Weighing: Add Gassner scale and update tests

Elwig/Helpers/Extensions.cs

@@ -0,0 +1,63 @@
+using System.IO;
+using System.Runtime.InteropServices;
+using System.Threading.Tasks;
+
+namespace Elwig.Helpers {
+    static partial class Extensions {
+
+        [LibraryImport("msvcrt.dll")]
+        [UnmanagedCallConv(CallConvs = [typeof(System.Runtime.CompilerServices.CallConvCdecl)])]
+        private static unsafe partial int memcmp(void* b1, void* b2, long count);
+
+        public static unsafe int CompareBuffers(char[] buffer1, int offset1, char[] buffer2, int offset2, int count) {
+            fixed (char* b1 = buffer1, b2 = buffer2) {
+                return memcmp(b1 + offset1, b2 + offset2, count);
+            }
+        }
+
+        public static string? ReadUntil(this StreamReader reader, string delimiter) {
+            return ReadUntil(reader, delimiter.ToCharArray());
+        }
+
+        public static string? ReadUntil(this StreamReader reader, char delimiter) {
+            return ReadUntil(reader, new char[] { delimiter });
+        }
+
+        public static string? ReadUntil(this StreamReader reader, char[] delimiter) {
+            var buf = new char[512];
+            int bufSize = 0, ret;
+            while (!reader.EndOfStream && bufSize < buf.Length - 1) {
+                if ((ret = reader.Read()) == -1)
+                    return null;
+                buf[bufSize++] = (char)ret;
+
+                if (bufSize >= delimiter.Length && CompareBuffers(buf, bufSize - delimiter.Length, delimiter, 0, delimiter.Length) == 0)
+                    return new string(buf, 0, bufSize);
+            }
+            return null;
+        }
+
+        public static Task<string?> ReadUntilAsync(this StreamReader reader, string delimiter) {
+            return ReadUntilAsync(reader, delimiter.ToCharArray());
+        }
+
+        public static Task<string?> ReadUntilAsync(this StreamReader reader, char delimiter) {
+            return ReadUntilAsync(reader, new char[] { delimiter });
+        }
+
+        public static async Task<string?> ReadUntilAsync(this StreamReader reader, char[] delimiter) {
+            var buf = new char[512];
+            int bufSize = 0;
+            var tmpBuf = new char[1];
+            while (!reader.EndOfStream && bufSize < buf.Length - 1) {
+                if ((await reader.ReadAsync(tmpBuf, 0, 1)) != 1)
+                    return null;
+                buf[bufSize++] = tmpBuf[0];
+
+                if (bufSize >= delimiter.Length && CompareBuffers(buf, bufSize - delimiter.Length, delimiter, 0, delimiter.Length) == 0)
+                    return new string(buf, 0, bufSize);
+            }
+            return null;
+        }
+    }
+}