/usr/include/kj/parse/char.h is in libcapnp-dev 0.4.0-1ubuntu2.
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// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this
// list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
// ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// This file contains parsers useful for character stream inputs, including parsers to parse
// common kinds of tokens like identifiers, numbers, and quoted strings.
#ifndef KJ_PARSE_CHAR_H_
#define KJ_PARSE_CHAR_H_
#include "common.h"
#include "../string.h"
#include <inttypes.h>
namespace kj {
namespace parse {
// =======================================================================================
// Exact char/string.
class ExactString_ {
public:
constexpr inline ExactString_(const char* str): str(str) {}
template <typename Input>
Maybe<Tuple<>> operator()(Input& input) const {
const char* ptr = str;
while (*ptr != '\0') {
if (input.atEnd() || input.current() != *ptr) return nullptr;
input.next();
++ptr;
}
return Tuple<>();
}
private:
const char* str;
};
constexpr inline ExactString_ exactString(const char* str) {
return ExactString_(str);
}
template <char c>
constexpr ExactlyConst_<char, c> exactChar() {
// Returns a parser that matches exactly the character given by the template argument (returning
// no result).
return ExactlyConst_<char, c>();
}
// =======================================================================================
// Char ranges / sets
class CharGroup_ {
public:
constexpr inline CharGroup_(): bits{0, 0, 0, 0} {}
constexpr inline CharGroup_ orRange(unsigned char first, unsigned char last) const {
return CharGroup_(bits[0] | (oneBits(last + 1) & ~oneBits(first )),
bits[1] | (oneBits(last - 63) & ~oneBits(first - 64)),
bits[2] | (oneBits(last - 127) & ~oneBits(first - 128)),
bits[3] | (oneBits(last - 191) & ~oneBits(first - 192)));
}
constexpr inline CharGroup_ orAny(const char* chars) const {
return *chars == 0 ? *this : orChar(*chars).orAny(chars + 1);
}
constexpr inline CharGroup_ orChar(unsigned char c) const {
return CharGroup_(bits[0] | bit(c),
bits[1] | bit(c - 64),
bits[2] | bit(c - 128),
bits[3] | bit(c - 256));
}
constexpr inline CharGroup_ orGroup(CharGroup_ other) const {
return CharGroup_(bits[0] | other.bits[0],
bits[1] | other.bits[1],
bits[2] | other.bits[2],
bits[3] | other.bits[3]);
}
constexpr inline CharGroup_ invert() const {
return CharGroup_(~bits[0], ~bits[1], ~bits[2], ~bits[3]);
}
template <typename Input>
Maybe<char> operator()(Input& input) const {
if (input.atEnd()) return nullptr;
unsigned char c = input.current();
if ((bits[c / 64] & (1ll << (c % 64))) != 0) {
input.next();
return c;
} else {
return nullptr;
}
}
private:
typedef unsigned long long Bits64;
constexpr inline CharGroup_(Bits64 a, Bits64 b, Bits64 c, Bits64 d): bits{a, b, c, d} {}
Bits64 bits[4];
static constexpr inline Bits64 oneBits(int count) {
return count <= 0 ? 0ll : count >= 64 ? -1ll : ((1ll << count) - 1);
}
static constexpr inline Bits64 bit(int index) {
return index < 0 ? 0 : index >= 64 ? 0 : (1ll << index);
}
};
constexpr inline CharGroup_ charRange(char first, char last) {
// Create a parser which accepts any character in the range from `first` to `last`, inclusive.
// For example: `charRange('a', 'z')` matches all lower-case letters. The parser's result is the
// character matched.
//
// The returned object has methods which can be used to match more characters. The following
// produces a parser which accepts any letter as well as '_', '+', '-', and '.'.
//
// charRange('a', 'z').orRange('A', 'Z').orChar('_').orAny("+-.")
//
// You can also use `.invert()` to match the opposite set of characters.
return CharGroup_().orRange(first, last);
}
constexpr inline CharGroup_ anyOfChars(const char* chars) {
// Returns a parser that accepts any of the characters in the given string (which should usually
// be a literal). The returned parser is of the same type as returned by `charRange()` -- see
// that function for more info.
return CharGroup_().orAny(chars);
}
// =======================================================================================
namespace _ { // private
struct ArrayToString {
inline String operator()(const Array<char>& arr) const {
return heapString(arr);
}
};
} // namespace _ (private)
template <typename SubParser>
constexpr inline auto charsToString(SubParser&& subParser)
-> decltype(transform(kj::fwd<SubParser>(subParser), _::ArrayToString())) {
// Wraps a parser that returns Array<char> such that it returns String instead.
return parse::transform(kj::fwd<SubParser>(subParser), _::ArrayToString());
}
// =======================================================================================
// Basic character classes.
constexpr auto alpha = charRange('a', 'z').orRange('A', 'Z');
constexpr auto digit = charRange('0', '9');
constexpr auto alphaNumeric = alpha.orGroup(digit);
constexpr auto nameStart = alpha.orChar('_');
constexpr auto nameChar = alphaNumeric.orChar('_');
constexpr auto hexDigit = charRange('0', '9').orRange('a', 'f').orRange('A', 'F');
constexpr auto octDigit = charRange('0', '7');
constexpr auto whitespaceChar = anyOfChars(" \f\n\r\t\v");
constexpr auto controlChar = charRange(0, 0x1f).invert().orGroup(whitespaceChar).invert();
constexpr auto whitespace = many(anyOfChars(" \f\n\r\t\v"));
constexpr auto discardWhitespace = discard(many(discard(anyOfChars(" \f\n\r\t\v"))));
// Like discard(whitespace) but avoids some memory allocation.
// =======================================================================================
// Identifiers
namespace _ { // private
struct IdentifierToString {
inline String operator()(char first, const Array<char>& rest) const {
String result = heapString(rest.size() + 1);
result[0] = first;
memcpy(result.begin() + 1, rest.begin(), rest.size());
return result;
}
};
} // namespace _ (private)
constexpr auto identifier = transform(sequence(nameStart, many(nameChar)), _::IdentifierToString());
// Parses an identifier (e.g. a C variable name).
// =======================================================================================
// Integers
namespace _ { // private
inline char parseDigit(char c) {
if (c < 'A') return c - '0';
if (c < 'a') return c - 'A' + 10;
return c - 'a' + 10;
}
template <uint base>
struct ParseInteger {
inline uint64_t operator()(const Array<char>& digits) const {
return operator()('0', digits);
}
uint64_t operator()(char first, const Array<char>& digits) const {
uint64_t result = parseDigit(first);
for (char digit: digits) {
result = result * base + parseDigit(digit);
}
return result;
}
};
} // namespace _ (private)
constexpr auto integer = sequence(
oneOf(
transform(sequence(exactChar<'0'>(), exactChar<'x'>(), many(hexDigit)), _::ParseInteger<16>()),
transform(sequence(exactChar<'0'>(), many(octDigit)), _::ParseInteger<8>()),
transform(sequence(charRange('1', '9'), many(digit)), _::ParseInteger<10>())),
notLookingAt(alpha.orAny("_.")));
// =======================================================================================
// Numbers (i.e. floats)
namespace _ { // private
struct ParseFloat {
double operator()(const Array<char>& digits,
const Maybe<Array<char>>& fraction,
const Maybe<Tuple<Maybe<char>, Array<char>>>& exponent) const;
};
} // namespace _ (private)
constexpr auto number = transform(
sequence(
oneOrMore(digit),
optional(sequence(exactChar<'.'>(), many(digit))),
optional(sequence(discard(anyOfChars("eE")), optional(anyOfChars("+-")), many(digit))),
notLookingAt(alpha.orAny("_."))),
_::ParseFloat());
// =======================================================================================
// Quoted strings
namespace _ { // private
struct InterpretEscape {
char operator()(char c) const {
switch (c) {
case 'a': return '\a';
case 'b': return '\b';
case 'f': return '\f';
case 'n': return '\n';
case 'r': return '\r';
case 't': return '\t';
case 'v': return '\v';
default: return c;
}
}
};
struct ParseHexEscape {
inline char operator()(char first, char second) const {
return (parseDigit(first) << 4) | parseDigit(second);
}
};
struct ParseOctEscape {
inline char operator()(char first, Maybe<char> second, Maybe<char> third) const {
char result = first - '0';
KJ_IF_MAYBE(digit1, second) {
result = (result << 3) | (*digit1 - '0');
KJ_IF_MAYBE(digit2, third) {
result = (result << 3) | (*digit2 - '0');
}
}
return result;
}
};
} // namespace _ (private)
constexpr auto escapeSequence =
sequence(exactChar<'\\'>(), oneOf(
transform(anyOfChars("abfnrtv'\"\\\?"), _::InterpretEscape()),
transform(sequence(exactChar<'x'>(), hexDigit, hexDigit), _::ParseHexEscape()),
transform(sequence(octDigit, optional(octDigit), optional(octDigit)),
_::ParseOctEscape())));
// A parser that parses a C-string-style escape sequence (starting with a backslash). Returns
// a char.
constexpr auto doubleQuotedString = charsToString(sequence(
exactChar<'\"'>(),
many(oneOf(anyOfChars("\\\n\"").invert(), escapeSequence)),
exactChar<'\"'>()));
// Parses a C-style double-quoted string.
constexpr auto singleQuotedString = charsToString(sequence(
exactChar<'\''>(),
many(oneOf(anyOfChars("\\\n\'").invert(), escapeSequence)),
exactChar<'\''>()));
// Parses a C-style single-quoted string.
} // namespace parse
} // namespace kj
#endif // KJ_PARSE_CHAR_H_
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