void cf_blockwise_acc_pad(uint8_t *partial, size_t *npartial,
size_t nblock,
uint8_t fbyte, uint8_t mbyte, uint8_t lbyte,
size_t nbytes,
cf_blockwise_in_fn process,
void *ctx)
{
switch (nbytes)
{
case 0: break;
case 1: fbyte ^= lbyte;
cf_blockwise_accumulate(partial, npartial, nblock, &fbyte, 1, process, ctx);
break;
case 2:
cf_blockwise_accumulate(partial, npartial, nblock, &fbyte, 1, process, ctx);
cf_blockwise_accumulate(partial, npartial, nblock, &lbyte, 1, process, ctx);
break;
default:
cf_blockwise_accumulate(partial, npartial, nblock, &fbyte, 1, process, ctx);
/* If the middle and last bytes differ, then process the last byte separately.
* Otherwise, just extend the middle block size. */
if (lbyte != mbyte)
{
cf_blockwise_acc_byte(partial, npartial, nblock, mbyte, nbytes - 2, process, ctx);
cf_blockwise_accumulate(partial, npartial, nblock, &lbyte, 1, process, ctx);
} else {
cf_blockwise_acc_byte(partial, npartial, nblock, mbyte, nbytes - 1, process, ctx);
}
break;
}
}
void cf_cbcmac_stream_pad_final(cf_cbcmac_stream *ctx, uint8_t out[CF_MAXBLOCK])
{
uint8_t npad = ctx->prp->blocksz - ctx->used;
cf_blockwise_acc_byte(ctx->buffer, &ctx->used, ctx->prp->blocksz,
npad, npad,
cbcmac_process, ctx);
cf_cbcmac_stream_nopad_final(ctx, out);
}
