Update LZMS compressor - can now output literals

[wimlib] / src / lzms-common.c

diff --git a/src/lzms-common.c b/src/lzms-common.c
index 946c655e7afc14ae112a0b0a5981610e42aacc21..a6fc80149d3fcb044cbed00778e4f70bd6bce1dc 100644 (file)
--- a/src/lzms-common.c
+++ b/src/lzms-common.c
@@ -28,14 +28,108 @@
 #  include "config.h"
 #endif
 
-#include "wimlib/lzms.h"
 #include "wimlib/endianness.h"
+#include "wimlib/error.h"
+#include "wimlib/lzms.h"
+#include "wimlib/util.h"
+
+#include <pthread.h>
+
+/* A table that maps position slots to their base values.  These are constants
+ * computed at runtime by lzms_compute_slot_bases().  */
+u32 lzms_position_slot_base[LZMS_MAX_NUM_OFFSET_SYMS + 1];
+
+/* A table that maps length slots to their base values.  These are constants
+ * computed at runtime by lzms_compute_slot_bases().  */
+u32 lzms_length_slot_base[LZMS_NUM_LEN_SYMS + 1];
+
+/* Return the slot for the specified value.  */
+unsigned
+lzms_get_slot(u32 value, const u32 slot_base_tab[], unsigned num_slots)
+{
+       unsigned slot = 0;
+
+       while (slot_base_tab[slot + 1] <= value)
+               slot++;
+
+       return slot;
+}
+
+
+static void
+lzms_decode_delta_rle_slot_bases(u32 slot_bases[],
+                                const u8 delta_run_lens[], size_t num_run_lens)
+{
+       u32 delta = 1;
+       u32 base = 0;
+       size_t slot = 0;
+       for (size_t i = 0; i < num_run_lens; i++) {
+               u8 run_len = delta_run_lens[i];
+               while (run_len--) {
+                       base += delta;
+                       slot_bases[slot++] = base;
+               }
+               delta <<= 1;
+       }
+}
+
+/* Initialize the global position and length slot tables.  */
+static void
+lzms_compute_slot_bases(void)
+{
+       /* If an explicit formula that maps LZMS position and length slots to
+        * slot bases exists, then it could be used here.  But until one is
+        * found, the following code fills in the slots using the observation
+        * that the increase from one slot base to the next is an increasing
+        * power of 2.  Therefore, run-length encoding of the delta of adjacent
+        * entries can be used.  */
+       static const u8 position_slot_delta_run_lens[] = {
+               9,   0,   9,   7,   10,  15,  15,  20,
+               20,  30,  33,  40,  42,  45,  60,  73,
+               80,  85,  95,  105, 6,
+       };
+
+       static const u8 length_slot_delta_run_lens[] = {
+               27,  4,   6,   4,   5,   2,   1,   1,
+               1,   1,   1,   0,   0,   0,   0,   0,
+               1,
+       };
+
+       lzms_decode_delta_rle_slot_bases(lzms_position_slot_base,
+                                        position_slot_delta_run_lens,
+                                        ARRAY_LEN(position_slot_delta_run_lens));
+
+       lzms_position_slot_base[LZMS_MAX_NUM_OFFSET_SYMS] = 0x7fffffff;
+
+       lzms_decode_delta_rle_slot_bases(lzms_length_slot_base,
+                                        length_slot_delta_run_lens,
+                                        ARRAY_LEN(length_slot_delta_run_lens));
+
+       lzms_length_slot_base[LZMS_NUM_LEN_SYMS] = 0x400108ab;
+}
+
+/* Initialize the global position length slot tables if not done so already.  */
+void
+lzms_init_slot_bases(void)
+{
+       static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
+       static bool already_computed = false;
+
+       if (unlikely(!already_computed)) {
+               pthread_mutex_lock(&mutex);
+               if (!already_computed) {
+                       lzms_compute_slot_bases();
+                       already_computed = true;
+               }
+               pthread_mutex_unlock(&mutex);
+       }
+}
 
 static s32
-lzms_maybe_do_x86_translation(u8 data[], s32 i, s32 num_op_bytes,
-                             s32 *closest_target_usage_p,
-                             s32 last_target_usages[], s32 max_trans_offset,
-                             bool undo)
+lzms_maybe_do_x86_translation(u8 data[restrict], s32 i, s32 num_op_bytes,
+                             s32 * restrict closest_target_usage_p,
+                             s32 last_target_usages[restrict],
+                             s32 max_trans_offset, bool undo)
 {
        u16 pos;
 
@@ -71,7 +165,8 @@ lzms_maybe_do_x86_translation(u8 data[], s32 i, s32 num_op_bytes,
 }
 
 static s32
-lzms_may_x86_translate(const u8 p[], s32 *max_offset_ret)
+lzms_may_x86_translate(const u8 p[restrict],
+                      s32 *restrict max_offset_ret)
 {
        /* Switch on first byte of the opcode, assuming it is really an x86
         * instruction.  */
@@ -135,7 +230,10 @@ lzms_may_x86_translate(const u8 p[], s32 *max_offset_ret)
  * @last_target_usages is a temporary array of length >= 65536.
  */
 void
-lzms_x86_filter(u8 data[], s32 size, s32 last_target_usages[], bool undo)
+lzms_x86_filter(u8 data[restrict],
+               s32 size,
+               s32 last_target_usages[restrict],
+               bool undo)
 {
        s32 closest_target_usage = -LZMS_X86_MAX_TRANSLATION_OFFSET - 1;