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SHA256Write.c
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/*====================================================================*
*
* void SHA256Write (struct sha256 * sha256, void const * memory, size_t extent);
*
* SHA256.h
*
* write a block of data to an SHA256 digest; this function behaves
* like function write() but returns no value and does not fail; an
* unlimited amount of data may be written using successive writes;
*
* to start a new digest, use function SHA266Reset(); to read the
* digest, use function SHA256Fetch();
*
* Read standard FIPS180-2 sec 5.3.2 for an explanation;
*
* Motley Tools by Charles Maier <cmaier@cmassoc.net>;
* Copyright (c) 2001-2006 by Charles Maier Associates;
* Licensed under the Internet Software Consortium License;
*
*--------------------------------------------------------------------*/
#ifndef SHA256WRITE_SOURCE
#define SHA256WRITE_SOURCE
#include "../key/SHA256.h"
void SHA256Write (struct sha256 * sha256, void const * memory, size_t extent)
{
if (extent)
{
uint8_t * buffer = (uint8_t *)(memory);
unsigned left = sha256->count [0] & 0x3F;
unsigned fill = sizeof (sha256->block) - left;
sha256->count [0] += (uint32_t)(extent);
sha256->count [0] &= 0xFFFFFFFF;
if (sha256->count [0] < extent)
{
sha256->count [1]++;
}
if ((left) && (extent >= fill))
{
memcpy (sha256->block + left, buffer, fill);
SHA256Block (sha256, sha256->block);
extent -= fill;
buffer += fill;
left = 0;
}
while (extent >= sizeof (sha256->block))
{
SHA256Block (sha256, buffer);
extent -= sizeof (sha256->block);
buffer += sizeof (sha256->block);
}
if (extent)
{
memcpy (sha256->block + left, buffer, extent);
}
}
return;
}
#endif
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