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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		; 0x0C

	jz	.old1

	cmp	eax, 40		; 0x28

	jz	.normal

	cmp	eax, 56		; 0x38

	je	.normal

	cmp	eax, 0x6C

	je	.normal

	cmp	eax, 0x7C

	jnz	.error

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

.normal:

	m2m	eax, Image.bpp8i

	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.bpp8i

	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