private static SqlTokenInfo ReadQuotedString(ReadOnlySpan <char> peekBuffer, int peekLength, SqlCharReader reader)
{
Debug.Assert(peekBuffer.Length >= 1);
Debug.Assert(peekLength >= 1);
Debug.Assert(!(reader is null));
// Perf: Assume string is N chars
const int averageLen = 256;
var cap = peekLength + averageLen;
var sb = new StringBuilder(cap);
// We already know the incoming data is "<quote>", so keep it
var len = peekBuffer[0] == '\'' || peekBuffer[0] == '"' ? 1 : 2;
sb.Append(peekBuffer.Slice(0, len));
// Undo any extraneous data
if (peekLength > len)
{
reader.Undo(peekBuffer.Slice(len, peekLength - len));
}
// Read string value
switch (peekBuffer[0])
{
case '"': // "abc"
{
SqlTokenInfo token = ReadQuotedString(sb, '"', reader);
return(token);
}
case '\'': // 'abc'
{
SqlTokenInfo token = ReadQuotedString(sb, '\'', reader);
return(token);
}
case 'N': // N'abc'
if (peekLength >= 2 && peekBuffer[1] == '\'')
{
SqlTokenInfo token = ReadQuotedString(sb, '\'', reader);
return(token);
}
break;
}
throw new ArgumentException("Invalid quoted string: " + new string(peekBuffer.Slice(0, peekLength)));
}
private static SqlTokenInfo ReadSymbol(char[] peekBuffer, int peekLength, SqlCharReader reader)
{
Debug.Assert(peekBuffer != null);
Debug.Assert(peekBuffer.Length >= 1);
Debug.Assert(peekLength >= 1);
Debug.Assert(reader != null);
if (peekLength >= 2)
{
// First check if it's a double-symbol
var peek = new string(peekBuffer, 0, 2);
switch (peek)
{
// Math
case "+=":
case "-=":
case "*=":
case "/=":
case "%=":
// Logical
case "&=":
case "|=":
case "^=":
// Comparison
case ">=":
case "<=":
case "<>":
case "!<":
case "!=":
case "!>":
// Programmatic
case "::":
var doubleToken = new SqlTokenInfo(SqlTokenKind.Symbol, peekBuffer, 0, peekLength);
return(doubleToken);
}
}
// It must have been a single symbol
reader.Undo(peekBuffer, 1, peekLength - 1);
var token = new SqlTokenInfo(SqlTokenKind.Symbol, peekBuffer, 0, 1);
return(token);
}
private static SqlTokenInfo ReadLiteral(char[] peekBuffer, int peekLength, SqlCharReader reader)
{
Debug.Assert(peekBuffer != null);
Debug.Assert(peekBuffer.Length >= 1);
Debug.Assert(peekLength >= 1);
Debug.Assert(reader != null);
// Sql literals are generally short
var cap = peekLength + 32;
var buffer = new char[cap];
var sb = new StringBuilder(cap);
// We already know the incoming data is "<literal>", so keep it
sb.Append(peekBuffer, 0, 1);
// Undo any extraneous data
if (peekLength >= 2)
{
reader.Undo(peekBuffer, 1, peekLength - 1);
}
while (true)
{
reader.FillRemaining(buffer, 0, out var count);
if (count <= 0)
{
break;
}
for (var i = 0; i < count; i++)
{
switch (buffer[i])
{
// Math
case '+':
case '-':
case '*':
case '/':
case '%':
// Logical
case '&':
case '|':
case '^':
case '~':
// Comparison
case '>':
case '<':
case '!':
case '=':
// Quote
case '\'':
case '"':
// Symbol
case ',':
case '.':
case ';':
case ':':
case '(':
case ')':
// Exit if delimiter
break;
default:
// Exit if whitespace
if (char.IsWhiteSpace(buffer[i]))
{
break;
}
// Loop if not whitespace
continue;
}
if (i >= 1)
{
sb.Append(buffer, 0, i);
}
reader.Undo(buffer, i, count - i);
var t1 = new SqlTokenInfo(SqlTokenKind.Literal, sb);
return(t1);
}
sb.Append(buffer, 0, count);
}
var token = new SqlTokenInfo(SqlTokenKind.Literal, sb);
return(token);
}
/// <summary>
///
/// </summary>
/// <param name="peekBuffer"></param>
/// <param name="peekLength"></param>
/// <param name="isBlockComment"></param>
/// <param name="reader"></param>
/// <param name="skipSundry">Do not emit sundry tokens (such as comments and whitespace) in the output.</param>
/// <returns></returns>
private static SqlTokenInfo ReadLineComment(char[] peekBuffer, SqlCharReader reader, bool skipSundry)
{
Debug.Assert(reader != null);
Debug.Assert(peekBuffer != null);
Debug.Assert(peekBuffer.Length >= 1);
// Perf: Assume comment is N chars
const int bufferLen = 30;
var buffer = new char[bufferLen];
var sb = skipSundry ? null : new StringBuilder(2 + bufferLen);
// We already know the peeked token is --, so keep it
if (!skipSundry)
{
sb.Append("--");
}
while (true)
{
reader.FillLength(buffer, bufferLen, out var count);
if (count <= 0)
{
break;
}
// Try find a delimiter
var idx = -1;
for (var i = 0; i < count; i++)
{
// Final character in both Windows (\r\n) and Linux (\n) line-endings is \n.
if (!Contains(buffer, i, count, '\n'))
{
continue;
}
idx = i;
break;
}
// If we found a delimiter
if (idx >= 0)
{
// Undo any extraneous data and exit the loop
if (!skipSundry)
{
sb.Append(buffer, 0, idx + 1);
}
reader.Undo(buffer, idx + 1, count - idx - 1);
break;
}
if (!skipSundry)
{
sb.Append(buffer, 0, count);
}
// Exit if eof
if (count < bufferLen)
{
break;
}
}
var token = new SqlTokenInfo(SqlTokenKind.LineComment, sb);
return(token);
}
private static SqlTokenInfo ReadQuotedString(StringBuilder sb, char delimiter, SqlCharReader reader)
{
Debug.Assert(sb != null);
Debug.Assert(reader != null);
var buffer = new char[sb.Capacity];
while (true)
{
reader.FillLength(buffer, 4, out var count);
if (count <= 0)
{
break;
}
var eof = count <= 3;
var cnt = eof ? count : count - 3;
// Try find a delimiter
var idx = -1;
for (var i = 0; i < cnt; i++)
{
if (!Contains(buffer, i, count, delimiter))
{
continue;
}
idx = i;
break;
}
// If we found a delimiter
if (idx >= 0)
{
// If it is an escaped delimiter
if (idx >= 1 && Contains(buffer, idx - 1, count, delimiter, delimiter))
{
// Keep going
sb.Append(buffer, 0, idx + 2);
reader.Undo(buffer, idx + 2, count - idx - 2);
continue;
}
// Else undo any extraneous data and exit the loop
sb.Append(buffer, 0, idx + 1);
reader.Undo(buffer, idx + 1, count - idx - 1);
break;
}
sb.Append(buffer, 0, cnt);
// Exit if no more data
if (eof)
{
break;
}
// Ensure we can peek again
reader.Undo(buffer, cnt, 3);
}
var token = new SqlTokenInfo(SqlTokenKind.QuotedString, sb);
return(token);
}
private static SqlTokenInfo ReadSquareString(char[] peekBuffer, int peekLength, SqlCharReader reader)
{
Debug.Assert(peekBuffer != null);
Debug.Assert(peekBuffer.Length >= 1);
Debug.Assert(peekBuffer[0] == '[');
Debug.Assert(peekLength >= 1);
Debug.Assert(reader != null);
// Sql Identifiers are max 128 chars
var cap = peekLength + 128;
var buffer = new char[cap];
var sb = new StringBuilder(cap);
// We already know the incoming data is [, so keep it
sb.Append(peekBuffer, 0, 1);
// Undo any extraneous data
if (peekLength > 1)
{
reader.Undo(peekBuffer, 1, peekLength - 1);
}
while (true)
{
reader.FillLength(buffer, 4, out var count);
if (count <= 0)
{
break;
}
var eof = count <= 3;
var cnt = eof ? count : count - 3;
// Try find a delimiter
var idx = -1;
for (var i = 0; i < cnt; i++)
{
if (!Contains(buffer, i, count, ']'))
{
continue;
}
idx = i;
break;
}
// If we found a delimiter
if (idx >= 0)
{
// If it is an escaped delimiter
// https://docs.microsoft.com/en-us/sql/t-sql/functions/quotename-transact-sql
if (idx >= 1 && Contains(buffer, idx, count, ']', ']'))
{
// Keep going
sb.Append(buffer, 0, idx + 2);
reader.Undo(buffer, idx + 2, count - idx - 2);
continue;
}
// Else undo any extraneous data and exit the loop
sb.Append(buffer, 0, idx + 1);
reader.Undo(buffer, idx + 1, count - idx - 1);
break;
}
sb.Append(buffer, 0, cnt);
// Exit if no more data
if (eof)
{
break;
}
// Ensure we can peek again
reader.Undo(buffer, cnt, 3);
}
var token = new SqlTokenInfo(SqlTokenKind.SquareString, sb);
return(token);
}
/// <summary>
///
/// </summary>
/// <param name="peekBuffer"></param>
/// <param name="peekLength"></param>
/// <param name="reader"></param>
/// <param name="skipSundry">Do not emit sundry tokens (such as comments and whitespace) in the output.</param>
/// <returns></returns>
private static SqlTokenInfo ReadWhitespace(char[] peekBuffer, int peekLength, SqlCharReader reader, bool skipSundry)
{
Debug.Assert(peekBuffer != null);
Debug.Assert(peekBuffer.Length >= 1);
Debug.Assert(peekLength >= 1);
Debug.Assert(reader != null);
// Fast path for single whitespace
if (peekLength >= 2 &&
!char.IsWhiteSpace(peekBuffer[1]))
{
// Undo any extraneous data
reader.Undo(peekBuffer, 1, peekLength - 1);
var t0 = new SqlTokenInfo(SqlTokenKind.Whitespace, peekBuffer[0]);
return(t0);
}
// Perf: Assume whitespace is N chars
const int averageLen = 10;
var cap = peekLength + averageLen;
var buffer = new char[cap];
var sb = skipSundry ? null : new StringBuilder(cap);
// We already know the incoming data is "<whitespace>", so keep it
if (!skipSundry)
{
sb.Append(peekBuffer, 0, peekLength);
}
while (true)
{
reader.FillRemaining(buffer, 0, out var count);
if (count <= 0)
{
break;
}
// Try find any non-whitespace in current batch
var idx = -1;
for (var i = 0; i < count; i++)
{
if (!char.IsWhiteSpace(buffer[i]))
{
idx = i;
break;
}
}
// If we found any non-whitespace
if (idx >= 0)
{
// Undo any extraneous data and exit the loop
if (!skipSundry)
{
sb.Append(buffer, 0, idx);
}
reader.Undo(buffer, idx, count - idx);
break;
}
// Else keep the whitespace and check next batch
if (!skipSundry)
{
sb.Append(buffer, 0, count);
}
}
var token = new SqlTokenInfo(SqlTokenKind.Whitespace, sb);
return(token);
}
/// <summary>
///
/// </summary>
/// <param name="peekBuffer"></param>
/// <param name="reader"></param>
/// <param name="skipSundry">Do not emit sundry tokens (such as comments and whitespace) in the output.</param>
private static SqlTokenInfo ReadBlockComment(SqlCharReader reader, bool skipSundry)
{
Debug.Assert(!(reader is null));
// Perf: Assume comment is N chars
const int bufferLen = 50;
Span <char> buffer = stackalloc char[bufferLen];
StringBuilder sb = skipSundry ? null : new StringBuilder(2 + bufferLen);
// We already know the peeked token is /*, so keep it
if (!skipSundry)
{
sb.Append("/*");
}
while (true)
{
reader.FillLength(buffer, bufferLen, out var count);
if (count <= 0)
{
break;
}
// Try find a delimiter
var idx = -1;
for (var i = 0; i < count; i++)
{
if (!Contains(buffer.Slice(i, count - i), '*', '/'))
{
continue;
}
idx = i;
break;
}
// If we found a delimiter
if (idx >= 0)
{
// Undo any extraneous data and exit the loop
if (!skipSundry)
{
sb.Append(buffer.Slice(0, idx + 2));
}
reader.Undo(buffer.Slice(idx + 2, count - idx - 2));
break;
}
if (!skipSundry)
{
sb.Append(buffer.Slice(0, count));
}
// Exit if eof
if (count < bufferLen)
{
break;
}
}
var token = new SqlTokenInfo(SqlTokenKind.BlockComment, sb);
return(token);
}