SQL Server Base64函数

IF OBJECT_ID(N'dbo.c_GetUTF8Code') IS NOT NULL
    DROP FUNCTION dbo.c_GetUTF8Code;
GO

CREATE FUNCTION [dbo].[c_GetUTF8Code]  
(
    @char Nchar
)
RETURNS int

AS

--UTF8转码

BEGIN

 Declare @Code int
 Select @Code=Cast(Unicode(@char) as int)
 Declare @Utf8Code int
 Set @Utf8Code=0
 if(@Code<128)
 begin
  --0-127
  --0000-007F
  --0xxxxxxx
  --01100010 Unocide
  --01100010 UTF-8
  Set @Utf8Code=@Code 
 end
 else if(@Code>127 and @Code<2048)
 begin
  --128-2047
  --0080-07FF
  --110xxx xx10xx xxxx
  --110  7      F    F
  Declare @C1 int
  Declare @C2 int
  Declare @C3 int
  Select @C1=@Code/0x100 
  Select @C2=(@Code%0x100)/0x10
  Select @C3=@Code%0x10
  Select @Utf8Code=0xC080+0x400*@C1+0x100*(@C2/4)+0x10*(@C2%4)+@C3
 end
 else if(@Code>2047 and @Code<65536)
 begin
  --2047-65535
  --0110 0010 0001 0001
  --1110 xxxx 10xx xxxx 10xx xxxx
  --1110 0110 1000 1000 1001 0001
  Declare @C11 int
  Declare @C12 int
  Declare @C13 int
  Declare @C14 int
  Select @C11=@Code/0x1000
  Select @C12=(@Code%0x1000)/0x100
  Select @C13=(@Code%0x100)/0x10
  Select @C14=@Code%0x10
  Select @Utf8Code=0xE08080+0x10000*@C11+0x400*@C12+0x100*(@C13/4)+0x10*(@C13%4)+@C14 
 end
 return @Utf8Code
End

GO

-------加密函数[dbo].[base64_utf8encode]----

IF OBJECT_ID(N'dbo.base64_utf8encode') IS NOT NULL
    DROP FUNCTION dbo.base64_utf8encode;
GO
 
CREATE FUNCTION [dbo].[base64_utf8encode]  
(  
 @plain_text varchar(max)  
)  

RETURNS varchar(max)  

AS BEGIN
--Base64解密
 DECLARE @output varchar(max)
 DECLARE @block_start integer
 DECLARE @map char(64)  
 SET @map='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/' 
 SET @output=''
 SET @block_start=0
 Declare @plain_textLength int
 Set @plain_textLength=Len(@plain_text)
 Declare @RestTransfer int--转码数累积
 Declare @RestTransferLenth int
 Set @RestTransfer=0
 Set @RestTransferLenth=0
 Declare @CodeInt int
 Declare @block_val BINARY(3)
 WHILE @block_start<@plain_textLength
 BEGIN 
  Set @CodeInt=0
  SELECT @CodeInt= [dbo].[c_GetUTF8Code](SubString(@plain_text,@block_start+1,1))
  Declare @CodeTransfer int
  Set @CodeTransfer=0
  --0-127 1位
  --128-2047 2位
  --2047-65535 3位
  if(@CodeInt<128)
  begin
   --+1位
   if(@RestTransferLenth=0 or @RestTransferLenth=1)
   begin
    Set @RestTransfer=@RestTransfer*0x100+@CodeInt
    Set @RestTransferLenth=@RestTransferLenth+1
   end
   else if(@RestTransferLenth=2)
   begin
    Set @CodeTransfer=@RestTransfer*0x100+@CodeInt
    Set @RestTransfer=0
    Set @RestTransferLenth=0
   end
  end
  else if(@CodeInt>127 and @CodeInt<2048)
  begin
   --+2位
   if(@RestTransferLenth=0)
   begin
    Set @RestTransfer=@CodeInt
    Set @RestTransferLenth=2
   end
   else if(@RestTransferLenth=1)
   begin
    Set @CodeTransfer=0x10000*@RestTransfer+@CodeInt
    Set @RestTransfer=0
    Set @RestTransferLenth=0
   end
   else if(@RestTransferLenth=2)
   begin
    Set @CodeTransfer=0x100*@RestTransfer+@CodeInt/0x100
    Set @RestTransfer=@CodeInt%0x100
    Set @RestTransferLenth=1
   end
  end
  else if(@CodeInt>2047)
  begin
   --+3位
   if(@RestTransferLenth=0)
   begin
    Set @CodeTransfer=@CodeInt
    Set @RestTransfer=0
    Set @RestTransferLenth=0
   end
   else if(@RestTransferLenth=1)
   begin
    Set @CodeTransfer=0x10000*@RestTransfer+@CodeInt/0x100
    Set @RestTransfer=@CodeInt%0x100
    Set @RestTransferLenth=1
   end
   else if(@RestTransferLenth=2)
   begin
    --剩余部分十六进制右移两位与新数据前两位之和
    Set @CodeTransfer=0x100*@RestTransfer+@CodeInt/0x10000
    Set @RestTransfer=@CodeInt%0x10000
    Set @RestTransferLenth=2
   end
  end
  ---累积到3位，执行加密转换
  if(@CodeTransfer>0x100000)
  begin
   SET @block_val = CAST(@CodeTransfer AS BINARY(3))  
   SET @output = @output
   + SUBSTRING(@map , @block_val/262144  +1,1)
   + SUBSTRING(@map ,(@block_val/4096&63)+1,1)
   + SUBSTRING(@map ,(@block_val/64  &63)+1,1)
   + SUBSTRING(@map ,(@block_val&63)     +1,1)
  end
  SET @block_start=@block_start+1  
 END 
 IF @RestTransferLenth>0  
  BEGIN 
  SET @block_val=Cast(@RestTransfer*(Case @RestTransferLenth When 1 Then 65536 Else 256 end) as BINARY(3))
  SET @output=@output 
   +SUBSTRING(@map , @block_val/262144+1,    1)  
   +SUBSTRING(@map ,(@block_val/4096  &63)+1,1)  
   +CASE WHEN @RestTransferLenth =1
   THEN REPLACE(SUBSTRING(@map ,(@block_val/64&63)+1,1),'A','=')  
   ELSE SUBSTRING(@map ,(@block_val/64&63)+1,1)
    END
   +CASE WHEN @RestTransferLenth=1  
   THEN '=' 
   ELSE REPLACE(SUBSTRING(@map ,(@block_val&63)+1,1),'A','=')
    END 
  END
 RETURN @output 
END

GO
----------解密函数----------
IF OBJECT_ID(N'dbo.base64_utf8decode') IS NOT NULL

    DROP FUNCTION dbo.base64_utf8decode;

GO

CREATE FUNCTION [dbo].[base64_utf8decode]  
   (  
       @encoded_text varchar(max)  
   )  
   RETURNS varchar(max)  

   AS BEGIN

--BASE64加密
DECLARE @output varchar(max)
DECLARE @block_start int
DECLARE @encoded_length int
DECLARE @decoded_length int
DECLARE @mapr binary(122)  
 
SET @output = '' 
SET @mapr =  
  0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF    --    1-33  
  +0xFFFFFFFFFFFFFFFFFFFF3EFFFFFF3F3435363738393A3B3C3DFFFFFF00FFFFFF    --    33-64  
  +0x000102030405060708090A0B0C0D0E0F10111213141516171819FFFFFFFFFFFF    --    65-96  
  +0x1A1B1C1D1E1F202122232425262728292A2B2C2D2E2F30313233--    97-122  
SET @encoded_length=LEN(@encoded_text)  
SET @decoded_length=@encoded_length/4*3
SET @block_start=1  
Declare @Code int
Set @Code=0
Declare @CodeLength int--累计连接数，1，2，3
Set @CodeLength =0
WHILE @block_start<@encoded_length
BEGIN
 Declare @Integer Integer
 Set @Integer=substring(@mapr,Unicode(substring(@encoded_text,@block_start  ,1)),1)*262144  
     + substring(@mapr,Unicode(substring(@encoded_text,@block_start+1,1)),1)*4096  
     + substring(@mapr,Unicode(substring(@encoded_text,@block_start+2,1)),1)*64  
     + substring(@mapr,Unicode(substring(@encoded_text,@block_start+3,1)),1)

 Declare @C1 int
 Declare @C2 int
 Declare @C3 int
 --0xFF FF FF
 Set @C1=@Integer/0x10000
 Set @C2=(@Integer/0x100)%0x100
 Set @C3=@Integer%0x100
 -------------------------------------@C1
 if(@C1<0x80)
 begin
  if(@CodeLength=2)
  begin
   --128-2047
   --0080-07FF
   --110x xx xx 10xx xxxx
   Set @Code=((@Code%0x2000)/0x100)*0x10+@Code%0x40
   SET @output=@output+NCHAR(@Code)
   --print @Code 
   Set @Code=0
   Set @CodeLength=0
  end
  SET @output=@output+CAST(Cast(@C1 AS BINARY(1))AS VARCHAR(1))
 end
 else
 begin
  --码字连接
  Set @Code=@Code*0x100+@C1
  SET @CodeLength=@CodeLength+1
  if(@CodeLength=3)
  begin
   --0110 0010 0001 0001
   --1110 xxxx 10xx xxxx 10xx xxxx
   --1110 0110 1000 1000 1001 0001
   Set @Code=((@Code%0x100000)/0x10000)*0x1000+((@Code%0x4000)/0x100)*0x40+@Code%0x40
   SET @output=@output+NCHAR(@Code)
   Set @Code=0
   Set @CodeLength=0
  end
 end

 -------------------------------------@C2
 if(@C2<0x80)
 begin
  if(@CodeLength=2)
  begin
   --128-2047
   --0080-07FF
   --110x xx xx 10xx xxxx
   Set @Code=((@Code%0x2000)/0x100)*0x10+@Code%0x40
   SET @output=@output+NCHAR(@Code)
   --print @Code 
   Set @Code=0
   Set @CodeLength=0
  end
  SET @output=@output+CAST(Cast(@C2 AS BINARY(1))AS VARCHAR(1))
 end
 else
 begin
  --码字连接
  Set @Code=@Code*0x100+@C2
  SET @CodeLength=@CodeLength+1
  if(@CodeLength=3)
  begin
   --0110 0010 0001 0001
   --1110 xxxx 10xx xxxx 10xx xxxx
   --1110 0110 1000 1000 1001 0001
   Set @Code=((@Code%0x100000)/0x10000)*0x1000+((@Code%0x4000)/0x100)*0x40+@Code%0x40
   SET @output=@output+NCHAR(@Code)
   Set @Code=0
   Set @CodeLength=0
  end
 end
 -------------------------------------@C3
 if(@C3<0x80)
 begin
  if(@CodeLength=2)
  begin
   --128-2047
   --0080-07FF
   --110x xx xx 10xx xxxx
   Set @Code=((@Code%0x2000)/0x100)*0x10+@Code%0x40
   SET @output=@output+NCHAR(@Code)
   --print @Code 
   Set @Code=0
   Set @CodeLength=0
  end
  SET @output=@output+CAST(Cast(@C3 AS BINARY(1))AS VARCHAR(1))
 end
 else
 begin
  --码字连接
  Set @Code=@Code*0x100+@C3
  SET @CodeLength=@CodeLength+1
  if(@CodeLength=3)
  begin
   --0110 0010 0001 0001
   --1110 xxxx 10xx xxxx 10xx xxxx
   --1110 0110 1000 1000 1001 0001
   Set @Code=((@Code%0x100000)/0x10000)*0x1000+((@Code%0x4000)/0x100)*0x40+@Code%0x40
   SET @output=@output+NCHAR(@Code)
   Set @Code=0
   Set @CodeLength=0
  end
 end
 SET @block_start = @block_start + 4  
END 
IF RIGHT(@encoded_text,2)='=='
 SET @decoded_length=@decoded_length-2
ELSE IF RIGHT(@encoded_text,1)='='
 SET @decoded_length=@decoded_length-1
RETURN LEFT(@output ,@decoded_length)  
END