X-Git-Url: https://wimlib.net/git/?p=wimlib;a=blobdiff_plain;f=src%2Flzms-compress.c;h=7c103f7b42150695b366ef69170b161a9160b432;hp=0e9f0c3657d996bdaf9fe2dc669abc699e1e7961;hb=dd38de3e27916c2d7fe97158c3df38c6b9b43e0d;hpb=b7071062542143113ad654d89ee6b0603b23b524

diff --git a/src/lzms-compress.c b/src/lzms-compress.c
index 0e9f0c36..7c103f7b 100644
--- a/src/lzms-compress.c
+++ b/src/lzms-compress.c
@@ -116,7 +116,7 @@ struct lzms_range_encoder {
 	 * lzms_range_encoder_raw.  */
 	struct lzms_range_encoder_raw *rc;
 
-	/* Bits recently encoded by this range encoder.  This are used as in
+	/* Bits recently encoded by this range encoder.  This is used as an
 	 * index into @prob_entries.  */
 	u32 state;
 
@@ -669,17 +669,9 @@ lzms_do_init_rc_costs(void)
 static void
 lzms_init_rc_costs(void)
 {
-	static bool done = false;
-	static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
-
-	if (unlikely(!done)) {
-		pthread_mutex_lock(&mutex);
-		if (!done) {
-			lzms_do_init_rc_costs();
-			done = true;
-		}
-		pthread_mutex_unlock(&mutex);
-	}
+	static pthread_once_t once = PTHREAD_ONCE_INIT;
+
+	pthread_once(&once, lzms_do_init_rc_costs);
 }
 
 /*
@@ -734,7 +726,7 @@ lzms_offset_cost(const struct lzms_huffman_encoder *enc, u32 offset)
 }
 
 static u32
-lzms_length_cost(const struct lzms_huffman_encoder *enc, u32 length)
+lzms_get_length_cost(const struct lzms_huffman_encoder *enc, u32 length)
 {
 	u32 slot;
 	u32 num_extra_bits;
@@ -782,9 +774,8 @@ lzms_get_literal_cost(struct lzms_compressor *ctx,
 }
 
 static u32
-lzms_get_lz_match_cost(struct lzms_compressor *ctx,
-		       struct lzms_adaptive_state *state,
-		       u32 length, u32 offset)
+lzms_get_lz_match_cost_nolen(struct lzms_compressor *ctx,
+			     struct lzms_adaptive_state *state, u32 offset)
 {
 	u32 cost = 0;
 	int recent_offset_idx;
@@ -827,7 +818,6 @@ lzms_get_lz_match_cost(struct lzms_compressor *ctx,
 			state->lru.recent_offsets[i] = state->lru.recent_offsets[i + 1];
 	}
 
-	cost += lzms_length_cost(&ctx->length_encoder, length);
 
 	state->lru.upcoming_offset = offset;
 	lzms_update_lz_lru_queues(&state->lru);
@@ -835,6 +825,15 @@ lzms_get_lz_match_cost(struct lzms_compressor *ctx,
 	return cost;
 }
 
+static u32
+lzms_get_lz_match_cost(struct lzms_compressor *ctx,
+		       struct lzms_adaptive_state *state,
+		       u32 length, u32 offset)
+{
+	return lzms_get_lz_match_cost_nolen(ctx, state, offset) +
+	       lzms_get_length_cost(&ctx->length_encoder, length);
+}
+
 static struct raw_match
 lzms_match_chooser_reverse_list(struct lzms_compressor *ctx, unsigned cur_pos)
 {
@@ -878,7 +877,6 @@ lzms_get_near_optimal_match(struct lzms_compressor *ctx)
 	u32 longest_len;
 	u32 longest_rep_len;
 	u32 longest_rep_offset;
-	struct raw_match *matchptr;
 	unsigned cur_pos;
 	unsigned end_pos;
 	struct lzms_adaptive_state initial_state;
@@ -896,7 +894,7 @@ lzms_get_near_optimal_match(struct lzms_compressor *ctx)
 	ctx->optimum_end_idx = 0;
 
 	longest_rep_len = ctx->params.min_match_length - 1;
-	if (lz_bt_get_position(&ctx->mf) >= 1) {
+	if (lz_bt_get_position(&ctx->mf) >= LZMS_MAX_INIT_RECENT_OFFSET) {
 		u32 limit = min(ctx->params.max_match_length,
 				lz_bt_get_remaining_size(&ctx->mf));
 		for (int i = 0; i < LZMS_NUM_RECENT_OFFSETS; i++) {
@@ -946,18 +944,26 @@ lzms_get_near_optimal_match(struct lzms_compressor *ctx)
 						     *(lz_bt_get_window_ptr(&ctx->mf) - 1));
 	ctx->optimum[1].prev.link = 0;
 
-	matchptr = matches;
-	for (u32 len = 2; len <= longest_len; len++) {
-		u32 offset = matchptr->offset;
-
-		ctx->optimum[len].state = initial_state;
-		ctx->optimum[len].prev.link = 0;
-		ctx->optimum[len].prev.match_offset = offset;
-		ctx->optimum[len].cost = lzms_get_lz_match_cost(ctx,
-								&ctx->optimum[len].state,
-								len, offset);
-		if (len == matchptr->len)
-			matchptr++;
+	for (u32 i = 0, len = 2; i < num_matches; i++) {
+		u32 offset = matches[i].offset;
+		struct lzms_adaptive_state state;
+		u32 position_cost;
+
+		state = initial_state;
+		position_cost = 0;
+		position_cost += lzms_get_lz_match_cost_nolen(ctx, &state, offset);
+
+		do {
+			u32 cost;
+
+			cost = position_cost;
+			cost += lzms_get_length_cost(&ctx->length_encoder, len);
+
+			ctx->optimum[len].state = state;
+			ctx->optimum[len].prev.link = 0;
+			ctx->optimum[len].prev.match_offset = offset;
+			ctx->optimum[len].cost = cost;
+		} while (++len <= matches[i].len);
 	}
 	end_pos = longest_len;
 
@@ -992,18 +998,20 @@ lzms_get_near_optimal_match(struct lzms_compressor *ctx)
 			return lzms_match_chooser_reverse_list(ctx, cur_pos);
 
 		longest_rep_len = ctx->params.min_match_length - 1;
-		u32 limit = min(ctx->params.max_match_length,
-				lz_bt_get_remaining_size(&ctx->mf));
-		for (int i = 0; i < LZMS_NUM_RECENT_OFFSETS; i++) {
-			u32 offset = ctx->optimum[cur_pos].state.lru.recent_offsets[i];
-			const u8 *strptr = lz_bt_get_window_ptr(&ctx->mf);
-			const u8 *matchptr = strptr - offset;
-			u32 len = 0;
-			while (len < limit && strptr[len] == matchptr[len])
-				len++;
-			if (len > longest_rep_len) {
-				longest_rep_len = len;
-				longest_rep_offset = offset;
+		if (lz_bt_get_position(&ctx->mf) >= LZMS_MAX_INIT_RECENT_OFFSET) {
+			u32 limit = min(ctx->params.max_match_length,
+					lz_bt_get_remaining_size(&ctx->mf));
+			for (int i = 0; i < LZMS_NUM_RECENT_OFFSETS; i++) {
+				u32 offset = ctx->optimum[cur_pos].state.lru.recent_offsets[i];
+				const u8 *strptr = lz_bt_get_window_ptr(&ctx->mf);
+				const u8 *matchptr = strptr - offset;
+				u32 len = 0;
+				while (len < limit && strptr[len] == matchptr[len])
+					len++;
+				if (len > longest_rep_len) {
+					longest_rep_len = len;
+					longest_rep_offset = offset;
+				}
 			}
 		}
 
@@ -1053,23 +1061,28 @@ lzms_get_near_optimal_match(struct lzms_compressor *ctx)
 			ctx->optimum[cur_pos + 1].prev.link = cur_pos;
 		}
 
-		matchptr = matches;
-		for (u32 len = 2; len <= longest_len; len++) {
-			u32 offset;
+		for (u32 i = 0, len = 2; i < num_matches; i++) {
+			u32 offset = matches[i].offset;
+			struct lzms_adaptive_state state;
+			u32 position_cost;
 
-			offset = matchptr->offset;
 			state = ctx->optimum[cur_pos].state;
+			position_cost = ctx->optimum[cur_pos].cost;
+			position_cost += lzms_get_lz_match_cost_nolen(ctx, &state, offset);
 
-			cost = ctx->optimum[cur_pos].cost +
-				lzms_get_lz_match_cost(ctx, &state, len, offset);
-			if (cost < ctx->optimum[cur_pos + len].cost) {
-				ctx->optimum[cur_pos + len].state = state;
-				ctx->optimum[cur_pos + len].prev.link = cur_pos;
-				ctx->optimum[cur_pos + len].prev.match_offset = offset;
-				ctx->optimum[cur_pos + len].cost = cost;
-			}
-			if (len == matchptr->len)
-				matchptr++;
+			do {
+				u32 cost;
+
+				cost = position_cost;
+				cost += lzms_get_length_cost(&ctx->length_encoder, len);
+
+				if (cost < ctx->optimum[cur_pos + len].cost) {
+					ctx->optimum[cur_pos + len].state = state;
+					ctx->optimum[cur_pos + len].prev.link = cur_pos;
+					ctx->optimum[cur_pos + len].prev.match_offset = offset;
+					ctx->optimum[cur_pos + len].cost = cost;
+				}
+			} while (++len <= matches[i].len);
 		}
 
 		if (longest_rep_len >= ctx->params.min_match_length) {