ClickHouse/src/Functions/numLiteralChars.h
2023-03-06 17:08:55 +08:00

45 lines
1.2 KiB
C++

#pragma once
#include <base/types.h>
namespace DB
{
/// Counts the number of literal characters in Joda format string until the next closing literal
/// sequence single quote. Returns -1 if no literal single quote was found.
/// In Joda format string(https://joda-time.sourceforge.net/apidocs/org/joda/time/format/DateTimeFormat.html)
/// literal content must be quoted with single quote. and two single quote means literal with one single quote.
/// For example:
/// Format string: "'aaaa'", unescaped literal: "aaaa";
/// Format string: "'aa''aa'", unescaped literal: "aa'aa";
/// Format string: "'aaa''aa" is not valid because of missing of end single quote.
inline Int64 numLiteralChars(const char * cur, const char * end)
{
bool found = false;
Int64 count = 0;
while (cur < end)
{
if (*cur == '\'')
{
if (cur + 1 < end && *(cur + 1) == '\'')
{
count += 2;
cur += 2;
}
else
{
found = true;
break;
}
}
else
{
++count;
++cur;
}
}
return found ? count : -1;
}
}