Merge branch 'hotfix/StlReader_opens_binary_stl_with_ascii_reader'

Musashi178 · Nov 11, 2014 · a91bee9 · a91bee9
2 parents a1d672f + 70810d0
commit a91bee9
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Showing 10 changed files with 148 additions and 22 deletions.
diff --git a/...s/BinaryStlWriterTests.Write_WithLargeHeader_ReturnsExpectedResult.approved.stl b/...s/BinaryStlWriterTests.Write_WithLargeHeader_ReturnsExpectedResult.approved.stl
diff --git a/...s/BinaryStlWriterTests.Write_WithSmallHeader_ReturnsExpectedResult.approved.stl b/...s/BinaryStlWriterTests.Write_WithSmallHeader_ReturnsExpectedResult.approved.stl
diff --git a/GenericStl.Tests/BinaryStlWriterTests.cs b/GenericStl.Tests/BinaryStlWriterTests.cs
@@ -1,5 +1,7 @@
 using System;
 using System.IO;
+using System.Linq;
+using System.Text;
 using ApprovalTests;
 using ApprovalTests.Reporters;
 using GenericStl.Tests.TestDataStructures;
@@ -37,5 +39,23 @@ public void Write_WithBlock_ReturnsExpectedResult()
             var result = ObjectUnderTest.Write(TestHelpers.BlockExpectedResult);
             Approvals.VerifyBinaryFile(result, ".stl");
         }
+
+        [Test]
+        public void Write_WithSmallHeader_ReturnsExpectedResult()
+        {
+            var hdr = new ASCIIEncoding().GetBytes("short header");
+            var result = ObjectUnderTest.Write(TestHelpers.BlockExpectedResult, hdr);
+            Approvals.VerifyBinaryFile(result, ".stl");
+        }
+
+        [Test]
+        public void Write_WithLargeHeader_ReturnsExpectedResult()
+        {
+            var hdr = string.Join("", Enumerable.Repeat("abcdefghijklmnopqrstuvwxyz1234567890", 10));
+            var hdrBytes = new ASCIIEncoding().GetBytes(hdr);
+
+            var result = ObjectUnderTest.Write(TestHelpers.BlockExpectedResult, hdrBytes);
+            Approvals.VerifyBinaryFile(result, ".stl");
+        }
     }
 }
diff --git a/GenericStl.Tests/GenericStl.Tests.csproj b/GenericStl.Tests/GenericStl.Tests.csproj
@@ -78,6 +78,7 @@
   <ItemGroup>
     <Compile Include="AsciiStlReaderTests.cs" />
     <Compile Include="AsciiStlWriterTests.cs" />
+    <Compile Include="StlFileTests.cs" />
     <Compile Include="StlReaderBaseTests.cs" />
     <Compile Include="StlReaderTests.cs" />
     <Compile Include="StlWriterBaseTests.cs" />
@@ -101,6 +102,9 @@
     <None Include="TestData\binary_block.stl">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </None>
+    <None Include="TestData\binary_block_with_solid_header.stl">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\GenericStl\GenericStl.csproj">

diff --git a/GenericStl.Tests/StlFileTests.cs b/GenericStl.Tests/StlFileTests.cs
@@ -0,0 +1,31 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using GenericStl.Tests.TestDataStructures;
+using NUnit.Framework;
+
+namespace GenericStl.Tests
+{
+    [TestFixture]
+    public class StlFileTests
+    {
+        public IEnumerable IsBinaryFileTestCases
+        {
+            get
+            {
+                yield return new TestCaseData(@".\TestData\ascii_block.stl").SetName("Ascii file").Returns(false);
+                yield return new TestCaseData(@".\TestData\binary_block.stl").SetName("Binary block file").Returns(true);
+                yield return new TestCaseData(@".\TestData\binary_block_with_solid_header.stl").SetName("Binary file with solid header").Returns(true);
+            }
+        }
+
+        [TestCaseSource("IsBinaryFileTestCases")]
+        public bool IsBinaryFile_ReturnsExpected(string filename)
+        {
+            return StlFile.IsBinaryFile(filename);
+        }
+    }
+}
diff --git a/GenericStl.Tests/TestData/binary_block_with_solid_header.stl b/GenericStl.Tests/TestData/binary_block_with_solid_header.stl
diff --git a/GenericStl/BinaryStlWriter.cs b/GenericStl/BinaryStlWriter.cs
@@ -60,14 +60,11 @@ public void WriteToStream(Stream s, IEnumerable<TTriangle> triangles, byte[] hea
                 throw new ArgumentNullException("triangles");
             }
 
-            if (header != null && header.Length != 80)
-            {
-                throw new ArgumentException("header must have a size of 80 bytes.", "header");
-            }
+            var hdr = PrepareHeader(header);
 
             using (var w = new BinaryWriter(s, new UTF8Encoding(false, true), true))
             {
-                WriteHeader(w, header ?? new byte[HeaderLengthInByte]);
+                WriteHeader(w, hdr);
                 WriteLength(w, 0);
 
                 var length = 0;
@@ -84,6 +81,32 @@ public void WriteToStream(Stream s, IEnumerable<TTriangle> triangles, byte[] hea
             }
         }
 
+        private static byte[] PrepareHeader(byte[] header)
+        {
+            if (header == null)
+            {
+                return new byte[HeaderLengthInByte];
+            }
+
+            if (header.Length == HeaderLengthInByte)
+            {
+                return header;
+            }
+
+            var newHdr = new byte[HeaderLengthInByte];
+
+            if (header.Length < HeaderLengthInByte)
+            {
+               Array.Copy(header, newHdr, header.Length);
+            }
+            else if (header.Length > HeaderLengthInByte)
+            {
+                Array.Copy(header, newHdr, newHdr.Length);
+            }
+
+            return newHdr;
+        }
+
         private void WriteTriangle(BinaryWriter w, TTriangle t)
         {
             var triangleData = ExtractTriangle(t);

diff --git a/GenericStl/GenericStl.csproj b/GenericStl/GenericStl.csproj
@@ -47,6 +47,7 @@
     <Compile Include="IDataStructureCreator.cs" />
     <Compile Include="IDataStructureExtractor.cs" />
     <Compile Include="IStlWriter.cs" />
+    <Compile Include="StlFile.cs" />
     <Compile Include="StlReader.cs" />
     <Compile Include="StlWriterBase.cs" />
     <Compile Include="BinaryStlReader.cs" />

diff --git a/GenericStl/StlFile.cs b/GenericStl/StlFile.cs
@@ -0,0 +1,51 @@
+using System;
+using System.IO;
+using System.Text;
+
+namespace GenericStl
+{
+    public static class StlFile
+    {
+        public static bool IsBinaryFile(string filename)
+        {
+            if (!File.Exists(filename))
+            {
+                throw new FileNotFoundException("filename could not be found.", filename);
+            }
+
+            using (var fs = File.OpenRead(filename))
+            {
+                return IsBinary(fs);
+            }
+        }
+
+        public static bool IsBinary(Stream stream)
+        {
+            try
+            {
+                using(var r = new BinaryReader(stream, Encoding.UTF8, true))
+                {
+                    var firstChars = new string(r.ReadChars(5));
+
+                    if (!string.Equals(firstChars, "solid", StringComparison.OrdinalIgnoreCase))
+                    {
+                        return true;
+                    }
+
+                    var numberOfCharsToReadAtEnd = "endsolid".Length + 300;
+                    numberOfCharsToReadAtEnd = numberOfCharsToReadAtEnd > stream.Length ? (int)stream.Length : numberOfCharsToReadAtEnd;
+
+                    stream.Seek(-numberOfCharsToReadAtEnd , SeekOrigin.End);
+
+                    var lastChars = new string(r.ReadChars(numberOfCharsToReadAtEnd));
+
+                    return !lastChars.Contains("endsolid");
+                }
+            }
+            finally
+            {
+                stream.Seek(0, SeekOrigin.Begin);
+            }
+        }
+    }
+}
diff --git a/GenericStl/StlReader.cs b/GenericStl/StlReader.cs
@@ -1,7 +1,6 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
-using System.Text;
 
 namespace GenericStl
 {
@@ -11,6 +10,10 @@ public StlReader(Func<TVertex, TVertex, TVertex, TNormal, TTriangle> createTrian
         {
         }
 
+        public StlReader(IDataStructureCreator<TTriangle, TVertex, TNormal> dataStructureCreator) : base(dataStructureCreator)
+        {
+        }
+
         public override IEnumerable<TTriangle> ReadFromFile(string fileName)
         {
             using (var fs = File.OpenRead(fileName))
@@ -24,30 +27,23 @@ public override IEnumerable<TTriangle> ReadFromFile(string fileName)
 
         public override IEnumerable<TTriangle> ReadFromStream(Stream s)
         {
-            if (IsBinaryStl(s))
+            if (s == null)
             {
-                return new BinaryStlReader<TTriangle, TVertex, TNormal>(CreateTriangle, CreateVertex, CreateNormal).ReadFromStream(s);
+                throw new ArgumentNullException("s", "Stream must not be null.");
             }
 
-            return new AsciiStlReader<TTriangle, TVertex, TNormal>(CreateTriangle, CreateVertex, CreateNormal).ReadFromStream(s);
+            var reader = GetReaderFor(s);
+            return reader.ReadFromStream(s);
         }
 
-        public static bool IsBinaryStl(Stream stream)
+        private IStlReader<TTriangle> GetReaderFor(Stream s)
         {
-            try
-            {
-                using (var r = new StreamReader(stream, Encoding.UTF8, true, 1024, true))
-                {
-                    var buf = new char[20];
-                    r.ReadBlock(buf, 0, 20);
-                    var start = new string(buf);
-                    return !start.TrimStart().StartsWith("solid", StringComparison.OrdinalIgnoreCase);
-                }
-            }
-            finally
+            if (StlFile.IsBinary(s))
             {
-                stream.Seek(0, SeekOrigin.Begin);
+                return new BinaryStlReader<TTriangle, TVertex, TNormal>(CreateTriangle, CreateVertex, CreateNormal);
             }
+
+            return new AsciiStlReader<TTriangle, TVertex, TNormal>(CreateTriangle, CreateVertex, CreateNormal);
         }
     }
 }