Code to determine whether the passed in string is a C style comment block - in T-SQL

[honey the codewitch]

In my defense this code was generated by a tool. It's still some of the weirdest code to do string ops in SQL I've seen. Part of it is due to the fact that it converts everything to UTF32 as it goes, even though in this routine it really doesn't need to.

-- Matches the block end for CommentBlock
DROP PROCEDURE [dbo].[SqlCompiledChecker_IsCommentBlockBlockEnd]
GO
CREATE PROCEDURE [dbo].[SqlCompiledChecker_IsCommentBlockBlockEnd] @value NVARCHAR(MAX), @index INT, @ch INT
AS
BEGIN
DECLARE @adv INT
DECLARE @matched INT
DECLARE @valueEnd INT = DATALENGTH(@value)/2+1
DECLARE @tch BIGINT
DECLARE @accept INT = -1
DECLARE @result INT = 0
WHILE @ch <> -1
BEGIN
SET @matched = 0
-- q0
IF @ch = 42
BEGIN

        SET @index = @index + 1
        SET @adv = 1
        IF @index < @valueEnd
        BEGIN
        	SET @ch = UNICODE(SUBSTRING(@value, @index, 1))
        	SET @tch = @ch - 0xd800
        	IF @tch < 0 SET @tch = @tch + 2147483648
        	IF @tch < 2048
        	BEGIN
        		SET @ch = @ch \* 1024
        		SET @index = @index + 1
        		SET @adv = 2
        		IF @index >= @valueEnd RETURN -1
        		SET @ch = @ch + UNICODE(SUBSTRING(@value, @index, 1)) - 0x35fdc00
        	END
        END
        ELSE
        BEGIN
        	SET @ch = -1
        END
        SET @matched = 1
        GOTO q1
    END -- IF {range match}
    GOTO next
q1:
    IF @ch = 47
    BEGIN
        
        SET @index = @index + 1
        SET @adv = 1
        IF @index < @valueEnd
        BEGIN
        	SET @ch = UNICODE(SUBSTRING(@value, @index, 1))
        	SET @tch = @ch - 0xd800
        	IF @tch < 0 SET @tch = @tch + 2147483648
        	IF @tch < 2048
        	BEGIN
        		SET @ch = @ch \* 1024
        		SET @index = @index + 1
        		SET @adv = 2
        		IF @index >= @valueEnd RETURN -1
        		SET @ch = @ch + UNICODE(SUBSTRING(@value, @index, 1)) - 0x35fdc00
        	END
        END
        ELSE
        BEGIN
        	SET @ch = -1
        END
        SET @matched = 1
        GOTO q2
    END -- IF {range match}
    GOTO next
q2:
    RETURN CASE @ch WHEN -1 THEN 1 ELSE 0 END
next:
    IF @matched = 0
    BEGIN
        SET @index = @index + 1

[Jorgen Andersson]

UTF16 ain't good enough for you?

Wrong is evil and must be defeated. - Jeff Ello

[Maximilien]

code salad.

CI/CD = Continuous Impediment/Continuous Despair

[honey the codewitch]

UTF16 surrogate pairs exist, so no. Frankly, I wish UTF16 didn't exist at all. It seems a waste of everyone's time. No wonder MS adopted it.

Real programmers use butterflies

[Brisingr Aerowing]

With a side of syntax soup.

What do you get when you cross a joke with a rhetorical question? The metaphorical solid rear-end expulsions have impacted the metaphorical motorized bladed rotating air movement mechanism. Do questions with multiple question marks annoy you???

[James Curran]

I'm dying to know what sin in a past life led you to NEED to determine whether the passed in string is a C style comment block - in T-SQL.

Truth, James

[honey the codewitch]

The comment block was test code. The error of my ways was an outdated idea of restricting access to tables in SQL coupled with stored procedure based field validation, which is where this came in. There is a code generator that produced this particular matcher.

Real programmers use butterflies