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Add 8-byte hash support

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simon987
2020-04-10 18:55:20 -04:00
parent a7c41e4959
commit 82291d600d
3 changed files with 61 additions and 9 deletions
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39
hamming.c
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@@ -3,7 +3,7 @@
PG_MODULE_MAGIC;
PG_FUNCTION_INFO_V1(hash_is_within_distance);
PG_FUNCTION_INFO_V1(hash_is_within_distance18);
/**
* Check if the hamming distance of the two raw byte arrays
@@ -18,7 +18,7 @@ PG_FUNCTION_INFO_V1(hash_is_within_distance);
*
* @return the hamming distance between the two arrays
*/
Datum hash_is_within_distance(PG_FUNCTION_ARGS) {
Datum hash_is_within_distance18(PG_FUNCTION_ARGS) {
char *h1 = VARDATA(PG_GETARG_BYTEA_P(0));
char *h2 = VARDATA(PG_GETARG_BYTEA_P(1));
@@ -45,7 +45,30 @@ Datum hash_is_within_distance(PG_FUNCTION_ARGS) {
PG_RETURN_BOOL(distance <= max_distance);
}
PG_FUNCTION_INFO_V1(hash_distance);
PG_FUNCTION_INFO_V1(hash_is_within_distance8);
Datum hash_is_within_distance8(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);
if (__builtin_popcountll(*((uint64 *) h1) ^ *((uint64 *) h2)) > max_distance) {
PG_RETURN_BOOL(false);
}
PG_RETURN_BOOL(true);
}
PG_FUNCTION_INFO_V1(hash_distance8);
Datum hash_distance8(PG_FUNCTION_ARGS) {
char *h1 = VARDATA(PG_GETARG_BYTEA_P(0));
char *h2 = VARDATA(PG_GETARG_BYTEA_P(1));
int distance = __builtin_popcountll(*((uint64 *) h1) ^ *((uint64 *) h2));
PG_RETURN_INT32(distance);
}
PG_FUNCTION_INFO_V1(hash_distance18);
/**
* Hamming distance of two raw byte arrays
@@ -59,7 +82,7 @@ PG_FUNCTION_INFO_V1(hash_distance);
*
* @return the hamming distance between the two arrays
*/
Datum hash_distance(PG_FUNCTION_ARGS) {
Datum hash_distance18(PG_FUNCTION_ARGS) {
char *h1 = VARDATA(PG_GETARG_BYTEA_P(0));
char *h2 = VARDATA(PG_GETARG_BYTEA_P(1));
@@ -80,7 +103,7 @@ Datum hash_distance(PG_FUNCTION_ARGS) {
}
PG_FUNCTION_INFO_V1(hash_is_within_distance_any);
PG_FUNCTION_INFO_V1(hash_is_within_distance18_any);
/**
* Check if the first argument matches any (within distance 'max_distance')
@@ -96,7 +119,7 @@ PG_FUNCTION_INFO_V1(hash_is_within_distance_any);
*
* @return true if at least 1 hash matches
*/
Datum hash_is_within_distance_any(PG_FUNCTION_ARGS) {
Datum hash_is_within_distance18_any(PG_FUNCTION_ARGS) {
char *h = VARDATA(PG_GETARG_BYTEA_P(0));
bytea *h_bytea = PG_GETARG_BYTEA_P(1);
@@ -134,7 +157,7 @@ Datum hash_is_within_distance_any(PG_FUNCTION_ARGS) {
PG_RETURN_BOOL(false);
}
PG_FUNCTION_INFO_V1(hash_equ_any);
PG_FUNCTION_INFO_V1(hash_equ18_any);
/**
* Check if the first argument exactly matches any hashes among an array of hashes
@@ -148,7 +171,7 @@ PG_FUNCTION_INFO_V1(hash_equ_any);
LANGUAGE C STRICT;
* @return true if at least 1 hash is equal
*/
Datum hash_equ_any(PG_FUNCTION_ARGS) {
Datum hash_equ18_any(PG_FUNCTION_ARGS) {
char *h = VARDATA(PG_GETARG_BYTEA_P(0));
bytea *h_bytea = PG_GETARG_BYTEA_P(1);