Adjust naming of (de)compression files

[wimlib] / include / wimlib / lzx_common.h

diff --git a/include/wimlib/lzx_common.h b/include/wimlib/lzx_common.h
new file mode 100644 (file)
index 0000000..b3ae85a
--- /dev/null
+++ b/include/wimlib/lzx_common.h
@@ -0,0 +1,74 @@
+/*
+ * lzx_common.h
+ *
+ * Declarations shared between LZX compression and decompression.
+ */
+
+#ifndef _LZX_COMMON_H
+#define _LZX_COMMON_H
+
+#include "wimlib/assert.h"
+#include "wimlib/bitops.h"
+#include "wimlib/compiler.h"
+#include "wimlib/lzx_constants.h"
+#include "wimlib/util.h"
+#include "wimlib/types.h"
+
+//#define ENABLE_LZX_DEBUG
+#ifdef ENABLE_LZX_DEBUG
+#       define LZX_ASSERT wimlib_assert
+#else
+#      define LZX_ASSERT(...)
+#endif
+
+extern const u32 lzx_offset_slot_base[LZX_MAX_OFFSET_SLOTS];
+
+extern const u8 lzx_extra_offset_bits[LZX_MAX_OFFSET_SLOTS];
+
+/* Returns the LZX offset slot that corresponds to a given adjusted offset.
+ *
+ * Logically, this returns the smallest i such that
+ * adjusted_offset >= lzx_offset_slot_base[i].
+ *
+ * The actual implementation below takes advantage of the regularity of the
+ * numbers in the lzx_offset_slot_base array to calculate the slot directly from
+ * the adjusted offset without actually looking at the array.
+ */
+static inline unsigned
+lzx_get_offset_slot_raw(u32 adjusted_offset)
+{
+       if (adjusted_offset >= 196608) {
+               return (adjusted_offset >> 17) + 34;
+       } else {
+               LZX_ASSERT(2 <= adjusted_offset && adjusted_offset < 655360);
+               unsigned mssb_idx = fls32(adjusted_offset);
+               return (mssb_idx << 1) |
+                       ((adjusted_offset >> (mssb_idx - 1)) & 1);
+       }
+}
+
+extern unsigned lzx_get_window_order(size_t max_block_size);
+
+extern unsigned lzx_get_num_main_syms(unsigned window_order);
+
+/* Least-recently used queue for match offsets.  */
+struct lzx_lru_queue {
+       u32 R[LZX_NUM_RECENT_OFFSETS];
+} _aligned_attribute(sizeof(unsigned long));
+
+/* 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)
+{
+       for (unsigned i = 0; i < LZX_NUM_RECENT_OFFSETS; i++)
+               queue->R[i] = 1;
+}
+
+extern void
+lzx_do_e8_preprocessing(u8 *data, u32 size);
+
+extern void
+lzx_undo_e8_preprocessing(u8 *data, u32 size);
+
+#endif /* _LZX_COMMON_H */