Fixing issues with alignment, undefined behaviour and endianness in the FieldTrial::HashName functi…

base/sys_byteorder.h

Index: base/sys_byteorder.h
diff --git a/base/sys_byteorder.h b/base/sys_byteorder.h
index 500999d6423e7fd4a1d369301f550c954359841a..97e33acfdab33d5093cf5441284eb5f25a314c2b 100644
--- a/base/sys_byteorder.h
+++ b/base/sys_byteorder.h
@@ -69,6 +69,30 @@ inline uint64 ByteSwap(uint64 x) {
 #endif
 }
 
+// Converts the bytes in |x| from host order (endianness) to little endian, and
+// returns the result.
+inline uint16 ByteSwapToLE16(uint16 x) {
+#if defined(ARCH_CPU_LITTLE_ENDIAN)
+  return x;
+#else
+  return ByteSwap(x);
+#endif
+}
+inline uint32 ByteSwapToLE32(uint32 x) {
+#if defined(ARCH_CPU_LITTLE_ENDIAN)
+  return x;
+#else
+  return ByteSwap(x);
+#endif
+}
+inline uint64 ByteSwapToLE64(uint64 x) {
+#if defined(ARCH_CPU_LITTLE_ENDIAN)
+  return x;
+#else
+  return ByteSwap(x);
+#endif

[Ilya Sherman, 2012/04/13 20:19:20]

Hmm, why are you adding these functions rather than just using HostToNet32()? 
Is it important that the bytes be in little-endian order rather than in
big-endian order?

[jwd, 2012/04/13 20:33:44]

We decided that we wanted the values in little-endian because of the existing
data and some arguments about the servers being mostly little-endian right now
anyway. 
On 2012/04/13 20:19:20, Ilya Sherman wrote:

[Ilya Sherman, 2012/04/13 21:27:33]

Ok, fair enough.  Thanks :)

+}
+
 // Converts the bytes in |x| from network to host order (endianness), and
 // returns the result.
 inline uint16 NetToHost16(uint16 x) {