MySQL base64 functions
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Ian Gulliver
173
files/base64.sql
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173
files/base64.sql
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-- base64.sql - MySQL base64 encoding/decoding functions
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-- Copyright (C) 2006 Ian Gulliver
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--
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-- This program is free software; you can redistribute it and/or modify
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-- it under the terms of version 2 of the GNU General Public License as
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-- published by the Free Software Foundation.
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--
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-- This program is distributed in the hope that it will be useful,
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-- but WITHOUT ANY WARRANTY; without even the implied warranty of
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-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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-- GNU General Public License for more details.
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--
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-- You should have received a copy of the GNU General Public License
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-- along with this program; if not, write to the Free Software
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-- Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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delimiter |
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DROP TABLE IF EXISTS base64_data |
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CREATE TABLE base64_data (c CHAR(1) BINARY, val TINYINT) |
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INSERT INTO base64_data VALUES
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('A',0), ('B',1), ('C',2), ('D',3), ('E',4), ('F',5), ('G',6), ('H',7), ('I',8), ('J',9),
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('K',10), ('L',11), ('M',12), ('N',13), ('O',14), ('P',15), ('Q',16), ('R',17), ('S',18), ('T',19),
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('U',20), ('V',21), ('W',22), ('X',23), ('Y',24), ('Z',25), ('a',26), ('b',27), ('c',28), ('d',29),
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('e',30), ('f',31), ('g',32), ('h',33), ('i',34), ('j',35), ('k',36), ('l',37), ('m',38), ('n',39),
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('o',40), ('p',41), ('q',42), ('r',43), ('s',44), ('t',45), ('u',46), ('v',47), ('w',48), ('x',49),
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('y',50), ('z',51), ('0',52), ('1',53), ('2',54), ('3',55), ('4',56), ('5',57), ('6',58), ('7',59),
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('8',60), ('9',61), ('+',62), ('/',63), ('=',0) |
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DROP FUNCTION IF EXISTS BASE64_DECODE |
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CREATE FUNCTION BASE64_DECODE (input BLOB)
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RETURNS BLOB
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CONTAINS SQL
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DETERMINISTIC
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SQL SECURITY INVOKER
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BEGIN
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DECLARE ret BLOB DEFAULT '';
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DECLARE done TINYINT DEFAULT 0;
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IF input IS NULL THEN
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RETURN NULL;
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END IF;
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each_block:
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WHILE NOT done DO BEGIN
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DECLARE accum_value BIGINT UNSIGNED DEFAULT 0;
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DECLARE in_count TINYINT DEFAULT 0;
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DECLARE out_count TINYINT DEFAULT 3;
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each_input_char:
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WHILE in_count < 4 DO BEGIN
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DECLARE first_char CHAR(1);
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IF LENGTH(input) = 0 THEN
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RETURN ret;
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END IF;
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SET first_char = SUBSTRING(input,1,1);
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SET input = SUBSTRING(input,2);
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BEGIN
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DECLARE tempval TINYINT UNSIGNED;
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DECLARE error TINYINT DEFAULT 0;
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DECLARE base64_getval CURSOR FOR SELECT val FROM base64_data WHERE c = first_char;
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DECLARE CONTINUE HANDLER FOR SQLSTATE '02000' SET error = 1;
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OPEN base64_getval;
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FETCH base64_getval INTO tempval;
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CLOSE base64_getval;
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IF error THEN
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ITERATE each_input_char;
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END IF;
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SET accum_value = (accum_value << 6) + tempval;
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END;
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SET in_count = in_count + 1;
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IF first_char = '=' THEN
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SET done = 1;
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SET out_count = out_count - 1;
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END IF;
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END; END WHILE;
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-- We've now accumulated 24 bits; deaccumulate into bytes
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-- We have to work from the left, so use the third byte position and shift left
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WHILE out_count > 0 DO BEGIN
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SET ret = CONCAT(ret,CHAR((accum_value & 0xff0000) >> 16));
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SET out_count = out_count - 1;
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SET accum_value = (accum_value << 8) & 0xffffff;
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END; END WHILE;
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END; END WHILE;
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RETURN ret;
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END |
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DROP FUNCTION IF EXISTS BASE64_ENCODE |
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CREATE FUNCTION BASE64_ENCODE (input BLOB)
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RETURNS BLOB
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CONTAINS SQL
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DETERMINISTIC
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SQL SECURITY INVOKER
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BEGIN
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DECLARE ret BLOB DEFAULT '';
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DECLARE done TINYINT DEFAULT 0;
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IF input IS NULL THEN
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RETURN NULL;
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END IF;
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each_block:
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WHILE NOT done DO BEGIN
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DECLARE accum_value BIGINT UNSIGNED DEFAULT 0;
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DECLARE in_count TINYINT DEFAULT 0;
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DECLARE out_count TINYINT;
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each_input_char:
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WHILE in_count < 3 DO BEGIN
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DECLARE first_char CHAR(1);
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IF LENGTH(input) = 0 THEN
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SET done = 1;
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SET accum_value = accum_value << (8 * (3 - in_count));
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LEAVE each_input_char;
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END IF;
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SET first_char = SUBSTRING(input,1,1);
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SET input = SUBSTRING(input,2);
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SET accum_value = (accum_value << 8) + ASCII(first_char);
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SET in_count = in_count + 1;
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END; END WHILE;
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-- We've now accumulated 24 bits; deaccumulate into base64 characters
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-- We have to work from the left, so use the third byte position and shift left
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CASE
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WHEN in_count = 3 THEN SET out_count = 4;
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WHEN in_count = 2 THEN SET out_count = 3;
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WHEN in_count = 1 THEN SET out_count = 2;
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ELSE RETURN ret;
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END CASE;
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WHILE out_count > 0 DO BEGIN
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BEGIN
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DECLARE out_char CHAR(1);
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DECLARE base64_getval CURSOR FOR SELECT c FROM base64_data WHERE val = (accum_value >> 18);
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OPEN base64_getval;
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FETCH base64_getval INTO out_char;
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CLOSE base64_getval;
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SET ret = CONCAT(ret,out_char);
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SET out_count = out_count - 1;
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SET accum_value = accum_value << 6 & 0xffffff;
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END;
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END; END WHILE;
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CASE
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WHEN in_count = 2 THEN SET ret = CONCAT(ret,'=');
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WHEN in_count = 1 THEN SET ret = CONCAT(ret,'==');
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ELSE BEGIN END;
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END CASE;
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END; END WHILE;
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RETURN ret;
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END |
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