scuffed-code/icu4c/source/layout/CoverageTables.cpp
2001-10-16 00:39:01 +00:00

87 lines
1.9 KiB
C++

/*
* @(#)CoverageTables.cpp 1.5 00/03/15
*
* (C) Copyright IBM Corp. 1998, 1999, 2000, 2001 - All Rights Reserved
*
*/
#include "LETypes.h"
#include "OpenTypeTables.h"
#include "OpenTypeUtilities.h"
#include "CoverageTables.h"
#include "LESwaps.h"
U_NAMESPACE_BEGIN
le_int32 CoverageTable::getGlyphCoverage(LEGlyphID glyphID) const
{
switch(SWAPW(coverageFormat))
{
case 0:
return -1;
case 1:
{
const CoverageFormat1Table *f1Table = (const CoverageFormat1Table *) this;
return f1Table->getGlyphCoverage(glyphID);
}
case 2:
{
const CoverageFormat2Table *f2Table = (const CoverageFormat2Table *) this;
return f2Table->getGlyphCoverage(glyphID);
}
default:
return -1;
}
}
le_int32 CoverageFormat1Table::getGlyphCoverage(LEGlyphID glyphID) const
{
le_uint16 count = SWAPW(glyphCount);
le_uint8 bit = OpenTypeUtilities::highBit(count);
le_uint16 power = 1 << bit;
le_uint16 extra = count - power;
le_uint16 probe = power;
le_uint16 index = 0;
if (SWAPW(glyphArray[extra]) <= glyphID) {
index = extra;
}
while (probe > (1 << 0)) {
probe >>= 1;
if (SWAPW(glyphArray[index + probe]) <= glyphID) {
index += probe;
}
}
if (SWAPW(glyphArray[index]) == glyphID) {
return index;
}
return -1;
}
le_int32 CoverageFormat2Table::getGlyphCoverage(LEGlyphID glyphID) const
{
le_uint16 count = SWAPW(rangeCount);
le_int32 rangeIndex =
OpenTypeUtilities::getGlyphRangeIndex(glyphID, rangeRecordArray, count);
if (rangeIndex < 0) {
return -1;
}
LEGlyphID firstInRange = SWAPW(rangeRecordArray[rangeIndex].firstGlyph);
le_uint16 startCoverageIndex = SWAPW(rangeRecordArray[rangeIndex].rangeValue);
return startCoverageIndex + (glyphID - firstInRange);
}
U_NAMESPACE_END