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Add 32-byte hash support

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simon987
2020-04-11 21:08:51 -04:00
parent 82291d600d
commit ab3fb7191e
2 changed files with 58 additions and 12 deletions
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56
hamming.c
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@@ -58,6 +58,35 @@ Datum hash_is_within_distance8(PG_FUNCTION_ARGS) {
PG_RETURN_BOOL(true);
}
PG_FUNCTION_INFO_V1(hash_is_within_distance32);
Datum hash_is_within_distance32(PG_FUNCTION_ARGS) {
char *h1 = VARDATA(PG_GETARG_BYTEA_P(0));
char *h2 = VARDATA(PG_GETARG_BYTEA_P(1));
int32 max_distance = PG_GETARG_INT32(2);
int distance = 0;
distance += __builtin_popcountll(*((uint64 *) h1) ^ *((uint64 *) h2));
if (distance > max_distance) {
PG_RETURN_BOOL(false);
}
distance += __builtin_popcountll(*((uint64 *) h1 + 1) ^ *((uint64 *) h2 + 1));
if (distance > max_distance) {
PG_RETURN_BOOL(false);
}
distance += __builtin_popcountll(*((uint64 *) h1 + 2) ^ *((uint64 *) h2 + 2));
if (distance > max_distance) {
PG_RETURN_BOOL(false);
}
distance += __builtin_popcountll(*((uint64 *) h1 + 3) ^ *((uint64 *) h2 + 3));
if (distance > max_distance) {
PG_RETURN_BOOL(false);
}
PG_RETURN_BOOL(distance <= max_distance);
}
PG_FUNCTION_INFO_V1(hash_distance8);
Datum hash_distance8(PG_FUNCTION_ARGS) {
@@ -68,6 +97,21 @@ Datum hash_distance8(PG_FUNCTION_ARGS) {
PG_RETURN_INT32(distance);
}
PG_FUNCTION_INFO_V1(hash_distance32);
Datum hash_distance32(PG_FUNCTION_ARGS) {
char *h1 = VARDATA(PG_GETARG_BYTEA_P(0));
char *h2 = VARDATA(PG_GETARG_BYTEA_P(1));
int distance = 0;
distance += __builtin_popcountll(*((uint64 *) h1) ^ *((uint64 *) h2));
distance += __builtin_popcountll(*((uint64 *) h1 + 1) ^ *((uint64 *) h2 + 1));
distance += __builtin_popcountll(*((uint64 *) h1 + 2) ^ *((uint64 *) h2 + 2));
distance += __builtin_popcountll(*((uint64 *) h1 + 3) ^ *((uint64 *) h2 + 3));
PG_RETURN_INT32(distance);
}
PG_FUNCTION_INFO_V1(hash_distance18);
/**
@@ -89,15 +133,9 @@ Datum hash_distance18(PG_FUNCTION_ARGS) {
int distance = 0;
distance += __builtin_popcountll(
*((uint64 *) h1) ^ *((uint64 *) h2)
);
distance += __builtin_popcountll(
*((uint64 *) h1 + 1) ^ *((uint64 *) h2 + 1)
);
distance += __builtin_popcount(
*((uint16 *) h1 + 8) ^ *((uint16 *) h2 + 8)
);
distance += __builtin_popcountll(*((uint64 *) h1) ^ *((uint64 *) h2));
distance += __builtin_popcountll(*((uint64 *) h1 + 1) ^ *((uint64 *) h2 + 1));
distance += __builtin_popcount(*((uint16 *) h1 + 8) ^ *((uint16 *) h2 + 8));
PG_RETURN_INT32(distance);
}