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

;;//// gif.asm //// (c) mike.dld, 2007-2008 //////////////////////////////////////////////////////;;

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

;;//// Partial (c) by Willow, Diamond and HidnPlayr //////////////////////////////////////////////;;

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

;;                                                                                                ;;

;; 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. GIF LITE v3.0 (2004-2007)                                                                 ;;

;;      by Willow and Diamond                                                                     ;;

;;      svn://kolibrios.org/programs/media/gifview/trunk/gif_lite.inc                             ;;

;;   2. "GIF File Format Summary"                                                                 ;;

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

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

;;   3. "LZW and GIF explained" (1987)                                                            ;;

;;      by Steve Blackstock, IEEE                                                                 ;;

;;      http://www.cis.udel.edu/~amer/CISC651/lzw.and.gif.explained.html                          ;;

;;   4. "Graphics Interchange Format (tm)" (June 15, 1987)                                        ;;

;;      by CompuServe Incorporated                                                                ;;

;;      http://examples.oreilly.de/english_examples/gff/CDROM/GFF/VENDSPEC/GIF/GIF87A.TXT         ;;

;;   5. "Graphics Interchange Format (sm)" (July 31, 1990)                                        ;;

;;      by CompuServe Incorporated                                                                ;;

;;      http://examples.oreilly.de/english_examples/gff/CDROM/GFF/VENDSPEC/GIF/GIF89A.TXT         ;;

;;                                                                                                ;;

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

include 'gif.inc'

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

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

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

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

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

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

;> _length = data length                                                                          ;;

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

;< eax = false / true                                                                             ;;

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

	cmp	[_length], 6

	jb	.nope

	mov	eax, [_data]

	cmp	dword[eax], 'GIF8'

	jne	.nope

	cmp	word[eax + 4], '7a'

	je	.yep

	cmp	word[eax + 4], '9a'

	je	.yep

  .nope:

	xor	eax, eax

	ret

  .yep:

	xor	eax, eax

	inc	eax

	ret

endp

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

proc img.decode.gif _data, _length ;//////////////////////////////////////////////////////////////;;

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

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

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

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

;> _length = data length                                                                          ;;

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

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

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

locals

  img		     dd ?

  global_color_table dd ?

  global_color_table_size dd ?

endl

	push	ebx

; img.is.gif is called by caller (img.decode)

;	stdcall img.is.gif, [_data], [_length]

;	or	eax, eax

;	jz	.error

	mov	[global_color_table_size], 0

	mov	ebx, [_data]

	test	[ebx + gif.Header.lsd.Packed], gif.LSD.Packed.GlobalColorTableFlag

	jz	@f

	lea	eax, [ebx + sizeof.gif.Header]

	mov	[global_color_table], eax

	mov	cl, [ebx + gif.Header.lsd.Packed]

	and	cl, gif.LSD.Packed.SizeOfGlobalColorTableMask

	shr	cl, gif.LSD.Packed.SizeOfGlobalColorTableShift

	mov	eax, 2

	shl	eax, cl

	mov	[global_color_table_size], eax

	lea	eax, [eax * 3]

	add	ebx, eax

    @@: add	ebx, sizeof.gif.Header

	mov	[img], 0

;   @@: cmp     byte[ebx + gif.Block.Introducer], gif.Block.Introducer.Extension

;       jne     .next_image

;       cmp     byte[ebx + gif.Extension.Label], gif.Extension.Label.Comment

;       jne     .error

;       add     ebx, sizeof.gif.Extension

;       stdcall ._.skip_data

;       mov     ebx, eax

;       jmp     @b

  .next_image:

	stdcall img._.new

	or	eax, eax

	jz	.error

	mov	edx, [img]

	mov	[eax + Image.Previous], edx

	test	edx, edx

	jz	@f

	mov	[edx + Image.Next], eax

@@:

	mov	[img], eax

	mov	edx, eax

	mov	[eax + Image.Type], Image.bpp8

	invoke	mem.alloc, sizeof.gif.Image

	or	eax, eax

	jz	.error

	mov	[edx + Image.Extended], eax

	stdcall ._.process_extensions

	cmp	byte[ebx + gif.Block.Introducer], gif.Block.Introducer.ImageDescriptor

	jne	.error

	movzx	eax, [ebx + gif.ImageDescriptor.Width]

	movzx	ecx, [ebx + gif.ImageDescriptor.Height]

	stdcall img._.resize_data, [img], eax, ecx

	or	eax, eax

	jz	.error

	mov	esi, ebx

	mov	edi, [edx + Image.Extended]

	mov	ecx, sizeof.gif.ImageDescriptor

	rep	movsb

	mov	edi, [edx + Image.Palette]

	mov	esi, [global_color_table]

	mov	ecx, [global_color_table_size]

	test	[ebx + gif.ImageDescriptor.Packed], gif.ID.Packed.LocalColorTableFlag

	jz	@f

	lea	esi, [ebx + sizeof.gif.ImageDescriptor]

	mov	cl, [ebx + gif.ImageDescriptor.Packed]

	and	cl, gif.ID.Packed.SizeOfLocalColorTableMask

	shr	cl, gif.ID.Packed.SizeOfLocalColorTableShift

	mov	eax, 2

	shl	eax, cl

	mov	ecx, eax

	lea	eax, [eax*3]

	add	ebx, eax

@@:

	lodsd

	dec	esi

	bswap	eax

	shr	eax, 8

	stosd

	loop	@b

	add	ebx, sizeof.gif.ImageDescriptor

	stdcall ._.process_image

  .decoded:

	or	eax, eax

	jz	@f

	stdcall img.destroy, [img]

	jmp	.error

    @@: mov	eax, [img]

	ret

  .error:

	mov	eax, [img]

	test	eax, eax

	jz	@f

	stdcall	img.destroy, eax

@@:

	xor	eax, eax

	pop	ebx

	ret

endp

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

proc img.encode.gif _img, _p_length ;/////////////////////////////////////////////////////////////;;

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

;? Encode image into raw data in GIF 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.gif._.skip_data ;/////////////////////////////////////////////////////////////////;;

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

;? --- TBD ---                                                                                    ;;

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

;> ebx = pointer to data blocks array                                                             ;;

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

;< eax = pointer to data right after data blocks array                                            ;;

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

	push	ecx

	xor	ecx, ecx

    @@: mov	cl, [esi]

	or	cl, cl

	jz	@f

	lea	esi, [esi + ecx + 1]

	jmp	@b

    @@: pop	ecx

	ret

endp

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

proc img.decode.gif._.process_extensions ;////////////////////////////////////////////////////////;;

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

;? --- TBD ---                                                                                    ;;

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

;> ebx = raw image data                                                                           ;;

;> edx = image data                                                                               ;;

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

;< --- TBD ---                                                                                    ;;

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

	push	edx

	mov	esi, ebx

  .next_block:

	mov	al, [esi + gif.Block.Introducer]

	cmp	al, gif.Block.Introducer.Extension

	je	.ext_block

;       cmp     al, gif.Block.Introducer.ImageDescriptor

;       je      .exit

;       cmp     al, gif.Block.Introducer.EndOfFile

;       je      .exit

	jmp	.exit

  .ext_block:

	mov	al, [esi + gif.Extension.Label]

	cmp	al, gif.Extension.Label.PlainText

	je	.plain_text_ext

	cmp	al, gif.Extension.Label.GraphicsControl

	je	.graphics_control_ext

	cmp	al, gif.Extension.Label.Comment

	je	.comment_ext

	cmp	al, gif.Extension.Label.Application

	je	.application_ext

	jmp	.exit

  .plain_text_ext:

	add	esi, gif.PlainTextExtension.PlainTextData

	stdcall img.decode.gif._.skip_data

	jmp	.next_ext_block

  .graphics_control_ext:

	push	edi

	mov	edi, [edx + Image.Extended]

	add	edi, gif.Image.gce

	mov	ecx, sizeof.gif.GraphicsControlExtension

	rep	movsb

	pop	edi

	jmp	.next_ext_block

  .comment_ext:

	add	esi, gif.CommentExtension.CommentData

	stdcall img.decode.gif._.skip_data

	jmp	.next_ext_block

  .application_ext:

	add	esi, gif.ApplicationExtension.ApplicationData

	stdcall img.decode.gif._.skip_data

	jmp	.next_ext_block

  .next_ext_block:

	mov	al, [esi + gif.Block.Introducer]

	cmp	al, gif.Block.Introducer.EndOfData

	jne	.exit

	inc	esi

	jmp	.next_block

  .exit:

	mov	ebx, esi

	pop	edx

	ret

endp

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

proc img.decode.gif._.process_image ;/////////////////////////////////////////////////////////////;;

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

;? --- TBD ---                                                                                    ;;

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

;> ebx = raw image data                                                                           ;;

;> edx = image data                                                                               ;;

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

;< --- TBD ---                                                                                    ;;

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

locals

  width      dd ?

  img_start  dd ?

  img_end    dd ?

  row_end    dd ?

  pass	     dd ?

  codesize   dd ?

  compsize   dd ?

  workarea   dd ?

  block_ofs  dd ?

  bit_count  dd ?

  CC	     dd ?

  EOI	     dd ?

endl

	invoke	mem.alloc, 16 * 1024

	mov	[workarea], eax

	or	eax, eax

	jz	.error

	mov	ecx, [edx + Image.Width]

	mov	[width], ecx

	mov	eax, [edx + Image.Height]

	imul	eax, ecx

	mov	[img_end], eax

	inc	eax

	mov	[row_end], eax

	and	[pass], 0

	mov	eax, [edx + Image.Extended]

	test	[eax + gif.Image.info.Packed], gif.ID.Packed.InterleaceFlag

	jz	@f

	mov	[row_end], ecx

    @@: mov	esi, ebx

	mov	edi, [edx + Image.Data]

	push	edi

	movzx	ecx, byte[esi]

	inc	esi

	mov	[codesize], ecx

	inc	[codesize]

	mov	edi, [workarea]

	xor	eax, eax

	lodsb				; eax - block_count

	add	eax, esi

	mov	[block_ofs], eax

	mov	[bit_count], 8

	mov	eax, 1

	shl	eax, cl

	mov	[CC], eax

	mov	ecx, eax

	inc	eax

	mov	[EOI], eax

	mov	eax, gif.Null shl 16

  .filltable:

	stosd

	inc	eax

	loop	.filltable

	pop	edi

	mov	[img_start], edi

	add	[img_end], edi

	add	[row_end], edi

  .reinit:

	mov	edx, [EOI]

	inc	edx

	push	[codesize]

	pop	[compsize]

	call	.get_symbol

	cmp	eax, [CC]

	je	.reinit

	call	.output

  .cycle:

	movzx	ebx, ax

	call	.get_symbol

	cmp	eax, edx

	jae	.notintable

	cmp	eax, [CC]

	je	.reinit

	cmp	eax, [EOI]

	je	.end

	call	.output

  .add:

	mov	ecx, [workarea]

	mov	[ecx + edx * 4], ebx

	cmp	edx, 0x00000FFF

	jae	.cycle

	inc	edx

	bsr	ebx, edx

	cmp	ebx, [compsize]

	jne	.noinc

	inc	[compsize]

  .noinc:

	jmp	.cycle

  .notintable:

	push	eax

	mov	eax, ebx

	call	.output

	push	ebx

	movzx	eax, bx

	call	.output

	pop	ebx eax

	jmp	.add

  .end:

	mov	edi, [img_end]

	xor	eax, eax

  .exit:

	cmp	[workarea], 0

	je	@f

	invoke	mem.free, [workarea]

    @@: xor	eax, eax

	ret

  .error:

	cmp	[workarea], 0

	je	@f

	invoke	mem.free, [workarea]

    @@: xor	eax, eax

	inc	eax

	ret

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

img.decode.gif._.process_image.get_symbol:

	mov	ecx, [compsize]

	push	ecx

	xor	eax, eax

  .shift:

	ror	byte[esi], 1

	rcr	eax,1

	dec	[bit_count]

	jnz	.loop1

	inc	esi

	cmp	esi, [block_ofs]

	jb	.noblock

	push	eax

	xor	eax, eax

	lodsb

	test	eax, eax

	jnz	.nextbl

	mov	eax, [EOI]

	sub	esi, 2

	add	esp, 8

	jmp	.exit

  .nextbl:

	add	eax, esi

	mov	[block_ofs], eax

	pop	eax

  .noblock:

	mov	[bit_count], 8

  .loop1:

	loop	.shift

	pop	ecx

	rol	eax, cl

  .exit:

	xor	ecx, ecx

	retn

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

img.decode.gif._.process_image.output:

	push	esi eax edx

	mov	edx, [workarea]

  .next:

	pushw	[edx + eax * 4]

	mov	ax, [edx + eax * 4 + 2]

	inc	ecx

	cmp	ax, gif.Null

	jnz	.next

	shl	ebx, 16

	mov	bx, [esp]

  .loop2:

	pop	ax

	stosb

	cmp	edi, [row_end]

	jb	.norowend

	mov	eax, [width]

	push	eax

	sub	edi, eax

	add	eax, eax

	cmp	[pass], 3

	je	@f

	add	eax, eax

	cmp	[pass], 2

	je	@f

	add	eax, eax

    @@: add	edi, eax

	pop	eax

	cmp	edi, [img_end]

	jb	.nextrow

	mov	edi, [img_start]

	inc	[pass]

	add	edi, eax

	cmp	[pass], 3

	je	@f

	add	edi, eax

	cmp	[pass], 2

	je	@f

	add	edi, eax

	add	edi, eax

    @@:

  .nextrow:

	add	eax, edi

	mov	[row_end], eax

	xor	eax, eax

  .norowend:

	loop	.loop2

	pop	edx eax esi

	retn

endp

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

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

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

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

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

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

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

;