Restore workaround for unaligned reads in xxhash

The code was originally used inside the block processor, where 32 bit
aligned data could be guaranteed. If it is available in libutil, I
cannot possibly guarantee for alignment in future use elsewhere. Even
for the block processor it was rather risky "remember this detail very
well" buisness.

This commit restores the unaligned read treatment of the original.

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

1 files changed, 14 insertions, 5 deletions

diff --git a/lib/util/xxhash.c b/lib/util/xxhash.c
index 4e1e0e0..0644e75 100644
--- a/lib/util/xxhash.c
+++ b/lib/util/xxhash.c
@@ -37,6 +37,8 @@
 #include "config.h"
 #include "util.h"
 
+#include <string.h>
+
 #define xxh_rotl32(x, r) ((x << r) | (x >> (32 - r)))
 
 static const sqfs_u32 PRIME32_1 = 2654435761U;
@@ -53,6 +55,13 @@ static sqfs_u32 xxh32_round(sqfs_u32 seed, sqfs_u32 input)
 	return seed;
 }
 
+static sqfs_u32 XXH_readLE32(const sqfs_u8 *ptr)
+{
+	sqfs_u32 value;
+	memcpy(&value, ptr, sizeof(value));
+	return le32toh(value);
+}
+
 sqfs_u32 xxh32(const void *input, const size_t len)
 {
 	const sqfs_u8 *p = (const sqfs_u8 *)input;
@@ -67,10 +76,10 @@ sqfs_u32 xxh32(const void *input, const size_t len)
 		sqfs_u32 v4 = PRIME32_1;
 
 		do {
-			v1 = xxh32_round(v1, ((sqfs_u32 *)p)[0]);
-			v2 = xxh32_round(v2, ((sqfs_u32 *)p)[1]);
-			v3 = xxh32_round(v3, ((sqfs_u32 *)p)[2]);
-			v4 = xxh32_round(v4, ((sqfs_u32 *)p)[3]);
+			v1 = xxh32_round(v1, XXH_readLE32(p     ));
+			v2 = xxh32_round(v2, XXH_readLE32(p +  4));
+			v3 = xxh32_round(v3, XXH_readLE32(p +  8));
+			v4 = xxh32_round(v4, XXH_readLE32(p + 12));
 			p += 16;
 		} while (p <= limit);
 
@@ -83,7 +92,7 @@ sqfs_u32 xxh32(const void *input, const size_t len)
 	h32 += (sqfs_u32)len;
 
 	while (p + 4 <= b_end) {
-		h32 += (*((sqfs_u32 *)p)) * PRIME32_3;
+		h32 += XXH_readLE32(p) * PRIME32_3;
 		h32 = xxh_rotl32(h32, 17) * PRIME32_4;
 		p += 4;
 	}