X-Git-Url: https://wimlib.net/git/?p=wimlib;a=blobdiff_plain;f=src%2Flzms-compress.c;h=21c82ea87bf9f93e2005406018960f73bb6488f6;hp=b81de0528593b47637b94f1a1d7028c6a42555cc;hb=737676a62120667d39b5a00efc5b3e84624fa744;hpb=07df77014fd3d532bdece9a350d0f96795400055

diff --git a/src/lzms-compress.c b/src/lzms-compress.c
index b81de052..21c82ea8 100644
--- a/src/lzms-compress.c
+++ b/src/lzms-compress.c
@@ -3,7 +3,7 @@
  */
 
 /*
- * Copyright (C) 2013 Eric Biggers
+ * Copyright (C) 2013, 2014 Eric Biggers
  *
  * This file is part of wimlib, a library for working with WIM files.
  *
@@ -24,6 +24,9 @@
 /* This a compressor for the LZMS compression format.  More details about this
  * format can be found in lzms-decompress.c.
  *
+ * Also see lzx-compress.c for general information about match-finding and
+ * match-choosing that also applies to this LZMS compressor.
+ *
  * NOTE: this compressor currently does not code any delta matches.
  */
 
@@ -31,14 +34,13 @@
 #  include "config.h"
 #endif
 
-#include "wimlib.h"
 #include "wimlib/assert.h"
 #include "wimlib/compiler.h"
 #include "wimlib/compressor_ops.h"
 #include "wimlib/compress_common.h"
 #include "wimlib/endianness.h"
 #include "wimlib/error.h"
-#include "wimlib/lz_sarray.h"
+#include "wimlib/lz_mf.h"
 #include "wimlib/lzms.h"
 #include "wimlib/util.h"
 
@@ -46,18 +48,6 @@
 #include <limits.h>
 #include <pthread.h>
 
-struct lzms_compressor;
-struct lzms_adaptive_state {
-	struct lzms_lz_lru_queues lru;
-	u8 main_state;
-	u8 match_state;
-	u8 lz_match_state;
-	u8 lz_repeat_match_state[LZMS_NUM_RECENT_OFFSETS - 1];
-};
-#define LZ_ADAPTIVE_STATE struct lzms_adaptive_state
-#define LZ_COMPRESSOR	  struct lzms_compressor
-#include "wimlib/lz_optimal.h"
-
 /* Stucture used for writing raw bits to the end of the LZMS-compressed data as
  * a series of 16-bit little endian coding units.  */
 struct lzms_output_bitstream {
@@ -124,7 +114,7 @@ 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;
 
@@ -163,7 +153,14 @@ struct lzms_huffman_encoder {
 	u8 lens[LZMS_MAX_NUM_SYMS];
 
 	/* The codeword of each symbol in the Huffman code.  */
-	u16 codewords[LZMS_MAX_NUM_SYMS];
+	u32 codewords[LZMS_MAX_NUM_SYMS];
+};
+
+struct lzms_compressor_params {
+	u32 min_match_length;
+	u32 nice_match_length;
+	u32 max_search_depth;
+	u32 optim_array_length;
 };
 
 /* State of the LZMS compressor.  */
@@ -177,19 +174,24 @@ struct lzms_compressor {
 	/* Size of the data in @buffer.  */
 	u32 window_size;
 
-	/* Suffix array match-finder.  */
-	struct lz_sarray lz_sarray;
+	/* Lempel-Ziv match-finder.  */
+	struct lz_mf *mf;
 
 	/* Temporary space to store found matches.  */
-	struct raw_match *matches;
+	struct lz_match *matches;
 
-	/* Match-chooser.  */
-	struct lz_match_chooser mc;
+	/* Match-chooser data.  */
+	struct lzms_mc_pos_data *optimum;
+	unsigned optimum_cur_idx;
+	unsigned optimum_end_idx;
 
 	/* Maximum block size this compressor instantiation allows.  This is the
 	 * allocated size of @window.  */
 	u32 max_block_size;
 
+	/* Compression parameters.  */
+	struct lzms_compressor_params params;
+
 	/* Raw range encoder which outputs to the beginning of the compressed
 	 * data buffer, proceeding forwards.  */
 	struct lzms_range_encoder_raw rc;
@@ -220,6 +222,28 @@ struct lzms_compressor {
 	s32 last_target_usages[65536];
 };
 
+struct lzms_mc_pos_data {
+	u32 cost;
+#define MC_INFINITE_COST ((u32)~0UL)
+	union {
+		struct {
+			u32 link;
+			u32 match_offset;
+		} prev;
+		struct {
+			u32 link;
+			u32 match_offset;
+		} next;
+	};
+	struct lzms_adaptive_state {
+		struct lzms_lz_lru_queues lru;
+		u8 main_state;
+		u8 match_state;
+		u8 lz_match_state;
+		u8 lz_repeat_match_state[LZMS_NUM_RECENT_OFFSETS - 1];
+	} state;
+};
+
 /* Initialize the output bitstream @os to write forwards to the specified
  * compressed data buffer @out that is @out_limit 16-bit integers long.  */
 static void
@@ -534,7 +558,7 @@ lzms_encode_lz_match(struct lzms_compressor *ctx, u32 length, u32 offset)
 	/* Main bit: 1 = a match, not a literal.  */
 	lzms_range_encode_bit(&ctx->main_range_encoder, 1);
 
-	/* Match bit: 0 = a LZ match, not a delta match.  */
+	/* Match bit: 0 = an LZ match, not a delta match.  */
 	lzms_range_encode_bit(&ctx->match_range_encoder, 0);
 
 	/* Determine if the offset can be represented as a recent offset.  */
@@ -585,21 +609,6 @@ lzms_encode_lz_match(struct lzms_compressor *ctx, u32 length, u32 offset)
 	lzms_end_encode_item(ctx, length);
 }
 
-/* Fast heuristic cost evaluation to use in the inner loop of the match-finder.
- * Unlike lzms_get_lz_match_cost(), which does a true cost evaluation, this
- * simply prioritize matches based on their offset.  */
-static input_idx_t
-lzms_lz_match_cost_fast(input_idx_t length, input_idx_t offset, const void *_lru)
-{
-	const struct lzms_lz_lru_queues *lru = _lru;
-
-	for (input_idx_t i = 0; i < LZMS_NUM_RECENT_OFFSETS; i++)
-		if (offset == lru->recent_offsets[i])
-			return i;
-
-	return offset;
-}
-
 #define LZMS_COST_SHIFT 5
 
 /*#define LZMS_RC_COSTS_USE_FLOATING_POINT*/
@@ -666,17 +675,9 @@ 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);
 }
 
 /*
@@ -731,7 +732,7 @@ 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;
@@ -749,29 +750,22 @@ lzms_length_cost(const struct lzms_huffman_encoder *enc, u32 length)
 }
 
 static u32
-lzms_get_matches(struct lzms_compressor *ctx,
-		 const struct lzms_adaptive_state *state,
-		 struct raw_match **matches_ret)
+lzms_get_matches(struct lzms_compressor *ctx, struct lz_match **matches_ret)
 {
 	*matches_ret = ctx->matches;
-	return lz_sarray_get_matches(&ctx->lz_sarray,
-				     ctx->matches,
-				     lzms_lz_match_cost_fast,
-				     &state->lru);
+	return lz_mf_get_matches(ctx->mf, ctx->matches);
 }
 
 static void
-lzms_skip_bytes(struct lzms_compressor *ctx, input_idx_t n)
+lzms_skip_bytes(struct lzms_compressor *ctx, u32 n)
 {
-	while (n--)
-		lz_sarray_skip_position(&ctx->lz_sarray);
+	lz_mf_skip_positions(ctx->mf, n);
 }
 
 static u32
-lzms_get_prev_literal_cost(struct lzms_compressor *ctx,
-			   struct lzms_adaptive_state *state)
+lzms_get_literal_cost(struct lzms_compressor *ctx,
+		      struct lzms_adaptive_state *state, u8 literal)
 {
-	u8 literal = ctx->window[lz_sarray_get_pos(&ctx->lz_sarray) - 1];
 	u32 cost = 0;
 
 	state->lru.upcoming_offset = 0;
@@ -786,9 +780,8 @@ lzms_get_prev_literal_cost(struct lzms_compressor *ctx,
 }
 
 static u32
-lzms_get_lz_match_cost(struct lzms_compressor *ctx,
-		       struct lzms_adaptive_state *state,
-		       input_idx_t length, input_idx_t 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;
@@ -831,7 +824,6 @@ 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);
@@ -839,25 +831,288 @@ lzms_get_lz_match_cost(struct lzms_compressor *ctx,
 	return cost;
 }
 
-static struct raw_match
-lzms_get_near_optimal_match(struct lzms_compressor *ctx)
+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 lz_match
+lzms_match_chooser_reverse_list(struct lzms_compressor *ctx, unsigned cur_pos)
 {
+	unsigned prev_link, saved_prev_link;
+	unsigned prev_match_offset, saved_prev_match_offset;
+
+	ctx->optimum_end_idx = cur_pos;
+
+	saved_prev_link = ctx->optimum[cur_pos].prev.link;
+	saved_prev_match_offset = ctx->optimum[cur_pos].prev.match_offset;
+
+	do {
+		prev_link = saved_prev_link;
+		prev_match_offset = saved_prev_match_offset;
+
+		saved_prev_link = ctx->optimum[prev_link].prev.link;
+		saved_prev_match_offset = ctx->optimum[prev_link].prev.match_offset;
+
+		ctx->optimum[prev_link].next.link = cur_pos;
+		ctx->optimum[prev_link].next.match_offset = prev_match_offset;
+
+		cur_pos = prev_link;
+	} while (cur_pos != 0);
+
+	ctx->optimum_cur_idx = ctx->optimum[0].next.link;
+
+	return (struct lz_match)
+		{ .len = ctx->optimum_cur_idx,
+		  .offset = ctx->optimum[0].next.match_offset,
+		};
+}
+
+/* This is similar to lzx_choose_near_optimal_item() in lzx-compress.c.
+ * Read that one if you want to understand it.  */
+static struct lz_match
+lzms_get_near_optimal_item(struct lzms_compressor *ctx)
+{
+	u32 num_matches;
+	struct lz_match *matches;
+	struct lz_match match;
+	u32 longest_len;
+	u32 longest_rep_len;
+	u32 longest_rep_offset;
+	unsigned cur_pos;
+	unsigned end_pos;
 	struct lzms_adaptive_state initial_state;
 
+	if (ctx->optimum_cur_idx != ctx->optimum_end_idx) {
+		match.len = ctx->optimum[ctx->optimum_cur_idx].next.link -
+				    ctx->optimum_cur_idx;
+		match.offset = ctx->optimum[ctx->optimum_cur_idx].next.match_offset;
+
+		ctx->optimum_cur_idx = ctx->optimum[ctx->optimum_cur_idx].next.link;
+		return match;
+	}
+
+	ctx->optimum_cur_idx = 0;
+	ctx->optimum_end_idx = 0;
+
+	longest_rep_len = ctx->params.min_match_length - 1;
+	if (lz_mf_get_position(ctx->mf) >= LZMS_MAX_INIT_RECENT_OFFSET) {
+		u32 limit = lz_mf_get_bytes_remaining(ctx->mf);
+		for (int i = 0; i < LZMS_NUM_RECENT_OFFSETS; i++) {
+			u32 offset = ctx->lru.lz.recent_offsets[i];
+			const u8 *strptr = lz_mf_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 (longest_rep_len >= ctx->params.nice_match_length) {
+		lzms_skip_bytes(ctx, longest_rep_len);
+		return (struct lz_match) {
+			.len = longest_rep_len,
+			.offset = longest_rep_offset,
+		};
+	}
+
+	num_matches = lzms_get_matches(ctx, &matches);
+
+	if (num_matches) {
+		longest_len = matches[num_matches - 1].len;
+		if (longest_len >= ctx->params.nice_match_length) {
+			lzms_skip_bytes(ctx, longest_len - 1);
+			return matches[num_matches - 1];
+		}
+	} else {
+		longest_len = 1;
+	}
+
 	initial_state.lru = ctx->lru.lz;
 	initial_state.main_state = ctx->main_range_encoder.state;
 	initial_state.match_state = ctx->match_range_encoder.state;
 	initial_state.lz_match_state = ctx->lz_match_range_encoder.state;
 	for (int i = 0; i < LZMS_NUM_RECENT_OFFSETS - 1; i++)
-		initial_state.lz_repeat_match_state[i] =
-			ctx->lz_repeat_match_range_encoders[i].state;
-	return lz_get_near_optimal_match(&ctx->mc,
-					 lzms_get_matches,
-					 lzms_skip_bytes,
-					 lzms_get_prev_literal_cost,
-					 lzms_get_lz_match_cost,
-					 ctx,
-					 &initial_state);
+		initial_state.lz_repeat_match_state[i] = ctx->lz_repeat_match_range_encoders[i].state;
+
+	ctx->optimum[1].state = initial_state;
+	ctx->optimum[1].cost = lzms_get_literal_cost(ctx,
+						     &ctx->optimum[1].state,
+						     *(lz_mf_get_window_ptr(ctx->mf) - 1));
+	ctx->optimum[1].prev.link = 0;
+
+	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;
+
+	if (longest_rep_len >= ctx->params.min_match_length) {
+		struct lzms_adaptive_state state;
+		u32 cost;
+
+		while (end_pos < longest_rep_len)
+			ctx->optimum[++end_pos].cost = MC_INFINITE_COST;
+
+		state = initial_state;
+		cost = lzms_get_lz_match_cost(ctx,
+					      &state,
+					      longest_rep_len,
+					      longest_rep_offset);
+		if (cost <= ctx->optimum[longest_rep_len].cost) {
+			ctx->optimum[longest_rep_len].state = state;
+			ctx->optimum[longest_rep_len].prev.link = 0;
+			ctx->optimum[longest_rep_len].prev.match_offset = longest_rep_offset;
+			ctx->optimum[longest_rep_len].cost = cost;
+		}
+	}
+
+	cur_pos = 0;
+	for (;;) {
+		u32 cost;
+		struct lzms_adaptive_state state;
+
+		cur_pos++;
+
+		if (cur_pos == end_pos || cur_pos == ctx->params.optim_array_length)
+			return lzms_match_chooser_reverse_list(ctx, cur_pos);
+
+		longest_rep_len = ctx->params.min_match_length - 1;
+		if (lz_mf_get_position(ctx->mf) >= LZMS_MAX_INIT_RECENT_OFFSET) {
+			u32 limit = lz_mf_get_bytes_remaining(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_mf_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 (longest_rep_len >= ctx->params.nice_match_length) {
+			match = lzms_match_chooser_reverse_list(ctx, cur_pos);
+
+			ctx->optimum[cur_pos].next.match_offset = longest_rep_offset;
+			ctx->optimum[cur_pos].next.link = cur_pos + longest_rep_len;
+			ctx->optimum_end_idx = cur_pos + longest_rep_len;
+
+			lzms_skip_bytes(ctx, longest_rep_len);
+
+			return match;
+		}
+
+		num_matches = lzms_get_matches(ctx, &matches);
+
+		if (num_matches) {
+			longest_len = matches[num_matches - 1].len;
+			if (longest_len >= ctx->params.nice_match_length) {
+				match = lzms_match_chooser_reverse_list(ctx, cur_pos);
+
+				ctx->optimum[cur_pos].next.match_offset =
+					matches[num_matches - 1].offset;
+				ctx->optimum[cur_pos].next.link = cur_pos + longest_len;
+				ctx->optimum_end_idx = cur_pos + longest_len;
+
+				lzms_skip_bytes(ctx, longest_len - 1);
+
+				return match;
+			}
+		} else {
+			longest_len = 1;
+		}
+
+		while (end_pos < cur_pos + longest_len)
+			ctx->optimum[++end_pos].cost = MC_INFINITE_COST;
+
+		state = ctx->optimum[cur_pos].state;
+		cost = ctx->optimum[cur_pos].cost +
+			lzms_get_literal_cost(ctx,
+					      &state,
+					      *(lz_mf_get_window_ptr(ctx->mf) - 1));
+		if (cost < ctx->optimum[cur_pos + 1].cost) {
+			ctx->optimum[cur_pos + 1].state = state;
+			ctx->optimum[cur_pos + 1].cost = cost;
+			ctx->optimum[cur_pos + 1].prev.link = cur_pos;
+		}
+
+		for (u32 i = 0, len = 2; i < num_matches; i++) {
+			u32 offset = matches[i].offset;
+			struct lzms_adaptive_state state;
+			u32 position_cost;
+
+			state = ctx->optimum[cur_pos].state;
+			position_cost = ctx->optimum[cur_pos].cost;
+			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);
+
+				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) {
+
+			while (end_pos < cur_pos + longest_rep_len)
+				ctx->optimum[++end_pos].cost = MC_INFINITE_COST;
+
+			state = ctx->optimum[cur_pos].state;
+
+			cost = ctx->optimum[cur_pos].cost +
+				lzms_get_lz_match_cost(ctx,
+						       &state,
+						       longest_rep_len,
+						       longest_rep_offset);
+			if (cost <= ctx->optimum[cur_pos + longest_rep_len].cost) {
+				ctx->optimum[cur_pos + longest_rep_len].state =
+					state;
+				ctx->optimum[cur_pos + longest_rep_len].prev.link =
+					cur_pos;
+				ctx->optimum[cur_pos + longest_rep_len].prev.match_offset =
+					longest_rep_offset;
+				ctx->optimum[cur_pos + longest_rep_len].cost =
+					cost;
+			}
+		}
+	}
 }
 
 /*
@@ -865,39 +1120,33 @@ lzms_get_near_optimal_match(struct lzms_compressor *ctx)
  *
  * Notes:
  *
- * - This uses near-optimal LZ parsing backed by a suffix-array match-finder.
- *   More details can be found in the corresponding files (lz_optimal.h,
- *   lz_sarray.{h,c}).
- *
- * - This does not output any delta matches.  It would take a specialized
- *   algorithm to find them, then more code in lz_optimal.h and here to handle
- *   evaluating and outputting them.
+ * - This does not output any delta matches.
  *
  * - The costs of literals and matches are estimated using the range encoder
  *   states and the semi-adaptive Huffman codes.  Except for range encoding
  *   states, costs are assumed to be constant throughout a single run of the
- *   parsing algorithm, which can parse up to @optim_array_length (from the
- *   `struct wimlib_lzms_compressor_params') bytes of data.  This introduces a
- *   source of inaccuracy because the probabilities and Huffman codes can change
- *   over this part of the data.
+ *   parsing algorithm, which can parse up to @optim_array_length bytes of data.
+ *   This introduces a source of inaccuracy because the probabilities and
+ *   Huffman codes can change over this part of the data.
  */
 static void
 lzms_encode(struct lzms_compressor *ctx)
 {
-	struct raw_match match;
+	struct lz_match item;
 
-	/* Load window into suffix array match-finder.  */
-	lz_sarray_load_window(&ctx->lz_sarray, ctx->window, ctx->window_size);
+	/* Load window into the match-finder.  */
+	lz_mf_load_window(ctx->mf, ctx->window, ctx->window_size);
 
 	/* Reset the match-chooser.  */
-	lz_match_chooser_begin(&ctx->mc);
+	ctx->optimum_cur_idx = 0;
+	ctx->optimum_end_idx = 0;
 
 	while (ctx->cur_window_pos != ctx->window_size) {
-		match = lzms_get_near_optimal_match(ctx);
-		if (match.len <= 1)
+		item = lzms_get_near_optimal_item(ctx);
+		if (item.len <= 1)
 			lzms_encode_literal(ctx, ctx->window[ctx->cur_window_pos]);
 		else
-			lzms_encode_lz_match(ctx, match.len, match.offset);
+			lzms_encode_lz_match(ctx, item.len, item.offset);
 	}
 }
 
@@ -1054,6 +1303,110 @@ lzms_finalize(struct lzms_compressor *ctx, u8 *cdata, size_t csize_avail)
 	return compressed_size;
 }
 
+
+static void
+lzms_build_params(unsigned int compression_level,
+		  struct lzms_compressor_params *lzms_params)
+{
+	lzms_params->min_match_length  = (compression_level >= 50) ? 2 : 3;
+	lzms_params->nice_match_length = max(((u64)compression_level * 32) / 50,
+					     lzms_params->min_match_length);
+	lzms_params->max_search_depth  = ((u64)compression_level * 50) / 50;
+	lzms_params->optim_array_length = 224 + compression_level * 16;
+}
+
+static void
+lzms_build_mf_params(const struct lzms_compressor_params *lzms_params,
+		     u32 max_window_size, struct lz_mf_params *mf_params)
+{
+	memset(mf_params, 0, sizeof(*mf_params));
+
+	mf_params->algorithm = LZ_MF_DEFAULT;
+	mf_params->max_window_size = max_window_size;
+	mf_params->min_match_len = lzms_params->min_match_length;
+	mf_params->max_search_depth = lzms_params->max_search_depth;
+	mf_params->nice_match_len = lzms_params->nice_match_length;
+}
+
+static void
+lzms_free_compressor(void *_ctx);
+
+static u64
+lzms_get_needed_memory(size_t max_block_size, unsigned int compression_level)
+{
+	struct lzms_compressor_params params;
+	u64 size = 0;
+
+	if (max_block_size >= INT32_MAX)
+		return 0;
+
+	lzms_build_params(compression_level, &params);
+
+	size += sizeof(struct lzms_compressor);
+	size += max_block_size;
+	size += lz_mf_get_needed_memory(LZ_MF_DEFAULT, max_block_size);
+	size += params.max_search_depth * sizeof(struct lz_match);
+	size += (params.optim_array_length + params.nice_match_length) *
+		sizeof(struct lzms_mc_pos_data);
+
+	return size;
+}
+
+static int
+lzms_create_compressor(size_t max_block_size, unsigned int compression_level,
+		       void **ctx_ret)
+{
+	struct lzms_compressor *ctx;
+	struct lzms_compressor_params params;
+	struct lz_mf_params mf_params;
+
+	if (max_block_size >= INT32_MAX)
+		return WIMLIB_ERR_INVALID_PARAM;
+
+	lzms_build_params(compression_level, &params);
+	lzms_build_mf_params(&params, max_block_size, &mf_params);
+	if (!lz_mf_params_valid(&mf_params))
+		return WIMLIB_ERR_INVALID_PARAM;
+
+	ctx = CALLOC(1, sizeof(struct lzms_compressor));
+	if (!ctx)
+		goto oom;
+
+	ctx->params = params;
+	ctx->max_block_size = max_block_size;
+
+	ctx->window = MALLOC(max_block_size);
+	if (!ctx->window)
+		goto oom;
+
+	ctx->mf = lz_mf_alloc(&mf_params);
+	if (!ctx->mf)
+		goto oom;
+
+	ctx->matches = MALLOC(params.max_search_depth * sizeof(struct lz_match));
+	if (!ctx->matches)
+		goto oom;
+
+	ctx->optimum = MALLOC((params.optim_array_length +
+			       params.nice_match_length) *
+				sizeof(struct lzms_mc_pos_data));
+	if (!ctx->optimum)
+		goto oom;
+
+	/* Initialize position and length slot data if not done already.  */
+	lzms_init_slots();
+
+	/* Initialize range encoding cost table if not done already.  */
+	lzms_init_rc_costs();
+
+	*ctx_ret = ctx;
+	return 0;
+
+oom:
+	lzms_free_compressor(ctx);
+	return WIMLIB_ERR_NOMEM;
+}
+
 static size_t
 lzms_compress(const void *uncompressed_data, size_t uncompressed_size,
 	      void *compressed_data, size_t compressed_size_avail, void *_ctx)
@@ -1064,15 +1417,6 @@ lzms_compress(const void *uncompressed_data, size_t uncompressed_size,
 	LZMS_DEBUG("uncompressed_size=%zu, compressed_size_avail=%zu",
 		   uncompressed_size, compressed_size_avail);
 
-	/* Make sure the uncompressed size is compatible with this compressor.
-	 */
-	if (uncompressed_size > ctx->max_block_size) {
-		LZMS_DEBUG("Can't compress %zu bytes: LZMS context "
-			   "only supports %u bytes",
-			   uncompressed_size, ctx->max_block_size);
-		return 0;
-	}
-
 	/* Don't bother compressing extremely small inputs.  */
 	if (uncompressed_size < 4) {
 		LZMS_DEBUG("Input too small to bother compressing.");
@@ -1110,47 +1454,6 @@ lzms_compress(const void *uncompressed_data, size_t uncompressed_size,
 	LZMS_DEBUG("Compressed %zu => %zu bytes",
 		   uncompressed_size, compressed_size);
 
-#if defined(ENABLE_VERIFY_COMPRESSION) || defined(ENABLE_LZMS_DEBUG)
-	/* Verify that we really get the same thing back when decompressing.  */
-	{
-		struct wimlib_decompressor *decompressor;
-
-		LZMS_DEBUG("Verifying LZMS compression.");
-
-		if (0 == wimlib_create_decompressor(WIMLIB_COMPRESSION_TYPE_LZMS,
-						    ctx->max_block_size,
-						    NULL,
-						    &decompressor))
-		{
-			int ret;
-			ret = wimlib_decompress(compressed_data,
-						compressed_size,
-						ctx->window,
-						uncompressed_size,
-						decompressor);
-			wimlib_free_decompressor(decompressor);
-
-			if (ret) {
-				ERROR("Failed to decompress data we "
-				      "compressed using LZMS algorithm");
-				wimlib_assert(0);
-				return 0;
-			}
-			if (memcmp(uncompressed_data, ctx->window,
-				   uncompressed_size))
-			{
-				ERROR("Data we compressed using LZMS algorithm "
-				      "didn't decompress to original");
-				wimlib_assert(0);
-				return 0;
-			}
-		} else {
-			WARNING("Failed to create decompressor for "
-				"data verification!");
-		}
-	}
-#endif /* ENABLE_LZMS_DEBUG || ENABLE_VERIFY_COMPRESSION  */
-
 	return compressed_size;
 }
 
@@ -1161,138 +1464,14 @@ lzms_free_compressor(void *_ctx)
 
 	if (ctx) {
 		FREE(ctx->window);
+		lz_mf_free(ctx->mf);
 		FREE(ctx->matches);
-		lz_sarray_destroy(&ctx->lz_sarray);
-		lz_match_chooser_destroy(&ctx->mc);
+		FREE(ctx->optimum);
 		FREE(ctx);
 	}
 }
 
-static const struct wimlib_lzms_compressor_params lzms_default = {
-	.hdr = {
-		.size = sizeof(struct wimlib_lzms_compressor_params),
-	},
-	.min_match_length = 2,
-	.max_match_length = UINT32_MAX,
-	.nice_match_length = 32,
-	.max_search_depth = 50,
-	.max_matches_per_pos = 3,
-	.optim_array_length = 1024,
-};
-
-static bool
-lzms_params_valid(const struct wimlib_compressor_params_header *);
-
-static const struct wimlib_lzms_compressor_params *
-lzms_get_params(const struct wimlib_compressor_params_header *_params)
-{
-	const struct wimlib_lzms_compressor_params *params =
-		(const struct wimlib_lzms_compressor_params*)_params;
-
-	if (params == NULL)
-		params = &lzms_default;
-
-	LZMS_ASSERT(lzms_params_valid(&params->hdr));
-
-	return params;
-}
-
-static int
-lzms_create_compressor(size_t max_block_size,
-		       const struct wimlib_compressor_params_header *_params,
-		       void **ctx_ret)
-{
-	struct lzms_compressor *ctx;
-	const struct wimlib_lzms_compressor_params *params = lzms_get_params(_params);
-
-	if (max_block_size == 0 || max_block_size >= INT32_MAX) {
-		LZMS_DEBUG("Invalid max_block_size (%u)", max_block_size);
-		return WIMLIB_ERR_INVALID_PARAM;
-	}
-
-	ctx = CALLOC(1, sizeof(struct lzms_compressor));
-	if (ctx == NULL)
-		goto oom;
-
-	ctx->window = MALLOC(max_block_size);
-	if (ctx->window == NULL)
-		goto oom;
-
-	ctx->matches = MALLOC(min(params->max_match_length -
-					params->min_match_length + 1,
-				  params->max_matches_per_pos) *
-				sizeof(ctx->matches[0]));
-	if (ctx->matches == NULL)
-		goto oom;
-
-	if (!lz_sarray_init(&ctx->lz_sarray, max_block_size,
-			    params->min_match_length,
-			    min(params->max_match_length, LZ_SARRAY_LEN_MAX),
-			    params->max_search_depth,
-			    params->max_matches_per_pos))
-		goto oom;
-
-	if (!lz_match_chooser_init(&ctx->mc,
-				   params->optim_array_length,
-				   params->nice_match_length,
-				   params->max_match_length))
-		goto oom;
-
-	/* Initialize position and length slot data if not done already.  */
-	lzms_init_slots();
-
-	/* Initialize range encoding cost table if not done already.  */
-	lzms_init_rc_costs();
-
-	ctx->max_block_size = max_block_size;
-
-	*ctx_ret = ctx;
-	return 0;
-
-oom:
-	lzms_free_compressor(ctx);
-	return WIMLIB_ERR_NOMEM;
-}
-
-static u64
-lzms_get_needed_memory(size_t max_block_size,
-		       const struct wimlib_compressor_params_header *_params)
-{
-	const struct wimlib_lzms_compressor_params *params = lzms_get_params(_params);
-
-	u64 size = 0;
-
-	size += max_block_size;
-	size += sizeof(struct lzms_compressor);
-	size += lz_sarray_get_needed_memory(max_block_size);
-	size += lz_match_chooser_get_needed_memory(params->optim_array_length,
-						   params->nice_match_length,
-						   params->max_match_length);
-	size += min(params->max_match_length -
-		    params->min_match_length + 1,
-		    params->max_matches_per_pos) *
-		sizeof(((struct lzms_compressor*)0)->matches[0]);
-	return size;
-}
-
-static bool
-lzms_params_valid(const struct wimlib_compressor_params_header *_params)
-{
-	const struct wimlib_lzms_compressor_params *params =
-		(const struct wimlib_lzms_compressor_params*)_params;
-
-	if (params->hdr.size != sizeof(*params) ||
-	    params->max_match_length < params->min_match_length ||
-	    params->min_match_length < 2 ||
-	    params->optim_array_length == 0 ||
-	    min(params->max_match_length, params->nice_match_length) > 65536)
-		return false;
-
-	return true;
-}
-
 const struct compressor_ops lzms_compressor_ops = {
-	.params_valid	    = lzms_params_valid,
 	.get_needed_memory  = lzms_get_needed_memory,
 	.create_compressor  = lzms_create_compressor,
 	.compress	    = lzms_compress,