]> wimlib.net Git - wimlib/blobdiff - src/lzms-common.c
lzms-common.c, lzms-compress.c: Use pthread_once()
[wimlib] / src / lzms-common.c
index 946c655e7afc14ae112a0b0a5981610e42aacc21..c657ef4aabccd60f58df5c5061b8c2587e8b28d8 100644 (file)
 #  include "config.h"
 #endif
 
-#include "wimlib/lzms.h"
 #include "wimlib/endianness.h"
+#include "wimlib/lzms.h"
+#include "wimlib/util.h"
+
+#include <pthread.h>
+
+/***************************************************************
+ * Constant tables initialized by lzms_compute_slots():        *
+ ***************************************************************/
+
+/* Table: position slot => position slot base value  */
+u32 lzms_position_slot_base[LZMS_MAX_NUM_OFFSET_SYMS + 1];
+
+/* Table: position slot => number of extra position bits  */
+u8 lzms_extra_position_bits[LZMS_MAX_NUM_OFFSET_SYMS];
+
+/* Table: log2(position) => [lower bound, upper bound] on position slot  */
+u16 lzms_order_to_position_slot_bounds[30][2];
+
+/* Table: length slot => length slot base value  */
+u32 lzms_length_slot_base[LZMS_NUM_LEN_SYMS + 1];
+
+/* Table: length slot => number of extra length bits  */
+u8 lzms_extra_length_bits[LZMS_NUM_LEN_SYMS];
+
+/* Table: length (< LZMS_NUM_FAST_LENGTHS only) => length slot  */
+u8 lzms_length_slot_fast[LZMS_NUM_FAST_LENGTHS];
+
+u32
+lzms_get_slot(u32 value, const u32 slot_base_tab[], unsigned num_slots)
+{
+       u32 l = 0;
+       u32 r = num_slots - 1;
+       for (;;) {
+               LZMS_ASSERT(r >= l);
+               u32 slot = (l + r) / 2;
+               if (value >= slot_base_tab[slot]) {
+                       if (value < slot_base_tab[slot + 1])
+                               return slot;
+                       else
+                               l = slot + 1;
+               } else {
+                       r = slot - 1;
+               }
+       }
+}
+
+static void
+lzms_decode_delta_rle_slot_bases(u32 slot_bases[],
+                                u8 extra_bits[],
+                                const u8 delta_run_lens[],
+                                u32 num_run_lens,
+                                u32 final,
+                                u32 expected_num_slots)
+{
+       u32 order = 0;
+       u32 delta = 1;
+       u32 base = 0;
+       u32 slot = 0;
+       for (u32 i = 0; i < num_run_lens; i++) {
+               u8 run_len = delta_run_lens[i];
+               while (run_len--) {
+                       base += delta;
+                       if (slot > 0)
+                               extra_bits[slot - 1] = order;
+                       slot_bases[slot] = base;
+                       slot++;
+               }
+               delta <<= 1;
+               order++;
+       }
+       LZMS_ASSERT(slot == expected_num_slots);
+
+       slot_bases[slot] = final;
+       extra_bits[slot - 1] = bsr32(slot_bases[slot] - slot_bases[slot - 1]);
+}
+
+/* Initialize the global position and length slot tables.  */
+static void
+lzms_compute_slots(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,
+       };
+
+       /* Position slots  */
+       lzms_decode_delta_rle_slot_bases(lzms_position_slot_base,
+                                        lzms_extra_position_bits,
+                                        position_slot_delta_run_lens,
+                                        ARRAY_LEN(position_slot_delta_run_lens),
+                                        0x7fffffff,
+                                        LZMS_MAX_NUM_OFFSET_SYMS);
+
+       for (u32 order = 0; order < 30; order++) {
+               lzms_order_to_position_slot_bounds[order][0] =
+                       lzms_get_slot(1U << order, lzms_position_slot_base,
+                                     LZMS_MAX_NUM_OFFSET_SYMS);
+               lzms_order_to_position_slot_bounds[order][1] =
+                       lzms_get_slot((1U << (order + 1)) - 1, lzms_position_slot_base,
+                                     LZMS_MAX_NUM_OFFSET_SYMS);
+       }
+
+       /* Length slots  */
+       lzms_decode_delta_rle_slot_bases(lzms_length_slot_base,
+                                        lzms_extra_length_bits,
+                                        length_slot_delta_run_lens,
+                                        ARRAY_LEN(length_slot_delta_run_lens),
+                                        0x400108ab,
+                                        LZMS_NUM_LEN_SYMS);
+
+       /* Create table mapping short lengths to length slots.  */
+       for (u32 slot = 0, i = 0; i < LZMS_NUM_FAST_LENGTHS; i++) {
+               if (i >= lzms_length_slot_base[slot + 1])
+                       slot++;
+               lzms_length_slot_fast[i] = slot;
+       }
+}
+
+/* Initialize the global position and length slot tables if not done so already.
+ * */
+void
+lzms_init_slots(void)
+{
+       static pthread_once_t once = PTHREAD_ONCE_INIT;
+
+       pthread_once(&once, lzms_compute_slots);
+}
 
 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 +210,8 @@ 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.  */
@@ -135,14 +275,17 @@ 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;
 
        for (s32 i = 0; i < 65536; i++)
                last_target_usages[i] = -LZMS_X86_MAX_GOOD_TARGET_OFFSET - 1;
 
-       for (s32 i = 0; i < size - 11; ) {
+       for (s32 i = 0; i < size - 16; ) {
                s32 max_trans_offset;
                s32 n;
 
@@ -158,3 +301,70 @@ lzms_x86_filter(u8 data[], s32 size, s32 last_target_usages[], bool undo)
                }
        }
 }
+
+static void
+lzms_init_lz_lru_queues(struct lzms_lz_lru_queues *lz)
+{
+       /* Recent offsets for LZ matches  */
+       for (u32 i = 0; i < LZMS_NUM_RECENT_OFFSETS + 1; i++)
+               lz->recent_offsets[i] = i + 1;
+
+       lz->prev_offset = 0;
+       lz->upcoming_offset = 0;
+}
+
+static void
+lzms_init_delta_lru_queues(struct lzms_delta_lru_queues *delta)
+{
+       /* Recent offsets and powers for LZ matches  */
+       for (u32 i = 0; i < LZMS_NUM_RECENT_OFFSETS + 1; i++) {
+               delta->recent_offsets[i] = i + 1;
+               delta->recent_powers[i] = 0;
+       }
+       delta->prev_offset = 0;
+       delta->prev_power = 0;
+       delta->upcoming_offset = 0;
+       delta->upcoming_power = 0;
+}
+
+
+void
+lzms_init_lru_queues(struct lzms_lru_queues *lru)
+{
+       lzms_init_lz_lru_queues(&lru->lz);
+       lzms_init_delta_lru_queues(&lru->delta);
+}
+
+void
+lzms_update_lz_lru_queues(struct lzms_lz_lru_queues *lz)
+{
+       if (lz->prev_offset != 0) {
+               for (int i = LZMS_NUM_RECENT_OFFSETS - 1; i >= 0; i--)
+                       lz->recent_offsets[i + 1] = lz->recent_offsets[i];
+               lz->recent_offsets[0] = lz->prev_offset;
+       }
+       lz->prev_offset = lz->upcoming_offset;
+}
+
+void
+lzms_update_delta_lru_queues(struct lzms_delta_lru_queues *delta)
+{
+       if (delta->prev_offset != 0) {
+               for (int i = LZMS_NUM_RECENT_OFFSETS - 1; i >= 0; i--) {
+                       delta->recent_offsets[i + 1] = delta->recent_offsets[i];
+                       delta->recent_powers[i + 1] = delta->recent_powers[i];
+               }
+               delta->recent_offsets[0] = delta->prev_offset;
+               delta->recent_powers[0] = delta->prev_power;
+       }
+
+       delta->prev_offset = delta->upcoming_offset;
+       delta->prev_power = delta->upcoming_power;
+}
+
+void
+lzms_update_lru_queues(struct lzms_lru_queues *lru)
+{
+       lzms_update_lz_lru_queues(&lru->lz);
+       lzms_update_delta_lru_queues(&lru->delta);
+}