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;;================================================================================================;;

;;//// bmp.asm //// (c) mike.dld, 2007-2008, (c) diamond, 2009 ///////////////////////////////////;;

;;================================================================================================;;

;;                                                                                                ;;

;; This file is part of Common development libraries (Libs-Dev).                                  ;;

;;                                                                                                ;;

;; Libs-Dev is free software: you can redistribute it and/or modify it under the terms of the GNU ;;

;; Lesser General Public License as published by the Free Software Foundation, either version 2.1 ;;

;; of the License, or (at your option) any later version.                                         ;;

;;                                                                                                ;;

;; Libs-Dev is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without  ;;

;; even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU  ;;

;; Lesser General Public License for more details.                                                ;;

;;                                                                                                ;;

;; You should have received a copy of the GNU Lesser General Public License along with Libs-Dev.  ;;

;; If not, see .                                                    ;;

;;                                                                                                ;;

;;================================================================================================;;

;;                                                                                                ;;

;; References:                                                                                    ;;

;;   1. "Microsoft Windows Bitmap File Format Summary"                                            ;;

;;      from "Encyclopedia of Graphics File Formats" by O'Reilly                                  ;;

;;      http://www.fileformat.info/format/bmp/                                                    ;;

;;                                                                                                ;;

;;================================================================================================;;

include 'bmp.inc'

;;================================================================================================;;

;;proc img.is.bmp _data, _length ;////////////////////////////////////////////////////////////////;;

img.is.bmp:

;;------------------------------------------------------------------------------------------------;;

;? Determine if raw data could be decoded (is in BMP format)                                      ;;

;;------------------------------------------------------------------------------------------------;;

;> _data = raw data as read from file/stream                                                      ;;

;> _length = data length                                                                          ;;

;;------------------------------------------------------------------------------------------------;;

;< eax = false / true                                                                             ;;

;;================================================================================================;;

; test 1 (length of data): data must contain FileHeader and required fields from InfoHeader

	cmp	dword [esp+8], sizeof.bmp.FileHeader + 12

	jb	.nope

; test 2: signature

	mov	eax, [esp+4]

	cmp	word [eax], 'BM'

	je	.yep

  .nope:

	xor	eax, eax

	ret	8

  .yep:

	xor	eax, eax

	inc	eax

	ret	8

;endp

;;================================================================================================;;

proc img.decode.bmp _data, _length, _options ;////////////////////////////////////////////////////;;

;;------------------------------------------------------------------------------------------------;;

;? Decode data into image if it contains correctly formed raw data in BMP format                  ;;

;;------------------------------------------------------------------------------------------------;;

;> _data = raw data as read from file/stream                                                      ;;

;> _length = data length                                                                          ;;

;;------------------------------------------------------------------------------------------------;;

;< eax = 0 (error) or pointer to image                                                            ;;

;;================================================================================================;;

locals

  length_rest dd ?

  img dd ?

  bTopDown db ?

  bIsIco db ?

endl

img.decode.bmp.length_rest equ length_rest

	mov	[bIsIco], 0

.common: ; common place for BMP and ICO

	push	ebx esi edi

	mov	ebx, [_data]

	cmp	[bIsIco], 0

	jnz	@f

	add	ebx, sizeof.bmp.FileHeader

	sub	[_length], sizeof.bmp.FileHeader

   @@:

	mov	eax, [ebx + bmp.InfoHeader.Size]

; sanity check: file length must be greater than size of headers

	cmp	[_length], eax

	jbe	.error

	mov	[bTopDown], 0

	cmp	eax, 12

	jz	.old1

	cmp	eax, 40

	jz	.normal

	cmp	eax, 56

	jnz	.error

; convert images with <= 8 bpp to 8bpp, other - to 32 bpp

.normal:

	m2m	eax, Image.bpp8

	cmp	byte [ebx + 14], 8	; bit count

	jbe	@f

	mov	al, Image.bpp32

@@:

	push	eax

	mov	eax, [ebx + 8]	;[ebx + bmp.InfoHeader.Height]

	test	eax, eax

	jns	@f

	inc	[bTopDown]

	neg	eax

@@:

	cmp	[bIsIco], 0	; for icons Height is two times larger than image height

	jz	@f

	shr	eax, 1

@@:

	pushd	eax

	pushd	[ebx + 4]	;[ebx + bmp.InfoHeader.Width]

	jmp	.create

.old1:

	m2m	eax, Image.bpp8

	cmp	byte [ebx + 10], 8	; bit count

	jbe	@f

	mov	al, Image.bpp32

@@:

	push	eax

	movsx	eax, word [ebx + 6]	;[ebx + bmp.InfoHeader.OldHeight]

	test	eax, eax

	jns	@f

	inc	[bTopDown]

	neg	eax

@@:

	cmp	[bIsIco], 0	; for icons Height is two times larger than image height

	jz	@f

	shr	eax, 1

@@:

	push	eax

	movzx	eax, word [ebx + 4]	;[ebx + bmp.InfoHeader.OldWidth]

	push	eax

.create:

	call	img.create

	or	eax, eax

	jz	.error

	mov	[img], eax

	mov	edx, eax

	invoke	mem.alloc, sizeof.bmp.Image

	or	eax, eax

	jz	.error.free

	mov	[edx + Image.Extended], eax

	push	eax

	mov	edi, eax

	mov	ecx, sizeof.bmp.Image/4

	xor	eax, eax

	rep	stosd

	pop	edi

	push	edi

	mov	esi, ebx

	mov	ecx, [ebx]	;[ebx + bmp.InfoHeader.Size]

	cmp	ecx, 12

	jz	.old2

	rep	movsb

	jmp	.decode

.old2:

	movsd	; Size

	movzx	eax, word [esi]	; OldWidth -> Width

	stosd

	movsx	eax, word [esi+2]	; OldHeight -> Height

	stosd

	lodsd	; skip OldWidth+OldHeight

	movsd	; Planes+BitCount

.decode:

	pop	edi

	cmp	[bIsIco], 0

	jnz	@f

	mov	edi, [_length]

	add	edi, sizeof.bmp.FileHeader

	mov	esi, [ebx - sizeof.bmp.FileHeader + bmp.FileHeader.OffBits]

	jmp	.offset_calculated

@@:

	xor	esi, esi

	mov	cl, byte [edi + bmp.Image.info.BitCount]

	cmp	cl, 8

	ja	@f

	inc	esi

	add	cl, 2

	shl	esi, cl

@@:

	add	esi, [edi + bmp.Image.info.Size]

	mov	edi, [_length]

.offset_calculated:

	sub	edi, esi

	jbe	.error.free

	add	esi, [_data]

	mov	eax, [edx + Image.Extended]

	mov	eax, [eax + bmp.Image.info.Compression]

	cmp	eax, bmp.BI_RGB

	jne	@f

	stdcall ._.rgb

	jmp	.decoded

    @@: cmp	eax, bmp.BI_RLE8

	jne	@f

	cmp	word [ebx + 14], 8 ;bmp.InfoHeader.BitCount

	jnz	.error.free

	stdcall ._.rle

	jmp	.decoded

    @@: cmp	eax, bmp.BI_RLE4

	jne	@f

	cmp	word [ebx + 14], 4

	jnz	.error.free

	stdcall ._.rle

	jmp	.decoded

    @@: cmp	eax, bmp.BI_BITFIELDS

	jne	.error.free

	stdcall ._.bitfields

	jmp	.decoded

; BI_JPEG and BI_PNG constants are not valid values for BMP file,

; they are intended for WinAPI

;    @@: cmp	eax, bmp.BI_JPEG

;	jne	@f

;	stdcall ._.jpeg

;	jmp	.decoded

;    @@: cmp	eax, bmp.BI_PNG

;	jne	.error

;	stdcall ._.png

  .decoded:

	or	eax, eax

	jz	@f

  .error.free:

	stdcall img.destroy, [img]

	jmp	.error

    @@:

	cmp	[bTopDown], 0

	jnz	@f

	stdcall img.flip, [img], FLIP_VERTICAL

    @@:

	mov	eax, [img]

	mov	ecx, [length_rest]	; return length for ICO code

	cmp	[bIsIco], 0

	jz	@f

	mov	[esp + 4], esi	; return pointer to end-of-data for ICO code

    @@:

	pop	edi esi ebx

	ret

  .error:

	xor	eax, eax

	pop	edi esi ebx

	ret

endp

;;================================================================================================;;

proc img.encode.bmp _img, _p_length, _options ;///////////////////////////////////////////////////;;

;;------------------------------------------------------------------------------------------------;;

;? Encode image into raw data in BMP format                                                       ;;

;;------------------------------------------------------------------------------------------------;;

;> _img = pointer to image                                                                        ;;

;;------------------------------------------------------------------------------------------------;;

;< eax = 0 (error) or pointer to encoded data                                                     ;;

;< _p_length = encoded data length                                                                ;;

;;================================================================================================;;

	xor	eax, eax

	ret

endp

;;================================================================================================;;

;;////////////////////////////////////////////////////////////////////////////////////////////////;;

;;================================================================================================;;

;! Below are private procs you should never call directly from your code                          ;;

;;================================================================================================;;

;;////////////////////////////////////////////////////////////////////////////////////////////////;;

;;================================================================================================;;

;;================================================================================================;;

proc img.decode.bmp._.rgb ;///////////////////////////////////////////////////////////////////////;;

;;------------------------------------------------------------------------------------------------;;

;? --- TBD ---                                                                                    ;;

;;------------------------------------------------------------------------------------------------;;

;> ebx = raw image data                                                                           ;;

;> edx = image data                                                                               ;;

;;------------------------------------------------------------------------------------------------;;

;< --- TBD ---                                                                                    ;;

;;================================================================================================;;

	mov	ecx, [edx + Image.Extended]

	mov	[ecx + bmp.Image.info.AlphaMask], 0

	movzx	eax, [ecx + bmp.Image.info.BitCount]

	cmp	eax, 32

	je	.32bpp

	cmp	eax, 24

	je	.24bpp

	cmp	eax, 16

	je	.16bpp

	cmp	eax, 8

	je	.8bpp

	cmp	eax, 4

	je	.4bpp

	cmp	eax, 1

	je	.1bpp

	jmp	.error

;;------------------------------------------------------------------------------------------------;;

img.decode.bmp._.rgb.32bpp:

	mov	[ecx + bmp.Image.info.RedMask],   00000000111111110000000000000000b ; 8-0-0

	mov	[ecx + bmp.Image.info.GreenMask], 00000000000000001111111100000000b ; 0-8-0

	mov	[ecx + bmp.Image.info.BlueMask],  00000000000000000000000011111111b ; 0-0-8

	stdcall img.decode.bmp._.bitfields

	ret

;;------------------------------------------------------------------------------------------------;;

img.decode.bmp._.rgb.24bpp:

	mov	eax, [edx + Image.Width]

	lea	eax, [eax*3 + 3]

	and	eax, not 3

	mov	ecx, [edx + Image.Height]

	imul	eax, ecx

	sub	edi, eax

	jb	img.decode.bmp._.rgb.error

	mov	[img.decode.bmp.length_rest], edi

	mov	edi, [edx + Image.Data]

  .next_line:

	push	ecx edx

	mov	ecx, [edx + Image.Width]

	xor	edx, edx

  .next_line_pixel:

	movsd

	dec	esi

	inc	edx

	dec	ecx

	jnz	.next_line_pixel

	and	edx, 0x03

	add	esi, edx

	pop	edx ecx

	dec	ecx

	jnz	.next_line

	jmp	img.decode.bmp._.rgb.exit

;;------------------------------------------------------------------------------------------------;;

img.decode.bmp._.rgb.16bpp:

	mov	[ecx + bmp.Image.info.RedMask],   00000000000000000111110000000000b ; 5-0-0

	mov	[ecx + bmp.Image.info.GreenMask], 00000000000000000000001111100000b ; 0-5-0

	mov	[ecx + bmp.Image.info.BlueMask],  00000000000000000000000000011111b ; 0-0-5

	stdcall img.decode.bmp._.bitfields

	ret

;;------------------------------------------------------------------------------------------------;;

img.decode.bmp._.rgb.8bpp:

	mov	eax, [edx + Image.Width]

	add	eax, 3

	call	img.decode.bmp._.rgb.prepare_palette

	jc	img.decode.bmp._.rgb.error

  .next_line:

	push	ecx

	mov	ecx, [edx + Image.Width]

	mov	eax, ecx

	neg	eax

	and	eax, 3

	rep	movsb

	add	esi, eax

	pop	ecx

	dec	ecx

	jnz	.next_line

	jmp	img.decode.bmp._.rgb.exit

;;------------------------------------------------------------------------------------------------;;

img.decode.bmp._.rgb.4bpp:

	mov	eax, [edx + Image.Width]

	add	eax, 7

	shr	eax, 1

	call	img.decode.bmp._.rgb.prepare_palette

	jc	img.decode.bmp._.rgb.error

  .next_line:

	push	ecx edx

	mov	ecx, [edx + Image.Width]

  .next_line_dword:

	push	ecx

	lodsd

	bswap	eax

	xchg	edx, eax

	mov	ecx, 32 / 4

  .next_pixel:

	rol	edx, 4

	mov	al, dl

	and	al, 0x0000000F

	stosb

	dec	dword[esp]

	jz	@f

	dec	ecx

	jnz	.next_pixel

    @@: pop	ecx

	or	ecx, ecx

	jnz	.next_line_dword

	pop	edx ecx

	dec	ecx

	jnz	.next_line

	jmp	img.decode.bmp._.rgb.exit

;;------------------------------------------------------------------------------------------------;;

img.decode.bmp._.rgb.1bpp:

	mov	eax, [edx + Image.Width]

	add	eax, 31

	shr	eax, 3

	call	img.decode.bmp._.rgb.prepare_palette

	jc	img.decode.bmp._.rgb.error

  .next_line:

	push	ecx edx

	mov	ecx, [edx + Image.Width]

  .next_line_dword:

	push	ecx

	lodsd

	bswap	eax

	xchg	edx, eax

	mov	ecx, 32 / 1

  .next_pixel:

	rol	edx, 1

	mov	al, dl

	and	al, 0x00000001

	stosb

	dec	dword[esp]

	jz	@f

	dec	ecx

	jnz	.next_pixel

    @@: pop	ecx

	or	ecx, ecx

	jnz	.next_line_dword

	pop	edx ecx

	dec	ecx

	jnz	.next_line

	jmp	img.decode.bmp._.rgb.exit

;;------------------------------------------------------------------------------------------------;;

  img.decode.bmp._.rgb.exit:

	xor	eax, eax

	ret

  img.decode.bmp._.rgb.error:

	or	eax, -1

	ret

img.decode.bmp._.rgb.prepare_palette:

	and	eax, not 3

	mov	ecx, [edx + Image.Height]

	imul	eax, ecx

	sub	edi, eax

	jb	.ret

	mov	[img.decode.bmp.length_rest], edi

	push	esi

	sub	esi, ebx

	jc	.ret.pop

	sub	esi, [ebx + bmp.InfoHeader.Size]

	jc	.ret.pop

	mov	eax, esi

	mov	edi, [edx + Image.Palette]

	push	ecx

	mov	ecx, 256

	mov	esi, [ebx + bmp.InfoHeader.Size]

	cmp	esi, 12

	jz	.old

	shr	eax, 2

	add	esi, ebx

	cmp	ecx, eax

	jb	@f

	mov	ecx, eax

@@:

	rep	movsd

	jmp	.common

.old:

	add	esi, ebx

@@:

	movsd

	dec	esi

	sub	eax, 3

	jbe	@f

	sub	ecx, 1

	jnz	@b

@@:

.common:

	pop	ecx

	mov	edi, [edx + Image.Data]

	clc

.ret.pop:

	pop	esi

.ret:

	ret

endp

;;================================================================================================;;

proc img.decode.bmp._.rle ;///////////////////////////////////////////////////////////////////////;;

;;------------------------------------------------------------------------------------------------;;

;? --- TBD ---                                                                                    ;;

;;------------------------------------------------------------------------------------------------;;

;> ebx = raw image data                                                                           ;;

;> edx = image data                                                                               ;;

;;------------------------------------------------------------------------------------------------;;

;< --- TBD ---                                                                                    ;;

;;================================================================================================;;

locals

  scanline_len	dd ?

  marker_x	dd ?

  marker_y	dd ?

  abs_mode_addr dd ?

  enc_mode_addr dd ?

  height	dd ?

endl

	mov	[abs_mode_addr], .absolute_mode.rle8

	mov	[enc_mode_addr], .encoded_mode.rle8

	cmp	[ebx + bmp.InfoHeader.Compression], bmp.BI_RLE4

	jne	@f

	mov	[abs_mode_addr], .absolute_mode.rle4

	mov	[enc_mode_addr], .encoded_mode.rle4

    @@:

	push	edi

	xor	eax, eax	; do not check file size in .prepare_palette

	push	ebp

	mov	ebp, [ebp]	; set parent stack frame

	call	img.decode.bmp._.rgb.prepare_palette

	pop	ebp

	pop	ecx	; ecx = rest bytes in file

	jc	.error

	mov	eax, [edx + Image.Width]

	mov	[scanline_len], eax

	mov	eax, [edx + Image.Height]

	mov	[height], eax

	xor	eax, eax

	mov	[marker_x], eax

	mov	[marker_y], eax

	mov	edi, [edx + Image.Data]

  .next_run:

	sub	ecx, 1

	jc	.eof

	xor	eax, eax

	lodsb

	or	al, al

	jz	.escape_mode

	jmp	[enc_mode_addr]

  .escape_mode:

	sub	ecx, 1

	jc	.eof

	lodsb

	cmp	al, 0

	je	.end_of_scanline

	cmp	al, 1

	je	.exit

	cmp	al, 2

	je	.offset_marker

	jmp	[abs_mode_addr]

  .end_of_scanline: ; 0

	sub	edi, [marker_x]

	add	edi, [scanline_len]

	mov	[marker_x], 0

	mov	eax, [marker_y]

	inc	eax

	mov	[marker_y], eax

	cmp	eax, [height]

	jb	.next_run

	jmp	.exit

  .offset_marker: ; 2: dx, dy

	sub	ecx, 2

	jc	.eof

	lodsb

	mov	edx, [marker_x]

	add	edx, eax

	cmp	edx, [scanline_len]

	jae	.exit

	mov	[marker_x], edx

	add	edi, eax

	lodsb

	mov	edx, [marker_y]

	add	edx, eax

	cmp	edx, [height]

	jae	.exit

	mov	[marker_y], edx

	imul	eax, [scanline_len]

	add	edi, eax

	jmp	.next_run

  .encoded_mode.rle8: ; N: b1 * N

	call	.fix_marker

	sub	ecx, 1

	jc	.eof

	lodsb

	push	ecx

	mov	ecx, edx

	rep	stosb

	pop	ecx

	jmp	.check_eoi

  .absolute_mode.rle8: ; N: b1 .. bN

	call	.fix_marker

	cmp	ecx, edx

	jae	@f

	mov	edx, ecx

    @@:

	push	ecx

	mov	ecx, edx

	rep	movsb

	pop	ecx

	sub	ecx, edx

	jz	.eof

	test	edx, 1

	jz	.check_eoi

	sub	ecx, 1

	jc	.eof

	inc	esi

  .check_eoi:

	mov	eax, [marker_y]

	cmp	eax, [height]

	jb	.next_run

	jmp	.exit

  .encoded_mode.rle4: ; N: b1 * N

	call	.fix_marker

	sub	ecx, 1

	jc	.eof

	movzx	eax, byte [esi]

	inc	esi

	push	ecx

	mov	ecx, eax

	and	eax, 0xF

	shr	ecx, 4

    @@:

	dec	edx

	js	@f

	mov	[edi], cl

	dec	edx

	js	@f

	mov	[edi+1], al

	add	edi, 2

	jmp	@b

    @@:

	pop	ecx

	jmp	.check_eoi

  .absolute_mode.rle4: ; N: b1 .. bN

	call	.fix_marker

	lea	eax, [edx+1]

	shr	eax, 1

	cmp	ecx, eax

	jbe	@f

	lea	edx, [ecx*2]

    @@:

	push	ecx edx

    @@: dec	edx

	js	@f

	lodsb

	mov	cl, al

	shr	al, 4

	and	cl, 0xF

	stosb

	dec	edx

	js	@f

	mov	[edi], cl

	inc	edi

	jmp	@b

    @@: pop	eax ecx

	and	eax, 0x03

	jp	.check_eoi

	sub	ecx, 1

	jc	.eof

	inc	esi

	jmp	.check_eoi

  .fix_marker:

	mov	edx, eax

	add	eax, [marker_x]

	mov	[marker_x], eax

    @@:

	sub	eax, [scanline_len]

	jle	@f

	mov	[marker_x], eax

	push	eax

	mov	eax, [marker_y]

	inc	eax

	mov	[marker_y], eax

	cmp	eax, [height]

	pop	eax

	jb	@b

	sub	edx, eax

    @@:

        retn

  .exit:

  .eof:

	xor	eax, eax

	ret

  .error:

	or	eax, -1

	ret

endp

;;================================================================================================;;

proc img.decode.bmp._.bitfields ;/////////////////////////////////////////////////////////////////;;

;;------------------------------------------------------------------------------------------------;;

;? --- TBD ---                                                                                    ;;

;;------------------------------------------------------------------------------------------------;;

;> ebx = raw image data                                                                           ;;

;> edx = image data                                                                               ;;

;;------------------------------------------------------------------------------------------------;;

;< --- TBD ---                                                                                    ;;

;;================================================================================================;;

locals

  shift   bmp.RgbByteQuad

  unshift bmp.RgbByteQuad

  mask	  bmp.RgbQuad

  delta   dd ?

endl

	mov	[delta], 4

	mov	eax, [edx + Image.Extended]

	cmp	[eax + bmp.Image.info.BitCount], 32

	je	@f

	cmp	[eax + bmp.Image.info.BitCount], 16

	jne	.error

	mov	[delta], 2

    @@:

	mov	ecx, [edx + Image.Width]

	imul	ecx, [edx + Image.Height]

	imul	ecx, [delta]

	sub	edi, ecx

	jb	.error

	mov	ecx, [ebp]	; use parent stack frame

	mov	[ecx + img.decode.bmp.length_rest - ebp], edi	; !

	push	esi

	mov	esi, eax

	mov	ecx, [esi + bmp.Image.info.RedMask]

	call	.calc_shift

	mov	[shift.Red], al

	mov	[mask.Red], ecx

	call	.calc_unshift

	mov	[unshift.Red], al

	mov	ecx, [esi + bmp.Image.info.GreenMask]

	call	.calc_shift

	mov	[shift.Green], al

	mov	[unshift.Green], al

	mov	[mask.Green], ecx

	call	.calc_unshift

	mov	[unshift.Green], al

	mov	ecx, [esi + bmp.Image.info.BlueMask]

	call	.calc_shift

	mov	[shift.Blue], al

	mov	[unshift.Blue], al

	mov	[mask.Blue], ecx

	call	.calc_unshift

	mov	[unshift.Blue], al

	mov	ecx, [esi + bmp.Image.info.AlphaMask]

	call	.calc_shift

	mov	[shift.Alpha], al

	mov	[unshift.Alpha], al

	mov	[mask.Alpha], ecx

	call	.calc_unshift

	mov	[unshift.Alpha], al

	mov	edi, [edx + Image.Data]

	pop	esi

;;------------------------------------------------------------------------------------------------;;

	mov	ecx, [edx + Image.Height]

  .next_line:

	push	ecx

	mov	ecx, [edx + Image.Width]

  .next_pixel:

	push	ecx

	mov	eax, [esi]

	mov	cl, [shift.Blue]

	shr	eax, cl

	and	eax, [mask.Blue]

	mov	cl, [unshift.Blue]

	shl	eax, cl

	stosb

	mov	eax, [esi]

	mov	cl, [shift.Green]

	shr	eax, cl

	and	eax, [mask.Green]

	mov	cl, [unshift.Green]

	shl	eax, cl

	stosb

	mov	eax, [esi]

	mov	cl, [shift.Red]

	shr	eax, cl

	and	eax, [mask.Red]

	mov	cl, [unshift.Red]

	shl	eax, cl

	stosb

	mov	eax, [esi]

	mov	cl, [shift.Alpha]

	shr	eax, cl

	and	eax, [mask.Alpha]

	mov	cl, [unshift.Alpha]

	shl	eax, cl

	stosb

	add	esi, [delta]

	pop	ecx

	dec	ecx

	jnz	.next_pixel

	pop	ecx

	dec	ecx

	jnz	.next_line

;;------------------------------------------------------------------------------------------------;;

  .exit:

	xor	eax, eax

	pop	edi

	ret

  .error:

	or	eax, -1

	pop	edi

	ret

.calc_shift:

	xor	eax, eax

	or	ecx, ecx

	jnz	@f

	retn

    @@: test	ecx, 1

	jnz	@f

   .zz: shr	ecx, 1

	inc	eax

	jmp	@b

    @@: test	ecx, 0100000000b

	jnz	.zz

	retn

.calc_unshift:

	xor	eax, eax

	or	ecx, ecx

	jnz	@f

	retn

    @@: test	ecx, 1

	jz	@f

	shr	ecx, 1

	inc	eax

	jmp	@b

    @@: sub	eax, 8

	neg	eax

	retn

endp

if 0

;;================================================================================================;;

proc img.decode.bmp._.jpeg ;//////////////////////////////////////////////////////////////////////;;

;;------------------------------------------------------------------------------------------------;;

;? --- TBD ---                                                                                    ;;

;;------------------------------------------------------------------------------------------------;;

;> ebx = raw image data                                                                           ;;

;> edx = image data                                                                               ;;

;;------------------------------------------------------------------------------------------------;;

;< --- TBD ---                                                                                    ;;

;;================================================================================================;;

	xor	eax, eax

	ret

endp

;;================================================================================================;;

proc img.decode.bmp._.png ;///////////////////////////////////////////////////////////////////////;;

;;------------------------------------------------------------------------------------------------;;

;? --- TBD ---                                                                                    ;;

;;------------------------------------------------------------------------------------------------;;

;> ebx = raw image data                                                                           ;;

;> edx = image data                                                                               ;;

;;------------------------------------------------------------------------------------------------;;

;< --- TBD ---                                                                                    ;;

;;================================================================================================;;

	xor	eax, eax

	ret

endp

end if

;;================================================================================================;;

;;////////////////////////////////////////////////////////////////////////////////////////////////;;

;;================================================================================================;;

;! Below is private data you should never use directly from your code                             ;;

;;================================================================================================;;

;;////////////////////////////////////////////////////////////////////////////////////////////////;;

;;================================================================================================;;

;