--disable-verify-compression by default

[wimlib] / src / lzx-compress.c

diff --git a/src/lzx-compress.c b/src/lzx-compress.c
index 9a654b2d796586d1177adf234ff04b785e0d268f..b23c2df088642ce2d9001ebeba130d8fbba504d8 100644 (file)
--- a/src/lzx-compress.c
+++ b/src/lzx-compress.c
@@ -27,8 +27,8 @@
 
 
 /*
- * This file provides lzx_compress(), a function to compress an in-memory buffer
- * of data using LZX compression, as used in the WIM file format.
+ * This file provides wimlib_lzx_compress(), a function to compress an in-memory
+ * buffer of data using LZX compression, as used in the WIM file format.
  *
  * Please see the comments in lzx-decompress.c for more information about this
  * compression format.
@@ -57,6 +57,7 @@
  * blocks from one input chunk is not yet implemented.
  */
 
+#include "wimlib.h"
 #include "lzx.h"
 #include "compress.h"
 #include <stdlib.h>
@@ -566,7 +567,7 @@ lzx_write_compressed_tree(struct output_bitstream *out,
 
 /* Builds the canonical Huffman code for the main tree, the length tree, and the
  * aligned offset tree. */
-static void 
+static void
 lzx_make_huffman_codes(const struct lzx_freq_tables *freq_tabs,
                       struct lzx_codes *codes)
 {
@@ -638,26 +639,10 @@ static const struct lz_params lzx_lz_params = {
        .too_far        = 4096,
 };
 
-/*
- * Performs LZX 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.
- */
-int
-lzx_compress(const void *__uncompressed_data, unsigned uncompressed_len,
-            void *compressed_data, unsigned *compressed_len_ret)
+/* Documented in wimlib.h */
+WIMLIBAPI unsigned
+wimlib_lzx_compress(const void *__uncompressed_data, unsigned uncompressed_len,
+                   void *compressed_data)
 {
        struct output_bitstream ostream;
        u8 uncompressed_data[uncompressed_len + 8];
@@ -671,8 +656,10 @@ lzx_compress(const void *__uncompressed_data, unsigned uncompressed_len,
        int ret;
        int block_type = LZX_BLOCKTYPE_ALIGNED;
 
+       wimlib_assert(uncompressed_len <= 32768);
+
        if (uncompressed_len < 100)
-               return 1;
+               return 0;
 
        memset(&freq_tabs, 0, sizeof(freq_tabs));
        queue.R0 = 1;
@@ -682,6 +669,7 @@ lzx_compress(const void *__uncompressed_data, unsigned uncompressed_len,
        /* The input data must be preprocessed. To avoid changing the original
         * input, copy it to a temporary buffer. */
        memcpy(uncompressed_data, __uncompressed_data, uncompressed_len);
+       memset(uncompressed_data + uncompressed_len, 0, 8);
 
        /* Before doing any actual compression, do the call instruction (0xe8
         * byte) translation on the uncompressed data. */
@@ -728,55 +716,55 @@ lzx_compress(const void *__uncompressed_data, unsigned uncompressed_len,
         * main tree. */
        ret = lzx_write_compressed_tree(&ostream, codes.main_lens,
                                        LZX_NUM_CHARS);
-       if (ret != 0)
-               return ret;
+       if (ret)
+               return 0;
 
        /* Write the pre-tree and symbols for the rest of the main tree. */
        ret = lzx_write_compressed_tree(&ostream, codes.main_lens +
                                        LZX_NUM_CHARS,
                                        LZX_MAINTREE_NUM_SYMBOLS -
                                                LZX_NUM_CHARS);
-       if (ret != 0)
-               return ret;
+       if (ret)
+               return 0;
 
        /* Write the pre-tree and symbols for the length tree. */
        ret = lzx_write_compressed_tree(&ostream, codes.len_lens,
                                        LZX_LENTREE_NUM_SYMBOLS);
-       if (ret != 0)
-               return ret;
+       if (ret)
+               return 0;
 
        /* Write the compressed literals. */
        ret = lzx_write_compressed_literals(&ostream, block_type,
                                            match_tab, num_matches, &codes);
-       if (ret != 0)
-               return ret;
+       if (ret)
+               return 0;
 
        ret = flush_output_bitstream(&ostream);
-       if (ret != 0)
-               return ret;
+       if (ret)
+               return 0;
 
        compressed_len = ostream.bit_output - (u8*)compressed_data;
 
-       *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 = lzx_decompress(compressed_data, compressed_len, buf,
-                            uncompressed_len);
-       if (ret != 0) {
-               ERROR("lzx_compress(): Failed to decompress data we compressed");
-               abort();
-       }
-
-       for (i = 0; i < uncompressed_len; i++) {
-               if (buf[i] != *((u8*)__uncompressed_data + i)) {
-                       ERROR("lzx_compress(): Data we compressed didn't "
-                             "decompress to the original data (difference at "
-                             "byte %u of %u)", i + 1, uncompressed_len);
+       {
+               u8 buf[uncompressed_len];
+               ret = wimlib_lzx_decompress(compressed_data, compressed_len,
+                                           buf, uncompressed_len);
+               if (ret != 0) {
+                       ERROR("lzx_compress(): Failed to decompress data we compressed");
                        abort();
                }
+
+               for (i = 0; i < uncompressed_len; i++) {
+                       if (buf[i] != *((u8*)__uncompressed_data + i)) {
+                               ERROR("lzx_compress(): Data we compressed didn't "
+                                     "decompress to the original data (difference at "
+                                     "byte %u of %u)", i + 1, uncompressed_len);
+                               abort();
+                       }
+               }
        }
 #endif
-       return 0;
+       return compressed_len;
 }