mirror of
https://github.com/libretro/scummvm.git
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0436bdeb0f
Beware, it's full of shit and dirty hacks as I was never even dreaming about making either the source or binary public. But this has to be sufficient as I don't see the point in wasting my time rewriting a tool that noone needs in a clean way. svn-id: r19075
130 lines
2.8 KiB
C++
130 lines
2.8 KiB
C++
#include "stdafx.h"
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#include "KmpSearch.h"
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__declspec(naked) void __fastcall KmpSearch::init(const char *subStr) {
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__asm {
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// kmp initialization, make jump table for mismatches
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push esi
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push edi
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push ebp
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push ebx
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push ecx
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mov esi, edx // edx: subStr argument
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lea edi, [ecx + KmpSearch::_subStr] // this + 0x100
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lea ebx, [ecx + KmpSearch::_retarget] // this
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lea ebp, [ecx + 1]
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mov byte ptr [ebx], -1
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xor eax, eax
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loopStart:
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shr ecx, 8
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test al, 3
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jnz short dontLoad
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mov ecx, dword ptr [esi + eax] // load next 4 bytes of subStr
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mov dword ptr [edi], ecx // and copy them to this._subStr while we're at it
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lea edi, [edi + 4]
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dontLoad:
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or cl, cl // end of subStr?
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jz short endOfString
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mov edx, eax // save counter (i) in edx
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xlat // al = retarget[i]
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inc al
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mov byte ptr [ebp + edx], al // retarget[i + 1] = retarget[i] + 1
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jz short decLoopEnd
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decrementLoop:
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dec al
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mov ah, byte ptr [esi + eax] // ah = sub[retarget[i + 1] - 1]
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cmp ah, cl // if (ah == sub[i])
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jz short decLoopEnd // goto decLoopEnd
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xlat // al = retarget[retarget[i + 1] - 1]
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xor ah, ah
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inc al // al = retarget[retarget[i + 1] - 1] + 1
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mov byte ptr [ebp + edx], al // retarget[i + 1] = al
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jnz short decrementLoop
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decLoopEnd:
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lea eax, [edx + 1] // i = i + 1
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jmp short loopStart
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endOfString:
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pop ecx // this
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mov [ecx + KmpSearch::_strLen], eax // length of substring (without '\0')
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pop ebx
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pop ebp
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pop edi
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pop esi
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ret
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}
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}
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__declspec(naked) char * __fastcall KmpSearch::search(const char *str) {
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__asm {
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push esi
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push edi
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push ebx
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mov esi, edx // edx: str argument
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lea edi, [ecx + KmpSearch::_subStr]
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lea ebx, [ecx + KmpSearch::_retarget]
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mov ch, byte ptr [ecx + KmpSearch::_strLen]
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or ch, ch // if (_strLen == 0)
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jz short endOfString // goto endOfString
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xor edx, edx // index
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mov cl, 3
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searchLoop:
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shr eax, 8
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inc cl
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test cl, 4
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jz short skipRead
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lodsd
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xor cl, cl
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skipRead:
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test al, al
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jz short endOfString
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newIndexLoop:
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cmp al, byte ptr [edi + edx] // while (c != sub[index]) {
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jz short gotNewIndex
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or edx, edx // if (index == 0)
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jz short searchLoop // goto searchLoop
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movzx edx, byte ptr [ebx + edx] // index = retarget[index]
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jmp short newIndexLoop // }
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gotNewIndex:
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inc edx
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cmp dl, ch // if (index != _strLen)
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jne short searchLoop // goto searchLoop
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movzx ebx, cl // bytes of eax used
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movzx ecx, ch // length of subStr
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lea eax, [esi + ebx - 3]
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sub eax, ecx
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pop ebx
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pop edi
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pop esi
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ret
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endOfString:
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xor eax, eax // return NULL
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pop ebx
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pop edi
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pop esi
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ret
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}
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}
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