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Apply xor_into on unaligned buffers and be safe on word-aligned architectures #169

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Merged
dinosaure merged 1 commit into from
Jun 30, 2026
Merged

Apply xor_into on unaligned buffers and be safe on word-aligned architectures #169

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50 changes: 25 additions & 25 deletions src-c/native/misc.c
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Original file line number Diff line number Diff line change
@@ -1,40 +1,40 @@
#include "digestif.h"

#define u_long_s sizeof (unsigned long)
#define u_long_s sizeof(unsigned long)

static inline void xor_into (uint8_t *src, uint8_t *dst, size_t n) {
#if defined (__digestif_SSE2__)
static inline void xor_into(uint8_t *src, uint8_t *dst, size_t n) {
#if defined(__digestif_SSE2__)
while (n >= 16) {
_mm_storeu_si128 (
(__m128i*) dst,
_mm_xor_si128 (
_mm_loadu_si128 ((__m128i*) src),
_mm_loadu_si128 ((__m128i*) dst)));
_mm_storeu_si128((__m128i *)dst,
_mm_xor_si128(_mm_loadu_si128((__m128i *)src),
_mm_loadu_si128((__m128i *)dst)));
src += 16;
dst += 16;
n -= 16;
n -= 16;
}
#endif
while (n >= u_long_s) {
*((u_long *) dst) ^= *((u_long *) src);
src += u_long_s;
dst += u_long_s;
n -= u_long_s;
}
while (n-- > 0) {
*dst = *(src ++) ^ *dst;
dst++;
}
#ifdef ARCH_SIXTYFOUR
uint64_t s;
for (; n >= 8; n -= 8, src += 8, dst += 8)
*(uint64_t *)dst ^= *(uint64_t *)memcpy(&s, src, 8);
#endif

uint32_t t;
for (; n >= 4; n -= 4, src += 4, dst += 4)
*(uint32_t *)dst ^= *(uint32_t *)memcpy(&t, src, 4);

for (; n--; ++src, ++dst)
*dst = *src ^ *dst;
}

CAMLprim value
caml_digestif_ba_xor_into (value b1, value off1, value b2, value off2, value n) {
xor_into (_ba_uint8_off (b1, off1), _ba_uint8_off (b2, off2), Int_val (n));
CAMLprim value caml_digestif_ba_xor_into(value b1, value off1, value b2,
value off2, value n) {
xor_into(_ba_uint8_off(b1, off1), _ba_uint8_off(b2, off2), Int_val(n));
return Val_unit;
}

CAMLprim value
caml_digestif_st_xor_into (value b1, value off1, value b2, value off2, value n) {
xor_into (_st_uint8_off (b1, off1), _st_uint8_off (b2, off2), Int_val (n));
CAMLprim value caml_digestif_st_xor_into(value b1, value off1, value b2,
value off2, value n) {
xor_into(_st_uint8_off(b1, off1), _st_uint8_off(b2, off2), Int_val(n));
return Val_unit;
}
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