Parse bytes rather than chars

scoville · Oct 10, 2024 · 8abbdfb · 8abbdfb
1 parent e5621d3
commit 8abbdfb
Showing 1 changed file with 28 additions and 33 deletions.
diff --git a/ulid-to-uuid.sql b/ulid-to-uuid.sql
@@ -2,49 +2,44 @@ CREATE OR REPLACE FUNCTION parse_ulid(ulid text) RETURNS bytea AS $$
 DECLARE
   -- 16byte 
   bytes bytea = E'\\x00000000 00000000 00000000 00000000';
-  v     char[];
+  v     bytea;
   -- Allow for O(1) lookup of index values
-  dec   integer[] = ARRAY[
-    255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
-    255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
-    255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
-    255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
-    255, 255, 255, 255, 255, 255, 255,   0,   1,   2,
-      3,   4,   5,   6,   7,   8,   9, 255, 255, 255,
-    255, 255, 255, 255,  10,  11,  12,  13,  14,  15,
-     16,  17,   1,  18,  19,   1,  20,  21,   0,  22,
-     23,  24,  25,  26, 255,  27,  28,  29,  30,  31,
-    255, 255, 255, 255, 255, 255,  10,  11,  12,  13,
-     14,  15,  16,  17,   1,  18,  19,   1,  20,  21,
-      0,  22,  23,  24,  25,  26, 255,  27,  28,  29,
-     30,  31
-  ];
+  dec   bytea = '\x
+    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
+    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
+    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
+    00 01 02 03 04 05 06 07 08 09 00 00 00 00 00 00
+    00 0A 0B 0C 0D 0E 0F 10 11 00 12 13 00 14 15 00
+    16 17 18 19 1A 00 1B 1C 1D 1E 1F 00 00 00 00 00
+    00 0A 0B 0C 0D 0E 0F 10 11 00 12 13 00 14 15 00
+    16 17 18 19 1A 00 1B 1C 1D 1E 1F 00 00 00 00 00
+  ';
 BEGIN
   IF NOT ulid ~* '^[0-7][0-9ABCDEFGHJKMNPQRSTVWXYZ]{25}$' THEN
     RAISE EXCEPTION 'Invalid ULID: %', ulid;
   END IF;
 
-  v = regexp_split_to_array(ulid, '');
+  v = ulid::bytea;
 
   -- 6 bytes timestamp (48 bits)
-  bytes = SET_BYTE(bytes, 0, (dec[ASCII(v[1])] << 5) | dec[ASCII(v[2])]);
-  bytes = SET_BYTE(bytes, 1, (dec[ASCII(v[3])] << 3) | (dec[ASCII(v[4])] >> 2));
-  bytes = SET_BYTE(bytes, 2, (dec[ASCII(v[4])] << 6) | (dec[ASCII(v[5])] << 1) | (dec[ASCII(v[6])] >> 4));
-  bytes = SET_BYTE(bytes, 3, (dec[ASCII(v[6])] << 4) | (dec[ASCII(v[7])] >> 1));
-  bytes = SET_BYTE(bytes, 4, (dec[ASCII(v[7])] << 7) | (dec[ASCII(v[8])] << 2) | (dec[ASCII(v[9])] >> 3));
-  bytes = SET_BYTE(bytes, 5, (dec[ASCII(v[9])] << 5) | dec[ASCII(v[10])]);
+  bytes = SET_BYTE(bytes, 0, (GET_BYTE(dec, GET_BYTE(v, 0)) << 5) | GET_BYTE(dec, GET_BYTE(v, 1)));
+  bytes = SET_BYTE(bytes, 1, (GET_BYTE(dec, GET_BYTE(v, 2)) << 3) | (GET_BYTE(dec, GET_BYTE(v, 3)) >> 2));
+  bytes = SET_BYTE(bytes, 2, (GET_BYTE(dec, GET_BYTE(v, 3)) << 6) | (GET_BYTE(dec, GET_BYTE(v, 4)) << 1) | (GET_BYTE(dec, GET_BYTE(v, 5)) >> 4));
+  bytes = SET_BYTE(bytes, 3, (GET_BYTE(dec, GET_BYTE(v, 5)) << 4) | (GET_BYTE(dec, GET_BYTE(v, 6)) >> 1));
+  bytes = SET_BYTE(bytes, 4, (GET_BYTE(dec, GET_BYTE(v, 6)) << 7) | (GET_BYTE(dec, GET_BYTE(v, 7)) << 2) | (GET_BYTE(dec, GET_BYTE(v, 8)) >> 3));
+  bytes = SET_BYTE(bytes, 5, (GET_BYTE(dec, GET_BYTE(v, 8)) << 5) | GET_BYTE(dec, GET_BYTE(v, 9)));
 
   -- 10 bytes of entropy (80 bits);
-  bytes = SET_BYTE(bytes, 6, (dec[ASCII(v[11])] << 3) | (dec[ASCII(v[12])] >> 2));
-  bytes = SET_BYTE(bytes, 7, (dec[ASCII(v[12])] << 6) | (dec[ASCII(v[13])] << 1) | (dec[ASCII(v[14])] >> 4));
-  bytes = SET_BYTE(bytes, 8, (dec[ASCII(v[14])] << 4) | (dec[ASCII(v[15])] >> 1));
-  bytes = SET_BYTE(bytes, 9, (dec[ASCII(v[15])] << 7) | (dec[ASCII(v[16])] << 2) | (dec[ASCII(v[17])] >> 3));
-  bytes = SET_BYTE(bytes, 10, (dec[ASCII(v[17])] << 5) | dec[ASCII(v[18])]);
-  bytes = SET_BYTE(bytes, 11, (dec[ASCII(v[19])] << 3) | (dec[ASCII(v[20])] >> 2));
-  bytes = SET_BYTE(bytes, 12, (dec[ASCII(v[20])] << 6) | (dec[ASCII(v[21])] << 1) | (dec[ASCII(v[22])] >> 4));
-  bytes = SET_BYTE(bytes, 13, (dec[ASCII(v[22])] << 4) | (dec[ASCII(v[23])] >> 1));
-  bytes = SET_BYTE(bytes, 14, (dec[ASCII(v[23])] << 7) | (dec[ASCII(v[24])] << 2) | (dec[ASCII(v[25])] >> 3));
-  bytes = SET_BYTE(bytes, 15, (dec[ASCII(v[25])] << 5) | dec[ASCII(v[26])]);
+  bytes = SET_BYTE(bytes, 6, (GET_BYTE(dec, GET_BYTE(v, 10)) << 3) | (GET_BYTE(dec, GET_BYTE(v, 11)) >> 2));
+  bytes = SET_BYTE(bytes, 7, (GET_BYTE(dec, GET_BYTE(v, 11)) << 6) | (GET_BYTE(dec, GET_BYTE(v, 12)) << 1) | (GET_BYTE(dec, GET_BYTE(v, 13)) >> 4));
+  bytes = SET_BYTE(bytes, 8, (GET_BYTE(dec, GET_BYTE(v, 13)) << 4) | (GET_BYTE(dec, GET_BYTE(v, 14)) >> 1));
+  bytes = SET_BYTE(bytes, 9, (GET_BYTE(dec, GET_BYTE(v, 14)) << 7) | (GET_BYTE(dec, GET_BYTE(v, 15)) << 2) | (GET_BYTE(dec, GET_BYTE(v, 16)) >> 3));
+  bytes = SET_BYTE(bytes, 10, (GET_BYTE(dec, GET_BYTE(v, 16)) << 5) | GET_BYTE(dec, GET_BYTE(v, 17)));
+  bytes = SET_BYTE(bytes, 11, (GET_BYTE(dec, GET_BYTE(v, 18)) << 3) | (GET_BYTE(dec, GET_BYTE(v, 19)) >> 2));
+  bytes = SET_BYTE(bytes, 12, (GET_BYTE(dec, GET_BYTE(v, 19)) << 6) | (GET_BYTE(dec, GET_BYTE(v, 20)) << 1) | (GET_BYTE(dec, GET_BYTE(v, 21)) >> 4));
+  bytes = SET_BYTE(bytes, 13, (GET_BYTE(dec, GET_BYTE(v, 21)) << 4) | (GET_BYTE(dec, GET_BYTE(v, 22)) >> 1));
+  bytes = SET_BYTE(bytes, 14, (GET_BYTE(dec, GET_BYTE(v, 22)) << 7) | (GET_BYTE(dec, GET_BYTE(v, 23)) << 2) | (GET_BYTE(dec, GET_BYTE(v, 24)) >> 3));
+  bytes = SET_BYTE(bytes, 15, (GET_BYTE(dec, GET_BYTE(v, 24)) << 5) | GET_BYTE(dec, GET_BYTE(v, 25)));
 
   RETURN bytes;
 END