static void bitstring_xor_worker(int ds, char *bit_string, long bit_string_length, uint64_t *resultbuffer) {
long remaininglength = bit_string_length * 8; // convert bytes to bits
char *current_bit_string_pos;
current_bit_string_pos = bit_string;
long long offset = 0;
int block_size = xordatastoretable[ds].sizeofablock;
char *datastorebase;
datastorebase = (char *) xordatastoretable[ds].datastore;
int dwords_per_block = block_size / sizeof(uint64_t);
int bit = 128;
while (remaininglength >0) {
if ((*current_bit_string_pos) & bit) {
XOR_fullblocks(resultbuffer, (uint64_t *) (datastorebase+offset), dwords_per_block);
}
offset += block_size;
bit /= 2;
remaininglength -=1;
if (bit == 0) {
bit = 128;
current_bit_string_pos++;
}
}
}
// This function needs to be fast. It is a good candidate for releasing Python's GIL
static void multi_bitstring_xor_worker(int ds, char *bit_string, long bit_string_length, unsigned int numstrings, __m128i *resultbuffer) {
long one_bit_string_length = bit_string_length / numstrings; // length of one bit string
long remaininglength = one_bit_string_length * 8; // convert bytes to bits
char *current_bit_string_pos;
current_bit_string_pos = bit_string;
long long offset = 0;
int block_size = xordatastoretable[ds].sizeofablock;
char *datastorebase;
datastorebase = (char *) xordatastoretable[ds].datastore;
int dwords_per_block = block_size / sizeof(__m128i);
unsigned char bit = 128;
unsigned int i;
while (remaininglength > 0) {
for(i = 0; i < numstrings; i++){
if ( *(current_bit_string_pos + one_bit_string_length * i) & bit) {
XOR_fullblocks(resultbuffer + dwords_per_block * i, (__m128i *) (datastorebase + offset), dwords_per_block);
}
}
offset += block_size;
bit /= 2;
remaininglength -=1;
if (bit == 0) {
bit = 128;
current_bit_string_pos++;
}
}
}
// This XORs data with the starting data in dest
static char *fast_XOR(char *dest, const char *data, long stringlength) {
int leadingmisalignedbytes;
long fulllengthblocks;
int remainingbytes;
// If it's shorter than a block, use char-based XOR
if (stringlength <= sizeof(uint64_t)) {
return slow_XOR(dest,data,stringlength);
}
// I would guess these should be similarly DWORD aligned...
if (((long) dest) % sizeof(uint64_t) == ((long) data) % sizeof(uint64_t)) {
printf("Error, assumed that dest and data are identically DWORD aligned!\n");
return NULL;
}
// Let's XOR any stray bytes at the front...
// This is the number of bytes that are before we get DWORD aligned
// To compute this we do (8 - (pos % 8)) % 8)
leadingmisalignedbytes = (sizeof(uint64_t) - (((long)data) % sizeof(uint64_t))) % sizeof(uint64_t);
XOR_byteblocks(dest, data, leadingmisalignedbytes);
// The middle will be done with full sized blocks...
fulllengthblocks = (stringlength-leadingmisalignedbytes) / sizeof(uint64_t);
XOR_fullblocks((uint64_t *) (dest+leadingmisalignedbytes), (uint64_t *) (data + leadingmisalignedbytes), fulllengthblocks);
// XOR anything left over at the end...
remainingbytes = stringlength - (leadingmisalignedbytes + fulllengthblocks * sizeof(uint64_t));
XOR_byteblocks(dest+stringlength-remainingbytes, data+stringlength-remainingbytes, remainingbytes);
return dest;
}
