/// <summary>
/// Checks 9 bytes from <paramref name="begin"/> correspond to a known HTTP version.
/// </summary>
/// <remarks>
/// A "known HTTP version" Is is either HTTP/1.0 or HTTP/1.1.
/// Since those fit in 8 bytes, they can be optimally looked up by reading those bytes as a long. Once
/// in that format, it can be checked against the known versions.
/// The Known versions will be checked with the required '\r'.
/// To optimize performance the HTTP/1.1 will be checked first.
/// </remarks>
/// <param name="begin">The iterator from which to start the known string lookup.</param>
/// <param name="scan">If we found a valid method, then scan will be updated to new position</param>
/// <param name="knownVersion">A reference to a pre-allocated known string, if the input matches any.</param>
/// <returns><c>true</c> if the input matches a known string, <c>false</c> otherwise.</returns>
public static bool GetKnownVersion(this MemoryPoolIterator begin, ref MemoryPoolIterator scan, out string knownVersion)
{
knownVersion = null;
var value = begin.PeekLong();
if (value == _http11VersionLong)
{
knownVersion = Http11Version;
scan.Skip(8);
if (scan.Take() == '\r')
{
return(true);
}
}
else if (value == _http10VersionLong)
{
knownVersion = Http10Version;
scan.Skip(8);
if (scan.Take() == '\r')
{
return(true);
}
}
knownVersion = null;
return(false);
}
public int GetLength(MemoryPoolIterator end)
{
if (IsDefault || end.IsDefault)
{
return(-1);
}
var block = _block;
var index = _index;
var length = 0;
checked
{
while (true)
{
if (block == end._block)
{
return(length + end._index - index);
}
else if (block.Next == null)
{
throw new InvalidOperationException("end did not follow iterator");
}
else
{
length += block.End - index;
block = block.Next;
index = block.Start;
}
}
}
}
public static ArraySegment <byte> GetArraySegment(this MemoryPoolIterator start, MemoryPoolIterator end)
{
if (start.IsDefault || end.IsDefault)
{
return(default(ArraySegment <byte>));
}
if (end.Block == start.Block)
{
return(new ArraySegment <byte>(start.Block.Array, start.Index, end.Index - start.Index));
}
var length = start.GetLength(end);
var array = new byte[length];
start.CopyTo(array, 0, length, out length);
return(new ArraySegment <byte>(array, 0, length));
}
/// <summary>
/// Checks that up to 8 bytes from <paramref name="begin"/> correspond to a known HTTP method.
/// </summary>
/// <remarks>
/// A "known HTTP method" can be an HTTP method name defined in the HTTP/1.1 RFC.
/// Since all of those fit in at most 8 bytes, they can be optimally looked up by reading those bytes as a long. Once
/// in that format, it can be checked against the known method.
/// The Known Methods (CONNECT, DELETE, GET, HEAD, PATCH, POST, PUT, OPTIONS, TRACE) are all less than 8 bytes
/// and will be compared with the required space. A mask is used if the Known method is less than 8 bytes.
/// To optimize performance the GET method will be checked first.
/// </remarks>
/// <param name="begin">The iterator from which to start the known string lookup.</param>
/// <param name="scan">If we found a valid method, then scan will be updated to new position</param>
/// <param name="knownMethod">A reference to a pre-allocated known string, if the input matches any.</param>
/// <returns><c>true</c> if the input matches a known string, <c>false</c> otherwise.</returns>
public static bool GetKnownMethod(this MemoryPoolIterator begin, ref MemoryPoolIterator scan, out string knownMethod)
{
knownMethod = null;
var value = begin.PeekLong();
if ((value & _mask4Chars) == _httpGetMethodLong)
{
knownMethod = HttpGetMethod;
scan.Skip(4);
return(true);
}
foreach (var x in _knownMethods)
{
if ((value & x.Item1) == x.Item2)
{
knownMethod = x.Item3;
scan.Skip(knownMethod.Length + 1);
return(true);
}
}
return(false);
}
public unsafe static string GetAsciiString(this MemoryPoolIterator start, MemoryPoolIterator end)
{
if (start.IsDefault || end.IsDefault)
{
return(null);
}
var length = start.GetLength(end);
if (length == 0)
{
return(null);
}
// Bytes out of the range of ascii are treated as "opaque data"
// and kept in string as a char value that casts to same input byte value
// https://tools.ietf.org/html/rfc7230#section-3.2.4
var inputOffset = start.Index;
var block = start.Block;
var asciiString = new string('\0', length);
fixed(char *outputStart = asciiString)
{
var output = outputStart;
var remaining = length;
var endBlock = end.Block;
var endIndex = end.Index;
while (true)
{
int following = (block != endBlock ? block.End : endIndex) - inputOffset;
if (following > 0)
{
fixed(byte *blockStart = block.Array)
{
var input = blockStart + inputOffset;
var i = 0;
while (i < following - 11)
{
i += 12;
*(output) = (char)*(input);
*(output + 1) = (char)*(input + 1);
*(output + 2) = (char)*(input + 2);
*(output + 3) = (char)*(input + 3);
*(output + 4) = (char)*(input + 4);
*(output + 5) = (char)*(input + 5);
*(output + 6) = (char)*(input + 6);
*(output + 7) = (char)*(input + 7);
*(output + 8) = (char)*(input + 8);
*(output + 9) = (char)*(input + 9);
*(output + 10) = (char)*(input + 10);
*(output + 11) = (char)*(input + 11);
output += 12;
input += 12;
}
if (i < following - 5)
{
i += 6;
*(output) = (char)*(input);
*(output + 1) = (char)*(input + 1);
*(output + 2) = (char)*(input + 2);
*(output + 3) = (char)*(input + 3);
*(output + 4) = (char)*(input + 4);
*(output + 5) = (char)*(input + 5);
output += 6;
input += 6;
}
if (i < following - 3)
{
i += 4;
*(output) = (char)*(input);
*(output + 1) = (char)*(input + 1);
*(output + 2) = (char)*(input + 2);
*(output + 3) = (char)*(input + 3);
output += 4;
input += 4;
}
while (i < following)
{
i++;
*output = (char)*input;
output++;
input++;
}
remaining -= following;
}
}
if (remaining == 0)
{
break;
}
block = block.Next;
inputOffset = block.Start;
}
}
return(asciiString);
}
public static string GetUtf8String(this MemoryPoolIterator start, MemoryPoolIterator end)
{
if (start.IsDefault || end.IsDefault)
{
return(default(string));
}
if (end.Block == start.Block)
{
return(_utf8.GetString(start.Block.Array, start.Index, end.Index - start.Index));
}
var decoder = _utf8.GetDecoder();
var length = start.GetLength(end);
var charLength = length * 2;
var chars = new char[charLength];
var charIndex = 0;
var block = start.Block;
var index = start.Index;
var remaining = length;
while (true)
{
int bytesUsed;
int charsUsed;
bool completed;
var following = block.End - index;
if (remaining <= following)
{
decoder.Convert(
block.Array,
index,
remaining,
chars,
charIndex,
charLength - charIndex,
true,
out bytesUsed,
out charsUsed,
out completed);
return(new string(chars, 0, charIndex + charsUsed));
}
else if (block.Next == null)
{
decoder.Convert(
block.Array,
index,
following,
chars,
charIndex,
charLength - charIndex,
true,
out bytesUsed,
out charsUsed,
out completed);
return(new string(chars, 0, charIndex + charsUsed));
}
else
{
decoder.Convert(
block.Array,
index,
following,
chars,
charIndex,
charLength - charIndex,
false,
out bytesUsed,
out charsUsed,
out completed);
charIndex += charsUsed;
remaining -= following;
block = block.Next;
index = block.Start;
}
}
}
