xref: /xnu-8792.61.2/osfmk/corecrypto/ccdigest_update.c (revision 42e220869062b56f8d7d0726fd4c88954f87902c)

/* Copyright (c) (2010,2011,2014,2015,2016,2018,2019) Apple Inc. All rights reserved.
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 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
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 *
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 */

#include "cc_internal.h"
#include <corecrypto/ccdigest.h>
#include <corecrypto/cc_priv.h>

void
ccdigest_update(const struct ccdigest_info *di, ccdigest_ctx_t ctx, size_t len, const void *data)
{
	CC_ENSURE_DIT_ENABLED

	const char * data_ptr = data;
	size_t nblocks, nbytes;

	// Sanity check to recover from ctx corruptions.
	if (ccdigest_num(di, ctx) >= di->block_size) {
		ccdigest_num(di, ctx) = 0;
	}

	while (len > 0) {
		if (ccdigest_num(di, ctx) == 0 && len > di->block_size) {
			if (di->block_size == 1 << 6) { // md5 & sha1 & sha256
				nblocks = len >> 6;
				nbytes = nblocks << 6;
			} else if (di->block_size == 1 << 7) { // sha384 & sha512
				nblocks = len >> 7;
				nbytes = nblocks << 7;
			} else {
				nblocks = len / di->block_size;
				nbytes = nblocks * di->block_size;
			}

			di->compress(ccdigest_state(di, ctx), nblocks, data_ptr);
			len -= nbytes;
			data_ptr += nbytes;
			ccdigest_nbits(di, ctx) += (uint64_t) (nbytes) * 8;
		} else {
			size_t n = CC_MIN(di->block_size - ccdigest_num(di, ctx), len);
			cc_memcpy(ccdigest_data(di, ctx) + ccdigest_num(di, ctx), data_ptr, n);
			/* typecast: less than block size, will always fit into an int */
			ccdigest_num(di, ctx) += (unsigned int)n;
			len -= n;
			data_ptr += n;
			if (ccdigest_num(di, ctx) == di->block_size) {
				di->compress(ccdigest_state(di, ctx), 1, ccdigest_data(di, ctx));
				ccdigest_nbits(di, ctx) += ccdigest_num(di, ctx) * 8;
				ccdigest_num(di, ctx) = 0;
			}
		}
	}
}