Add Encoding.GetBytes(string, offset, count) (dotnet/coreclr#8651)

Commit migrated from dotnet/coreclr@8891481
picenka21 · Dec 19, 2016 · 650ecef · 650ecef
1 parent 94efcbc
commit 650ecef
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Showing 2 changed files with 71 additions and 2 deletions.
diff --git a/src/coreclr/src/mscorlib/model.xml b/src/coreclr/src/mscorlib/model.xml
@@ -7767,10 +7767,12 @@
  <Member Name="GetByteCount(System.Char[])" />
  <Member Name="GetByteCount(System.Char[],System.Int32,System.Int32)" />
  <Member Name="GetByteCount(System.String)" />
+ <Member Name="GetByteCount(System.String,System.Int32,System.Int32)" />
  <Member Name="GetBytes(System.Char[])" />
  <Member Name="GetBytes(System.Char[],System.Int32,System.Int32)" />
  <Member Name="GetBytes(System.Char[],System.Int32,System.Int32,System.Byte[],System.Int32)" />
  <Member Name="GetBytes(System.String)" />
+ <Member Name="GetBytes(System.String,System.Int32,System.Int32)" />
  <Member Name="GetBytes(System.String,System.Int32,System.Int32,System.Byte[],System.Int32)" />
  <Member Name="GetBytes(System.Char*,System.Int32,System.Byte*,System.Int32)" />
  <Member Name="GetCharCount(System.Byte[])" />

diff --git a/src/coreclr/src/mscorlib/src/System/Text/Encoding.cs b/src/coreclr/src/mscorlib/src/System/Text/Encoding.cs
@@ -869,7 +869,7 @@ public virtual int GetByteCount(char[] chars)
  [Pure]
  public virtual int GetByteCount(String s)
  {
- if (s==null)
+ if (s == null)
  throw new ArgumentNullException(nameof(s));
  Contract.EndContractBlock();
 
@@ -884,6 +884,34 @@ public virtual int GetByteCount(String s)
  [Pure]
  public abstract int GetByteCount(char[] chars, int index, int count);
 
+ // Returns the number of bytes required to encode a string range.
+ //
+ [Pure]
+ public int GetByteCount(string s, int index, int count)
+ {
+ if (s == null)
+ throw new ArgumentNullException(nameof(s), 
+ Environment.GetResourceString("ArgumentNull_String"));
+ if (index < 0)
+ throw new ArgumentOutOfRangeException(nameof(index),
+ Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
+ if (count < 0)
+ throw new ArgumentOutOfRangeException(nameof(count),
+ Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
+ if (index > s.Length - count)
+ throw new ArgumentOutOfRangeException(nameof(index),
+ Environment.GetResourceString("ArgumentOutOfRange_IndexCount"));
+ Contract.EndContractBlock();
+
+ unsafe
+ {
+ fixed (char* pChar = s)
+ {
+ return GetByteCount(pChar + index, count);
+ }
+ }
+ }
+
  // We expect this to be the workhorse for NLS encodings
  // unfortunately for existing overrides, it has to call the [] version,
  // which is really slow, so this method should be avoided if you're calling
@@ -978,10 +1006,49 @@ public virtual byte[] GetBytes(String s)
  return bytes;
  }
 
+ // Returns a byte array containing the encoded representation of the given
+ // string range.
+ //
+ [Pure]
+ public byte[] GetBytes(string s, int index, int count)
+ {
+ if (s == null)
+ throw new ArgumentNullException(nameof(s),
+ Environment.GetResourceString("ArgumentNull_String"));
+ if (index < 0)
+ throw new ArgumentOutOfRangeException(nameof(index),
+ Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
+ if (count < 0)
+ throw new ArgumentOutOfRangeException(nameof(count),
+ Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
+ if (index > s.Length - count)
+ throw new ArgumentOutOfRangeException(nameof(index),
+ Environment.GetResourceString("ArgumentOutOfRange_IndexCount"));
+ Contract.EndContractBlock();
+
+ unsafe
+ {
+ fixed (char* pChar = s)
+ {
+ int byteCount = GetByteCount(pChar + index, count);
+ if (byteCount == 0)
+ return Array.Empty<byte>();
+
+ byte[] bytes = new byte[byteCount];
+ fixed (byte* pBytes = &bytes[0])
+ {
+ int bytesReceived = GetBytes(pChar + index, count, pBytes, byteCount);
+ Debug.Assert(byteCount == bytesReceived);
+ }
+ return bytes;
+ }
+ }
+ }
+
  public virtual int GetBytes(String s, int charIndex, int charCount,
  byte[] bytes, int byteIndex)
  {
- if (s==null)
+ if (s == null)
  throw new ArgumentNullException(nameof(s));
  Contract.EndContractBlock();
  return GetBytes(s.ToCharArray(), charIndex, charCount, bytes, byteIndex);