[Performance] Speed up string reading by 30% (especially for scn)

UlyssesWu · Jul 31, 2018 · 0a07a11 · 0a07a11
1 parent 3d7cb41
commit 0a07a11
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Showing 3 changed files with 141 additions and 6 deletions.
diff --git a/FreeMote.Psb/Psb.cs b/FreeMote.Psb/Psb.cs
@@ -2,7 +2,6 @@
 //#define DEBUG_OBJECT_WRITE //Enable if you want to check how much bytes each object costs.
 using System;
 using System.Collections.Generic;
-using System.Collections.Specialized;
 using System.Diagnostics;
 using System.IO;
 using System.Linq;

diff --git a/FreeMote.Tests/FreeMoteTest.cs b/FreeMote.Tests/FreeMoteTest.cs
@@ -4,6 +4,7 @@
 using System.Drawing.Imaging;
 using System.IO;
 using System.Linq;
+using System.Text;
 using FreeMote.Plugins;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 
@@ -226,5 +227,133 @@ public void TestRGBA4444()
 
             RL.ConvertToImageFile(bts, "rgba4444.png", 2048, 2048, PsbImageFormat.Png, PsbPixelFormat.WinRGBA4444);
         }
+
+        [TestMethod]
+        public void TestReadWriteZeroTrimString()
+        {
+            string ReadPeekAndAppend(BinaryReader br)
+            {
+                StringBuilder sb = new StringBuilder();
+                while (br.PeekChar() != 0)
+                {
+                    sb.Append(br.ReadChar());
+                }
+                br.ReadByte(); //skip \0 - fail if end without \0
+                return sb.ToString();
+            }
+
+            string ReadDetectAndSwallow(BinaryReader br)
+            {
+                var pos = br.BaseStream.Position;
+                var length = 0;
+                while (br.ReadByte() > 0)
+                {
+                    length++;
+                }
+                br.BaseStream.Position = pos;
+                var str = Encoding.UTF8.GetString(br.ReadBytes(length));
+                br.ReadByte(); //skip \0 - fail if end without \0
+                return str;
+            }
+
+            //Generate super long string
+            var theNatureOfHuman = "人类的本质是:";
+            var bts = Encoding.UTF8.GetBytes(theNatureOfHuman);
+            using (var ms = new MemoryStream())
+            using (var bw = new BinaryWriter(ms))
+            using (var br = new BinaryReader(ms))
+            {
+                for (int i = 0; i < 100_0000; i++)
+                {
+                    bw.Write(bts);
+                }
+                bw.Write((byte)0);
+
+                Console.WriteLine("Read 1 long string:");
+                ms.Position = 0;
+                Stopwatch sw = Stopwatch.StartNew();
+                var r = ReadPeekAndAppend(br);
+                sw.Stop();
+                var time = sw.Elapsed;
+                Console.WriteLine($"Time of {nameof(ReadPeekAndAppend)}: \t{time}");
+
+                ms.Position = 0;
+                sw.Restart();
+                r = ReadDetectAndSwallow(br);
+                sw.Stop();
+                time = sw.Elapsed;
+                Console.WriteLine($"Time of {nameof(ReadDetectAndSwallow)}: \t{time}");
+
+                ms.SetLength(0); //Clear
+                for (int i = 0; i < 100_0000; i++)
+                {
+                    bw.Write(bts);
+                    bw.Write((byte)0);
+                }
+
+                Console.WriteLine("Read 100_0000 short strings:");
+                ms.Position = 0;
+                sw.Restart();
+                while (br.BaseStream.Position < br.BaseStream.Length)
+                {
+                    r = ReadPeekAndAppend(br);
+                }
+                sw.Stop();
+                time = sw.Elapsed;
+                Console.WriteLine($"Time of {nameof(ReadPeekAndAppend)}:\t{time}");
+
+                ms.Position = 0;
+                sw.Restart();
+                while (br.BaseStream.Position < br.BaseStream.Length)
+                {
+                    r = ReadDetectAndSwallow(br);
+                }
+                sw.Stop();
+                time = sw.Elapsed;
+                Console.WriteLine($"Time of {nameof(ReadDetectAndSwallow)}:\t{time}");
+
+                ms.Position = 0;
+                Console.WriteLine("PeekChar vs AppendChar:");
+
+                sw.Restart();
+                for (int i = 0; i < 100_0000; i++)
+                {
+                    br.PeekChar();
+                }
+                sw.Stop();
+                time = sw.Elapsed;
+                Console.WriteLine($"Time of PeekChar: \t{time}");
+
+                StringBuilder sb = new StringBuilder();
+                sw.Restart();
+                for (int i = 0; i < 100_0000; i++)
+                {
+                    sb.Append('咕');
+                }
+                //r = sb.ToString();
+                sw.Stop();
+                time = sw.Elapsed;
+                Console.WriteLine($"Time of Append: \t{time}");
+
+                Console.WriteLine("Write 1 long string:");
+                ms.SetLength(0);
+                r = sb.ToString();
+
+                sw.Restart();
+                bw.Write(r.ToCharArray());
+                bw.Write((byte) 0);
+                sw.Stop();
+                time = sw.Elapsed;
+                Console.WriteLine($"Time of ToCharArray: \t{time}");
+
+                sw.Restart();
+                bw.Write(Encoding.UTF8.GetBytes(r));
+                bw.Write((byte)0);
+                sw.Stop();
+                time = sw.Elapsed;
+                Console.WriteLine($"Time of GetBytes: \t{time}");
+            }
+
+        }
     }
 }
diff --git a/FreeMote/PsbConstants.cs b/FreeMote/PsbConstants.cs
@@ -23,6 +23,8 @@ public static class PsbConstants
         /// </summary>
         public const uint Key3 = 521288629;
 
+        public static Encoding PsbEncoding { get; set; } = Encoding.UTF8;
+
         public static string ToStringForPsb(this PsbPixelFormat pixelFormat)
         {
             switch (pixelFormat)
@@ -98,17 +100,22 @@ public static void Write(this PsbStreamContext context, ushort value, BinaryWrit
 
         public static string ReadStringZeroTrim(this BinaryReader br)
         {
-            StringBuilder sb = new StringBuilder();
-            while (br.PeekChar() != 0)
+            var pos = br.BaseStream.Position;
+            var length = 0;
+            while (br.ReadByte() > 0)
             {
-                sb.Append(br.ReadChar());
+                length++;
             }
-            return sb.ToString();
+            br.BaseStream.Position = pos;
+            var str = PsbEncoding.GetString(br.ReadBytes(length));
+            br.ReadByte(); //skip \0 - fail if end without \0
+            return str;
         }
 
         public static void WriteStringZeroTrim(this BinaryWriter bw, string str)
         {
-            bw.Write(str.ToCharArray());
+            //bw.Write(str.ToCharArray());
+            bw.Write(PsbEncoding.GetBytes(str));
             bw.Write((byte)0);
         }