Checksumming updates

[fio.git] / crc / sha256.c

diff --git a/crc/sha256.c b/crc/sha256.c
index 3a72a5bfb2e14bbcc0d718acfa9e296ec9c48ded..ae9ff4d99508190788f6ad33c4d8e5c501fe5676 100644 (file)
--- a/crc/sha256.c
+++ b/crc/sha256.c
@@ -237,37 +237,57 @@ void fio_sha256_init(struct fio_sha256_ctx *sctx)
        sctx->state[5] = H5;
        sctx->state[6] = H6;
        sctx->state[7] = H7;
-       sctx->count[0] = sctx->count[1] = 0;
+       sctx->count = 0;
 }
 
 void fio_sha256_update(struct fio_sha256_ctx *sctx, const uint8_t *data,
                       unsigned int len)
 {
-       unsigned int i, idx, part_len;
+       unsigned int partial, done;
+       const uint8_t *src;
 
-       /* Compute number of bytes mod 128 */
-       idx = (unsigned int)((sctx->count[0] >> 3) & 0x3f);
+       partial = sctx->count & 0x3f;
+       sctx->count += len;
+       done = 0;
+       src = data;
 
-       /* Update number of bits */
-       if ((sctx->count[0] += (len << 3)) < (len << 3)) {
-               sctx->count[1]++;
-               sctx->count[1] += (len >> 29);
+       if ((partial + len) > 63) {
+               if (partial) {
+                       done = -partial;
+                       memcpy(sctx->buf + partial, data, done + 64);
+                       src = sctx->buf;
+               }
+
+               do {
+                       sha256_transform(sctx->state, src);
+                       done += 64;
+                       src = data + done;
+               } while (done + 63 < len);
+
+               partial = 0;
        }
+       memcpy(sctx->buf + partial, src, len - done);
+}
+
+void fio_sha256_final(struct fio_sha256_ctx *sctx)
+{
+       uint64_t bits;
+       unsigned int index, pad_len;
+       int i;
+       static const uint8_t padding[64] = { 0x80, };
 
-       part_len = 64 - idx;
+       /* Save number of bits */
+       bits = sctx->count << 3;
 
-       /* Transform as many times as possible. */
-       if (len >= part_len) {
-               memcpy(&sctx->buf[idx], data, part_len);
-               sha256_transform(sctx->state, sctx->buf);
+       /* Pad out to 56 mod 64. */
+       index = sctx->count & 0x3f;
+       pad_len = (index < 56) ? (56 - index) : ((64+56) - index);
+       fio_sha256_update(sctx, padding, pad_len);
 
-               for (i = part_len; i + 63 < len; i += 64)
-                       sha256_transform(sctx->state, &data[i]);
-               idx = 0;
-       } else {
-               i = 0;
-       }
-       
-       /* Buffer remaining input */
-       memcpy(&sctx->buf[idx], &data[i], len-i);
+       /* Append length (before padding) */
+       fio_sha256_update(sctx, (const uint8_t *)&bits, sizeof(bits));
+
+       /* Store state in digest */
+       for (i = 0; i < 8; i++)
+               sctx->buf[i] = sctx->state[i];
 }