[Imp] mpt/base/alloc.hpp: Add mpt::erase(std::vector, value) and mpt::erase_if(std::vector, pred), like C++20 std::erase and std::erase_if.

git-svn-id: https://source.openmpt.org/svn/openmpt/trunk/OpenMPT@24783 56274372-70c3-4bfc-bfc3-4c3a0b034d27

Author: manxorist

src/mpt/base/alloc.hpp

@@ -5,11 +5,14 @@
 
 
 
-#include "mpt/base/namespace.hpp"
-
+#include "mpt/base/detect.hpp"
 #include "mpt/base/memory.hpp"
+#include "mpt/base/namespace.hpp"
 #include "mpt/base/span.hpp"
 
+#if MPT_CXX_BEFORE(20)
+#include <algorithm>
+#endif // C++20
 #include <iterator>
 #include <memory>
 #include <string>
@@ -114,6 +117,33 @@ inline Tcont1 & append(Tcont1 & cont1, Tit2 beg, Tit2 end) {
 
 
 
+#if MPT_CXX_AT_LEAST(20)
+
+using std::erase;
+using std::erase_if;
+
+#else // !C++20
+
+template <typename T, typename U>
+inline typename std::vector<T>::size_type erase(std::vector<T> & c, const U & value) {
+	auto it = std::remove(c.begin(), c.end(), value);
+	auto r = c.end() - it;
+	c.erase(it, c.end());
+	return r;
+}
+
+template <typename T, typename Pred>
+inline typename std::vector<T>::size_type erase_if(std::vector<T> & c, Pred pred) {
+	auto it = std::remove_if(c.begin(), c.end(), pred);
+	auto r = c.end() - it;
+	c.erase(it, c.end());
+	return r;
+}
+
+#endif // C++20
+
+
+
 template <typename Tdst, typename Tsrc>
 struct buffer_cast_impl {
 	inline Tdst operator()(const Tsrc & src) const {