* */
#include "wimlib/assert.h"
+#include "wimlib/compiler.h"
+#include "wimlib/util.h"
#include "wimlib/types.h"
//#define ENABLE_LZX_DEBUG
#define LZX_BLOCKTYPE_ALIGNED 2
#define LZX_BLOCKTYPE_UNCOMPRESSED 3
-#define LZX_NUM_PRIMARY_LENS 7 /* this one missing from spec! */
+#define LZX_NUM_PRIMARY_LENS 7
-/* NOTE: There are really 51 position slots in the LZX format as a whole, but
- * only 30 are needed to allow for the window to be up to 32768 bytes long,
- * which is the maximum in the WIM format. */
-#define LZX_NUM_POSITION_SLOTS 30
+/* The number of position slots varies from 30 to 51 depending on the window
+ * size (see comment in lzx-decompress.c). */
+#define LZX_MAX_POSITION_SLOTS 51
+
+#define LZX_MIN_WINDOW_ORDER 15
+#define LZX_MAX_WINDOW_ORDER 21
+#define LZX_MIN_WINDOW_SIZE (1U << LZX_MIN_WINDOW_ORDER) /* 32768 */
+#define LZX_MAX_WINDOW_SIZE (1U << LZX_MAX_WINDOW_ORDER) /* 2097152 */
/* Read the LZX specification for information about the Huffman trees used in
* the LZX compression format. Basically there are 4 of them: The main tree,
* A PRECODE is used to encode the code lengths for the main tree and the length
* tree. There is a separate pretree for each half of the main tree. */
-#define LZX_MAINCODE_NUM_SYMBOLS (LZX_NUM_CHARS + \
- (LZX_NUM_POSITION_SLOTS << 3))
+#define LZX_MAINCODE_MAX_NUM_SYMBOLS (LZX_NUM_CHARS + (LZX_MAX_POSITION_SLOTS << 3))
#define LZX_MAINCODE_TABLEBITS 11
#define LZX_LENCODE_NUM_SYMBOLS 249
#define LZX_ALIGNEDCODE_NUM_SYMBOLS 8
#define LZX_ALIGNEDCODE_TABLEBITS 7
-#define LZX_ALIGNEDCODE_ELEMENT_SIZE 3
+#define LZX_ALIGNEDCODE_ELEMENT_SIZE 3
/* Maximum allowed length of Huffman codewords. */
#define LZX_MAX_MAIN_CODEWORD_LEN 16
* different as well. */
#define LZX_WIM_MAGIC_FILESIZE 12000000
-#define LZX_BLOCKTYPE_NBITS 3
-#define LZX_BLOCKSIZE_NBITS 16
+/* Assumed LZX block size when the encoded block size begins with a 0 bit. */
+#define LZX_DEFAULT_BLOCK_SIZE 32768
#define USE_LZX_EXTRA_BITS_ARRAY
#ifdef USE_LZX_EXTRA_BITS_ARRAY
-extern const u8 lzx_extra_bits[];
+extern const u8 lzx_extra_bits[LZX_MAX_POSITION_SLOTS];
#endif
-/* Given the number of a LZX position slot, return the number of extra bits that
+/* Given the number of an LZX position slot, return the number of extra bits that
* are needed to encode the match offset. */
static inline unsigned
lzx_get_num_extra_bits(unsigned position_slot)
#endif
}
-extern const u32 lzx_position_base[];
+extern const u32 lzx_position_base[LZX_MAX_POSITION_SLOTS];
+
+/* Returns the LZX position slot that corresponds to a given formatted offset.
+ *
+ * Logically, this returns the smallest i such that
+ * formatted_offset >= lzx_position_base[i].
+ *
+ * The actual implementation below takes advantage of the regularity of the
+ * numbers in the lzx_position_base array to calculate the slot directly from
+ * the formatted offset without actually looking at the array.
+ */
+static inline unsigned
+lzx_get_position_slot_raw(u32 formatted_offset)
+{
+ if (formatted_offset >= 196608) {
+ return (formatted_offset >> 17) + 34;
+ } else {
+ LZX_ASSERT(2 <= formatted_offset && formatted_offset < 655360);
+ unsigned mssb_idx = bsr32(formatted_offset);
+ return (mssb_idx << 1) |
+ ((formatted_offset >> (mssb_idx - 1)) & 1);
+ }
+}
+
+extern bool lzx_window_size_valid(size_t window_size);
+extern unsigned lzx_get_num_main_syms(u32 window_size);
#define LZX_NUM_RECENT_OFFSETS 3
/* Least-recently used queue for match offsets. */
struct lzx_lru_queue {
u32 R[LZX_NUM_RECENT_OFFSETS];
-};
+}
+#ifdef __x86_64__
+_aligned_attribute(8) /* Improves performance of LZX compression by 1% - 2%;
+ specifically, this speeds up
+ lzx_choose_near_optimal_match(). */
+#endif
+;
/* In the LZX format, an offset of n bytes is actually encoded
* as (n + LZX_OFFSET_OFFSET). */
#define LZX_OFFSET_OFFSET (LZX_NUM_RECENT_OFFSETS - 1)
+/* Initialize the LZX least-recently-used match offset queue at the beginning of
+ * a new window for either decompression or compression. */
static inline void
lzx_lru_queue_init(struct lzx_lru_queue *queue)
{
queue->R[i] = 1;
}
+extern void
+lzx_do_e8_preprocessing(u8 *data, s32 size);
+
+extern void
+lzx_undo_e8_preprocessing(u8 *data, s32 size);
+
#endif /* _WIMLIB_LZX_H */