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/* See LICENSE file for copyright and license details. */
#include "common.h"
#ifdef __GNUC__
# pragma GCC diagnostic push
# pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
#endif
#define have(v) (spec->v != LIBKECCAK_GENERALISED_SPEC_AUTOMATIC)
#define copy(v) (v = spec->v)
#define deft(v, dv) (have_##v ? v : (dv))
/**
* Convert a `struct libkeccak_generalised_spec` to a `struct libkeccak_spec`
*
* If you are interrested in finding errors, you should call
* `libkeccak_spec_check(output)` if this function returns zero
*
* @param spec The generalised input specifications, will be update with resolved automatic values
* @param output_spec The specification datastructure to fill in
* @return Zero if `spec` is valid, a `LIBKECCAK_GENERALISED_SPEC_ERROR_*` if an error was found
*/
int
libkeccak_degeneralise_spec(struct libkeccak_generalised_spec *restrict spec,
struct libkeccak_spec *restrict output_spec)
{
long int state_size, word_size, capacity, bitrate, output;
const int have_state_size = have(state_size);
const int have_word_size = have(word_size);
const int have_capacity = have(capacity);
const int have_bitrate = have(bitrate);
const int have_output = have(output);
if (have_state_size) {
copy(state_size);
if (state_size <= 0) return LIBKECCAK_GENERALISED_SPEC_ERROR_STATE_NONPOSITIVE;
if (state_size > 1600) return LIBKECCAK_GENERALISED_SPEC_ERROR_STATE_TOO_LARGE;
if (state_size % 25) return LIBKECCAK_GENERALISED_SPEC_ERROR_STATE_MOD_25;
}
if (have_word_size) {
copy(word_size);
if (word_size <= 0) return LIBKECCAK_GENERALISED_SPEC_ERROR_WORD_NONPOSITIVE;
if (word_size > 64) return LIBKECCAK_GENERALISED_SPEC_ERROR_WORD_TOO_LARGE;
if (have_state_size && state_size != word_size * 25)
return LIBKECCAK_GENERALISED_SPEC_ERROR_STATE_WORD_INCOHERENCY;
else if (!have_state_size)
spec->state_size = 1, state_size = word_size * 25;
}
if (have_capacity) {
copy(capacity);
if (capacity <= 0) return LIBKECCAK_GENERALISED_SPEC_ERROR_CAPACITY_NONPOSITIVE;
if (capacity & 7) return LIBKECCAK_GENERALISED_SPEC_ERROR_CAPACITY_MOD_8;
}
if (have_bitrate) {
copy(bitrate);
if (bitrate <= 0) return LIBKECCAK_GENERALISED_SPEC_ERROR_BITRATE_NONPOSITIVE;
if (bitrate & 7) return LIBKECCAK_GENERALISED_SPEC_ERROR_BITRATE_MOD_8;
}
if (have_output) {
copy(output);
if (output <= 0) return LIBKECCAK_GENERALISED_SPEC_ERROR_OUTPUT_NONPOSITIVE;
}
if (!have_bitrate && !have_capacity && !have_output) {
state_size = deft(state_size, 1600L);
output = ((state_size << 5) / 100L + 7L) & ~0x07L;
bitrate = output << 1;
capacity = state_size - bitrate;
output = output >= 8 ? output : 8;
} else if (!have_bitrate && !have_capacity) {
bitrate = 1024;
capacity = 1600 - 1024;
state_size = deft(state_size, bitrate + capacity);
} else if (!have_bitrate) {
state_size = deft(state_size, 1600L);
bitrate = state_size - capacity;
output = deft(output, capacity == 8 ? 8 : (capacity << 1));
} else if (!have_capacity) {
state_size = deft(state_size, 1600L);
capacity = state_size - bitrate;
output = deft(output, capacity == 8 ? 8 : (capacity << 1));
} else {
state_size = deft(state_size, bitrate + capacity);
output = deft(output, capacity == 8 ? 8 : (capacity << 1));
}
spec->capacity = output_spec->capacity = capacity;
spec->bitrate = output_spec->bitrate = bitrate;
spec->output = output_spec->output = output;
spec->state_size = state_size;
spec->word_size = state_size / 25;
return 0;
}
#undef deft
#undef copy
#undef have
#ifdef __GNUC__
# pragma GCC diagnostic pop
#endif
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