我在Github Gist中找到了针对Base58编码器的MySQL函数 。
DELIMITER $$ CREATE FUNCTION base58_encode (num int) RETURNS varchar(255) DETERMINISTIC BEGIN DECLARE alphabet varchar(255); DECLARE base_count int DEFAULT 0; DECLARE encoded varchar(255); DECLARE divisor DECIMAL(10,4); DECLARE mode int DEFAULT 0; SET alphabet = '123456789abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ'; SET base_count = CHAR_LENGTH(alphabet); SET encoded = ""; WHILE num >= base_count DO SET divisor = num / base_count; SET mode = (num - (base_count* TRUNCATE(divisor,0))); SET encoded = CONCAT(SUBSTRING(alphabet FROM mode+1 FOR 1), encoded); SET num = TRUNCATE(divisor,0); END WHILE; SET encoded = CONCAT(SUBSTRING(alphabet FROM num+1 FOR 1), encoded); RETURN (encoded); END
我是新手PostgreSQL,很难将上述函数转换为PostgreSQL函数。
PostgreSQL
PostgreSQL上面的SQL代码片段对Base58 Encoder的等效功能如何?
我想出的PostgreSQL中的等效函数如下。
CREATE FUNCTION base58_encode(num INT) RETURNS VARCHAR(255) AS $encoded$ DECLARE alphabet VARCHAR(255); base_count INT DEFAULT 0; encoded VARCHAR(255); divisor DECIMAL(10, 4); mod INT DEFAULT 0; BEGIN alphabet := '123456789abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ'; base_count := char_length(alphabet); encoded := ''; WHILE num >= base_count LOOP divisor := num / base_count; mod := (num - (base_count * trunc(divisor, 0))); encoded := concat(substring(alphabet FROM mod + 1 FOR 1), encoded); num := trunc(divisor, 0); END LOOP; encoded = concat(substring(alphabet FROM num + 1 FOR 1), encoded); RETURN (encoded); END; $encoded$ LANGUAGE PLPGSQL;