MoonWorksDearImGuiScaffold/lib/ImGui.NET/Util.cs

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C#
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2023-12-22 00:03:12 +01:00
using System;
using System.Runtime.InteropServices;
using System.Text;
namespace ImGuiNET
{
internal static unsafe class Util
{
internal const int StackAllocationSizeLimit = 2048;
public static string StringFromPtr(byte* ptr)
{
int characters = 0;
while (ptr[characters] != 0)
{
characters++;
}
return Encoding.UTF8.GetString(ptr, characters);
}
internal static bool AreStringsEqual(byte* a, int aLength, byte* b)
{
for (int i = 0; i < aLength; i++)
{
if (a[i] != b[i]) { return false; }
}
if (b[aLength] != 0) { return false; }
return true;
}
internal static byte* Allocate(int byteCount) => (byte*)Marshal.AllocHGlobal(byteCount);
internal static void Free(byte* ptr) => Marshal.FreeHGlobal((IntPtr)ptr);
#if NETSTANDARD2_1_OR_GREATER || NETCOREAPP2_1_OR_GREATER
internal static int CalcSizeInUtf8(ReadOnlySpan<char> s, int start, int length)
#else
internal static int CalcSizeInUtf8(string s, int start, int length)
#endif
{
if (start < 0 || length < 0 || start + length > s.Length)
{
throw new ArgumentOutOfRangeException();
}
if(s.Length == 0) return 0;
fixed (char* utf16Ptr = s)
{
return Encoding.UTF8.GetByteCount(utf16Ptr + start, length);
}
}
#if NETSTANDARD2_1_OR_GREATER || NETCOREAPP2_1_OR_GREATER
internal static int GetUtf8(ReadOnlySpan<char> s, byte* utf8Bytes, int utf8ByteCount)
{
if (s.IsEmpty)
{
return 0;
}
fixed (char* utf16Ptr = s)
{
return Encoding.UTF8.GetBytes(utf16Ptr, s.Length, utf8Bytes, utf8ByteCount);
}
}
#endif
internal static int GetUtf8(string s, byte* utf8Bytes, int utf8ByteCount)
{
fixed (char* utf16Ptr = s)
{
return Encoding.UTF8.GetBytes(utf16Ptr, s.Length, utf8Bytes, utf8ByteCount);
}
}
#if NETSTANDARD2_1_OR_GREATER || NETCOREAPP2_1_OR_GREATER
internal static int GetUtf8(ReadOnlySpan<char> s, int start, int length, byte* utf8Bytes, int utf8ByteCount)
#else
internal static int GetUtf8(string s, int start, int length, byte* utf8Bytes, int utf8ByteCount)
#endif
{
if (start < 0 || length < 0 || start + length > s.Length)
{
throw new ArgumentOutOfRangeException();
}
if (s.Length == 0) return 0;
fixed (char* utf16Ptr = s)
{
return Encoding.UTF8.GetBytes(utf16Ptr + start, length, utf8Bytes, utf8ByteCount);
}
}
}
}