Changeset 153 in libcf

Timestamp:

10/31/13 10:41:51 (10 years ago)

Author:

cheese

Message:

#1 fix bitwise simplify

File:

• trunk/src/cf_bitwise.c (modified) (3 diffs)

trunk/src/cf_bitwise.c

@@ -16 +16 @@
     if ((x))            \
         return CF_ERROR_BITWISE_INVALID_ARGS
+
 /**
  * 비트열을 왼쪽으로 시프트
@@ -37 +38 @@
     size_t  remain = offset % 8;
     size_t  byteSize = size / 8;
-
+    size_t  loop = byteSize - quota;
+
+    size_t  idx = 0;
     size_t  maskPos = 8 - remain;
-    cf_byte mask = 0;
-    cf_byte buf = 0;
-
-    ASSERT_ARGS (!in || !out);
-
-    for (iter = 0 ; iter < remain ; iter++)
-        mask |= (cf_byte)(0x80 >> iter);
+    cf_byte mask = (cf_byte)(0xff << (8 - remain));
+
+    ASSERT_ARGS (!in || !out);
 
     out[0] = (cf_byte)(in[0 + quota] << remain);
 
-    for (iter = 1 ; iter < byteSize - quota ; iter++)
+    for (iter = 1 ; iter < loop ; iter++)
     {
-        buf = in[iter + quota] & mask;
-
-        out[iter    ]  = (cf_byte)(in[iter + quota] << remain);
-        out[iter - 1] |= (cf_byte)(buf >> maskPos);
+        idx = iter + quota;
+
+        out[iter    ]  = (cf_byte)((in[idx]       ) << remain);
+        out[iter - 1] |= (cf_byte)((in[idx] & mask) >> maskPos);
     }
 
@@ -81 +80 @@
     size_t  remain = offset % 8;
     size_t  byteSize = size / 8;
-
+    size_t  loop = quota - 1;
+
+    size_t  idx = 0;
     size_t  maskPos = 8 - remain;
-    cf_byte mask = 0;
-    cf_byte buf = 0;
-
-    ASSERT_ARGS (!in || !out);
-
-    for (iter = 0 ; iter < remain ; iter++)
-        mask |= (cf_byte)(0x01 << iter);
+    cf_byte mask = (cf_byte)(0xff >> (8 - remain));
+
+    ASSERT_ARGS (!in || !out);
 
     out[byteSize - 1] = (cf_byte)(in[byteSize - 1 - quota] >> remain);
 
-    for (iter = byteSize - 2 ; iter > quota - 1 ; iter--)
+    for (iter = byteSize - 2 ; iter > loop ; iter--)
     {
-        buf = in[iter - quota] & mask;
-
-        out[iter    ]  = (cf_byte)(in[iter - quota] >> remain);
-        out[iter + 1] |= (cf_byte)(buf << maskPos);
+        idx = iter - quota;
+
+        out[iter    ]  = (cf_byte)((in[idx]       ) >> remain);
+        out[iter + 1] |= (cf_byte)((in[idx] & mask) << maskPos);
     }