www.pudn.com > HgzVip1.2_code.rar > BASE64.pas
unit BASE64;
interface
{.DEFINE SpeedDecode}
{$IFNDEF SpeedDecode}
{$DEFINE ValidityCheck}
{$ENDIF}
uses SysUtils;
// codiert einen String in die zugeh?rige Base64-Darstellung
function EncodeBase64(const InText: AnsiString): AnsiString; overload;
// decodiert die Base64-Darstellung eines Strings in den zugeh?rigen String
function DecodeBase64(const InText: AnsiString): AnsiString; overload;
// bestimmt die Gr??e der Base64-Darstellung
function CalcEncodedSize(InSize: Cardinal): Cardinal;
// bestimmt die Gr??e der bin?ren Darstellung
function CalcDecodedSize(const InBuffer; InSize: Cardinal): Cardinal;
// codiert einen Buffer in die zugeh?rige Base64-Darstellung
procedure Base64Encode(const InBuffer; InSize: Cardinal; var OutBuffer); overload; register;
// decodiert die Base64-Darstellung in einen Buffer
{$IFDEF SpeedDecode}
procedure Base64Decode(const InBuffer; InSize: Cardinal; var OutBuffer); overload; register;
{$ENDIF}
{$IFDEF ValidityCheck}
function Base64Decode(const InBuffer; InSize: Cardinal; var OutBuffer): Boolean; overload; register;
{$ENDIF}
// codiert einen String in die zugeh?rige Base64-Darstellung
procedure Base64Encode(const InText: AnsiString; var OutText: AnsiString); overload;
// decodiert die Base64-Darstellung eines Strings in den zugeh?rigen String
procedure Base64Decode(const InText: AnsiString; var OutText: AnsiString); overload;
implementation
const
cBase64Codec: array[0..63] of AnsiChar =
'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
Base64Filler = '=';
function EncodeBase64(const InText: string): string; overload;
begin
Base64Encode(InText, Result);
end;
function DecodeBase64(const InText: string): string; overload;
begin
Base64Decode(InText, Result);
end;
function CalcEncodedSize(InSize: Cardinal): Cardinal;
begin
// no buffers passed along, calculate outbuffer size needed
Result := (InSize div 3) shl 2;
if ((InSize mod 3) > 0)
then Inc(Result, 4);
end;
function CalcDecodedSize(const InBuffer; InSize: Cardinal): Cardinal;
type
BA = array of Byte;
begin
Result := 0;
if InSize = 0 then
Exit;
if InSize mod 4 <> 0 then
Exit;
Result := InSize div 4 * 3;
if (BA(InBuffer)[InSize - 2] = Ord(Base64Filler))
then Dec(Result, 2)
else if BA(InBuffer)[InSize - 1] = Ord(Base64Filler)
then Dec(Result);
end;
procedure Base64Encode(const InBuffer; InSize: Cardinal; var OutBuffer
); register;
var
ByThrees, LeftOver: Cardinal;
// reset in- and outbytes positions
asm
// load addresses for source and destination
// PBYTE(InBuffer);
mov ESI, [EAX]
// PBYTE(OutBuffer);
mov EDI, [ECX]
// ByThrees := InSize div 3;
// LeftOver := InSize mod 3;
// load InSize (stored in EBX)
mov EAX, EBX
// load 3
mov ECX, $03
// clear upper 32 bits
xor EDX, EDX
// divide by ECX
div ECX
// save result
mov ByThrees, EAX
// save remainder
mov LeftOver, EDX
// load addresses
lea ECX, cBase64Codec[0]
// while I < ByThrees do
// begin
xor EAX, EAX
xor EBX, EBX
xor EDX, EDX
cmp ByThrees, 0
jz @@LeftOver
@@LoopStart:
// load the first two bytes of the source triplet
LODSW
// write Bits 0..5 to destination
mov BL, AL
shr BL, 2
mov DL, BYTE PTR [ECX + EBX]
// save the Bits 12..15 for later use [1]
mov BH, AH
and BH, $0F
// save Bits 6..11
rol AX, 4
and AX, $3F
mov DH, BYTE PTR [ECX + EAX]
mov AX, DX
// store the first two bytes of the destination quadruple
STOSW
// laod last byte (Bits 16..23) of the source triplet
LODSB
// extend bits 12..15 [1] with Bits 16..17 and save them
mov BL, AL
shr BX, 6
mov DL, BYTE PTR [ECX + EBX]
// save bits 18..23
and AL, $3F
xor AH, AH
mov DH, BYTE PTR [ECX + EAX]
mov AX, DX
// store the last two bytes of the destination quadruple
STOSW
dec ByThrees
jnz @@LoopStart
@@LeftOver:
// there are up to two more bytes to encode
cmp LeftOver, 0
jz @@Done
// clear result
xor EAX, EAX
xor EBX, EBX
xor EDX, EDX
// get left over 1
LODSB
// load the first six bits
shl AX, 6
mov BL, AH
// save them
mov DL, BYTE PTR [ECX + EBX]
// another byte ?
dec LeftOver
jz @@SaveOne
// save remaining two bits
shl AX, 2
and AH, $03
// get left over 2
LODSB
// load next 4 bits
shl AX, 4
mov BL, AH
// save all 6 bits
mov DH, BYTE PTR [ECX + EBX]
shl EDX, 16
// save last 4 bits
shr AL, 2
mov BL, AL
// save them
mov DL, BYTE PTR [ECX + EBX]
// load base 64 'no more data flag'
mov DH, Base64Filler
jmp @@WriteLast4
@@SaveOne:
// adjust the last two bits
shr AL, 2
mov BL, AL
// save them
mov DH, BYTE PTR [ECX + EBX]
shl EDX, 16
// load base 64 'no more data flags'
mov DH, Base64Filler
mov DL, Base64Filler
// ignore jump, as jump reference is next line !
// jmp @@WriteLast4
@@WriteLast4:
// load and adjust result
mov EAX, EDX
ror EAX, 16
// save it to destination
STOSD
@@Done:
end;
{$IFDEF SpeedDecode}
procedure Base64Decode(const InBuffer; InSize: Cardinal; var OutBuffer);
overload; register;
{$ENDIF}
{$IFDEF ValidityCheck}
function Base64Decode(const InBuffer; InSize: Cardinal; var OutBuffer):
Boolean; overload; register;
{$ENDIF}
const
{$IFDEF SpeedDecode}
cBase64Codec: array[0..127] of Byte =
{$ENDIF}
{$IFDEF ValidityCheck}
cBase64Codec: array[0..255] of Byte =
{$ENDIF}
(
$FF, $FF, $FF, $FF, $FF, {005>} $FF, $FF, $FF, $FF, $FF, // 000..009
$FF, $FF, $FF, $FF, $FF, {015>} $FF, $FF, $FF, $FF, $FF, // 010..019
$FF, $FF, $FF, $FF, $FF, {025>} $FF, $FF, $FF, $FF, $FF, // 020..029
$FF, $FF, $FF, $FF, $FF, {035>} $FF, $FF, $FF, $FF, $FF, // 030..039
$FF, $FF, $FF, $3E, $FF, {045>} $FF, $FF, $3F, $34, $35, // 040..049
$36, $37, $38, $39, $3A, {055>} $3B, $3C, $3D, $FF, $FF, // 050..059
$FF, $FF, $FF, $FF, $FF, {065>} $00, $01, $02, $03, $04, // 060..069
$05, $06, $07, $08, $09, {075>} $0A, $0B, $0C, $0D, $0E, // 070..079
$0F, $10, $11, $12, $13, {085>} $14, $15, $16, $17, $18, // 080..089
$19, $FF, $FF, $FF, $FF, {095>} $FF, $FF, $1A, $1B, $1C, // 090..099
$1D, $1E, $1F, $20, $21, {105>} $22, $23, $24, $25, $26, // 100..109
$27, $28, $29, $2A, $2B, {115>} $2C, $2D, $2E, $2F, $30, // 110..119
$31, $32, $33, $FF, $FF, {125>} $FF, $FF, $FF // 120..127
{$IFDEF ValidityCheck}
{125>} , $FF, $FF, // 128..129
$FF, $FF, $FF, $FF, $FF, {135>} $FF, $FF, $FF, $FF, $FF, // 130..139
$FF, $FF, $FF, $FF, $FF, {145>} $FF, $FF, $FF, $FF, $FF, // 140..149
$FF, $FF, $FF, $FF, $FF, {155>} $FF, $FF, $FF, $FF, $FF, // 150..159
$FF, $FF, $FF, $FF, $FF, {165>} $FF, $FF, $FF, $FF, $FF, // 160..169
$FF, $FF, $FF, $FF, $FF, {175>} $FF, $FF, $FF, $FF, $FF, // 170..179
$FF, $FF, $FF, $FF, $FF, {185>} $FF, $FF, $FF, $FF, $FF, // 180..189
$FF, $FF, $FF, $FF, $FF, {195>} $FF, $FF, $FF, $FF, $FF, // 190..199
$FF, $FF, $FF, $FF, $FF, {205>} $FF, $FF, $FF, $FF, $FF, // 200..209
$FF, $FF, $FF, $FF, $FF, {215>} $FF, $FF, $FF, $FF, $FF, // 210..219
$FF, $FF, $FF, $FF, $FF, {225>} $FF, $FF, $FF, $FF, $FF, // 220..229
$FF, $FF, $FF, $FF, $FF, {235>} $FF, $FF, $FF, $FF, $FF, // 230..239
$FF, $FF, $FF, $FF, $FF, {245>} $FF, $FF, $FF, $FF, $FF, // 240..249
$FF, $FF, $FF, $FF, $FF, {255>} $FF // 250..255
{$ENDIF}
);
asm
push EBX
mov ESI, [EAX]
mov EDI, [ECX]
{$IFDEF ValidityCheck}
mov EAX, InSize
and EAX, $03
cmp EAX, $00
jz @@DecodeStart
jmp @@ErrorDone
@@DecodeStart:
{$ENDIF}
mov EAX, InSize
shr EAX, 2
jz @@Done
lea ECX, cBase64Codec[0]
xor EBX, EBX
dec EAX
jz @@LeftOver
push EBP
mov EBP, EAX
@@LoopStart:
// load four bytes into EAX
LODSD
// save them to EDX as AX is used to store results
mov EDX, EAX
// get bits 0..5
mov BL, DL
// decode
mov AH, BYTE PTR [ECX + EBX]
{$IFDEF ValidityCheck}
// check valid code
cmp AH, $FF
jz @@ErrorDoneAndPopEBP
{$ENDIF}
// get bits 6..11
mov BL, DH
// decode
mov AL, BYTE PTR [ECX + EBX]
{$IFDEF ValidityCheck}
// check valid code
cmp AL, $FF
jz @@ErrorDoneAndPopEBP
{$ENDIF}
// align last 6 bits
shl AL, 2
// get first 8 bits
ror AX, 6
// store first byte
STOSB
// align remaining 4 bits
shr AX, 12
// get next two bytes from source quad
shr EDX, 16
// load bits 12..17
mov BL, DL
// decode
mov AH, BYTE PTR [ECX + EBX]
{$IFDEF ValidityCheck}
// check valid code
cmp AH, $FF
jz @@ErrorDoneAndPopEBP
{$ENDIF}
// align ...
shl AH, 2
// ... and adjust
rol AX, 4
// get last bits 18..23
mov BL, DH
// decord
mov BL, BYTE PTR [ECX + EBX]
{$IFDEF ValidityCheck}
// check valid code
cmp BL, $FF
jz @@ErrorDoneAndPopEBP
{$ENDIF}
// enter in destination word
or AH, BL
// and store to destination
STOSW
// more coming ?
dec EBP
jnz @@LoopStart
pop EBP
// no
// last four bytes are handled separately, as special checking is needed
// on the last two bytes (may be end of data signals '=' or '==')
@@LeftOver:
// get the last four bytes
LODSD
// save them to EDX as AX is used to store results
mov EDX, EAX
// get bits 0..5
mov BL, DL
// decode
mov AH, BYTE PTR [ECX + EBX]
{$IFDEF ValidityCheck}
// check valid code
cmp AH, $FF
jz @@ErrorDone
{$ENDIF}
// get bits 6..11
mov BL, DH
// decode
mov AL, BYTE PTR [ECX + EBX]
{$IFDEF ValidityCheck}
// check valid code
cmp AL, $FF
jz @@ErrorDone
{$ENDIF}
// align last 6 bits
shl AL, 2
// get first 8 bits
ror AX, 6
// store first byte
STOSB
// get next two bytes from source quad
shr EDX, 16
// check DL for "end of data signal"
cmp DL, Base64Filler
jz @@SuccessDone
// align remaining 4 bits
shr AX, 12
// load bits 12..17
mov BL, DL
// decode
mov AH, BYTE PTR [ECX + EBX]
{$IFDEF ValidityCheck}
// check valid code
cmp AH, $FF
jz @@ErrorDone
{$ENDIF}
// align ...
shl AH, 2
// ... and adjust
rol AX, 4
// store second byte
STOSB
// check DH for "end of data signal"
cmp DH, Base64Filler
jz @@SuccessDone
// get last bits 18..23
mov BL, DH
// decord
mov BL, BYTE PTR [ECX + EBX]
{$IFDEF ValidityCheck}
// check valid code
cmp BL, $FF
jz @@ErrorDone
{$ENDIF}
// enter in destination word
or AH, BL
// AH - AL for saving last byte
mov AL, AH
// store third byte
STOSB
@@SuccessDone:
{$IFDEF ValidityCheck}
mov Result, $01
jmp @@Done
@@ErrorDoneAndPopEBP:
pop EBP
@@ErrorDone:
mov Result, $00
{$ENDIF}
@@Done:
pop EBX
end;
procedure Base64Encode(const InText: AnsiString; var OutText: AnsiString);
overload;
var
InSize, OutSize: Cardinal;
PIn, POut: Pointer;
begin
// get size of source
InSize := Length(InText);
// calculate size for destination
OutSize := CalcEncodedSize(InSize);
// prepare string length to fit result data
SetLength(OutText, OutSize);
PIn := @InText[1];
POut := @OutText[1];
// encode !
Base64Encode(PIn, InSize, POut);
end;
procedure Base64Decode(const InText: AnsiString; var OutText: AnsiString);
overload;
var
InSize, OutSize: Cardinal;
PIn, POut: Pointer;
begin
// get size of source
InSize := Length(InText);
// calculate size for destination
PIn := @InText[1];
OutSize := CalcDecodedSize(PIn, InSize);
// prepare string length to fit result data
SetLength(OutText, OutSize);
FillChar(OutText[1], OutSize, '.');
POut := @OutText[1];
// encode !
{$IFDEF SpeedDecode}
Base64Decode(PIn, InSize, POut);
{$ENDIF}
{$IFDEF ValidityCheck}
if not Base64Decode(PIn, InSize, POut) then
SetLength(OutText, 0);
{$ENDIF}
end;
end.