branches/5.1: Fix for bug# 36793. This is a back port from branches/zip. This

code has been tested on a big-endian machine too.

include/mach0data.h

@@ -331,10 +331,10 @@ mach_write_to_2_little_endian(
 Convert integral type from storage byte order (big endian) to
 host byte order. */
 UNIV_INLINE
-void
+ullint
 mach_read_int_type(
 /*===============*/
-	byte*		dest,		/* out: where to write */
+					/* out: integer value */
 	const byte*	src,		/* in: where to read from */
 	ulint		len,		/* in: length of src */
 	ibool		unsigned_type);	/* in: signed or unsigned flag */

include/mach0data.ic

@@ -696,33 +696,39 @@ mach_write_to_2_little_endian(
 Convert integral type from storage byte order (big endian) to
 host byte order. */
 UNIV_INLINE
-void
+ullint
 mach_read_int_type(
 /*===============*/
-	byte*		dest,		/* out: where to write */
+					/* out: integer value */
 	const byte*	src,		/* in: where to read from */
 	ulint		len,		/* in: length of src */
 	ibool		unsigned_type)	/* in: signed or unsigned flag */
 {
-#ifdef WORDS_BIGENDIAN
-	memcpy(dest, src, len);
+	/* XXX this can be optimized on big-endian machines */
+
+	ullint	ret;
+	uint	i;
+
+	if (unsigned_type || (src[0] & 0x80)) {
 
-	if (!unsigned_type) {
-		dest[0] ^= 128;
+		ret = 0x0000000000000000ULL;
+	} else {
+
+		ret = 0xFFFFFFFFFFFFFF00ULL;
 	}
-#else
-	byte*		ptr;
 
-	/* Convert integer data from Innobase to a little-endian format,
-	sign bit restored to normal. */
+	if (unsigned_type) {
+
+		ret |= src[0];
+	} else {
 
-	for (ptr = dest + len; ptr != dest; ++src) {
-		--ptr;
-		*ptr = *src;
+		ret |= src[0] ^ 0x80;
 	}
 
-	if (!unsigned_type) {
-		dest[len - 1] ^= 128;
+	for (i = 1; i < len; i++) {
+		ret <<= 8;
+		ret |= src[i];
 	}
-#endif
+
+	return(ret);
 }

row/row0sel.c

@@ -4563,8 +4563,6 @@ row_search_autoinc_read_column(
 	const byte*	data;
 	ib_ulonglong	value;
 	mem_heap_t*	heap = NULL;
-	/* Our requirement is that dest should be word aligned. */
-	byte		dest[sizeof(value)];
 	ulint		offsets_[REC_OFFS_NORMAL_SIZE];
 	ulint*		offsets	= offsets_;
 
@@ -4582,40 +4580,13 @@ row_search_autoinc_read_column(
 	ut_a(len != UNIV_SQL_NULL);
 	ut_a(len <= sizeof value);
 
-	mach_read_int_type(dest, data, len, unsigned_type);
-
-	/* The assumption here is that the AUTOINC value can't be negative
-	and that dest is word aligned. */
-	switch (len) {
-	case 8:
-		value = *(ib_ulonglong*) dest;
-		break;
-
-	case 4:
-		value = *(ib_uint32_t*) dest;
-		break;
-
-	case 3:
-		value = *(ib_uint32_t*) dest;
-		value &= 0xFFFFFF;
-		break;
-
-	case 2:
-		value = *(uint16 *) dest;
-		break;
-
-	case 1:
-		value = *dest;
-		break;
-
-	default:
-		ut_error;
-	}
+	value = mach_read_int_type(data, len, unsigned_type);
 
 	if (UNIV_LIKELY_NULL(heap)) {
 		mem_heap_free(heap);
 	}
 
+	/* We assume that the autoinc counter can't be negative. */
 	if (!unsigned_type && (ib_longlong) value < 0) {
 		value = 0;
 	}