1/*
2**********************************************************************
3* Copyright (c) 2002-2005, International Business Machines
4* Corporation and others.  All Rights Reserved.
5**********************************************************************
6* 2002-09-20 aliu Created.
7*/
8
9#include "unicode/utypes.h"
10#include "cmemory.h"
11#include "bitset.h"
12
13// TODO: have a separate capacity, so the len can just be set to
14// zero in the clearAll() method, and growth can be smarter.
15
16const int32_t SLOP = 8;
17
18const int32_t BYTES_PER_WORD = sizeof(int32_t);
19
20BitSet::BitSet() {
21    len = SLOP;
22    data = (int32_t*) uprv_malloc(len * BYTES_PER_WORD);
23    clearAll();
24}
25
26BitSet::~BitSet() {
27    uprv_free(data);
28}
29
30UBool BitSet::get(int32_t bitIndex) const {
31    uint32_t longIndex = bitIndex >> 5;
32    int32_t bitInLong = bitIndex & 0x1F;
33    return (longIndex < len) ? (((data[longIndex] >> bitInLong) & 1) != 0)
34        : FALSE;
35}
36
37void BitSet::set(int32_t bitIndex) {
38    uint32_t longIndex = bitIndex >> 5;
39    int32_t bitInLong = bitIndex & 0x1F;
40    if (longIndex >= len) {
41        ensureCapacity(longIndex+1);
42    }
43    data[longIndex] |= (1 << bitInLong);
44}
45
46void BitSet::clearAll() {
47    for (uint32_t i=0; i<len; ++i) data[i] = 0;
48}
49
50void BitSet::ensureCapacity(uint32_t minLen) {
51    uint32_t newLen = len;
52    while (newLen < minLen) newLen <<= 1; // grow exponentially
53    int32_t* newData = (int32_t*) uprv_malloc(newLen * BYTES_PER_WORD);
54    uprv_memcpy(newData, data, len * BYTES_PER_WORD);
55    uprv_free(data);
56    data = newData;
57    int32_t* p = data + len;
58    int32_t* limit = data + newLen;
59    while (p < limit) *p++ = 0;
60    len = newLen;
61}
62
63//eof
64