汇编写的BASE64
汇编写的BASE64
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 | unit Base64; { procedure TForm1.Button1Click(Sender: TObject); var Source, Dest: TStream; begin if OpenDialog1.Execute then begin Source := TFileStream.Create(OpenDialog1.FileName, fmOpenRead); // 打开源文件 Dest := TFileStream.Create( 'Base64EncodeTest.txt' , fmCreate); // Base64编码文件 try Base64Encode(Source, Dest); finally Source.Free; Dest.Free; end; Source := TFileStream.Create( 'Base64EncodeTest.txt' , fmOpenRead); // 打开编码文件 Dest := TFileStream.Create( '2.exe' , fmCreate); // 还原源文件内容 try Base64Decode(Source, Dest); Dest.Position := 0; finally Source.Free; Dest.Free; end; end; end; } interface uses SysUtils, Classes; type {$IFDEF UNICODE} Base64String = AnsiString; {$ELSE} Base64String = string ; {$ENDIF} // 按源长度SourceSize返回Base64编码所需缓冲区字节数 function Base64EncodeBufSize(SourceSize: Integer): Integer; // 获取Sourec的Base64编码,Base64Buf必须有足够长度。返回实际编码字节数 function Base64Encode( const Source; SourceSize: Integer; var Base64Buf): Integer; overload; // 将Source编码为Base64字符串返回 function Base64Encode( const Source; SourceSize: Integer): Base64String; overload; // 将Source从StartPos开始的Size长度的内容源编码为Base64,写入流Dest。 // Size=0 表示一直编码到文件尾 procedure Base64Encode(Source, Dest: TStream; StartPos: Int64 = 0; Size: Int64 = 0); overload; // 把字符串Str编码为Base64字符串返回 {$IFDEF UNICODE} function StrToBase64( const Str: AnsiString): Base64String; overload; function StrToBase64( const Str: string ): Base64String; overload; {$ELSE} function StrToBase64( const Str: string ): Base64String; {$ENDIF} // 按给定的编码源Source和长度SourceSize计算并返回解码缓冲区所需字节数 function Base64DecodeBufSize( const Base64Source; SourceSize: Integer): Integer; // 将Base64编码源Base64Source解码,Buf必须有足够长度。返回实际解码字节数 function Base64Decode( const Base64Source; SourceSize: Integer; var Buf): Integer; overload; // 将Source从StartPos开始的Size长度的Base64编码内容解码,写入流Dest。 // Size=0 表示一直解码到文件尾 procedure Base64Decode(Source, Dest: TStream; StartPos: Int64 = 0; Size: Int64 = 0); overload; // 将Base64编码源Base64Source解码为字符串返回 function Base64Decode( const Base64Source; SourceSize: Integer): string ; overload; // 把Base64字符串Base64Str解码为字符串返回 function Base64ToStr( const Base64Str: Base64String): string ; implementation const Base64_Chars: array[0..63] of AnsiChar = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/' ; Base64_Bytes: array[0..79] of Byte = (62, 0, 0, 0, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 0, 0, 0, 0, 0, 0, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51); type Base64Proc = function( const Source; SourceSize: Integer; var Buf): Integer; procedure Base64Stream(Source, Dest: TStream; Proc: Base64Proc; StartPos, Size: Int64; RBufSize, WBufSize: Integer); var RBuf: array of Byte; WBuf: array of Byte; RSize, WSize: Integer; begin if (StartPos < 0) or (StartPos >= Source.Size) then Exit; Source.Position := StartPos; if (Size <= 0) or (Size > Source.Size - Source.Position) then Size := Source.Size else Size := Size + Source.Position; SetLength(RBuf, RBufSize); SetLength(WBuf, WBufSize); while Size <> Source.Position do begin if RBufSize > Size - Source.Position then RBufSize := Size - Source.Position; RSize := Source.Read(RBuf[0], RBufSize); WSize := Proc(RBuf[0], RSize, WBuf[0]); Dest.Write(WBuf[0], WSize); end; end; function Base64EncodeBufSize(SourceSize: Integer): Integer; begin Result := ((SourceSize + 2) div 3) shl 2; end; (**************************************************************************** * * * BASE64 Encode hint: * * * * addr: (high) 4 byte 3 byte 2 byte 1 byte (low) * * sourec ASCII(3 bytes): 33333333 22222222 11111111 * * bswap: 11111111 22222222 33333333 00000000 * * b4 = Base64_Chars[(source >> 8) & 63]: [00333333]->44444444 * * b3 = Base64_Chars[(source >> 14) & 63]: [00222233]->33333333 * * b2 = Base64_Chars[(source >> 20) & 63]: [00112222]->22222222 * * b1 = Base64_Chars[source >> 26]: [00111111]->11111111 * * b4 << 24 b3 << 16 b2 << 8 b1 * * dest BASE64(4 bytes) 44444444 33333333 22222222 11111111 * * * ****************************************************************************) function Base64Encode( const Source; SourceSize: Integer; var Base64Buf): Integer; asm push ebp push esi push edi push ebx mov esi, eax // esi = Source mov edi, ecx // edi = Buf mov eax, edx cdq mov ecx, 3 DIV ecx // edx = SourceSize % 3 mov ecx, eax // ecx = SourceSize / 3 test edx, edx jz @@1 inc eax // eax = (SourceSize + 2) / 3 @@1: push eax push edx lea ebp, Base64_Chars jecxz @Last cld @EncodeLoop: // while (ecx > 0){ mov edx, [esi] // edx = 00000000 33333333 22222222 11111111 bswap edx // edx = 11111111 22222222 33333333 00000000 push edx push edx push edx pop ebx // ebx = edx SHR edx, 20 SHR ebx, 26 // ebx = 00111111 AND edx, 63 // edx = 00112222 mov ah, [ebp + edx] // *(word*)edi = (Base64_Chars[edx] << 8) | mov al, [ebp + ebx] // Base64_Chars[ebx] stosw // edi += 2 pop edx // edx = 11111111 22222222 33333333 00000000 pop ebx // ebx = edx SHR edx, 8 SHR ebx, 14 AND edx, 63 // edx = 00333333 AND ebx, 63 // ebx = 00222233 mov ah, [ebp + edx] // *(word*)edi = (Base64_Chars[edx] << 8) | mov al, [ebp + ebx] // Base64_Chars[ebx] stosw // edi += 2 add esi, 3 // esi += 3 loop @EncodeLoop // } @Last: pop ecx // ecx = SourceSize % 3 jecxz @END // if (ecx == 0) return mov eax, 3d3d0000h // preset 2 bytes '=' mov [edi], eax test ecx, 2 jnz @@3 mov al, [esi] // if (ecx == 1) SHL eax, 4 // eax = *esi << 4 jmp @@4 @@3: mov ax, [esi] // else xchg al, ah // eax = ((*esi << 8) or *(esi + 1)) << 2 SHL eax, 2 @@4: add edi, ecx // edi += ecx inc ecx // ecx = last encode bytes @LastLoop: mov edx, eax // for (; cex > 0; ecx --, edi --) AND edx, 63 // { mov dl, [ebp + edx] // edx = eax & 63 mov [edi], dl // *edi = Base64_Chars[edx] SHR eax, 6 // eax >>= 6 dec edi // } loop @LastLoop @end: pop eax SHL eax, 2 // return encode bytes pop ebx pop edi pop esi pop ebp end; function Base64Encode( const Source; SourceSize: Integer): Base64String; begin SetLength(Result, Base64EncodeBufSize(SourceSize)); Base64Encode(Source, SourceSize, Result[1]); end; procedure Base64Encode(Source, Dest: TStream; StartPos: Int64; Size: Int64); begin Base64Stream(Source, Dest, Base64Encode, StartPos, Size, 6144, 8192); end; {$IFDEF UNICODE} function StrToBase64( const Str: AnsiString): Base64String; begin Result := Base64Encode(Str[1], Length(Str)); end; function StrToBase64( const Str: string ): Base64String; begin Result := StrToBase64(AnsiString(Str)); end; {$ELSE} function StrToBase64( const Str: string ): Base64String; begin Result := Base64Encode(Str[1], Length(Str)); end; {$ENDIF} function Base64DecodeBufSize( const Base64Source; SourceSize: Integer): Integer; asm mov ecx, eax // ecx = Source + Size add ecx, edx mov eax, edx // eax = Size / 4 * 3 SHR edx, 2 SHR eax, 1 add eax, edx mov edx, eax jz @@2 @@1: dec ecx cmp byte ptr[ecx], 61 jne @@2 // if (*--ecx == '=') dec eax // eax -- jmp @@1 @@2: // return eax: BufSize; edx: Size / 4 * 3 end; function Base64Decode( const Base64Source; SourceSize: Integer; var Buf): Integer; asm push ebp push esi push edi push ebx mov esi, eax // esi = Source mov edi, ecx // edi = Buf mov ebx, edx call Base64DecodeBufSize push eax // eax = Base64DecodeBufSize(Source, SourceSize) sub edx, eax // edx -= eax // edx: '=' count lea ebp, Base64_Bytes SHR ebx, 2 // ebx = SourceSize / 4 test ebx, ebx jz @END push edx cld @DecodeLoop: // for (; ebx > 0; ebx --; edi += 3) mov ecx, 4 // { XOR eax, eax @xchgLoop: // for (ecx = 4, eax = 0; ecx > 0; ecx --) movzx edx, [esi] // { sub edx, 43 // edx = *(int*)esi - 43 SHL eax, 6 // eax <<= 6 OR al, [ebp + edx] // al |= Base64_Bytes[edx] inc esi // esi ++ loop @xchgLoop // } bswap eax // bswap(eax) dec ebx // if (ebx == 1) break jz @Last SHR eax, 8 // eax >>= 8 stosw // *edi = ax; edi += 2 SHR eax, 16 // eax >>= 16 stosb // *edi++ = al jmp @DecodeLoop // } @Last: pop ecx XOR ecx, 3 // ecx = last bytes @LastLoop: // for (; ecx > 0; ecx --) SHR eax, 8 // { stosb // eax >>= 8; *edi ++ = al loop @LastLoop // } @end: pop eax // return eax pop ebx pop edi pop esi pop ebp end; procedure Base64Decode(Source, Dest: TStream; StartPos: Int64; Size: Int64); begin Base64Stream(Source, Dest, Base64Decode, StartPos, Size, 8192, 6144); end; {$IFDEF UNICODE} function Base64Decode( const Base64Source; SourceSize: Integer): string ; var s: AnsiString; begin SetLength(s, Base64DecodeBufSize(Base64Source, SourceSize)); Base64Decode(Base64Source, SourceSize, s[1]); Result := string (s); end; {$ELSE} function Base64Decode( const Base64Source; SourceSize: Integer): string ; begin SetLength(Result, Base64DecodeBufSize(Base64Source, SourceSize)); Base64Decode(Base64Source, SourceSize, Result[1]); end; {$ENDIF} function Base64ToStr( const Base64Str: Base64String): string ; begin Result := Base64Decode(Base64Str[1], Length(Base64Str)); end; end. |
本文来自博客园,作者:{咏南中间件},转载请注明原文链接:https://www.cnblogs.com/hnxxcxg/p/11797077.html
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