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//===-- include/flang/Parser/char-block.h -----------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef FORTRAN_PARSER_CHAR_BLOCK_H_
#define FORTRAN_PARSER_CHAR_BLOCK_H_
// Describes a contiguous block of characters; does not own their storage.
#include "flang/Common/interval.h"
#include <algorithm>
#include <cstddef>
#include <cstring>
#include <iosfwd>
#include <string>
#include <utility>
namespace llvm {
class raw_ostream;
}
namespace Fortran::parser {
class CharBlock {
public:
constexpr CharBlock() {}
constexpr CharBlock(const char *x, std::size_t n = 1) : interval_{x, n} {}
constexpr CharBlock(const char *b, const char *ep1)
: interval_{b, static_cast<std::size_t>(ep1 - b)} {}
CharBlock(const std::string &s) : interval_{s.data(), s.size()} {}
constexpr CharBlock(const CharBlock &) = default;
constexpr CharBlock(CharBlock &&) = default;
constexpr CharBlock &operator=(const CharBlock &) = default;
constexpr CharBlock &operator=(CharBlock &&) = default;
constexpr bool empty() const { return interval_.empty(); }
constexpr std::size_t size() const { return interval_.size(); }
constexpr const char *begin() const { return interval_.start(); }
constexpr const char *end() const {
return interval_.start() + interval_.size();
}
constexpr const char &operator[](std::size_t j) const {
return interval_.start()[j];
}
bool Contains(const CharBlock &that) const {
return interval_.Contains(that.interval_);
}
void ExtendToCover(const CharBlock &that) {
interval_.ExtendToCover(that.interval_);
}
// Returns the block's first non-blank character, if it has
// one; otherwise ' '.
char FirstNonBlank() const {
for (char ch : *this) {
if (ch != ' ' && ch != '\t') {
return ch;
}
}
return ' '; // non no-blank character
}
// Returns the block's only non-blank character, if it has
// exactly one non-blank character; otherwise ' '.
char OnlyNonBlank() const {
char result{' '};
for (char ch : *this) {
if (ch != ' ' && ch != '\t') {
if (result == ' ') {
result = ch;
} else {
return ' ';
}
}
}
return result;
}
std::size_t CountLeadingBlanks() const {
std::size_t n{size()};
std::size_t j{0};
for (; j < n; ++j) {
char ch{(*this)[j]};
if (ch != ' ' && ch != '\t') {
break;
}
}
return j;
}
bool IsBlank() const { return FirstNonBlank() == ' '; }
std::string ToString() const {
return std::string{interval_.start(), interval_.size()};
}
// Convert to string, stopping early at any embedded '\0'.
std::string NULTerminatedToString() const {
return std::string{interval_.start(),
/*not in std::*/ strnlen(interval_.start(), interval_.size())};
}
bool operator<(const CharBlock &that) const { return Compare(that) < 0; }
bool operator<=(const CharBlock &that) const { return Compare(that) <= 0; }
bool operator==(const CharBlock &that) const { return Compare(that) == 0; }
bool operator!=(const CharBlock &that) const { return Compare(that) != 0; }
bool operator>=(const CharBlock &that) const { return Compare(that) >= 0; }
bool operator>(const CharBlock &that) const { return Compare(that) > 0; }
bool operator<(const char *that) const { return Compare(that) < 0; }
bool operator<=(const char *that) const { return Compare(that) <= 0; }
bool operator==(const char *that) const { return Compare(that) == 0; }
bool operator!=(const char *that) const { return Compare(that) != 0; }
bool operator>=(const char *that) const { return Compare(that) >= 0; }
bool operator>(const char *that) const { return Compare(that) > 0; }
friend bool operator<(const char *, const CharBlock &);
friend bool operator<=(const char *, const CharBlock &);
friend bool operator==(const char *, const CharBlock &);
friend bool operator!=(const char *, const CharBlock &);
friend bool operator>=(const char *, const CharBlock &);
friend bool operator>(const char *, const CharBlock &);
private:
int Compare(const CharBlock &that) const {
// "memcmp" in glibc has "nonnull" attributes on the input pointers.
// Avoid passing null pointers, since it would result in an undefined
// behavior.
if (size() == 0)
return that.size() == 0 ? 0 : -1;
if (that.size() == 0)
return 1;
std::size_t bytes{std::min(size(), that.size())};
int cmp{std::memcmp(static_cast<const void *>(begin()),
static_cast<const void *>(that.begin()), bytes)};
if (cmp != 0) {
return cmp;
}
return size() < that.size() ? -1 : size() > that.size();
}
int Compare(const char *that) const {
std::size_t bytes{size()};
if (int cmp{std::strncmp(begin(), that, bytes)}) {
return cmp;
}
return that[bytes] == '\0' ? 0 : -1;
}
common::Interval<const char *> interval_{nullptr, 0};
};
inline bool operator<(const char *left, const CharBlock &right) {
return right > left;
}
inline bool operator<=(const char *left, const CharBlock &right) {
return right >= left;
}
inline bool operator==(const char *left, const CharBlock &right) {
return right == left;
}
inline bool operator!=(const char *left, const CharBlock &right) {
return right != left;
}
inline bool operator>=(const char *left, const CharBlock &right) {
return right <= left;
}
inline bool operator>(const char *left, const CharBlock &right) {
return right < left;
}
// An alternative comparator based on pointer values; use with care!
struct CharBlockPointerComparator {
bool operator()(CharBlock x, CharBlock y) const {
return x.end() < y.begin();
}
};
llvm::raw_ostream &operator<<(llvm::raw_ostream &os, const CharBlock &x);
} // namespace Fortran::parser
// Specializations to enable std::unordered_map<CharBlock, ...> &c.
template <> struct std::hash<Fortran::parser::CharBlock> {
std::size_t operator()(const Fortran::parser::CharBlock &x) const {
std::size_t hash{0}, bytes{x.size()};
for (std::size_t j{0}; j < bytes; ++j) {
hash = (hash * 31) ^ x[j];
}
return hash;
}
};
#endif // FORTRAN_PARSER_CHAR_BLOCK_H_
|
