/****************************************************************************\
 Part of the XeTeX typesetting system
 copyright (c) 1994-2006 by SIL International
 written by Jonathan Kew

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"Software"), to deal in the Software without restriction, including  
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included in all copies or substantial portions of the Software.

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\****************************************************************************/

#define XETEX_OT_MATH_IMPLEMENTATION 1
#include "XeTeXOTMath.h"

#include "XeTeX_ext.h"
#include "XeTeXLayoutInterface.h"
#include "XeTeXFontInst.h"

#include "CoverageTables.h"

#define kMATHTableTag	0x4D415448

typedef void*	voidptr;

extern "C" {
	extern voidptr*	fontlayoutengine;
	extern integer*	fontarea;
	extern integer*	fontsize;
}

#include "LESwaps.h"

static SInt16 getMathConstant(LEFontInstance* fontInst, mathConstantIndex whichConstant)
{
	const char* table = (const char*)fontInst->getFontTable(kMATHTableTag);
	if (table == NULL)
		return 0;

	const UInt16* constants = (const UInt16*)(table + SWAPW(((const MathTableHeader*)table)->mathConstants));

	if (whichConstant < firstMathValueRecord) {
		/* it's a simple 16-bit value */
		return SWAPW(constants[whichConstant]);
	}
	else if (whichConstant <= lastMathValueRecord) {
		const MathValueRecord* valueRecords = (const MathValueRecord*)
			((char*)constants + firstMathValueRecord * sizeof(UInt16) - firstMathValueRecord * sizeof(MathValueRecord));
		return SWAPW(valueRecords[whichConstant].value);
	}
	else if (whichConstant <= lastMathConstant) {
		return SWAPW(constants[whichConstant + (lastMathValueRecord - firstMathValueRecord + 1)]);
	}
	else
		return 0; /* or abort, with "internal error" or something */
}

int
getotmathconstant(int f, int n)
{
	int	rval = 0;

	if (fontarea[f] == OTGR_FONT_FLAG) {
		XeTeXFontInst*	font = (XeTeXFontInst*)getFont((XeTeXLayoutEngine)fontlayoutengine[f]);
		rval = getMathConstant(font, (mathConstantIndex)n);
		/* scale according to font size, except the ones that are percentages */
		if (n > scriptScriptPercentScaleDown && n < radicalDegreeBottomRaisePercent)
			rval = X2Fix(rval * Fix2X(fontsize[f]) / font->getUnitsPerEM());
	}
	return rval;
}

/* fontdimen IDs for math symbols font (family 2) */
#define math_x_height	5
#define math_quad		6
#define num1			8	/* numerator shift-up in display styles */
#define num2			9	/* numerator shift-up in non-display, non-\.{\\atop} */
#define num3			10	/* numerator shift-up in non-display \.{\\atop} */
#define denom1			11	/* denominator shift-down in display styles */
#define denom2			12	/* denominator shift-down in non-display styles */
#define sup1			13	/* superscript shift-up in uncramped display style */
#define sup2			14	/* superscript shift-up in uncramped non-display */
#define sup3			15	/* superscript shift-up in cramped styles */
#define sub1			16	/* subscript shift-down if superscript is absent */
#define sub2			17	/* subscript shift-down if superscript is present */
#define sup_drop		18	/* superscript baseline below top of large box */
#define sub_drop		19	/* subscript baseline below bottom of large box */
#define delim1			20	/* size of \.{\\atopwithdelims} delimiters */
#define delim2			21	/* size of \.{\\atopwithdelims} delimiters in non-displays */
#define axis_height		22	/* height of fraction lines above the baseline */

const mathConstantIndex TeX_sym_to_OT_map[] = {
	unknown,
	unknown,
	unknown,
	unknown,
	unknown,
	accentBaseHeight, // x-height
	unknown, // quad
	unknown,
	fractionNumeratorDisplayStyleShiftUp,
	fractionNumeratorShiftUp,
	stackTopShiftUp,
	fractionDenominatorDisplayStyleShiftDown,
	fractionDenominatorShiftDown,
	superscriptShiftUp, // ??
	superscriptShiftUp, // ??
	superscriptShiftUpCramped,
	subscriptShiftDown, // ??
	subscriptShiftDown, // ??
	superscriptBaselineDropMax, // ??
	subscriptBaselineDropMin, // ??
	delimitedSubFormulaMinHeight,
	unknown, // using quad instead for now
	axisHeight
};

int
getnativemathsyparam(int f, int n)
{
	int	rval = 0;

	if (n == math_quad || n == delim2)
		rval = fontsize[f];
	else {
		if (n < sizeof(TeX_sym_to_OT_map) / sizeof(mathConstantIndex)) {
			mathConstantIndex ot_index = TeX_sym_to_OT_map[n];
			if (ot_index != unknown)
				rval = getotmathconstant(f, (int)ot_index);
		}
	}
//	fprintf(stderr, " math_sy(%d, %d) returns %.3f\n", f, n, Fix2X(rval));
	
	return rval;
}

/* fontdimen IDs for math extension font (family 3) */
#define default_rule_thickness	8	/* thickness of \.{\\over} bars */
#define big_op_spacing1			9	/* minimum clearance above a displayed op */
#define big_op_spacing2			10	/* minimum clearance below a displayed op */
#define big_op_spacing3			11	/* minimum baselineskip above displayed op */
#define big_op_spacing4			12	/* minimum baselineskip below displayed op */
#define big_op_spacing5			13	/* padding above and below displayed limits */

const mathConstantIndex TeX_ext_to_OT_map[] = {
	unknown,
	unknown,
	unknown,
	unknown,
	unknown,
	accentBaseHeight, // x-height
	unknown, // quad
	unknown,
	fractionRuleThickness, // default_rule_thickness
	upperLimitGapMin, // big_op_spacing1
	lowerLimitGapMin, // big_op_spacing2
	upperLimitBaselineRiseMin, // big_op_spacing3
	lowerLimitBaselineDropMin, // big_op_spacing4
	stackGapMin // big_op_spacing5
};

int
getnativemathexparam(int f, int n)
{
	int	rval = 0;

	if (n == math_quad)
		rval = fontsize[f];
	else {
		if (n < sizeof(TeX_ext_to_OT_map) / sizeof(mathConstantIndex)) {
			mathConstantIndex ot_index = TeX_ext_to_OT_map[n];
			if (ot_index != unknown)
				rval = getotmathconstant(f, (int)ot_index);
		}
	}
//	fprintf(stderr, " math_ex(%d, %d) returns %.3f\n", f, n, Fix2X(rval));
	
	return rval;
}

int
getotmathvariant(int f, int g, int v, integer* adv, int horiz)
{
	int	rval = g;
	*adv = -1;
	
	if (fontarea[f] == OTGR_FONT_FLAG) {
		XeTeXFontInst*	font = (XeTeXFontInst*)getFont((XeTeXLayoutEngine)fontlayoutengine[f]);

		const char* table = (const char*)font->getFontTable(kMATHTableTag);
		if (table == NULL)
			return rval;

		le_uint16	offset = SWAPW(((const MathTableHeader*)table)->mathVariants);
		if (offset == 0)
			return rval;
		const MathVariants* variants = (const MathVariants*)(table + offset);

		offset = horiz ? SWAPW(variants->horizGlyphCoverage) : SWAPW(variants->vertGlyphCoverage);
		if (offset == 0)
			return rval;
		const CoverageTable* coverage = (const CoverageTable*)(((const char*)variants) + offset);

		le_int32	index = coverage->getGlyphCoverage(g);
		if (index >= 0) {
			if (horiz)
				index += SWAPW(variants->vertGlyphCount);
			const MathGlyphConstruction*	construction = (const MathGlyphConstruction*)(((const char*)variants)
															+ SWAPW(variants->vertGlyphConstruction[index]));
			if (v < SWAPW(construction->variantCount)) {
				rval = SWAPW(construction->mathGlyphVariantRecord[v].variantGlyph);
				*adv = X2Fix(SWAPW(construction->mathGlyphVariantRecord[v].advanceMeasurement)
								* Fix2X(fontsize[f]) / font->getUnitsPerEM());
			}
		}
	}
	
	return rval;
}

void*
getotassemblyptr(int f, int g, int horiz)
{
	void*	rval = NULL;
	
	if (fontarea[f] == OTGR_FONT_FLAG) {
		XeTeXFontInst*	font = (XeTeXFontInst*)getFont((XeTeXLayoutEngine)fontlayoutengine[f]);

		const char* table = (const char*)font->getFontTable(kMATHTableTag);
		if (table == NULL)
			return rval;

		le_uint16	offset = SWAPW(((const MathTableHeader*)table)->mathVariants);
		if (offset == 0)
			return rval;
		const MathVariants* variants = (const MathVariants*)(table + offset);

		offset = horiz ? SWAPW(variants->horizGlyphCoverage) : SWAPW(variants->vertGlyphCoverage);
		if (offset == 0)
			return rval;
		const CoverageTable* coverage = (const CoverageTable*)(((const char*)variants) + offset);

		le_int32	index = coverage->getGlyphCoverage(g);
		if (index >= 0) {
			if (horiz)
				index += SWAPW(variants->vertGlyphCount);
			const MathGlyphConstruction*	construction = (const MathGlyphConstruction*)(((const char*)variants)
															+ SWAPW(variants->vertGlyphConstruction[index]));
			offset = SWAPW(construction->glyphAssembly);
			if (offset != 0)
				rval = (void*)(((const char*)construction) + offset);
		}
	}
	
	return rval;
}

int
getotmathitalcorr(int f, int g)
{
	int	rval = 0;
	
	if (fontarea[f] == OTGR_FONT_FLAG) {
		XeTeXFontInst*	font = (XeTeXFontInst*)getFont((XeTeXLayoutEngine)fontlayoutengine[f]);

		const char* table = (const char*)font->getFontTable(kMATHTableTag);
		if (table == NULL)
			return rval;

		le_uint16	offset = SWAPW(((const MathTableHeader*)table)->mathGlyphInfo);
		if (offset == 0)
			return rval;
		const MathGlyphInfo* glyphInfo = (const MathGlyphInfo*)(table + offset);

		offset = SWAPW(glyphInfo->mathItalicsCorrectionInfo);
		if (offset == 0)
			return rval;
		const MathItalicsCorrectionInfo* italCorrInfo = (const MathItalicsCorrectionInfo*)(((const char*)glyphInfo) + offset);

		offset = SWAPW(italCorrInfo->coverage);
		if (offset == 0)
			return rval;
		const CoverageTable* coverage = (const CoverageTable*)(((const char*)italCorrInfo) + offset);

		le_int32	index = coverage->getGlyphCoverage(g);
		if (index >= 0 && index < SWAPW(italCorrInfo->italicsCorrectionCount))
			rval = X2Fix(SWAPW(italCorrInfo->italicsCorrection[index].value) * Fix2X(fontsize[f]) / font->getUnitsPerEM());
	}
	
	return rval;
}

int
getotmathaccentpos(int f, int g)
{
	int	rval = 0x7fffffffUL;
	
	if (fontarea[f] == OTGR_FONT_FLAG) {
		XeTeXFontInst*	font = (XeTeXFontInst*)getFont((XeTeXLayoutEngine)fontlayoutengine[f]);

		const char* table = (const char*)font->getFontTable(kMATHTableTag);
		if (table == NULL)
			return rval;

		le_uint16	offset = SWAPW(((const MathTableHeader*)table)->mathGlyphInfo);
		if (offset == 0)
			return rval;
		const MathGlyphInfo* glyphInfo = (const MathGlyphInfo*)(table + offset);

		offset = SWAPW(glyphInfo->mathTopAccentAttachment);
		if (offset == 0)
			return rval;
		const MathTopAccentAttachment* accentAttachment = (const MathTopAccentAttachment*)(((const char*)glyphInfo) + offset);

		offset = SWAPW(accentAttachment->coverage);
		if (offset == 0)
			return rval;
		const CoverageTable* coverage = (const CoverageTable*)(((const char*)accentAttachment) + offset);

		le_int32	index = coverage->getGlyphCoverage(g);
		if (index >= 0 && index < SWAPW(accentAttachment->topAccentAttachmentCount)) {
			rval = (le_int16)SWAPW(accentAttachment->topAccentAttachment[index].value);
			rval = X2Fix(rval * Fix2X(fontsize[f]) / font->getUnitsPerEM());
		}
	}
	
	return rval;
}

int
otminconnectoroverlap(int f)
{
	int	rval = 0;
	
	if (fontarea[f] == OTGR_FONT_FLAG) {
		XeTeXFontInst*	font = (XeTeXFontInst*)getFont((XeTeXLayoutEngine)fontlayoutengine[f]);

		const char* table = (const char*)font->getFontTable(kMATHTableTag);
		if (table == NULL)
			return rval;

		le_uint16	offset = SWAPW(((const MathTableHeader*)table)->mathVariants);
		if (offset == 0)
			return rval;
		const MathVariants* variants = (const MathVariants*)(table + offset);

		rval = X2Fix(SWAPW(variants->minConnectorOverlap) * Fix2X(fontsize[f]) / font->getUnitsPerEM());
	}

	return rval;
}

int
otpartcount(const GlyphAssembly* a)
{
	return SWAPW(a->partCount);
}

int
otpartglyph(const GlyphAssembly* a, int i)
{
	return SWAPW(a->partRecords[i].glyph);
}

int
otpartisextender(const GlyphAssembly* a, int i)
{
	return (SWAPW(a->partRecords[i].partFlags) & fExtender) != 0;
}

int
otpartstartconnector(int f, const GlyphAssembly* a, int i)
{
	int	rval = 0;
	
	if (fontarea[f] == OTGR_FONT_FLAG) {
		XeTeXFontInst*	font = (XeTeXFontInst*)getFont((XeTeXLayoutEngine)fontlayoutengine[f]);
		rval = X2Fix(SWAPW(a->partRecords[i].startConnectorLength) * Fix2X(fontsize[f]) / font->getUnitsPerEM());
	}
	
	return rval;
}

int
otpartendconnector(int f, const GlyphAssembly* a, int i)
{
	int	rval = 0;
	
	if (fontarea[f] == OTGR_FONT_FLAG) {
		XeTeXFontInst*	font = (XeTeXFontInst*)getFont((XeTeXLayoutEngine)fontlayoutengine[f]);
		rval = X2Fix(SWAPW(a->partRecords[i].endConnectorLength) * Fix2X(fontsize[f]) / font->getUnitsPerEM());
	}
	
	return rval;
}

int
otpartfulladvance(int f, const GlyphAssembly* a, int i)
{
	int	rval = 0;
	
	if (fontarea[f] == OTGR_FONT_FLAG) {
		XeTeXFontInst*	font = (XeTeXFontInst*)getFont((XeTeXLayoutEngine)fontlayoutengine[f]);
		rval = X2Fix(SWAPW(a->partRecords[i].fullAdvance) * Fix2X(fontsize[f]) / font->getUnitsPerEM());
	}
	
	return rval;
}