// 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.

#include "absl/strings/ascii.h"

#include <climits>

#include <cstring>

#include <string>

#include "absl/base/config.h"

namespace absl {

ABSL_NAMESPACE_BEGIN

namespace ascii_internal {

// # Table generated by this Python code (bit 0x02 is currently unused):

// TODO(mbar) Move Python code for generation of table to BUILD and link here.

// NOTE: The kAsciiPropertyBits table used within this code was generated by

// Python code of the following form. (Bit 0x02 is currently unused and

// available.)

//

// def Hex2(n):

//   return '0x' + hex(n/16)[2:] + hex(n%16)[2:]

// def IsPunct(ch):

//   return (ord(ch) >= 32 and ord(ch) < 127 and

//           not ch.isspace() and not ch.isalnum())

// def IsBlank(ch):

//   return ch in ' \t'

// def IsCntrl(ch):

//   return ord(ch) < 32 or ord(ch) == 127

// def IsXDigit(ch):

//   return ch.isdigit() or ch.lower() in 'abcdef'

// for i in range(128):

//   ch = chr(i)

//   mask = ((ch.isalpha() and 0x01 or 0) |

//           (ch.isalnum() and 0x04 or 0) |

//           (ch.isspace() and 0x08 or 0) |

//           (IsPunct(ch) and 0x10 or 0) |

//           (IsBlank(ch) and 0x20 or 0) |

//           (IsCntrl(ch) and 0x40 or 0) |

//           (IsXDigit(ch) and 0x80 or 0))

//   print Hex2(mask) + ',',

//   if i % 16 == 7:

//     print ' //', Hex2(i & 0x78)

//   elif i % 16 == 15:

//     print

// clang-format off

// Array of bitfields holding character information. Each bit value corresponds

// to a particular character feature. For readability, and because the value

// of these bits is tightly coupled to this implementation, the individual bits

// are not named. Note that bitfields for all characters above ASCII 127 are

// zero-initialized.

ABSL_DLL const unsigned char kPropertyBits[256] = {

    0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  // 0x00

    0x40, 0x68, 0x48, 0x48, 0x48, 0x48, 0x40, 0x40,

    0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  // 0x10

    0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,

    0x28, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10,  // 0x20

    0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10,

    0x84, 0x84, 0x84, 0x84, 0x84, 0x84, 0x84, 0x84,  // 0x30

    0x84, 0x84, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10,

    0x10, 0x85, 0x85, 0x85, 0x85, 0x85, 0x85, 0x05,  // 0x40

    0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05,

    0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05,  // 0x50

    0x05, 0x05, 0x05, 0x10, 0x10, 0x10, 0x10, 0x10,

    0x10, 0x85, 0x85, 0x85, 0x85, 0x85, 0x85, 0x05,  // 0x60

    0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05,

    0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05,  // 0x70

    0x05, 0x05, 0x05, 0x10, 0x10, 0x10, 0x10, 0x40,

};

// Array of characters for the ascii_tolower() function. For values 'A'

// through 'Z', return the lower-case character; otherwise, return the

// identity of the passed character.

ABSL_DLL const char kToLower[256] = {

  '\x00', '\x01', '\x02', '\x03', '\x04', '\x05', '\x06', '\x07',

  '\x08', '\x09', '\x0a', '\x0b', '\x0c', '\x0d', '\x0e', '\x0f',

  '\x10', '\x11', '\x12', '\x13', '\x14', '\x15', '\x16', '\x17',

  '\x18', '\x19', '\x1a', '\x1b', '\x1c', '\x1d', '\x1e', '\x1f',

  '\x20', '\x21', '\x22', '\x23', '\x24', '\x25', '\x26', '\x27',

  '\x28', '\x29', '\x2a', '\x2b', '\x2c', '\x2d', '\x2e', '\x2f',

  '\x30', '\x31', '\x32', '\x33', '\x34', '\x35', '\x36', '\x37',

  '\x38', '\x39', '\x3a', '\x3b', '\x3c', '\x3d', '\x3e', '\x3f',

  '\x40',    'a',    'b',    'c',    'd',    'e',    'f',    'g',

     'h',    'i',    'j',    'k',    'l',    'm',    'n',    'o',

     'p',    'q',    'r',    's',    't',    'u',    'v',    'w',

     'x',    'y',    'z', '\x5b', '\x5c', '\x5d', '\x5e', '\x5f',

  '\x60', '\x61', '\x62', '\x63', '\x64', '\x65', '\x66', '\x67',

  '\x68', '\x69', '\x6a', '\x6b', '\x6c', '\x6d', '\x6e', '\x6f',

  '\x70', '\x71', '\x72', '\x73', '\x74', '\x75', '\x76', '\x77',

  '\x78', '\x79', '\x7a', '\x7b', '\x7c', '\x7d', '\x7e', '\x7f',

  '\x80', '\x81', '\x82', '\x83', '\x84', '\x85', '\x86', '\x87',

  '\x88', '\x89', '\x8a', '\x8b', '\x8c', '\x8d', '\x8e', '\x8f',

  '\x90', '\x91', '\x92', '\x93', '\x94', '\x95', '\x96', '\x97',

  '\x98', '\x99', '\x9a', '\x9b', '\x9c', '\x9d', '\x9e', '\x9f',

  '\xa0', '\xa1', '\xa2', '\xa3', '\xa4', '\xa5', '\xa6', '\xa7',

  '\xa8', '\xa9', '\xaa', '\xab', '\xac', '\xad', '\xae', '\xaf',

  '\xb0', '\xb1', '\xb2', '\xb3', '\xb4', '\xb5', '\xb6', '\xb7',

  '\xb8', '\xb9', '\xba', '\xbb', '\xbc', '\xbd', '\xbe', '\xbf',

  '\xc0', '\xc1', '\xc2', '\xc3', '\xc4', '\xc5', '\xc6', '\xc7',

  '\xc8', '\xc9', '\xca', '\xcb', '\xcc', '\xcd', '\xce', '\xcf',

  '\xd0', '\xd1', '\xd2', '\xd3', '\xd4', '\xd5', '\xd6', '\xd7',

  '\xd8', '\xd9', '\xda', '\xdb', '\xdc', '\xdd', '\xde', '\xdf',

  '\xe0', '\xe1', '\xe2', '\xe3', '\xe4', '\xe5', '\xe6', '\xe7',

  '\xe8', '\xe9', '\xea', '\xeb', '\xec', '\xed', '\xee', '\xef',

  '\xf0', '\xf1', '\xf2', '\xf3', '\xf4', '\xf5', '\xf6', '\xf7',

  '\xf8', '\xf9', '\xfa', '\xfb', '\xfc', '\xfd', '\xfe', '\xff',

};

// Array of characters for the ascii_toupper() function. For values 'a'

// through 'z', return the upper-case character; otherwise, return the

// identity of the passed character.

ABSL_DLL const char kToUpper[256] = {

  '\x00', '\x01', '\x02', '\x03', '\x04', '\x05', '\x06', '\x07',

  '\x08', '\x09', '\x0a', '\x0b', '\x0c', '\x0d', '\x0e', '\x0f',

  '\x10', '\x11', '\x12', '\x13', '\x14', '\x15', '\x16', '\x17',

  '\x18', '\x19', '\x1a', '\x1b', '\x1c', '\x1d', '\x1e', '\x1f',

  '\x20', '\x21', '\x22', '\x23', '\x24', '\x25', '\x26', '\x27',

  '\x28', '\x29', '\x2a', '\x2b', '\x2c', '\x2d', '\x2e', '\x2f',

  '\x30', '\x31', '\x32', '\x33', '\x34', '\x35', '\x36', '\x37',

  '\x38', '\x39', '\x3a', '\x3b', '\x3c', '\x3d', '\x3e', '\x3f',

  '\x40', '\x41', '\x42', '\x43', '\x44', '\x45', '\x46', '\x47',

  '\x48', '\x49', '\x4a', '\x4b', '\x4c', '\x4d', '\x4e', '\x4f',

  '\x50', '\x51', '\x52', '\x53', '\x54', '\x55', '\x56', '\x57',

  '\x58', '\x59', '\x5a', '\x5b', '\x5c', '\x5d', '\x5e', '\x5f',

  '\x60',    'A',    'B',    'C',    'D',    'E',    'F',    'G',

     'H',    'I',    'J',    'K',    'L',    'M',    'N',    'O',

     'P',    'Q',    'R',    'S',    'T',    'U',    'V',    'W',

     'X',    'Y',    'Z', '\x7b', '\x7c', '\x7d', '\x7e', '\x7f',

  '\x80', '\x81', '\x82', '\x83', '\x84', '\x85', '\x86', '\x87',

  '\x88', '\x89', '\x8a', '\x8b', '\x8c', '\x8d', '\x8e', '\x8f',

  '\x90', '\x91', '\x92', '\x93', '\x94', '\x95', '\x96', '\x97',

  '\x98', '\x99', '\x9a', '\x9b', '\x9c', '\x9d', '\x9e', '\x9f',

  '\xa0', '\xa1', '\xa2', '\xa3', '\xa4', '\xa5', '\xa6', '\xa7',

  '\xa8', '\xa9', '\xaa', '\xab', '\xac', '\xad', '\xae', '\xaf',

  '\xb0', '\xb1', '\xb2', '\xb3', '\xb4', '\xb5', '\xb6', '\xb7',

  '\xb8', '\xb9', '\xba', '\xbb', '\xbc', '\xbd', '\xbe', '\xbf',

  '\xc0', '\xc1', '\xc2', '\xc3', '\xc4', '\xc5', '\xc6', '\xc7',

  '\xc8', '\xc9', '\xca', '\xcb', '\xcc', '\xcd', '\xce', '\xcf',

  '\xd0', '\xd1', '\xd2', '\xd3', '\xd4', '\xd5', '\xd6', '\xd7',

  '\xd8', '\xd9', '\xda', '\xdb', '\xdc', '\xdd', '\xde', '\xdf',

  '\xe0', '\xe1', '\xe2', '\xe3', '\xe4', '\xe5', '\xe6', '\xe7',

  '\xe8', '\xe9', '\xea', '\xeb', '\xec', '\xed', '\xee', '\xef',

  '\xf0', '\xf1', '\xf2', '\xf3', '\xf4', '\xf5', '\xf6', '\xf7',

  '\xf8', '\xf9', '\xfa', '\xfb', '\xfc', '\xfd', '\xfe', '\xff',

};

// clang-format on

template <bool ToUpper>

constexpr void AsciiStrCaseFold(char* p, char* end) {

  // The upper- and lowercase versions of ASCII characters differ by only 1 bit.

  // When we need to flip the case, we can xor with this bit to achieve the

  // desired result. Note that the choice of 'a' and 'A' here is arbitrary. We

  // could have chosen 'z' and 'Z', or any other pair of characters as they all

  // have the same single bit difference.

  constexpr unsigned char kAsciiCaseBitFlip = 'a' ^ 'A';

  constexpr char ch_a = ToUpper ? 'a' : 'A';

  constexpr char ch_z = ToUpper ? 'z' : 'Z';

  for (; p < end; ++p) {

    unsigned char v = static_cast<unsigned char>(*p);

    // We use & instead of && to ensure this always stays branchless

    // We use static_cast<int> to suppress -Wbitwise-instead-of-logical

    bool is_in_range = static_cast<bool>(static_cast<int>(ch_a <= v) &

                                         static_cast<int>(v <= ch_z));

    v ^= is_in_range ? kAsciiCaseBitFlip : 0;

    *p = static_cast<char>(v);

  }

}

Unexecuted instantiation: void absl::ascii_internal::AsciiStrCaseFold<false>(char*, char*)

Unexecuted instantiation: void absl::ascii_internal::AsciiStrCaseFold<true>(char*, char*)

static constexpr size_t ValidateAsciiCasefold() {

  constexpr size_t num_chars = 1 + CHAR_MAX - CHAR_MIN;

  size_t incorrect_index = 0;

  char lowered[num_chars] = {};

  char uppered[num_chars] = {};

  for (unsigned int i = 0; i < num_chars; ++i) {

    uppered[i] = lowered[i] = static_cast<char>(i);

  }

  AsciiStrCaseFold<false>(&lowered[0], &lowered[num_chars]);

  AsciiStrCaseFold<true>(&uppered[0], &uppered[num_chars]);

  for (size_t i = 0; i < num_chars; ++i) {

    const char ch = static_cast<char>(i),

               ch_upper = ('a' <= ch && ch <= 'z' ? 'A' + (ch - 'a') : ch),

               ch_lower = ('A' <= ch && ch <= 'Z' ? 'a' + (ch - 'A') : ch);

    if (uppered[i] != ch_upper || lowered[i] != ch_lower) {

      incorrect_index = i > 0 ? i : num_chars;

      break;

    }

  }

  return incorrect_index;

}

static_assert(ValidateAsciiCasefold() == 0, "error in case conversion");

}  // namespace ascii_internal

void AsciiStrToLower(std::string* s) {

  char* p = &(*s)[0];  // Guaranteed to be valid for empty strings

  return ascii_internal::AsciiStrCaseFold<false>(p, p + s->size());

}

void AsciiStrToUpper(std::string* s) {

  char* p = &(*s)[0];  // Guaranteed to be valid for empty strings

  return ascii_internal::AsciiStrCaseFold<true>(p, p + s->size());

}

void RemoveExtraAsciiWhitespace(std::string* str) {

  auto stripped = StripAsciiWhitespace(*str);

  if (stripped.empty()) {

    str->clear();

    return;

  }

  auto input_it = stripped.begin();

  auto input_end = stripped.end();

  auto output_it = &(*str)[0];

  bool is_ws = false;

  for (; input_it < input_end; ++input_it) {

    if (is_ws) {

      // Consecutive whitespace?  Keep only the last.

      is_ws = absl::ascii_isspace(static_cast<unsigned char>(*input_it));

      if (is_ws) --output_it;

    } else {

      is_ws = absl::ascii_isspace(static_cast<unsigned char>(*input_it));

    }

    *output_it = *input_it;

    ++output_it;

  }

  str->erase(static_cast<size_t>(output_it - &(*str)[0]));

}

ABSL_NAMESPACE_END

}  // namespace absl