LZX: Allow max_block_size not a power of 2

[wimlib] / src / lzx-decompress.c

diff --git a/src/lzx-decompress.c b/src/lzx-decompress.c
index 0c95ac03ecefa1489ee9e69a76a5d9197245e7ad..1e8532741b3b9f2240db9a3a69246ed4049e0df6 100644 (file)
--- a/src/lzx-decompress.c
+++ b/src/lzx-decompress.c
@@ -94,12 +94,11 @@ struct lzx_tables {
 /* The main LZX decompressor structure.
  *
  * Note: we keep track of most of the decompression state outside this
- * structure.  This structure only exists so that (1) we can store
- * @max_window_size and @num_main_syms for multiple calls to lzx_decompress();
- * and (2) so that we don't have to allocate the large 'struct lzx_tables' on
- * the stack.  */
+ * structure.  This structure only exists so that (1) we can store @window_order
+ * and @num_main_syms for multiple calls to lzx_decompress(); and (2) so that we
+ * don't have to allocate the large 'struct lzx_tables' on the stack.  */
 struct lzx_decompressor {
-       u32 max_window_size;
+       unsigned window_order;
        unsigned num_main_syms;
        struct lzx_tables tables;
 };
@@ -265,7 +264,7 @@ lzx_read_codeword_lens(struct input_bitstream *istream, u8 lens[], unsigned num_
 static int
 lzx_read_block_header(struct input_bitstream *istream,
                      unsigned num_main_syms,
-                     u32 max_window_size,
+                     unsigned window_order,
                      int *block_type_ret,
                      u32 *block_size_ret,
                      struct lzx_tables *tables,
@@ -296,7 +295,7 @@ lzx_read_block_header(struct input_bitstream *istream,
                block_size <<= 8;
                block_size |= tmp;
 
-               if (max_window_size >= 65536) {
+               if (window_order >= 16) {
                        tmp = bitstream_read_bits(istream, 8);
                        block_size <<= 8;
                        block_size |= tmp;
@@ -593,9 +592,6 @@ lzx_decompress(const void *compressed_data, size_t compressed_size,
        bool may_have_e8_byte;
        int ret;
 
-       if (uncompressed_size > dec->max_window_size)
-               return -1;
-
        init_input_bitstream(&istream, compressed_data, compressed_size);
 
        /* Initialize the recent offsets queue.  */
@@ -619,7 +615,7 @@ lzx_decompress(const void *compressed_data, size_t compressed_size,
             window_pos += block_size)
        {
                ret = lzx_read_block_header(&istream, dec->num_main_syms,
-                                           dec->max_window_size, &block_type,
+                                           dec->window_order, &block_type,
                                            &block_size, &dec->tables, &queue);
                if (ret)
                        return ret;
@@ -683,11 +679,13 @@ lzx_free_decompressor(void *_dec)
 }
 
 static int
-lzx_create_decompressor(size_t max_window_size, void **dec_ret)
+lzx_create_decompressor(size_t max_block_size, void **dec_ret)
 {
        struct lzx_decompressor *dec;
+       unsigned window_order;
 
-       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;
 
        /* The aligned allocation is needed to ensure that the lzx_tables are
@@ -697,8 +695,8 @@ lzx_create_decompressor(size_t max_window_size, void **dec_ret)
        if (!dec)
                return WIMLIB_ERR_NOMEM;
 
-       dec->max_window_size = max_window_size;
-       dec->num_main_syms = lzx_get_num_main_syms(max_window_size);
+       dec->window_order = window_order;
+       dec->num_main_syms = lzx_get_num_main_syms(window_order);
 
        *dec_ret = dec;
        return 0;