Use Rotate*() functions instead of doing this manually.

src/base/bits.h

Index: src/base/bits.h
diff --git a/src/base/bits.h b/src/base/bits.h
index 0f4d4c712becc540dd767291b1766b12c526a09e..5c7cd74c610d5f8f59b21214d888d2b284825935 100644
--- a/src/base/bits.h
+++ b/src/base/bits.h
@@ -148,17 +148,30 @@ inline uint32_t RoundDownToPowerOfTwo32(uint32_t value) {
 }
 
 
+// Precondition: 0 <= shift < 32

[hans, 2015/03/04 06:02:51]

Any reason the preconditions are not some kind of assert or check?

[Nico, 2015/03/04 06:21:10]

I was worried that this might be performance-critical and things might get very
slow in debug builds. I don't know if that's true.

 inline uint32_t RotateRight32(uint32_t value, uint32_t shift) {
   if (shift == 0) return value;
   return (value >> shift) | (value << (32 - shift));
 }
 
+// Precondition: 0 <= shift < 32
+inline uint32_t RotateLeft32(uint32_t value, uint32_t shift) {
+  if (shift == 0) return value;
+  return (value << shift) | (value >> (32 - shift));
+}
 
+// Precondition: 0 <= shift < 64
 inline uint64_t RotateRight64(uint64_t value, uint64_t shift) {
   if (shift == 0) return value;
   return (value >> shift) | (value << (64 - shift));
 }
 
+// Precondition: 0 <= shift < 64
+inline uint64_t RotateLeft64(uint64_t value, uint64_t shift) {
+  if (shift == 0) return value;
+  return (value << shift) | (value >> (64 - shift));
+}
+
 
 // SignedAddOverflow32(lhs,rhs,val) performs a signed summation of |lhs| and
 // |rhs| and stores the result into the variable pointed to by |val| and