*/
#ifdef HAVE_CONFIG_H
-# include "config.h"
+# include <config.h>
#endif
#include "wimlib/compress.h"
* indicating the end of the hash chain.
*/
static inline unsigned
-insert_string(u16 hash_tab[], u16 prev_tab[],
+insert_string(input_idx_t hash_tab[], input_idx_t prev_tab[],
const u8 window[], unsigned str_pos,
unsigned hash)
{
*/
static unsigned
longest_match(const u8 window[], unsigned bytes_remaining,
- unsigned strstart, const u16 prev_tab[],
+ unsigned strstart, const input_idx_t prev_tab[],
unsigned cur_match, unsigned prev_len,
unsigned *match_start_ret,
const struct lz_params *params)
* Determines the sequence of matches and literals that a block of data will be
* compressed to.
*
- * @uncompressed_data: The data that is to be compressed.
- * @uncompressed_len: The length of @uncompressed_data, in bytes.
- * @match_tab: An array for the intermediate representation of matches.
- * @record_match: A function that will be called to produce the
- * intermediate representation of a match, given
- * the offset and length. This function should also
- * update the appropriate symbol frequency counts
- * so that any needed Huffman codes can be made
- * later.
- * @record_literal: A function that will be called to produce the
- * intermediate representation of a literal, given
- * the character of the literal. This function
- * should also update the appropriate symbol
- * frequency counts so that any needed Huffman
- * codes can be made later.
- * @record_match_arg_1:
- * @record_match_arg_2: Extra arguments to be passed to @record_match.
- * @record_literal_arg: Extra arguments to be passed to @record_literal.
+ * @window: The data that is to be compressed.
+ * @window_size: The length of @window, in bytes.
+ * @record_match: Consumer for matches.
+ * @record_literal: Consumer for literals.
+ * @record_ctx: Context passed to @record_match and @record_literal.
* @params: Structure that contains parameters that affect how the
* analysis proceeds (mainly how good the matches
* have to be).
- *
- * Returns the total number of matches and literal bytes that were found; this
- * is the number of slots in @match_tab that have been filled with the
- * intermediate representation of a match or literal byte.
*/
-unsigned
-lz_analyze_block(const u8 uncompressed_data[],
- unsigned uncompressed_len,
- u32 match_tab[],
+void
+lz_analyze_block(const u8 window[],
+ input_idx_t window_size,
lz_record_match_t record_match,
lz_record_literal_t record_literal,
- void *record_match_arg1,
- void *record_match_arg2,
- void *record_literal_arg,
+ void *record_ctx,
const struct lz_params *params)
{
- unsigned cur_match_pos = 0;
unsigned cur_input_pos = 0;
unsigned hash = 0;
unsigned hash_head = 0;
unsigned match_len = params->min_match - 1;
unsigned match_start = 0;
bool match_available = false;
- u16 hash_tab[HASH_SIZE];
- u32 match;
- u16 prev_tab[uncompressed_len];
+ input_idx_t hash_tab[HASH_SIZE];
+ input_idx_t prev_tab[window_size];
ZERO_ARRAY(hash_tab);
- ZERO_ARRAY(prev_tab);
do {
/* If there are at least 3 characters remaining in the input,
* insert the 3-character string beginning at
- * uncompressed_data[cur_input_pos] into the hash table.
+ * window[cur_input_pos] into the hash table.
*
* hash_head is set to the index of the previous string in the
* hash bucket, or 0 if there is no such string */
- if (uncompressed_len - cur_input_pos >= params->min_match) {
+ if (window_size - cur_input_pos >= params->min_match) {
hash = insert_string(hash_tab, prev_tab,
- uncompressed_data,
+ window,
cur_input_pos, hash);
hash_head = prev_tab[cur_input_pos];
} else {
* string of window index 0 (in particular we have to
* avoid a match of the string with itself at the start
* of the input file). */
- match_len = longest_match(uncompressed_data,
- uncompressed_len - cur_input_pos,
+ match_len = longest_match(window,
+ window_size - cur_input_pos,
cur_input_pos, prev_tab,
hash_head, prev_len,
&match_start, params);
*/
if (prev_len >= params->min_match && match_len <= prev_len) {
- /* Do not insert strings in hash table beyond this. */
- unsigned max_insert = uncompressed_len - params->min_match;
-
- /*DEBUG("Recording match (pos = %u, offset = %u, len = %u)\n",*/
- /*cur_input_pos - 1, */
- /*cur_input_pos - 1 - prev_start,*/
- /*prev_len);*/
- match = (*record_match)(cur_input_pos - 1 - prev_start,
- prev_len,
- record_match_arg1,
- record_match_arg2);
+ (*record_match)(prev_len,
+ cur_input_pos - 1 - prev_start,
+ record_ctx);
- match_tab[cur_match_pos++] = match;
+ /* Insert in hash table all strings up to the end of the
+ * match. strstart-1 and strstart are already inserted.
+ * If there is not enough lookahead, the last two
+ * strings are not inserted in the hash table. */
- /* Insert in hash table all strings up to the end of the match.
- * strstart-1 and strstart are already inserted. If there is not
- * enough lookahead, the last two strings are not inserted in
- * the hash table.
- */
+ /* Do not insert strings in hash table beyond this. */
+ unsigned max_insert = window_size - params->min_match;
#if LZ_MIN_MATCH == 2
if (prev_len >= 3)
#endif
do {
if (++cur_input_pos <= max_insert) {
hash = insert_string(hash_tab, prev_tab,
- uncompressed_data,
+ window,
cur_input_pos,
hash);
}
match_available = false;
match_len = params->min_match - 1;
} else if (match_available) {
- /* If there was no match at the previous position, output a
- * single literal. If there was a match but the current match
- * is longer, truncate the previous match to a single literal.
- */
-
- /*DEBUG("Recording litrl (pos = %u, value = %u)\n",*/
- /*cur_input_pos - 1, */
- /*uncompressed_data[cur_input_pos - 1]);*/
-
- match = (*record_literal)(
- uncompressed_data[cur_input_pos - 1],
- record_literal_arg);
- match_tab[cur_match_pos++] = match;
+ /* If there was no match at the previous position,
+ * output a single literal. If there was a match but the
+ * current match is longer, truncate the previous match
+ * to a single literal. */
+ (*record_literal)(window[cur_input_pos - 1], record_ctx);
} else {
/* There is no previous match to compare with, wait for
* the next step to decide. */
match_available = true;
}
- } while (++cur_input_pos < uncompressed_len);
-
- if (match_available) {
- match = (*record_literal)(uncompressed_data[cur_input_pos - 1],
- record_literal_arg);
- match_tab[cur_match_pos++] = match;
- }
- return cur_match_pos;
+ } while (++cur_input_pos < window_size);
+
+ if (match_available)
+ (*record_literal)(window[cur_input_pos - 1], record_ctx);
}
git://wimlib.net / wimlib / blobdiff