419 lines
21 KiB
Plaintext
419 lines
21 KiB
Plaintext
;*************************************************************************************
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; MODULE: BASE64.ASM DATE: JANUARY 27,1997
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; AUTHOR: SEAN M. KESSLER
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; TARGET: 32 BIT FLAT MODEL
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; FUNCTION : BASE64 DECODER
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;*************************************************************************************
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.386
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.MODEL FLAT
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INCLUDE devioctl.inc
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HANDLE STRUC
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PHANDLE TYPEDEF FAR PTR HANDLE
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HANDLE@@mHandle DD <0>
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HANDLE ENDS
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INVALID_HANDLE equ 0FFFFFFFFh
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STRSTR MACRO szStringOne,szStringTwo
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push offset szStringTwo ; save string one
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push offset szStringOne ; save string two
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call _strstr ; call standard library strstr
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add esp,08h ; reset stack frame
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ENDM
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STRCHR MACRO szString,charByte
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push charByte ; save charByte
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push offset szString ; save string
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call _strchr ; call standard library strchr
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add esp,08h ; reset stack frame
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ENDM
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STRLEN MACRO szData
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push edi ; save destination index register
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push ecx ; save ecx register
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mov edi,offset szData ; get string to destination index register
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mov ecx,0FFFFh ; move 65535 to ecx register
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xor eax,eax ; clear eax register
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repnz scasb ; scan string
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mov eax,0FFFFh ; move 65535 to eax
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sub eax,ecx ; subtract number of bytes scanned
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dec eax ; decrement result
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pop ecx ; restore ecx register
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pop edi ; restore destination index register
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ENDM
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MEMCPY MACRO szDstData,szSrcData,lengthCopy
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push esi ; save source index register
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push edi ; save destination index register
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mov esi,offset szSrcData ; move source data to source index register
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mov edi,offset szDstData ; move destination data to destination index register
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mov ecx,lengthCopy ; move number of bytes to copy to ecx register
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rep movsb ; copy data
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pop edi ; restore destination index register
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pop esi ; restore source index register
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ENDM
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STRCMP MACRO szStringOne,szStringTwo
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LOCAL @@STRCMPnotEqual,@@STRCMPequal,@@STRCMPexit
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push ecx ; save ecx register
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push edi ; save destination index register
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push esi ; save source index register
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mov edi,offset szStringOne ; move string one to destination index register
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mov esi,offset szStringTwo ; move string two to source index register
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STRLEN szStringOne ; get length of string one
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mov ecx,eax ; save length to ecx register
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STRLEN szStringTwo ; get length of string two
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cmp ecx,eax ; compare lengths
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jne @@STRCMPnotEqual ; if lengths differ, strings are not equal
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@@STRCMPloop: ; loop control
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mov al,byte ptr[esi] ; get byte from string two
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cmp al,byte ptr[edi] ; compare with byte from string one
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jne @@STRCMPnotEqual ; if bytes differ then we're done
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loop @@STRCMPloop ; iterate through string length
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@@STRCMPequal: ; equality control
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mov eax,0001h ; set return code
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jmp @@STRCMPexit ; we're done
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@@STRCMPnotEqual: ; inequality control
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xor eax,eax ; set return code
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@@STRCMPexit: ; exit sync address
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pop esi ; restore source index register
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pop edi ; restore destination index register
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pop ecx ; restore ecx register
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ENDM
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STRNCMP MACRO szStringOne,szStringTwo
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LOCAL @@STRNCMPloop,@@STRNCMPequal,@@STRNCMPnotEqual,@@STRNCMPexit
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push ecx ; save ecx register
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push edi ; save edi register
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push esi ; save source index register
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mov edi,offset szStringOne ; move string one to destination index register
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mov esi,offset szStringTwo ; move string two to source index register
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STRLEN szStringOne ; get length of string one
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mov ecx,eax ; save length to ecx register
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STRLEN szStringTwo ; get length of string two
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cmp ecx,eax ; compare the lengths
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jle @@STRNCMPloop ; string one is less equal to string two
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mov ecx,eax ; string two is less, so use it's length
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@@STRNCMPloop: ; loop control
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mov al,byte ptr[esi] ; get byte from string one
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cmp al,byte ptr[edi] ; compare with byte from string two
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jne @@STRNCMPnotEqual ; if byte are unequal, strings are unequal
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inc edi ; increment along string two
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inc esi ; increment along string one
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loop @@STRNCMPloop ; keep going
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@@STRNCMPequal: ; string equal sync address
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mov eax,0001h ; set return code
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jmp @@STRNCMPexit ; we're done
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@@STRNCMPnotEqual: ; string unequal sync address
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xor eax,eax ; set return code
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@@STRNCMPexit: ; exit sync address
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pop esi ; restore source index register
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pop edi ; restore destination index register
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pop ecx ; restore ecx register
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ENDM
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CREATEFILE MACRO pathFileName,access,share,open,attribute
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push 0000h ; save handle to template (null)
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push attribute ; save attributes
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push open ; save creation flags
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push 0000h ; save security attributes
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push share ; save share mode
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push access ; save acess mode
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push pathFileName ; save path file name
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call dword ptr __imp__CreateFileA@28 ; call create
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ENDM
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READFILE MACRO hFileHandle,szBuffer,sizeBuffer
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sub esp,04h ; create bytesRead on stack
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mov eax,esp ; move bytesRead address to eax
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push 0000h ; save overlapped structure address
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push eax ; save pointer to bytesRead
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push sizeBuffer ; save length of buffer
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push offset szBuffer ; save address of read buffer
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push hFileHandle ; save file handle
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call dword ptr __imp__ReadFile@20 ; call read
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mov eax,[esp] ; move bytesRead value to eax
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add esp,04h ; remove bytesRead variable from stack
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ENDM
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WRITEFILE MACRO hFileHandle,szBuffer,sizeBuffer
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sub esp,04h ; create bytesWritten variable on stack
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mov eax,esp ; move bytesWritten address to eax
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push 0000h ; save overlapped structure address
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push eax ; save bytesWritten address
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push sizeBuffer ; save write length
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push offset szBuffer ; save address of write buffer
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push hFileHandle ; save file handle
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call dword ptr __imp__WriteFile@20 ; call write
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mov eax,[esp] ; move number of bytes written to eax
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add esp,04h ; remove bytesWritten variable from stack
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ENDM
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CLOSEHANDLE MACRO handle
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push handle ; save file handle
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call dword ptr __imp__CloseHandle@4 ; call close
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ENDM
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FREAD MACRO sFileInfo,ptrByte
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LOCAL @@FREADreadError,@@FREADsimpleRead,@@FREADdone
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cmp sFileInfo.FileInfo@@mBufferIndex,00h ; is buffer index zero
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jne @@FREADsimpleRead ; if not then just grab next byte
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READFILE sFileInfo.FileInfo@@mhFileHandle,sFileInfo.FileInfo@@mszBuffer,MaxLength ; otherwise we fill the read buffer
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cmp eax,0000h ; did we read any data ?
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je @@FREADreadError ; if not then we're done
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mov sFileInfo.FileInfo@@mBufferIndex,eax ; move number of bytes read to buffer index
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mov eax,offset sFileInfo.FileInfo@@mszBuffer ; move address of buffer to eax
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mov sFileInfo.FileInfo@@mlpBufferPointer,eax ; move address of buffer to lpBufferPointer
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jmp @@FREADsimpleRead ; grab next byte
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@@FREADreadError: ; read error sync address
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xor eax,eax ; set return code
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jmp @@FREADdone ; we're done
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@@FREADsimpleRead: ; simple read sync address
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mov eax,sFileInfo.FileInfo@@mlpBufferPointer ; move address of buffer to eax
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mov al,byte ptr[eax] ; move byte value to al
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mov byte ptr[ptrByte],al ; move byte value to user buffer
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inc sFileInfo.FileInfo@@mlpBufferPointer ; increment along lpBufferPointer
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dec sFileInfo.FileInfo@@mBufferIndex ; decrement the buffer index
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mov eax,01h ; set the return code
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@@FREADdone: ; done reading sync
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ENDM
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FWRITE MACRO sFileInfo,ptrByte
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LOCAL @@FWRITEsimpleWrite,@@FWRITEuseBuffer
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cmp sFileInfo.FileInfo@@mBufferIndex,MaxLength ; compare buffer index to MaxLength
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jl @@FWRITEsimpleWrite ; if it's less then insert char into buffer
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WRITEFILE sFileInfo.FileInfo@@mhFileHandle,sFileInfo.FileInfo@@mszBuffer,MaxLength ; other wise
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mov sFileInfo.FileInfo@@mBufferIndex,0000h ; set buffer index to zero
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mov eax,offset sFileInfo.FileInfo@@mszBuffer ; move address of buffer to eax
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mov sFileInfo.FileInfo@@mlpBufferPointer,eax ; move address of buffer to lpBufferPointer
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@@FWRITEsimpleWrite: ; simple write sync address
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cmp sFileInfo.FileInfo@@mlpBufferPointer,0000h ; is buffer pointer null?
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jne @@FWRITEuseBuffer ; if not then just use it
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mov eax,offset sFileInfo.FileInfo@@mszBuffer ; move address of buffer to eax
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mov sFileInfo.FileInfo@@mlpBufferPointer,eax ; move address of buffer to lpBufferPointer
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@@FWRITEuseBuffer: ; use buffer sync address
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mov cl,byte ptr[ptrByte] ; move byte to write to cl
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mov eax,sFileInfo.FileInfo@@mlpBufferPointer ; move address of buffer to eax
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mov byte ptr[eax],cl ; move byte into buffer
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inc sFileInfo.FileInfo@@mlpBufferPointer ; increment buffer pointer
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inc sFileInfo.FileInfo@@mBufferIndex ; increment buffer index
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mov eax,01h ; set return code
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ENDM
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FFLUSH MACRO sFileInfo
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WRITEFILE sFileInfo.FileInfo@@mhFileHandle,sFileInfo.FileInfo@@mszBuffer,sFileInfo.FileInfo@@mBufferIndex ; write buffer to disk
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mov sFileInfo.FileInfo@@mBufferIndex,0000h ; set buffer index to zero
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mov eax,offset sFileInfo.FileInfo@@mszBuffer ; move address of buffer to eax
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mov sFileInfo.FileInfo@@mlpBufferPointer,eax ; move address of buffer to lpBufferPointer
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ENDM
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FGETS MACRO sFileInfo,szBuffer
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LOCAL @@FGETScont,@@FGETexit,@@FGETsetError,@@FGETScrlf
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push esi ; save source index register
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mov esi,offset szBuffer ; move address of buffer into esi
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@@FGETScont: ; loop control
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FREAD sFileInfo,esi ; read a byte
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cmp eax,0000h ; was our read successful?
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je @@FGETexit ; if not we're done
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cmp byte ptr[esi],0Dh ; is the byte a carriage return?
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je @@FGETScrlf ; if yes then jump to handler
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inc esi ; increment along esi
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jmp @@FGETScont ; keep reading
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@@FGETScrlf: ; carriage return control
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mov byte ptr[esi],00h ; move null into line data
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sub esp,04h ; create temp var on stack
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mov esi,esp ; esi points to temp var
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FREAD sFileInfo,esi ; read line-feed into temp var
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add esp,04h ; restore stack
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@@FGETexit: ; exit sync address
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pop esi ; restore source index register
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ENDM
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FileInfo STRUC
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MaxLength equ 800h
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FileInfo@@mhFileHandle HANDLE <0>
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FileInfo@@mszBuffer DB MaxLength DUP(0)
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FileInfo@@mBufferIndex DD (0)
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FileInfo@@mlpBufferPointer DD (0)
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FileInfo ENDS
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.DATA
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inputFile FileInfo <<0>>
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outputFile FileInfo <<0>>
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lineData DB 400h DUP(0)
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szDefaultOutputPathFileName DB 'IMAGE.JPG',00h
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szOutputPathFileName DB 0FFh DUP(0)
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szFileNameLiteral DB 'filename=',00h
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szOutBytes DB 04h DUP(0)
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szInputPathFileName DD ?
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szBase64ID DB '/9j/',00h
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szBase64Vector DB 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=',00h
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num DD ?
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lineLength DD ?
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itemIndex DD ?
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numIndex DD ?
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valueItem DD ?
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.CODE
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_decodeBase64 proc near ; WORD decodeBase64(const char *szPathFileName)
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push ebp ; save stack frame
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mov ebp,esp ; create new frame
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push esi ; save source index register
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push edi ; save destination index register
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push [ebp+8] ; save pathFileName
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pop szInputPathFileName ; restore into inputPathFileName
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cmp szInputPathFileName,0000h ; is the file na null
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je @@error ; if so then we've got an error
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CREATEFILE szInputPathFileName,GENERIC_READ,FILE_SHARE_READ,OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL
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mov inputFile.FileInfo@@mhFileHandle,eax ; store the handle
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cmp inputFile.FileInfo@@mhFileHandle,INVALID_HANDLE ; do we have a valid handle ?
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je @@error ; if the handle is invalid then we've got an error
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STRLEN szDefaultOutputPathFileName ; get the length of the default file name
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MEMCPY szOutputPathFileName,szDefaultOutputPathFileName,eax ; set output file name to default
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@@search: ; search sync address
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FGETS inputFile,lineData ; get input line
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cmp eax,0000h ; did we read anything
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je @@end ; if not we're done
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STRSTR lineData,szFileNameLiteral ; look for "filename=" literal
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cmp eax,0000h ; did we find it
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jne @@nameFile ; if so then extract the filename
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STRNCMP szBase64ID,lineData ; compare line to base64 identifier
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cmp eax,0001h ; if we've got it then we start decoding
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je @@beginDecode ; jump to decode handler
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jmp @@search ; keep going
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@@nameFile: ; nameFile sync address
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push eax ; save address of filename literal
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push offset szOutputPathFileName ; save address of filename buffer
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call _nameFile ; extract the file name
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add esp,08h ; reset stack frame
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jmp @@search ; keep going
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@@beginDecode: ; begin decode sync address
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CREATEFILE offset szOutputPathFileName,GENERIC_WRITE,FILE_SHARE_READ,CREATE_ALWAYS,FILE_ATTRIBUTE_NORMAL
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mov outputFile.FileInfo@@mhFileHandle,eax ; save handle
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@@continueDecode: ; continue decode sync address
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STRLEN lineData ; get length of lineData
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dec eax ; decrement line length
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mov lineLength,eax ; move line length into lineLength
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mov itemIndex,0000h ; set itemIndex to zero
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@@itemLoop: ; itemLoop sync address
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mov valueItem,0000h ; set valueItem to zero
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mov esi,offset lineData ; move ptr lineData to esi register
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add esi,itemIndex ; add itemIndex to address
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cmp byte ptr[esi+02h],'=' ; is pChar[2] equal to '='?
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je @@assignOne ; if so then num=1
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cmp byte ptr[esi+03h],'=' ; else if pChar[3]='='
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je @@assignTwo ; then num=2
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mov num,0003h ; otherwise num=3
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jmp @@assignContinue ; continue
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@@assignOne: ; assignment sync address
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mov num,0001h ; assign 1 to num
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jmp @@assignContinue ; continue
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@@assignTwo: ; assignment sync address
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mov num,0002h ; assign two to num
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jmp @@assignContinue ; continue
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@@assignContinue: ; end assignment sync address
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mov numIndex,0000h ; set numIndex to zero
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@@numLoop: ; numIndex loop sync address
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xor eax,eax ; clear out eax
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mov edi,numIndex ; move numIndex into destination index
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mov al,byte ptr[esi+edi] ; get the byte at pChar[numIndex]
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STRCHR szBase64Vector,eax ; ::strchar(szBase64Vector,pChar[numIndex])
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cmp eax,0000h ; did we find the token
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je @@end ; if not then we've got an error
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mov edi,eax ; move address of found token to edi (pTok)
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sub edi,offset szBase64Vector ; perform (pTok-szBase64Vector) result to edi
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mov eax,0003h ; move 3 into eax
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sub eax,numIndex ; perform (3-numIndex) result to eax
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mov edx,0006h ; move 6 into edx
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imul eax,edx ; perform (3-numIndex)*6 result to eax
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mov cl,al ; move shift value into cl register
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shl edi,cl ; perform (pTok-smszVec)<<((3-numIndex)*6) result to edi
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add valueItem,edi ; valueItem+=(pTok-smszVec)<<((3-numIndex)*6)
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inc numIndex ; increment numIndex
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mov eax,numIndex ; move numIndex into eax register
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cmp eax,num ; compare numIndex to num
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jle @@numLoop ; loop through <= operation
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mov numIndex,0002h ; set numIndex to 2
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@@nextNumLoop: ; next numLoop sync address
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mov esi,offset szOutBytes ; move szOutBytes address into esi
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mov edi,numIndex ; move numIndex into edi
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mov eax,valueItem ; move valueItem into eax register
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and eax,000000FFh ; apply bit mask
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mov byte ptr[esi+edi],al ; set byte in szOutBytes
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shr valueItem,08h ; shift valueItem right 8 bytes
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dec numIndex ; decrement numIndex
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cmp numIndex,0000h ; compare numIndex to zero
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jge @@nextNumLoop ; if >=0 keep going
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mov esi,offset szOutBytes ; move szOutBytes to esi
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xor edi,edi ; clear edi
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@@writeLoop: ; writeLoop sync address
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FWRITE outputFile,byte ptr[esi+edi] ; write out the byte
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inc edi ; increment edi
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cmp edi,num ; compare edi to num
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jl @@writeLoop ; if it's less then keep going
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add itemIndex,0004h ; increment itemIndex by four
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mov eax,itemIndex ; move itemIndex to eax
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cmp eax,lineLength ; compare itemIndex to lineLength
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jl @@itemLoop ; if it's less that keep going
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FGETS inputFile,lineData ; get another line
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cmp eax,0000h ; did we get a line?
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je @@end ; if not then we're done
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jmp @@continueDecode ; otherwise keep going
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@@end: ; end sync address
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FFLUSH outputFile ; flush the output file
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CLOSEHANDLE outputFile.FileInfo@@mhFileHandle ; close output file
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CLOSEHANDLE inputFile.FileInfo@@mhFileHandle ; close input file
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@@error: ; error sync address
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pop edi ; restore destination index register
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pop esi ; restore source index register
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pop ebp ; restore prior stack frame
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retn ; return near to caller
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_decodeBase64 endp
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_nameFile proc near
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push ebp ; save stack frame
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mov ebp,esp ; create new frame
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push esi ; save source index register
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push edi ; save destination index register
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mov edi,[ebp+8] ; move dest string to destination index register
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mov esi,[ebp+0Ch] ; move source string to source index register
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@@NAMEFILEquoteLoop: ; first quote loop control
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mov al,byte ptr[esi] ; move byte into al
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cmp al,00h ; is it null?
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je @@NAMEFILEerror ; if it's null then we've got an error
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cmp al,'"' ; is it the first quote ?
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je @@NAMEFILEreadFile ; if so then get the filename
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inc esi ; increment along esi
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jmp @@NAMEFILEquoteLoop ; keep going
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@@NAMEFILEreadFile: ; read file name sync address
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inc esi ; skip past the first quote
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mov al,byte ptr[esi] ; read from file name
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cmp al,'"' ; is the byte the closing quote?
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je @@NAMEFILEreadEnd ; if so then we're done
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cmp al,00h ; is the byte a null byte?
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je @@NAMEFILEreadEnd ; if so then we're done
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mov byte ptr[edi],al ; store the byte in destination
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inc edi ; increment along destination
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jmp @@NAMEFILEreadFile ; keep going
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@@NAMEFILEreadEnd: ; read end sync address
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mov byte ptr[edi],00h ; null terminate the string
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mov eax,0001h ; set return code
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jmp @@NAMEFILEend ; we're done
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@@NAMEFILEerror: ; error sync address
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xor eax,eax ; set error return
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@@NAMEFILEend: ; end proc sync address
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pop edi ; restore destination index register
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pop esi ; restore source index register
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pop ebp ; restore prior stack frame
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retn ; return near to caller
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_nameFile endp
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public _decodeBase64
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extrn __imp__WriteFile@20:near
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extrn __imp__CloseHandle@4:near
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extrn __imp__CreateFileA@28:near
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extrn __imp__GetLastError@0:near
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extrn __imp__ReadFile@20:near
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extrn __imp__WriteFile@20:near
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extrn _strstr:near
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extrn _strchr:near
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END
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