Po dlouhé diskuzi jsem konečně přišel na to, jaká vstupní data máte. Máte varbinary(128), který je vytvořen z binárního řetězce (jako '1000010010101... '), který je dlouhý 1024 znaků. SQL Server neposkytuje připravenou funkci, která takový převod provede. Postavil jsem jeden, aby mi umožnil testování. Tento převod provede následující funkce:
CREATE FUNCTION dbo.binStringToBinary(@inputString VARCHAR(1024)) RETURNS VARBINARY(128) AS
BEGIN
DECLARE @inputBinary VARBINARY(128) = convert(varbinary, '', 2)
DECLARE @octet int = 1
DECLARE @len int
SET @len = Len(@inputString)
while @octet < @len
BEGIN
DECLARE @i int = 0
DECLARE @Output int = 0
WHILE(@i < 7) BEGIN
SET @Output = @Output + POWER(CAST(SUBSTRING(@inputString, @octet + @i, 1) AS int) * 2, 7 - @i)
SET @i = @i + 1
END
SET @Output = @Output + CAST(SUBSTRING(@inputString, @octet + @i, 1) AS int)
select @inputBinary = @inputBinary + convert(varbinary(1), @Output)
-- PRINT substring(@inputString, @octet, 8) + ' ' + STR(@Output, 3, 0) + ' ' + convert(varchar(1024), @inputBinary, 2)
SET @octet = @octet + 8
END
RETURN @inputBinary
END
Pak jsem napsal funkci, která kontroluje bit pomocí varbinary(128) jako vstupu:
CREATE FUNCTION dbo.[DoBitsMatchFromBinary](@bitToCheck INT,@inputBinary VARBINARY(1024))
RETURNS BIT
AS
BEGIN
IF @bitToCheck < 1 OR @bitToCheck > 1024
RETURN 0
DECLARE @byte int = (@bitToCheck - 1) / 8
DECLARE @bit int = @bitToCheck - @byte * 8
DECLARE @bytemask int = POWER(2, [email protected])
SET @byte = @byte + 1
RETURN CASE WHEN CONVERT(int, CONVERT(binary(1), SUBSTRING(@inputBinary, @byte, 1), 2)) & @bytemask = @bytemask THEN 1 ELSE 0 END
END
Jako bonus jsem zde také zahrnul funkci, která provádí kontrolu bitů ze vstupního binárního řetězce (1024):
CREATE FUNCTION dbo.[DoBitsMatchFromBinString](@bitToCheck INT,@inputString VARCHAR(1024))
RETURNS BIT
AS
BEGIN
IF @bitToCheck < 1 OR @bitToCheck > 1024
RETURN 0
RETURN CASE WHEN SUBSTRING(@inputString, @bitToCheck, 1) = '1' THEN 1 ELSE 0 END
END
Podívejte se na SQL housle což demonstruje jejich použití.
DECLARE @inputBinary VARBINARY(128)
select @inputBinary = dbo.binStringToBinary('1010001000101111010111010100001101000100010111101011101010000101101000100010111101011101010000110100010001011110101110101000010110100010001011110101110101000011010001000101111010111010100001011010001000101111010111010100001101000100010111101011101010000101101000100010111101011101010000110100010001011110101110101000010110100010001011110101110101000011010001000101111010111010100001011010001000101111010111010100001101000100010111101011101010000101101000100010111101011101010000110100010001011110101110101000010110100010001011110101110101000011010001000101111010111010100001011010001000101111010111010100001101000100010111101011101010000101101000100010111101011101010000110100010001011110101110101000010110100010001011110101110101000011010001000101111010111010100001011010001000101111010111010100001101000100010111101011101010000101101000100010111101011101010000110100010001011110101110101000010110100010001011110101110101000011010001000101111010111010100001011010001000101111010111010100001101000100010111101011101010000101')
select dbo.[DoBitsMatchFromBinary](1, @inputBinary) bit1,
dbo.[DoBitsMatchFromBinary](2, @inputBinary) bit2,
dbo.[DoBitsMatchFromBinary](3, @inputBinary) bit3,
dbo.[DoBitsMatchFromBinary](4, @inputBinary) bit4,
dbo.[DoBitsMatchFromBinary](5, @inputBinary) bit5,
dbo.[DoBitsMatchFromBinary](6, @inputBinary) bit6,
dbo.[DoBitsMatchFromBinary](7, @inputBinary) bit7,
dbo.[DoBitsMatchFromBinary](8, @inputBinary) bit8,
dbo.[DoBitsMatchFromBinary](1017, @inputBinary) bit1017,
dbo.[DoBitsMatchFromBinary](1018, @inputBinary) bit1018,
dbo.[DoBitsMatchFromBinary](1019, @inputBinary) bit1019,
dbo.[DoBitsMatchFromBinary](1020, @inputBinary) bit1020,
dbo.[DoBitsMatchFromBinary](1021, @inputBinary) bit1021,
dbo.[DoBitsMatchFromBinary](1022, @inputBinary) bit1022,
dbo.[DoBitsMatchFromBinary](1023, @inputBinary) bit1023,
dbo.[DoBitsMatchFromBinary](1024, @inputBinary) bit1024
| bit1 | bit2 | bit3 | bit4 | bit5 | bit6 | bit7 | bit8 | bit1017 | bit1018 | bit1019 | bit1020 | bit1021 | bit1022 | bit1023 | bit1024 |
|------|-------|------|-------|-------|-------|------|-------|---------|---------|---------|---------|---------|---------|---------|---------|
| true | false | true | false | false | false | true | false | true | false | false | false | false | true | false | true |