Support loading large FSB5 chunks (#14)

* Large FSB5 files

* I messed up offset

Author: Masusder

Fmod5Sharp/FsbLoader.cs

@@ -23,9 +23,8 @@ public static class FsbLoader
             { 10, 96_000 },
         };
 
-        private static FmodSoundBank? LoadInternal(byte[] bankBytes, bool throwIfError)
+        private static FmodSoundBank? LoadInternal(Stream stream, bool throwIfError)
         {
-            using MemoryStream stream = new(bankBytes);
             using BinaryReader reader = new(stream);
 
             FmodAudioHeader header = new(reader);
@@ -38,24 +37,26 @@ public static class FsbLoader
                 return null;
             }
 
-            List<FmodSample> samples = new();
-
-            //Remove header from data block.
-            var bankData = bankBytes.AsSpan((int)(header.SizeOfThisHeader + header.SizeOfNameTable + header.SizeOfSampleHeaders));
+            long dataStartOffset = header.SizeOfThisHeader + header.SizeOfNameTable + header.SizeOfSampleHeaders;
 
+            List<FmodSample> samples = new(header.Samples.Count);
             for (var i = 0; i < header.Samples.Count; i++)
             {
                 var sampleMetadata = header.Samples[i];
 
-                var firstByteOfSample = (int)sampleMetadata.DataOffset;
-                var lastByteOfSample = (int)header.SizeOfData;
+                var firstByteOfSample = (long)sampleMetadata.DataOffset;
+                var lastByteOfSample = (long)header.SizeOfData;
 
                 if (i < header.Samples.Count - 1)
                 {
-                    lastByteOfSample = (int)header.Samples[i + 1].DataOffset;
+                    lastByteOfSample = (long)header.Samples[i + 1].DataOffset;
                 }
 
-                var sample = new FmodSample(sampleMetadata, bankData[firstByteOfSample..lastByteOfSample].ToArray());
+                byte[] sampleData = new byte[lastByteOfSample - firstByteOfSample];
+                stream.Position = dataStartOffset + firstByteOfSample;
+                stream.Read(sampleData, 0, sampleData.Length);
+
+                var sample = new FmodSample(sampleMetadata, sampleData);
 
                 if (header.SizeOfNameTable > 0)
                 {
@@ -65,7 +66,8 @@ public static class FsbLoader
 
                     nameOffset += header.SizeOfThisHeader + header.SizeOfSampleHeaders;
 
-                    sample.Name = bankBytes.ReadNullTerminatedString((int)nameOffset);
+                    stream.Position = nameOffset;
+                    sample.Name = stream.ReadNullTerminatedString();
                 }
 
                 samples.Add(sample);
@@ -74,13 +76,26 @@ public static class FsbLoader
             return new FmodSoundBank(header, samples);
         }
 
+        public static bool TryLoadFsbFromStream(Stream stream, out FmodSoundBank? bank)
+        {
+            bank = LoadInternal(stream, false);
+            return bank != null;
+        }
+
+        public static FmodSoundBank LoadFsbFromStream(Stream stream)
+            => LoadInternal(stream, true)!;
+
         public static bool TryLoadFsbFromByteArray(byte[] bankBytes, out FmodSoundBank? bank)
         {
-            bank = LoadInternal(bankBytes, false);
+            using var stream = new MemoryStream(bankBytes);
+            bank = LoadInternal(stream, false);
             return bank != null;
         }
 
         public static FmodSoundBank LoadFsbFromByteArray(byte[] bankBytes)
-            => LoadInternal(bankBytes, true)!;
+        {
+            using var stream = new MemoryStream(bankBytes);
+            return LoadInternal(stream, true)!;
+        }
     }
 }

Fmod5Sharp/Util/Extensions.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.IO;
 using System.Text;
 
@@ -41,13 +42,14 @@ internal static ulong Bits(this ulong raw, int lowestBit, int numBits)
             return (raw & mask) >> lowestBit;
         }
 
-        internal static string ReadNullTerminatedString(this byte[] bytes, int startOffset)
+        internal static string ReadNullTerminatedString(this Stream stream)
         {
-            var strLen = bytes.AsSpan(startOffset).IndexOf((byte)0);
-            if (strLen == -1)
-                throw new("Could not find null terminator");
-            
-            return Encoding.UTF8.GetString(bytes, startOffset, strLen);
+            List<byte> bytes = new(16);
+            int b;
+            while ((b = stream.ReadByte()) > 0)
+                bytes.Add((byte)b);
+
+            return Encoding.UTF8.GetString(bytes.ToArray());
         }
     }
 }