LZX: Allow max_block_size not a power of 2

[wimlib] / src / lzx-compress.c

diff --git a/src/lzx-compress.c b/src/lzx-compress.c
index 0a4edb0ea0db393a34e3138054fd7d4d6ccee423..96ea2e5dc157521710fa00162db83305377b5eed 100644 (file)
--- a/src/lzx-compress.c
+++ b/src/lzx-compress.c
@@ -328,14 +328,24 @@ struct lzx_compressor {
        /* Allocated size of @cur_window.  */
        u32 max_window_size;
 
        /* Allocated size of @cur_window.  */
        u32 max_window_size;
 

+       /* log2 order of the LZX window size for LZ match offset encoding
+        * purposes.  Will be >= LZX_MIN_WINDOW_ORDER and <=
+        * LZX_MAX_WINDOW_ORDER.
+        *
+        * Note: 1 << @window_order is normally equal to @max_window_size, but
+        * it will be greater than @max_window_size in the event that the
+        * compressor was created with a non-power-of-2 block size.  (See
+        * lzx_get_window_order().)  */
+       unsigned window_order;
+

        /* Compression parameters.  */
        struct lzx_compressor_params params;
 
        unsigned (*get_matches_func)(struct lzx_compressor *, const struct lz_match **);
        void (*skip_bytes_func)(struct lzx_compressor *, unsigned n);
 
        /* Compression parameters.  */
        struct lzx_compressor_params params;
 
        unsigned (*get_matches_func)(struct lzx_compressor *, const struct lz_match **);
        void (*skip_bytes_func)(struct lzx_compressor *, unsigned n);
 

-       /* Number of symbols in the main alphabet (depends on the
-        * @max_window_size since it determines the maximum allowed offset).  */
+       /* Number of symbols in the main alphabet (depends on the @window_order
+        * since it determines the maximum allowed offset).  */

        unsigned num_main_syms;
 
        /* The current match offset LRU queue.  */
        unsigned num_main_syms;
 
        /* The current match offset LRU queue.  */


@@ -998,7 +1008,7 @@ lzx_write_items(struct lzx_output_bitstream *os, int block_type,
 static void
 lzx_write_compressed_block(int block_type,
                           u32 block_size,
 static void
 lzx_write_compressed_block(int block_type,
                           u32 block_size,

-                          u32 max_window_size,
+                          unsigned window_order,

                           unsigned num_main_syms,
                           struct lzx_item * chosen_items,
                           u32 num_chosen_items,
                           unsigned num_main_syms,
                           struct lzx_item * chosen_items,
                           u32 num_chosen_items,


@@ -1033,7 +1043,7 @@ lzx_write_compressed_block(int block_type,
        } else {
                lzx_write_bits(os, 0, 1);
 
        } else {
                lzx_write_bits(os, 0, 1);
 

-               if (max_window_size >= 65536)
+               if (window_order >= 16)

                        lzx_write_bits(os, block_size >> 16, 8);
 
                lzx_write_bits(os, block_size & 0xFFFF, 16);
                        lzx_write_bits(os, block_size >> 16, 8);
 
                lzx_write_bits(os, block_size & 0xFFFF, 16);


@@ -1075,7 +1085,7 @@ lzx_write_all_blocks(struct lzx_compressor *c, struct lzx_output_bitstream *os)
 
                lzx_write_compressed_block(spec->block_type,
                                           spec->block_size,
 
                lzx_write_compressed_block(spec->block_type,
                                           spec->block_size,

-                                          c->max_window_size,
+                                          c->window_order,

                                           c->num_main_syms,
                                           spec->chosen_items,
                                           spec->num_chosen_items,
                                           c->num_main_syms,
                                           spec->chosen_items,
                                           spec->num_chosen_items,


@@ -2254,13 +2264,17 @@ static void
 lzx_free_compressor(void *_c);
 
 static u64
 lzx_free_compressor(void *_c);
 
 static u64

-lzx_get_needed_memory(size_t max_window_size, unsigned int compression_level)
+lzx_get_needed_memory(size_t max_block_size, unsigned int compression_level)

 {
        struct lzx_compressor_params params;
        u64 size = 0;
 {
        struct lzx_compressor_params params;
        u64 size = 0;

+       unsigned window_order;
+       u32 max_window_size;

 
 

-       if (!lzx_window_size_valid(max_window_size))
+       window_order = lzx_get_window_order(max_block_size);
+       if (window_order == 0)

                return 0;
                return 0;

+       max_window_size = max_block_size;

 
        lzx_build_params(compression_level, max_window_size, &params);
 
 
        lzx_build_params(compression_level, max_window_size, &params);
 


@@ -2286,15 +2300,19 @@ lzx_get_needed_memory(size_t max_window_size, unsigned int compression_level)
 }
 
 static int
 }
 
 static int

-lzx_create_compressor(size_t max_window_size, unsigned int compression_level,
+lzx_create_compressor(size_t max_block_size, unsigned int compression_level,

                      void **c_ret)
 {
        struct lzx_compressor *c;
        struct lzx_compressor_params params;
        struct lz_mf_params mf_params;
                      void **c_ret)
 {
        struct lzx_compressor *c;
        struct lzx_compressor_params params;
        struct lz_mf_params mf_params;

+       unsigned window_order;
+       u32 max_window_size;

 
 

-       if (!lzx_window_size_valid(max_window_size))
+       window_order = lzx_get_window_order(max_block_size);
+       if (window_order == 0)

                return WIMLIB_ERR_INVALID_PARAM;
                return WIMLIB_ERR_INVALID_PARAM;

+       max_window_size = max_block_size;

 
        lzx_build_params(compression_level, max_window_size, &params);
        lzx_build_mf_params(&params, max_window_size, &mf_params);
 
        lzx_build_params(compression_level, max_window_size, &params);
        lzx_build_mf_params(&params, max_window_size, &mf_params);


@@ -2306,8 +2324,9 @@ lzx_create_compressor(size_t max_window_size, unsigned int compression_level,
                goto oom;
 
        c->params = params;
                goto oom;
 
        c->params = params;

-       c->num_main_syms = lzx_get_num_main_syms(max_window_size);
+       c->num_main_syms = lzx_get_num_main_syms(window_order);

        c->max_window_size = max_window_size;
        c->max_window_size = max_window_size;

+       c->window_order = window_order;

 
        c->cur_window = ALIGNED_MALLOC(max_window_size, 16);
        if (!c->cur_window)
 
        c->cur_window = ALIGNED_MALLOC(max_window_size, 16);
        if (!c->cur_window)