Merge pull request #402 from iamcarbon/allocations-2

Introduce and use Indexed BufferReader methods
drewnoakes · Feb 6, 2024 · f48737f · f48737f
2 parents 60e3fe7 + bec7461
commit f48737f
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Showing 10 changed files with 600 additions and 346 deletions.
diff --git a/MetadataExtractor/Formats/Avi/AviRiffHandler.cs b/MetadataExtractor/Formats/Avi/AviRiffHandler.cs
@@ -52,7 +52,7 @@ public void ProcessChunk(string fourCc, byte[] payload)
             {
                 case "strh":
                 {
-                    var reader = new ByteArrayReader(payload, isMotorolaByteOrder: false);
+                    var reader = new BufferReader(payload, isBigEndian: false);
 
                     var directory = GetOrCreateAviDirectory();
                     try
@@ -101,8 +101,13 @@ public void ProcessChunk(string fourCc, byte[] payload)
                 {
                     var directory = GetOrCreateAviDirectory();
 
-                    var reader = new ByteArrayReader(payload, isMotorolaByteOrder: false);
-                    try
+                    var reader = new BufferReader(payload, isBigEndian: false);
+
+                    if (payload.Length < 40)
+                    {
+                        directory.AddError("Insufficient bytes for AviRiff chunk 'avih'");
+                    }
+                    else
                     {
                         //int dwMicroSecPerFrame = reader.GetInt32(0);
                         //int dwMaxBytesPerSec = reader.GetInt32(4);
@@ -120,21 +125,20 @@ public void ProcessChunk(string fourCc, byte[] payload)
                         directory.Set(AviDirectory.TagHeight, dwHeight);
                         directory.Set(AviDirectory.TagStreams, dwStreams);
                     }
-                    catch (IOException e)
-                    {
-                        directory.AddError("Exception reading AviRiff chunk 'avih' : " + e.Message);
-                    }
 
                     break;
                 }
                 case "IDIT":
                 {
-                    var reader = new ByteArrayReader(payload);
-                    var str = reader.GetString(0, payload.Length, Encoding.ASCII);
-                    if (str.Length == 26 && str.EndsWith("\n\0", StringComparison.Ordinal))
+                    string str;
+                    if (payload.Length is 26 && payload.AsSpan().EndsWith("\n\0"u8))
                     {
                         // ?0A 00? "New Line" + padded to nearest WORD boundary
-                        str = str.Substring(0, 24);
+                        str = Encoding.ASCII.GetString(payload.AsSpan(0, 24));
+                    }
+                    else
+                    {
+                        str = Encoding.ASCII.GetString(payload);
                     }
                     GetOrCreateAviDirectory().Set(AviDirectory.TagDateTimeOriginal, str);
                     break;

diff --git a/MetadataExtractor/Formats/Exif/ExifDescriptorBase.cs b/MetadataExtractor/Formats/Exif/ExifDescriptorBase.cs
@@ -575,7 +575,7 @@ public abstract class ExifDescriptorBase<T>(T directory)
                 return ret;
             }
 
-            IndexedReader reader = new ByteArrayReader(values);
+            var reader = new BufferReader(values, isBigEndian: true);
 
             // first two values should be read as 16-bits (2 bytes)
             var item0 = reader.GetInt16(0);
@@ -588,7 +588,7 @@ public abstract class ExifDescriptorBase<T>(T directory)
             if (end > values.Length) // sanity check in case of byte order problems; calculated 'end' should be <= length of the values
             {
                 // try swapping byte order (I have seen this order different than in EXIF)
-                reader = reader.WithByteOrder(!reader.IsMotorolaByteOrder);
+                reader = new BufferReader(values, isBigEndian: !reader.IsBigEndian);
                 item0 = reader.GetInt16(0);
                 item1 = reader.GetInt16(2);
 

diff --git a/MetadataExtractor/Formats/Exif/makernotes/PanasonicMakernoteDescriptor.cs b/MetadataExtractor/Formats/Exif/makernotes/PanasonicMakernoteDescriptor.cs
@@ -167,29 +167,25 @@ public sealed class PanasonicMakernoteDescriptor(PanasonicMakernoteDirectory dir
             if (values is null)
                 return null;
 
-            IndexedReader reader = new ByteArrayReader(values);
-
-            try
-            {
-                int val1 = reader.GetUInt16(0);
-                int val2 = reader.GetUInt16(2);
-                if (val1 == -1 && val2 == 1)
-                    return "Slim Low";
-                if (val1 == -3 && val2 == 2)
-                    return "Slim High";
-                if (val1 == 0 && val2 == 0)
-                    return "Off";
-                if (val1 == 1 && val2 == 1)
-                    return "Stretch Low";
-                if (val1 == 3 && val2 == 2)
-                    return "Stretch High";
-
-                return "Unknown (" + val1 + " " + val2 + ")";
-            }
-            catch (IOException)
+            if (values.Length < 2 + 2)
             {
                 return null;
             }
+
+            var reader = new BufferReader(values, isBigEndian: true);
+
+            int val1 = reader.GetUInt16(0);
+            int val2 = reader.GetUInt16(2);
+
+            return (val1, val2) switch
+            {
+                (-1, 1) => "Slim Low",
+                (-3, 2) => "Slim High",
+                (0, 0) => "Off",
+                (1, 1) => "Stretch Low",
+                (3, 2) => "Stretch High",
+                _ => $"Unknown ({val1} {val2})"
+            };
         }
 
         public string? GetIntelligentExposureDescription()

diff --git a/MetadataExtractor/Formats/Icc/IccDescriptor.cs b/MetadataExtractor/Formats/Icc/IccDescriptor.cs
@@ -48,7 +48,7 @@ private enum IccTagType
                 if (bytes is null)
                     return Directory.GetString(tagType);
 
-                var reader = new ByteArrayReader(bytes);
+                var reader = new BufferReader(bytes, isBigEndian: true);
 
                 var iccTagType = (IccTagType)reader.GetInt32(0);
 
@@ -71,6 +71,10 @@ private enum IccTagType
                     case IccTagType.Desc:
                     {
                         var stringLength = reader.GetInt32(8);
+
+                        if (stringLength < 0 || stringLength > bytes.Length)
+                            return null;
+
                         return Encoding.UTF8.GetString(bytes, 12, stringLength - 1);
                     }