Replace 2 allocations from string.ToCharArray() with ReadOnlySpan in …

…System.Private.Xml library (dotnet#67002) * Remove ToCharArray() used in BinHexDecoder * Replace ToCharArray() used in XmlSerializationReader with Span * Address feedback * Remove not necessary check for null * Remove OutOfMemoryException catch Co-authored-by: Trayan Zapryanov <[email protected]>
Nisden · Apr 8, 2022 · e6c8d42 · e6c8d42
1 parent 9cb6475
commit e6c8d42
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Showing 3 changed files with 13 additions and 24 deletions.
diff --git a/src/libraries/System.Private.Xml/src/System/Xml/BinHexDecoder.cs b/src/libraries/System.Private.Xml/src/System/Xml/BinHexDecoder.cs
@@ -116,7 +116,7 @@ internal override void SetNextOutputBuffer(Array buffer, int index, int count)
         //
         // Static methods
         //
-        public static byte[] Decode(char[] chars!!, bool allowOddChars)
+        public static byte[] Decode(ReadOnlySpan<char> chars, bool allowOddChars)
         {
             int len = chars.Length;
             if (len == 0)

diff --git a/src/libraries/System.Private.Xml/src/System/Xml/Serialization/XmlSerializationReader.cs b/src/libraries/System.Private.Xml/src/System/Xml/Serialization/XmlSerializationReader.cs
@@ -974,25 +974,24 @@ private SoapArrayInfo ParseArrayType(string value)
                 throw new ArgumentException(SR.Format(SR.XmlEmptyArrayType, CurrentTag()), nameof(value));
             }
 
-            char[] chars = value.ToCharArray();
-            int charsLength = chars.Length;
+            int charsLength = value.Length;
 
             SoapArrayInfo soapArrayInfo = default;
 
             // Parse backwards to get length first, then optional dimensions, then qname.
             int pos = charsLength - 1;
 
             // Must end with ]
-            if (chars[pos] != ']')
+            if (value[pos] != ']')
             {
                 throw new ArgumentException(SR.XmlInvalidArraySyntax, nameof(value));
             }
             pos--;
 
             // Find [
-            while (pos != -1 && chars[pos] != '[')
+            while (pos != -1 && value[pos] != '[')
             {
-                if (chars[pos] == ',')
+                if (value[pos] == ',')
                     throw new ArgumentException(SR.Format(SR.XmlInvalidArrayDimentions, CurrentTag()), nameof(value));
                 pos--;
             }
@@ -1004,19 +1003,9 @@ private SoapArrayInfo ParseArrayType(string value)
             int len = charsLength - pos - 2;
             if (len > 0)
             {
-                string lengthString = new string(chars, pos + 1, len);
-                try
-                {
-                    soapArrayInfo.length = int.Parse(lengthString, CultureInfo.InvariantCulture);
-                }
-                catch (Exception e)
-                {
-                    if (e is OutOfMemoryException)
-                    {
-                        throw;
-                    }
-                    throw new ArgumentException(SR.Format(SR.XmlInvalidArrayLength, lengthString), nameof(value));
-                }
+                ReadOnlySpan<char> lengthStringSpan = value.AsSpan(pos + 1, len);
+                if (!int.TryParse(lengthStringSpan, CultureInfo.InvariantCulture, out soapArrayInfo.length))
+                    throw new ArgumentException(SR.Format(SR.XmlInvalidArrayLength, new string(lengthStringSpan)), nameof(value));
             }
             else
             {
@@ -1026,14 +1015,14 @@ private SoapArrayInfo ParseArrayType(string value)
             pos--;
 
             soapArrayInfo.jaggedDimensions = 0;
-            while (pos != -1 && chars[pos] == ']')
+            while (pos != -1 && value[pos] == ']')
             {
                 pos--;
                 if (pos < 0)
                     throw new ArgumentException(SR.XmlMismatchedArrayBrackets, nameof(value));
-                if (chars[pos] == ',')
+                if (value[pos] == ',')
                     throw new ArgumentException(SR.Format(SR.XmlInvalidArrayDimentions, CurrentTag()), nameof(value));
-                else if (chars[pos] != '[')
+                else if (value[pos] != '[')
                     throw new ArgumentException(SR.XmlInvalidArraySyntax, nameof(value));
                 pos--;
                 soapArrayInfo.jaggedDimensions++;
@@ -1042,7 +1031,7 @@ private SoapArrayInfo ParseArrayType(string value)
             soapArrayInfo.dimensions = 1;
 
             // everything else is qname - validation of qnames?
-            soapArrayInfo.qname = new string(chars, 0, pos + 1);
+            soapArrayInfo.qname = new string(value.AsSpan(0, pos + 1));
             return soapArrayInfo;
         }
 

diff --git a/src/libraries/System.Private.Xml/src/System/Xml/XmlConvert.cs b/src/libraries/System.Private.Xml/src/System/Xml/XmlConvert.cs
@@ -314,7 +314,7 @@ internal static byte[] FromBinHexString(string s)
 
         internal static byte[] FromBinHexString(string s!!, bool allowOddCount)
         {
-            return BinHexDecoder.Decode(s.ToCharArray(), allowOddCount);
+            return BinHexDecoder.Decode(s.AsSpan(), allowOddCount);
         }
 
         internal static string ToBinHexString(byte[] inArray!!)