KSG_EncodeDecode.cpp
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上传日期:2019-04-29
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- //////////////////////////////////////////////////////////////////////////////////////
- //
- // FileName : KSG_EncodeDecode.cpp
- // Version : 1.0
- // Creater :
- // Date : 2003-6-3 10:28:57
- // Comment :
- //
- //////////////////////////////////////////////////////////////////////////////////////
- #include "stdafx.h"
- #include "KSG_EncodeDecode.h"
- int KSG_DecodeEncode(size_t uSize, unsigned char *pbyBuf, unsigned *puKey)
- {
- unsigned *puBuf = (unsigned *)pbyBuf;
- unsigned uKey = *puKey;
- unsigned uRemainSize = uSize % 4;
- uSize /= 4;
- while (uSize-- > 0)
- *puBuf++ ^= uKey;
- pbyBuf = (unsigned char *)puBuf;
-
- while (uRemainSize-- > 0)
- {
- *pbyBuf++ ^= (unsigned char)(uKey & 0xff);
- uKey >>= 8;
- }
- *puKey = (*puKey * 31) + 134775813L;
- return true;
- }
- int KSG_DecodeEncode_ASM(size_t uSize, unsigned char *pbyBuf, unsigned *puKey)
- {
- __asm mov eax, [uSize]
- __asm mov esi, [puKey]
- __asm mov edi, [pbyBuf]
- __asm mov ecx, eax
- __asm mov edx, [esi] // key
- __asm shr eax, 2
- __asm jz Next1
-
- Loop1:
- __asm mov ebx, [edi]
- __asm add edi, 4
- __asm xor ebx, edx
- __asm dec eax
- __asm mov [edi - 4], ebx
- __asm jnz Loop1
- Next1:
- __asm and ecx, 3
- __asm mov eax, edx // Key
- __asm jz Next2
- Loop2:
- __asm mov bl, [edi]
- __asm inc edi
- __asm xor bl, al
- __asm shr eax, 8
- __asm mov [edi - 1], bl
- __asm dec ecx
- __asm jnz Loop2
- Next2:
- __asm mov eax, edx // NewKey = OldKey * 31 + 134775813L
- __asm shl edx, 5
- __asm sub edx, eax
- __asm add edx, 134775813 // 08088405H
- __asm mov [esi], edx
- return true;
- }