
/*
 * @(#)ThaiLayoutEngine.cpp	1.2 00/03/15
 *
 * (C) Copyright IBM Corp. 1998, 1999, 2000 - All Rights Reserved
 *
 */

#include "LETypes.h"
#include "LayoutEngine.h"
#include "ThaiLayoutEngine.h"
#include "ScriptAndLanguageTags.h"

#include "ThaiShaping.h"

ThaiLayoutEngine::ThaiLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode)
    : LayoutEngine(fontInstance, scriptCode, languageCode)
{
    fErrorChar = 0x25CC;

    // Figure out which presentation forms the font uses
    if (fontInstance->canDisplay(0x0E64)) {
        // WorldType uses reserved space in Thai block
        fGlyphSet = 0;
    } else if (fontInstance->canDisplay(0xF701)) {
        // Microsoft corporate zone
        fGlyphSet = 1;

        if (!fontInstance->canDisplay(fErrorChar)) {
            fErrorChar = 0xF71B;
        }
    } else if (fontInstance->canDisplay(0xF885)) {
        // Apple corporate zone
        fGlyphSet = 2;
    } else {
        // no presentation forms in the font
        fGlyphSet = 3;
    }
}

ThaiLayoutEngine::~ThaiLayoutEngine()
{
    // nothing to do
}

// Input: characters (0..max provided for context)
// Output: glyphs, char indices
// Returns: the glyph count
// NOTE: this assumes that ThaiShaping::compose will allocate the outChars array...
le_int32 ThaiLayoutEngine::computeGlyphs(const LEUnicode chars[], le_int32 offset, le_int32 count, le_int32 max, le_bool rightToLeft, LEGlyphID *&glyphs, le_int32 *&charIndices, LEErrorCode &success)
{
	if (LE_FAILURE(success)) {
		return 0;
	}

	if (chars == NULL || offset < 0 || count < 0 || max < 0 || offset >= max || offset + count > max) {
		success = LE_ILLEGAL_ARGUMENT_ERROR;
		return 0;
	}

    LEUnicode *outChars;
    le_int32 glyphCount;
    
    // This is enough room for the worst-case expansion
    // (it says here...)
    outChars = new LEUnicode[count * 2];

	if (outChars == NULL) {
		success = LE_MEMORY_ALLOCATION_ERROR;
		return 0;
	}

    charIndices = new le_int32[count * 2];

	if (charIndices == NULL) {
		delete[] outChars;
		success = LE_MEMORY_ALLOCATION_ERROR;
		return 0;
	}

    glyphCount = ThaiShaping::compose(chars, offset, count, fGlyphSet, fErrorChar, outChars, charIndices);
    mapCharsToGlyphs(outChars, 0, glyphCount, false, false, glyphs, charIndices, success);

    delete[] outChars;

    return glyphCount;
}