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/*
* @(#)OpenTypeUtilities.cpp 1.6 00/03/15
*
* (C) Copyright IBM Corp. 1998, 1999, 2000, 2001 - All Rights Reserved
*
*/
#include "LETypes.h"
#include "OpenTypeTables.h"
#include "OpenTypeUtilities.h"
#include "LESwaps.h"
U_NAMESPACE_BEGIN
//
// Finds the high bit by binary searching
// through the bits in n.
//
le_int8 OpenTypeUtilities::highBit(le_int32 value)
{
if (value <= 0)
{
return -32;
}
le_uint8 bit = 0;
if (value >= 1 << 16)
{
value >>= 16;
bit += 16;
}
if (value >= 1 << 8)
{
value >>= 8;
bit += 8;
}
if (value >= 1 << 4)
{
value >>= 4;
bit += 4;
}
if (value >= 1 << 2)
{
value >>= 2;
bit += 2;
}
if (value >= 1 << 1)
{
value >>= 1;
bit += 1;
}
return bit;
}
Offset OpenTypeUtilities::getTagOffset(LETag tag, const TagAndOffsetRecord *records, le_int32 recordCount)
{
le_uint8 bit = highBit(recordCount);
le_int32 power = 1 << bit;
le_int32 extra = recordCount - power;
le_int32 probe = power;
le_int32 index = 0;
if (SWAPT(records[extra].tag) <= tag)
{
index = extra;
}
while (probe > (1 << 0))
{
probe >>= 1;
if (SWAPT(records[index + probe].tag) <= tag)
{
index += probe;
}
}
if (SWAPT(records[index].tag) == tag)
{
return SWAPW(records[index].offset);
}
return 0;
}
le_int32 OpenTypeUtilities::getGlyphRangeIndex(LEGlyphID glyphID, const GlyphRangeRecord *records, le_int32 recordCount)
{
le_uint8 bit = highBit(recordCount);
le_int32 power = 1 << bit;
le_int32 extra = recordCount - power;
le_int32 probe = power;
le_int32 range = 0;
if (SWAPW(records[extra].firstGlyph) <= glyphID)
{
range = extra;
}
while (probe > (1 << 0))
{
probe >>= 1;
if (SWAPW(records[range + probe].firstGlyph) <= glyphID)
{
range += probe;
}
}
if (SWAPW(records[range].firstGlyph) <= glyphID && SWAPW(records[range].lastGlyph) >= glyphID)
{
return range;
}
return -1;
}
le_int32 OpenTypeUtilities::search(le_uint32 value, const le_uint32 array[], le_int32 count)
{
le_int32 power = 1 << highBit(count);
le_int32 extra = count - power;
le_int32 probe = power;
le_int32 index = 0;
if (value >= array[extra]) {
index = extra;
}
while (probe > (1 << 0)) {
probe >>= 1;
if (value >= array[index + probe]) {
index += probe;
}
}
return index;
}
le_int32 OpenTypeUtilities::search(le_uint16 value, const le_uint16 array[], le_int32 count)
{
le_int32 power = 1 << highBit(count);
le_int32 extra = count - power;
le_int32 probe = power;
le_int32 index = 0;
if (value >= array[extra]) {
index = extra;
}
while (probe > (1 << 0)) {
probe >>= 1;
if (value >= array[index + probe]) {
index += probe;
}
}
return index;
}
//
// Straight insertion sort from Knuth vol. III, pg. 81
//
void OpenTypeUtilities::sort(le_uint16 *array, le_int32 count)
{
for (le_int32 j = 1; j < count; j += 1) {
le_int32 i;
le_uint16 v = array[j];
for (i = j - 1; i >= 0; i -= 1) {
if (v >= array[i]) {
break;
}
array[i + 1] = array[i];
}
array[i + 1] = v;
}
}
U_NAMESPACE_END
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