Check in the pristine copy of ICU 4.6...

icu46/source/test/perf/usetperf/bitset.cpp

+/*
+**********************************************************************
+* Copyright (c) 2002-2005, International Business Machines
+* Corporation and others.  All Rights Reserved.
+**********************************************************************
+* 2002-09-20 aliu Created.
+*/
+
+#include "unicode/utypes.h"
+#include "cmemory.h"
+#include "bitset.h"
+
+// TODO: have a separate capacity, so the len can just be set to
+// zero in the clearAll() method, and growth can be smarter.
+
+const int32_t SLOP = 8;
+
+const int32_t BYTES_PER_WORD = sizeof(int32_t);
+
+BitSet::BitSet() {
+    len = SLOP;
+    data = (int32_t*) uprv_malloc(len * BYTES_PER_WORD);
+    clearAll();
+}
+
+BitSet::~BitSet() {
+    uprv_free(data);
+}
+
+UBool BitSet::get(int32_t bitIndex) const {
+    uint32_t longIndex = bitIndex >> 5;
+    int32_t bitInLong = bitIndex & 0x1F;
+    return (longIndex < len) ? (((data[longIndex] >> bitInLong) & 1) != 0)
+        : FALSE;
+}
+
+void BitSet::set(int32_t bitIndex) {
+    uint32_t longIndex = bitIndex >> 5;
+    int32_t bitInLong = bitIndex & 0x1F;
+    if (longIndex >= len) {
+        ensureCapacity(longIndex+1);
+    }
+    data[longIndex] |= (1 << bitInLong);
+}
+
+void BitSet::clearAll() {
+    for (uint32_t i=0; i<len; ++i) data[i] = 0;
+}
+
+void BitSet::ensureCapacity(uint32_t minLen) {
+    uint32_t newLen = len;
+    while (newLen < minLen) newLen <<= 1; // grow exponentially
+    int32_t* newData = (int32_t*) uprv_malloc(newLen * BYTES_PER_WORD);
+    uprv_memcpy(newData, data, len * BYTES_PER_WORD);
+    uprv_free(data);
+    data = newData;
+    int32_t* p = data + len;
+    int32_t* limit = data + newLen;
+    while (p < limit) *p++ = 0;
+    len = newLen;
+}
+
+//eof