fish-shell/src/intern.cpp
2019-03-12 15:09:36 -07:00

40 lines
1.1 KiB
C++

// Library for pooling common strings.
#include "config.h" // IWYU pragma: keep
#include <stddef.h>
#include <cwchar>
#include <algorithm>
#include <memory>
#include <vector>
#include "common.h"
#include "fallback.h" // IWYU pragma: keep
#include "intern.h"
bool string_less_than_string(const wchar_t *a, const wchar_t *b) { return std::wcscmp(a, b) < 0; }
/// The table of intern'd strings.
owning_lock<std::vector<const wchar_t *>> string_table;
static const wchar_t *intern_with_dup(const wchar_t *in, bool dup) {
if (!in) return NULL;
debug(5, L"intern %ls", in);
auto table = string_table.acquire();
const wchar_t *result;
auto iter = std::lower_bound(table->begin(), table->end(), in, string_less_than_string);
if (iter != table->end() && std::wcscmp(*iter, in) == 0) {
result = *iter;
} else {
result = dup ? wcsdup(in) : in;
table->insert(iter, result);
}
return result;
}
const wchar_t *intern(const wchar_t *in) { return intern_with_dup(in, true); }
const wchar_t *intern_static(const wchar_t *in) { return intern_with_dup(in, false); }