/** ZSTD_ldm_gear_init():
*
* Initializes the rolling hash state such that it will honor the
* settings in params. */
private static void ZSTD_ldm_gear_init(ldmRollingHashState_t *state, ldmParams_t * @params)
{
uint maxBitsInMask = ((@params->minMatchLength) < (64) ? (@params->minMatchLength) : (64));
uint hashRateLog = @params->hashRateLog;
state->rolling = unchecked (~(uint)(0));
if (hashRateLog > 0 && hashRateLog <= maxBitsInMask)
{
state->stopMask = (((ulong)(1) << (int)hashRateLog) - 1) << (int)(maxBitsInMask - hashRateLog);
}
else
{
state->stopMask = ((ulong)(1) << (int)hashRateLog) - 1;
}
}
/** ZSTD_ldm_gear_feed():
*
* Registers in the splits array all the split points found in the first
* size bytes following the data pointer. This function terminates when
* either all the data has been processed or LDM_BATCH_SIZE splits are
* present in the splits array.
*
* Precondition: The splits array must not be full.
* Returns: The number of bytes processed. */
private static nuint ZSTD_ldm_gear_feed(ldmRollingHashState_t *state, byte *data, nuint size, nuint *splits, uint *numSplits)
{
nuint n;
ulong hash, mask;
hash = state->rolling;
mask = state->stopMask;
n = 0;
while (n + 3 < size)
{
{
hash = (hash << 1) + ZSTD_ldm_gearTab[data[n] & 0xff];
n += 1;
if (((hash & mask) == 0))
{
splits[*numSplits] = n;
*numSplits += 1;
if (*numSplits == 64)
{
goto done;
}
}
}
{
hash = (hash << 1) + ZSTD_ldm_gearTab[data[n] & 0xff];
n += 1;
if (((hash & mask) == 0))
{
splits[*numSplits] = n;
*numSplits += 1;
if (*numSplits == 64)
{
goto done;
}
}
}
{
hash = (hash << 1) + ZSTD_ldm_gearTab[data[n] & 0xff];
n += 1;
if (((hash & mask) == 0))
{
splits[*numSplits] = n;
*numSplits += 1;
if (*numSplits == 64)
{
goto done;
}
}
}
{
hash = (hash << 1) + ZSTD_ldm_gearTab[data[n] & 0xff];
n += 1;
if (((hash & mask) == 0))
{
splits[*numSplits] = n;
*numSplits += 1;
if (*numSplits == 64)
{
goto done;
}
}
}
}
while (n < size)
{
{
hash = (hash << 1) + ZSTD_ldm_gearTab[data[n] & 0xff];
n += 1;
if (((hash & mask) == 0))
{
splits[*numSplits] = n;
*numSplits += 1;
if (*numSplits == 64)
{
goto done;
}
}
}
}
done:
state->rolling = hash;
return(n);
}
