//

// Copyright 2017 The Abseil Authors.

//

// Licensed under the Apache License, Version 2.0 (the "License");

// you may not use this file except in compliance with the License.

// You may obtain a copy of the License at

//

//      https://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software

// distributed under the License is distributed on an "AS IS" BASIS,

// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

// See the License for the specific language governing permissions and

// limitations under the License.

//

// -----------------------------------------------------------------------------

// File: ascii.h

// -----------------------------------------------------------------------------

//

// This package contains functions operating on characters and strings

// restricted to standard ASCII. These include character classification

// functions analogous to those found in the ANSI C Standard Library <ctype.h>

// header file.

//

// C++ implementations provide <ctype.h> functionality based on their

// C environment locale. In general, reliance on such a locale is not ideal, as

// the locale standard is problematic (and may not return invariant information

// for the same character set, for example). These `ascii_*()` functions are

// hard-wired for standard ASCII, much faster, and guaranteed to behave

// consistently.  They will never be overloaded, nor will their function

// signature change.

//

// `ascii_isalnum()`, `ascii_isalpha()`, `ascii_isascii()`, `ascii_isblank()`,

// `ascii_iscntrl()`, `ascii_isdigit()`, `ascii_isgraph()`, `ascii_islower()`,

// `ascii_isprint()`, `ascii_ispunct()`, `ascii_isspace()`, `ascii_isupper()`,

// `ascii_isxdigit()`

//   Analogous to the <ctype.h> functions with similar names, these

//   functions take an unsigned char and return a bool, based on whether the

//   character matches the condition specified.

//

//   If the input character has a numerical value greater than 127, these

//   functions return `false`.

//

// `ascii_tolower()`, `ascii_toupper()`

//   Analogous to the <ctype.h> functions with similar names, these functions

//   take an unsigned char and return a char.

//

//   If the input character is not an ASCII {lower,upper}-case letter (including

//   numerical values greater than 127) then the functions return the same value

//   as the input character.

#ifndef ABSL_STRINGS_ASCII_H_

#define ABSL_STRINGS_ASCII_H_

#include <algorithm>

#include <cstddef>

#include <string>

#include <utility>

#include "absl/base/attributes.h"

#include "absl/base/config.h"

#include "absl/base/nullability.h"

#include "absl/strings/resize_and_overwrite.h"

#include "absl/strings/string_view.h"

namespace absl {

ABSL_NAMESPACE_BEGIN

namespace ascii_internal {

// Declaration for an array of bitfields holding character information.

ABSL_DLL extern const unsigned char kPropertyBits[256];

// Declaration for the array of characters to upper-case characters.

ABSL_DLL extern const char kToUpper[256];

// Declaration for the array of characters to lower-case characters.

ABSL_DLL extern const char kToLower[256];

void AsciiStrToLower(char* absl_nonnull dst, const char* absl_nullable src,

                     size_t n);

void AsciiStrToUpper(char* absl_nonnull dst, const char* absl_nullable src,

                     size_t n);

}  // namespace ascii_internal

// ascii_isalpha()

//

// Determines whether the given character is an alphabetic character.

inline bool ascii_isalpha(unsigned char c) {

  return (ascii_internal::kPropertyBits[c] & 0x01) != 0;

}

// ascii_isalnum()

//

// Determines whether the given character is an alphanumeric character.

inline bool ascii_isalnum(unsigned char c) {

  return (ascii_internal::kPropertyBits[c] & 0x04) != 0;

}

// ascii_isspace()

//

// Determines whether the given character is a whitespace character (space,

// tab, vertical tab, formfeed, linefeed, or carriage return).

inline bool ascii_isspace(unsigned char c) {

  return (ascii_internal::kPropertyBits[c] & 0x08) != 0;

}

// ascii_ispunct()

//

// Determines whether the given character is a punctuation character.

inline bool ascii_ispunct(unsigned char c) {

  return (ascii_internal::kPropertyBits[c] & 0x10) != 0;

}

// ascii_isblank()

//

// Determines whether the given character is a blank character (tab or space).

inline bool ascii_isblank(unsigned char c) {

  return (ascii_internal::kPropertyBits[c] & 0x20) != 0;

}

// ascii_iscntrl()

//

// Determines whether the given character is a control character.

inline bool ascii_iscntrl(unsigned char c) {

  return (ascii_internal::kPropertyBits[c] & 0x40) != 0;

}

// ascii_isxdigit()

//

// Determines whether the given character can be represented as a hexadecimal

// digit character (i.e. {0-9} or {A-F} or {a-f}).

inline bool ascii_isxdigit(unsigned char c) {

  return (ascii_internal::kPropertyBits[c] & 0x80) != 0;

}

// ascii_isdigit()

//

// Determines whether the given character can be represented as a decimal

// digit character (i.e. {0-9}).

inline constexpr bool ascii_isdigit(unsigned char c) {

  return c >= '0' && c <= '9';

}

// ascii_isprint()

//

// Determines whether the given character is printable, including spaces.

inline constexpr bool ascii_isprint(unsigned char c) {

  return c >= 32 && c < 127;

}

// ascii_isgraph()

//

// Determines whether the given character has a graphical representation.

inline constexpr bool ascii_isgraph(unsigned char c) {

  return c > 32 && c < 127;

}

// ascii_isupper()

//

// Determines whether the given character is uppercase.

inline constexpr bool ascii_isupper(unsigned char c) {

  return c >= 'A' && c <= 'Z';

}

// ascii_islower()

//

// Determines whether the given character is lowercase.

inline constexpr bool ascii_islower(unsigned char c) {

  return c >= 'a' && c <= 'z';

}

// ascii_isascii()

//

// Determines whether the given character is ASCII.

inline constexpr bool ascii_isascii(unsigned char c) { return c < 128; }

// ascii_tolower()

//

// Returns an ASCII character, converting to lowercase if uppercase is

// passed. Note that character values > 127 are simply returned.

inline char ascii_tolower(unsigned char c) {

  return ascii_internal::kToLower[c];

}

// Converts the characters in `s` to lowercase, changing the contents of `s`.

void AsciiStrToLower(std::string* absl_nonnull s);

// Creates a lowercase string from a given absl::string_view.

[[nodiscard]] inline std::string AsciiStrToLower(absl::string_view s) {

  std::string result;

  StringResizeAndOverwrite(result, s.size(), [s](char* buf, size_t buf_size) {

    ascii_internal::AsciiStrToLower(buf, s.data(), s.size());

    return buf_size;

  });

  return result;

}

// Creates a lowercase string from a given std::string&&.

//

// (Template is used to lower priority of this overload.)

template <int&... DoNotSpecify>

[[nodiscard]] inline std::string AsciiStrToLower(std::string&& s) {

  std::string result = std::move(s);

  absl::AsciiStrToLower(&result);

  return result;

}

// ascii_toupper()

//

// Returns the ASCII character, converting to upper-case if lower-case is

// passed. Note that characters values > 127 are simply returned.

inline char ascii_toupper(unsigned char c) {

  return ascii_internal::kToUpper[c];

}

// Converts the characters in `s` to uppercase, changing the contents of `s`.

void AsciiStrToUpper(std::string* absl_nonnull s);

// Creates an uppercase string from a given absl::string_view.

[[nodiscard]] inline std::string AsciiStrToUpper(absl::string_view s) {

  std::string result;

  StringResizeAndOverwrite(result, s.size(), [s](char* buf, size_t buf_size) {

    ascii_internal::AsciiStrToUpper(buf, s.data(), s.size());

    return buf_size;

  });

  return result;

}

// Creates an uppercase string from a given std::string&&.

//

// (Template is used to lower priority of this overload.)

template <int&... DoNotSpecify>

[[nodiscard]] inline std::string AsciiStrToUpper(std::string&& s) {

  std::string result = std::move(s);

  absl::AsciiStrToUpper(&result);

  return result;

}

// Returns absl::string_view with whitespace stripped from the beginning of the

// given string_view.

[[nodiscard]] inline absl::string_view StripLeadingAsciiWhitespace(

    absl::string_view str ABSL_ATTRIBUTE_LIFETIME_BOUND) {

  auto it = std::find_if_not(str.begin(), str.end(), absl::ascii_isspace);

  return str.substr(static_cast<size_t>(it - str.begin()));

}

// Strips in place whitespace from the beginning of the given string.

inline void StripLeadingAsciiWhitespace(std::string* absl_nonnull str) {

  auto it = std::find_if_not(str->begin(), str->end(), absl::ascii_isspace);

  str->erase(str->begin(), it);

}

// Returns absl::string_view with whitespace stripped from the end of the given

// string_view.

[[nodiscard]] inline absl::string_view StripTrailingAsciiWhitespace(

    absl::string_view str ABSL_ATTRIBUTE_LIFETIME_BOUND) {

  auto it = std::find_if_not(str.rbegin(), str.rend(), absl::ascii_isspace);

  return str.substr(0, static_cast<size_t>(str.rend() - it));

}

// Strips in place whitespace from the end of the given string

inline void StripTrailingAsciiWhitespace(std::string* absl_nonnull str) {

  auto it = std::find_if_not(str->rbegin(), str->rend(), absl::ascii_isspace);

  str->erase(static_cast<size_t>(str->rend() - it));

}

// Returns absl::string_view with whitespace stripped from both ends of the

// given string_view.

[[nodiscard]] inline absl::string_view StripAsciiWhitespace(

    absl::string_view str ABSL_ATTRIBUTE_LIFETIME_BOUND) {

  return StripTrailingAsciiWhitespace(StripLeadingAsciiWhitespace(str));

}

// Strips in place whitespace from both ends of the given string

inline void StripAsciiWhitespace(std::string* absl_nonnull str) {

  StripTrailingAsciiWhitespace(str);

  StripLeadingAsciiWhitespace(str);

}

// Removes leading, trailing, and consecutive internal whitespace.

void RemoveExtraAsciiWhitespace(std::string* absl_nonnull str);

ABSL_NAMESPACE_END

}  // namespace absl

#endif  // ABSL_STRINGS_ASCII_H_