1/*
2 * @(#)DeviceTables.cpp 1.5 00/03/15
3 *
4 * (C) Copyright IBM Corp. 1998 - 2006 - All Rights Reserved
5 *
6 */
7
8#include "LETypes.h"
9#include "OpenTypeTables.h"
10#include "DeviceTables.h"
11#include "LESwaps.h"
12
13U_NAMESPACE_BEGIN
14
15const le_uint16 DeviceTable::fieldMasks[]    = {0x0003, 0x000F, 0x00FF};
16const le_uint16 DeviceTable::fieldSignBits[] = {0x0002, 0x0008, 0x0080};
17const le_uint16 DeviceTable::fieldBits[]     = {     2,      4,      8};
18
19#define FORMAT_COUNT LE_ARRAY_SIZE(fieldBits)
20
21le_int16 DeviceTable::getAdjustment(le_uint16 ppem) const
22{
23    le_uint16 start = SWAPW(startSize);
24    le_uint16 format = SWAPW(deltaFormat) - 1;
25    le_int16 result = 0;
26
27    if (ppem >= start && ppem <= SWAPW(endSize) && format < FORMAT_COUNT) {
28        le_uint16 sizeIndex = ppem - start;
29        le_uint16 bits = fieldBits[format];
30        le_uint16 count = 16 / bits;
31        le_uint16 word = SWAPW(deltaValues[sizeIndex / count]);
32        le_uint16 fieldIndex = sizeIndex % count;
33        le_uint16 shift = 16 - (bits * (fieldIndex + 1));
34        le_uint16 field = (word >> shift) & fieldMasks[format];
35
36        result = field;
37
38        if ((field & fieldSignBits[format]) != 0) {
39            result |= ~ fieldMasks[format];
40        }
41    }
42
43    return result;
44}
45
46U_NAMESPACE_END
47