle_check(unpacked, unpacked + inpos, inputsize, fast);
// check for a potential back reference
if (rle.size < LONG_RUN_SIZE && inpos < inputsize - 3)
backref = ref_search(unpacked, unpacked + inpos, inputsize, fast);
backref = ref_search(unpacked, unpacked + inpos, inputsize, offsets, fast);
else backref.size = 0;
// if the backref is a better candidate, use it
if (backref.size > 3 && backref.size > rle.size) {
if (outpos + dontpacksize + backref.size >= DATA_SIZE) {
free_offsets();
free_offsets(offsets);
return 0;
}
@ -140,7 +140,7 @@ size_t pack(uint8_t *unpacked, size_t inputsize, uint8_t *packed, int fast) {
// or if the RLE is a better candidate, use it instead
else if (rle.size >= 2) {
if (outpos + dontpacksize + rle.size >= DATA_SIZE) {
free_offsets();
free_offsets(offsets);
return 0;
}
@ -157,7 +157,7 @@ size_t pack(uint8_t *unpacked, size_t inputsize, uint8_t *packed, int fast) {
dontpack[dontpacksize++] = unpacked[inpos++];
if (outpos + dontpacksize >= DATA_SIZE) {
free_offsets();
free_offsets(offsets);
return 0;
}
@ -171,7 +171,7 @@ size_t pack(uint8_t *unpacked, size_t inputsize, uint8_t *packed, int fast) {
// flush any remaining uncompressed data
if (outpos + dontpacksize + 1 > DATA_SIZE) {
free_offsets();
free_offsets(offsets);
return 0;
}
@ -180,11 +180,11 @@ size_t pack(uint8_t *unpacked, size_t inputsize, uint8_t *packed, int fast) {
//add the terminating byte
packed[outpos++] = 0xFF;
free_offsets();
free_offsets(offsets);
return (size_t)outpos;
}
void free_offsets() {
void free_offsets(tuple_t *offsets) {
tuple_t *curr, *temp;
HASH_ITER(hh, offsets, curr, temp) {
HASH_DEL(offsets, curr);
@ -411,7 +411,7 @@ rle_t rle_check (uint8_t *start, uint8_t *current, uint32_t insize, int fast) {
// Searches for the best possible back reference.
// start and current are positions within the uncompressed input stream.
// fast enables fast mode which only uses regular forward references
backref_t ref_search (uint8_t *start, uint8_t *current, uint32_t insize, int fast) {
backref_t ref_search (uint8_t *start, uint8_t *current, uint32_t insize, tuple_t *offsets, int fast) {
backref_t candidate = { 0, 0, 0 };
uint16_t size;
int currbytes;