Amebis/ZRCola
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Index search method added

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This commit is contained in:
Simon Rozman 2016-03-03 16:06:59 +01:00
parent 48e0fc9639
commit 0ec73e44ca
1 changed files with 45 additions and 0 deletions
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45
lib/libZRCola/include/zrcola/common.h
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@ -69,6 +69,7 @@ namespace ZRCola {
///
index(_In_ std::vector<T> &h) : host(h) {}
///
/// Sorts index
///
@ -77,6 +78,7 @@ namespace ZRCola {
qsort_s(data(), size(), sizeof(T_idx), compare_s, this);
}
///
/// Compares two elements
///
@ -90,6 +92,49 @@ namespace ZRCola {
///
virtual int compare(_In_ const T &a, _In_ const T &b) const = 0;
///
/// Search for the element in the index
/// The elements matching \p el are located on the interval [\p start, \p end) in the index.
///
/// \param[in] el Element we are looking for (needle)
/// \param[out] start Index of the first matching element found
/// \param[out] end Index of the first non-matching element found
///
/// \returns
/// - true if found
/// - false otherwise
///
bool find(_In_ const T &el, _Out_ size_type &start, _Out_ size_type &end) const
{
// Start with the full search area.
for (start = 0, end = size(); start < end; ) {
size_type m = (start + end) / 2;
int r = compare(el, host[at(m)]);
if (r < 0) end = m;
else if (r > 0) start = m + 1;
else {
// Narrow the search area on the left to start at the first element in the run.
for (size_type end2 = m; start < end2;) {
size_type m = (start + end2) / 2;
int r = compare(el, host[at(m)]);
if (r <= 0) end2 = m; else start = m + 1;
}
// Narrow the search area on the right to end at the first element not in the run.
for (size_type start2 = m + 1; start2 < end;) {
size_type m = (start2 + end) / 2;
int r = compare(el, host[at(m)]);
if (0 <= r) start2 = m + 1; else end = m;
}
return true;
}
}
return false;
}
private:
static int __cdecl compare_s(void *p, const void *a, const void *b)
{