Function SHA512_Pad

freebsd/crypto/sha2/sha512c.c:229–255

Add padding and terminating bit-count. */

/* Add padding and terminating bit-count. */
static void
SHA512_Pad(SHA512_CTX * ctx)
{
	size_t r;

	/* Figure out how many bytes we have buffered. */
	r = (ctx->count[1] >> 3) & 0x7f;

	/* Pad to 112 mod 128, transforming if we finish a block en route. */
	if (r < 112) {
		/* Pad to 112 mod 128. */
		memcpy(&ctx->buf[r], PAD, 112 - r);
	} else {
		/* Finish the current block and mix. */
		memcpy(&ctx->buf[r], PAD, 128 - r);
		SHA512_Transform(ctx->state, ctx->buf);

		/* The start of the final block is all zeroes. */
		memset(&ctx->buf[0], 0, 112);
	}

	/* Add the terminating bit-count. */
	be64enc_vect(&ctx->buf[112], ctx->count, 16);

	/* Mix in the final block. */
	SHA512_Transform(ctx->state, ctx->buf);
}

/* SHA-512 initialization.  Begins a SHA-512 operation. */
void