// Unescapes entire string and checks if it has unicode chars
// Also checks for sequences that are 3986 Unreserved characters as these should be un-escaped
private static bool CheckForUnicodeOrEscapedUnreserved(string data)
{
for (int i = 0; i < data.Length; i++)
{
char c = data[i];
if (c == '%')
{
if ((uint)(i + 2) < (uint)data.Length)
{
char value = UriHelper.DecodeHexChars(data[i + 1], data[i + 2]);
if (value >= UriHelper.UnreservedTable.Length || UriHelper.UnreservedTable[value])
{
return(true);
}
i += 2;
}
}
else if (c > 0x7F)
{
return(true);
}
}
return(false);
}
//
// IRI normalization for strings containing characters that are not allowed or
// escaped characters that should be unescaped in the context of the specified Uri component.
//
internal static unsafe string EscapeUnescapeIri(char *pInput, int start, int end, UriComponents component)
{
int size = end - start;
ValueStringBuilder dest = size <= 256
? new ValueStringBuilder(stackalloc char[256])
: new ValueStringBuilder(size);
Span <byte> maxUtf8EncodedSpan = stackalloc byte[4];
for (int i = start; i < end; ++i)
{
char ch = pInput[i];
if (ch == '%')
{
if (end - i > 2)
{
ch = UriHelper.DecodeHexChars(pInput[i + 1], pInput[i + 2]);
// Do not unescape a reserved char
if (ch == Uri.c_DummyChar || ch == '%' || CheckIsReserved(ch, component) || UriHelper.IsNotSafeForUnescape(ch))
{
// keep as is
dest.Append(pInput[i++]);
dest.Append(pInput[i++]);
dest.Append(pInput[i]);
continue;
}
else if (ch <= '\x7F')
{
Debug.Assert(ch < 0xFF, "Expecting ASCII character.");
//ASCII
dest.Append(ch);
i += 2;
continue;
}
else
{
// possibly utf8 encoded sequence of unicode
int charactersRead = PercentEncodingHelper.UnescapePercentEncodedUTF8Sequence(
pInput + i,
end - i,
ref dest,
component == UriComponents.Query,
iriParsing: true);
Debug.Assert(charactersRead > 0);
i += charactersRead - 1; // -1 as i will be incremented in the loop
}
}
else
{
dest.Append(pInput[i]);
}
}
else if (ch > '\x7f')
{
// unicode
bool isInIriUnicodeRange;
bool surrogatePair = false;
char ch2 = '\0';
if ((char.IsHighSurrogate(ch)) && (i + 1 < end))
{
ch2 = pInput[i + 1];
isInIriUnicodeRange = CheckIriUnicodeRange(ch, ch2, out surrogatePair, component == UriComponents.Query);
}
else
{
isInIriUnicodeRange = CheckIriUnicodeRange(ch, component == UriComponents.Query);
}
if (isInIriUnicodeRange)
{
dest.Append(ch);
if (surrogatePair)
{
dest.Append(ch2);
}
}
else
{
Rune rune;
if (surrogatePair)
{
rune = new Rune(ch, ch2);
}
else if (!Rune.TryCreate(ch, out rune))
{
rune = Rune.ReplacementChar;
}
int bytesWritten = rune.EncodeToUtf8(maxUtf8EncodedSpan);
Span <byte> encodedBytes = maxUtf8EncodedSpan.Slice(0, bytesWritten);
foreach (byte b in encodedBytes)
{
UriHelper.EscapeAsciiChar(b, ref dest);
}
}
if (surrogatePair)
{
i++;
}
}
else
{
// just copy the character
dest.Append(pInput[i]);
}
}
return(dest.ToString());
}
//
// IRI normalization for strings containing characters that are not allowed or
// escaped characters that should be unescaped in the context of the specified Uri component.
//
internal static unsafe string EscapeUnescapeIri(char *pInput, int start, int end, UriComponents component)
{
int size = end - start;
ValueStringBuilder dest = new ValueStringBuilder(size);
byte[]? bytes = null;
int next = start;
char ch;
Span <byte> maxUtf8EncodedSpan = stackalloc byte[4];
for (; next < end; ++next)
{
if ((ch = pInput[next]) == '%')
{
if (next + 2 < end)
{
ch = UriHelper.DecodeHexChars(pInput[next + 1], pInput[next + 2]);
// Do not unescape a reserved char
if (ch == Uri.c_DummyChar || ch == '%' || CheckIsReserved(ch, component) || UriHelper.IsNotSafeForUnescape(ch))
{
// keep as is
dest.Append(pInput[next++]);
dest.Append(pInput[next++]);
dest.Append(pInput[next]);
continue;
}
else if (ch <= '\x7F')
{
Debug.Assert(ch < 0xFF, "Expecting ASCII character.");
//ASCII
dest.Append(ch);
next += 2;
continue;
}
else
{
// possibly utf8 encoded sequence of unicode
// check if safe to unescape according to Iri rules
Debug.Assert(ch < 0xFF, "Expecting ASCII character.");
int startSeq = next;
int byteCount = 1;
// lazy initialization of max size, will reuse the array for next sequences
if (bytes is null)
{
bytes = new byte[end - next];
}
bytes[0] = (byte)ch;
next += 3;
while (next < end)
{
// Check on exit criterion
if ((ch = pInput[next]) != '%' || next + 2 >= end)
{
break;
}
// already made sure we have 3 characters in str
ch = UriHelper.DecodeHexChars(pInput[next + 1], pInput[next + 2]);
//invalid hex sequence ?
if (ch == Uri.c_DummyChar)
{
break;
}
// character is not part of a UTF-8 sequence ?
else if (ch < '\x80')
{
break;
}
else
{
//a UTF-8 sequence
bytes[byteCount++] = (byte)ch;
next += 3;
}
Debug.Assert(ch < 0xFF, "Expecting ASCII character.");
}
next--; // for loop will increment
// Using encoder with no replacement fall-back will skip all invalid UTF-8 sequences.
Encoding noFallbackCharUTF8 = Encoding.GetEncoding(
Encoding.UTF8.CodePage,
new EncoderReplacementFallback(""),
new DecoderReplacementFallback(""));
char[] unescapedChars = new char[bytes.Length];
int charCount = noFallbackCharUTF8.GetChars(bytes, 0, byteCount, unescapedChars, 0);
if (charCount != 0)
{
// If invalid sequences were present in the original escaped string, we need to
// copy the escaped versions of those sequences.
// Decoded Unicode values will be kept only when they are allowed by the URI/IRI RFC
// rules.
UriHelper.MatchUTF8Sequence(ref dest, unescapedChars, charCount, bytes,
byteCount, component == UriComponents.Query, true);
}
else
{
// copy escaped sequence as is
for (int i = startSeq; i <= next; ++i)
{
dest.Append(pInput[i]);
}
}
}
}
else
{
dest.Append(pInput[next]);
}
}
else if (ch > '\x7f')
{
// unicode
bool isInIriUnicodeRange;
bool surrogatePair = false;
char ch2 = '\0';
if ((char.IsHighSurrogate(ch)) && (next + 1 < end))
{
ch2 = pInput[next + 1];
isInIriUnicodeRange = CheckIriUnicodeRange(ch, ch2, out surrogatePair, component == UriComponents.Query);
}
else
{
isInIriUnicodeRange = CheckIriUnicodeRange(ch, component == UriComponents.Query);
}
if (isInIriUnicodeRange)
{
dest.Append(ch);
if (surrogatePair)
{
dest.Append(ch2);
}
}
else
{
Rune rune;
if (surrogatePair)
{
rune = new Rune(ch, ch2);
}
else if (!Rune.TryCreate(ch, out rune))
{
rune = Rune.ReplacementChar;
}
int bytesWritten = rune.EncodeToUtf8(maxUtf8EncodedSpan);
Span <byte> encodedBytes = maxUtf8EncodedSpan.Slice(0, bytesWritten);
foreach (byte b in encodedBytes)
{
UriHelper.EscapeAsciiChar(b, ref dest);
}
}
if (surrogatePair)
{
next++;
}
}
else
{
// just copy the character
dest.Append(pInput[next]);
}
}
string result = dest.ToString();
return(result);
}
public static unsafe int UnescapePercentEncodedUTF8Sequence(char *input, int length, ref ValueStringBuilder dest, bool isQuery, bool iriParsing)
{
// The following assertions rely on the input not mutating mid-operation, as is the case currently since callers are working with strings
// If we start accepting input such as spans, this method must be audited to ensure no buffer overruns/infinite loops could occur
// As an optimization, this method should only be called after the first character is known to be a part of a non-ascii UTF8 sequence
Debug.Assert(length >= 3);
Debug.Assert(input[0] == '%');
Debug.Assert(UriHelper.DecodeHexChars(input[1], input[2]) != Uri.c_DummyChar);
Debug.Assert(UriHelper.DecodeHexChars(input[1], input[2]) >= 128);
uint fourByteBuffer = 0;
int bytesLeftInBuffer = 0;
int totalCharsConsumed = 0;
int charsToCopy = 0;
int bytesConsumed = 0;
RefillBuffer:
int i = totalCharsConsumed + (bytesLeftInBuffer * 3);
ReadByteFromInput:
if ((uint)(length - i) <= 2 || input[i] != '%')
{
goto NoMoreOrInvalidInput;
}
uint value = input[i + 1];
if ((uint)((value - 'A') & ~0x20) <= ('F' - 'A'))
{
value = (value | 0x20) - 'a' + 10;
}
else if ((value - '8') <= ('9' - '8'))
{
value -= '0';
}
else
{
goto NoMoreOrInvalidInput; // First character wasn't hex or was <= 7F (Ascii)
}
uint second = (uint)input[i + 2] - '0';
if (second <= 9)
{
// second is already [0, 9]
}
else if ((uint)((second - ('A' - '0')) & ~0x20) <= ('F' - 'A'))
{
second = ((second + '0') | 0x20) - 'a' + 10;
}
else
{
goto NoMoreOrInvalidInput; // Second character wasn't Hex
}
value = (value << 4) | second;
Debug.Assert(value >= 128);
// Rotate the buffer and overwrite the last byte
if (BitConverter.IsLittleEndian)
{
fourByteBuffer = (fourByteBuffer >> 8) | (value << 24);
}
else
{
fourByteBuffer = (fourByteBuffer << 8) | value;
}
if (++bytesLeftInBuffer != 4)
{
i += 3;
goto ReadByteFromInput;
}
DecodeRune:
Debug.Assert(totalCharsConsumed % 3 == 0);
Debug.Assert(bytesLeftInBuffer == 2 || bytesLeftInBuffer == 3 || bytesLeftInBuffer == 4);
Debug.Assert((fourByteBuffer & (BitConverter.IsLittleEndian ? 0x00000080 : 0x80000000)) != 0);
Debug.Assert((fourByteBuffer & (BitConverter.IsLittleEndian ? 0x00008000 : 0x00800000)) != 0);
Debug.Assert(bytesLeftInBuffer < 3 || (fourByteBuffer & (BitConverter.IsLittleEndian ? 0x00800000 : 0x00008000)) != 0);
Debug.Assert(bytesLeftInBuffer < 4 || (fourByteBuffer & (BitConverter.IsLittleEndian ? 0x80000000 : 0x00000080)) != 0);
uint temp = fourByteBuffer; // make a copy so that the *copy* (not the original) is marked address-taken
if (Rune.DecodeFromUtf8(new ReadOnlySpan <byte>(&temp, bytesLeftInBuffer), out Rune rune, out bytesConsumed) == OperationStatus.Done)
{
Debug.Assert(bytesConsumed >= 2, $"Rune.DecodeFromUtf8 consumed {bytesConsumed} bytes, likely indicating input was modified concurrently during UnescapePercentEncodedUTF8Sequence's execution");
if (!iriParsing || IriHelper.CheckIriUnicodeRange((uint)rune.Value, isQuery))
{
if (charsToCopy != 0)
{
dest.Append(input + totalCharsConsumed - charsToCopy, charsToCopy);
charsToCopy = 0;
}
dest.Append(rune);
goto AfterDecodeRune;
}
}