Implement favor LZO method

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

diff --git a/mkfs.ubifs/compr.c b/mkfs.ubifs/compr.c
index 73c7a0146c86d5a5ee3c7b73fe164519033074ee..8ed2904f9f94c5c7c17b6cdaebce380bc853d7c6 100644 (file)
--- a/mkfs.ubifs/compr.c
+++ b/mkfs.ubifs/compr.c
@@ -48,7 +48,7 @@ static int zlib_deflate(void *in_buf, size_t in_len, void *out_buf,
        strm.zfree = NULL;
 
        /*
-        * Match exactly the zlib parameters used by the linux kernel crypto
+        * Match exactly the zlib parameters used by the Linux kernel crypto
         * API.
         */
         if (deflateInit2(&strm, DEFLATE_DEF_LEVEL, Z_DEFLATED,
@@ -108,29 +108,82 @@ static int no_compress(void *in_buf, size_t in_len, void *out_buf,
        return 0;
 }
 
+static char *zlib_buf;
+
+static int favor_lzo_compress(void *in_buf, size_t in_len, void *out_buf,
+                              size_t *out_len, int *type)
+{
+       int lzo_ret, zlib_ret;
+       size_t lzo_len, zlib_len;
+
+       lzo_len = zlib_len = *out_len;
+       lzo_ret = lzo_compress(in_buf, in_len, out_buf, &lzo_len);
+       zlib_ret = zlib_deflate(in_buf, in_len, zlib_buf, &zlib_len);
+
+       if (lzo_ret && zlib_ret)
+               /* Both compressors failed */
+               return -1;
+
+       if (!lzo_ret && !zlib_ret) {
+               double percent;
+
+               /* Both compressors succeeded */
+               if (lzo_len <= zlib_len )
+                       goto select_lzo;
+
+               percent = (double)zlib_len / (double)lzo_len;
+               percent *= 100;
+               if (percent > 100 - c->favor_lzo)
+                       goto select_lzo;
+               goto select_zlib;
+       }
+
+       if (lzo_ret)
+               /* Only zlib compressor succeeded */
+               goto select_zlib;
+
+       /* Only LZO compressor succeeded */
+
+select_lzo:
+       *out_len = lzo_len;
+       *type = MKFS_UBIFS_COMPR_LZO;
+       return 0;
+
+select_zlib:
+       *out_len = zlib_len;
+       *type = MKFS_UBIFS_COMPR_ZLIB;
+       memcpy(out_buf, zlib_buf, zlib_len);
+       return 0;
+}
+
 int compress_data(void *in_buf, size_t in_len, void *out_buf, size_t *out_len,
                  int type)
 {
-       int ret = 1;
+       int ret;
 
        if (in_len < UBIFS_MIN_COMPR_LEN) {
                no_compress(in_buf, in_len, out_buf, out_len);
                return MKFS_UBIFS_COMPR_NONE;
        }
 
-       switch (type) {
-       case MKFS_UBIFS_COMPR_LZO:
-               ret = lzo_compress(in_buf, in_len, out_buf, out_len);
-               break;
-       case MKFS_UBIFS_COMPR_ZLIB:
-               ret = zlib_deflate(in_buf, in_len, out_buf, out_len);
-               break;
-       case MKFS_UBIFS_COMPR_NONE:
-               ret = 1;
-               break;
-       default:
-               errcnt += 1;
-               break;
+       if (c->favor_lzo)
+               ret = favor_lzo_compress(in_buf, in_len, out_buf, out_len, &type);
+       else {
+               switch (type) {
+               case MKFS_UBIFS_COMPR_LZO:
+                       ret = lzo_compress(in_buf, in_len, out_buf, out_len);
+                       break;
+               case MKFS_UBIFS_COMPR_ZLIB:
+                       ret = zlib_deflate(in_buf, in_len, out_buf, out_len);
+                       break;
+               case MKFS_UBIFS_COMPR_NONE:
+                       ret = 1;
+                       break;
+               default:
+                       errcnt += 1;
+                       ret = 1;
+                       break;
+               }
        }
        if (ret || *out_len >= in_len) {
                no_compress(in_buf, in_len, out_buf, out_len);
@@ -144,11 +197,19 @@ int init_compression(void)
        lzo_mem = malloc(LZO1X_999_MEM_COMPRESS);
        if (!lzo_mem)
                return -1;
+
+       zlib_buf = malloc(UBIFS_BLOCK_SIZE * WORST_COMPR_FACTOR);
+       if (!zlib_buf) {
+               free(lzo_mem);
+               return -1;
+       }
+
        return 0;
 }
 
 void destroy_compression(void)
 {
+       free(zlib_buf);
        free(lzo_mem);
        if (errcnt)
                fprintf(stderr, "%llu compression errors occurred\n", errcnt);