Remove unneeded parameter from compression functions

[wimlib] / src / xpress-compress.c

diff --git a/src/xpress-compress.c b/src/xpress-compress.c
index 6d2836f050e6b3b02f86c3b0b3c6410a2324d292..548c32cbc8a9cd5d1f56e7d011668eb5a65d3858 100644 (file)
--- a/src/xpress-compress.c
+++ b/src/xpress-compress.c
@@ -142,23 +142,12 @@ static const struct lz_params xpress_lz_params = {
 /*
  * Performs XPRESS compression on a block of data.
  *
- * @__uncompressed_data:  Pointer to the data to be compressed.
- * @uncompressed_len:  Length, in bytes, of the data to be compressed.
- * @__compressed_data: Pointer to a location at least (@uncompressed_len - 1)
- *                             bytes long into which the compressed data may be
- *                             written.
- * @compressed_len_ret:        A pointer to an unsigned int into which the length of
- *                             the compressed data may be returned.
- *
- * Returns zero if compression was successfully performed.  In that case
- * @compressed_data and @compressed_len_ret will contain the compressed data and
- * its length.  A return value of nonzero means that compressing the data did
- * not reduce its size, and @compressed_data will not contain the full
- * compressed data.
+ * Please see the documentation for the 'compress_func_t' type in write.c for
+ * the exact behavior of this function and how to call it.
  */
-int
+unsigned
 xpress_compress(const void *__uncompressed_data, unsigned uncompressed_len,
-               void *__compressed_data, unsigned *compressed_len_ret)
+               void *__compressed_data)
 {
        const u8 *uncompressed_data = __uncompressed_data;
        u8 *compressed_data = __compressed_data;
@@ -172,6 +161,8 @@ xpress_compress(const void *__uncompressed_data, unsigned uncompressed_len,
        unsigned i;
        int ret;
 
+       wimlib_assert(uncompressed_len <= 32768);
+
        /* XPRESS requires 256 bytes of overhead for the Huffman tables, so it's
         * impossible cannot compress 256 bytes or less of data to less than the
         * input size.
@@ -182,7 +173,7 @@ xpress_compress(const void *__uncompressed_data, unsigned uncompressed_len,
         * +4 to take into account that init_output_bitstream() requires at
         * least 4 bytes of data. */
        if (uncompressed_len < XPRESS_NUM_SYMBOLS / 2 + 1 + 4)
-               return 1;
+               return 0;
 
        ZERO_ARRAY(freq_tab);
        num_matches = lz_analyze_block(uncompressed_data, uncompressed_len,
@@ -216,13 +207,13 @@ xpress_compress(const void *__uncompressed_data, unsigned uncompressed_len,
 
        ret = xpress_write_compressed_literals(&ostream, match_tab,
                                               num_matches, codewords, lens);
-       if (ret != 0)
-               return ret;
+       if (ret)
+               return 0;
 
        /* Flush any bits that are buffered. */
        ret = flush_output_bitstream(&ostream);
-       if (ret != 0)
-               return ret;
+       if (ret)
+               return 0;
 
        /* Assert that there are no output bytes between the ostream.output
         * pointer and the ostream.next_bit_output pointer.  This can only
@@ -242,20 +233,18 @@ xpress_compress(const void *__uncompressed_data, unsigned uncompressed_len,
         * they may precede a number of bytes embedded into the bitstream.) */
        if (ostream.bit_output >
            (const u8*)__compressed_data + uncompressed_len - 3)
-               return 1;
+               return 0;
        *(u16*)ostream.bit_output = cpu_to_le16(0);
        compressed_len = ostream.next_bit_output - (const u8*)__compressed_data;
 
        wimlib_assert(compressed_len <= uncompressed_len - 1);
 
-       *compressed_len_ret = compressed_len;
-
 #ifdef ENABLE_VERIFY_COMPRESSION
        /* Verify that we really get the same thing back when decompressing. */
        u8 buf[uncompressed_len];
        ret = xpress_decompress(__compressed_data, compressed_len, buf,
                                uncompressed_len);
-       if (ret != 0) {
+       if (ret) {
                ERROR("xpress_compress(): Failed to decompress data we "
                      "compressed");
                abort();
@@ -269,5 +258,5 @@ xpress_compress(const void *__uncompressed_data, unsigned uncompressed_len,
                }
        }
 #endif
-       return 0;
+       return compressed_len;
 }