String.h

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/*
 * Copyright 2011-present Facebook, Inc.
 *
 * 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
 *
 *   http://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.
 */

#pragma once
#define FOLLY_STRING_H_

#include <cstdarg>
#include <exception>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>

#include <folly/Conv.h>
#include <folly/ExceptionString.h>
#include <folly/FBString.h>
#include <folly/FBVector.h>
#include <folly/Portability.h>
#include <folly/Range.h>
#include <folly/ScopeGuard.h>
#include <folly/Traits.h>

// Compatibility function, to make sure toStdString(s) can be called
// to convert a std::string or fbstring variable s into type std::string
// with very little overhead if s was already std::string
namespace folly {

inline std::string toStdString(const folly::fbstring& s) {
  return std::string(s.data(), s.size());
}

inline const std::string& toStdString(const std::string& s) {
  return s;
}

// If called with a temporary, the compiler will select this overload instead
// of the above, so we don't return a (lvalue) reference to a temporary.
inline std::string&& toStdString(std::string&& s) {
  return std::move(s);
}

template <class String>
void cEscape(StringPiece str, String& out);

template <class String>
String cEscape(StringPiece str) {
  String out;
  cEscape(str, out);
  return out;
}

template <class String>
void cUnescape(StringPiece str, String& out, bool strict = true);

template <class String>
String cUnescape(StringPiece str, bool strict = true) {
  String out;
  cUnescape(str, out, strict);
  return out;
}

enum class UriEscapeMode : unsigned char {
  // The values are meaningful, see generate_escape_tables.py
  ALL = 0,
  QUERY = 1,
  PATH = 2
};
template <class String>
void uriEscape(
    StringPiece str,
    String& out,
    UriEscapeMode mode = UriEscapeMode::ALL);

template <class String>
String uriEscape(StringPiece str, UriEscapeMode mode = UriEscapeMode::ALL) {
  String out;
  uriEscape(str, out, mode);
  return out;
}

template <class String>
void uriUnescape(
    StringPiece str,
    String& out,
    UriEscapeMode mode = UriEscapeMode::ALL);

template <class String>
String uriUnescape(StringPiece str, UriEscapeMode mode = UriEscapeMode::ALL) {
  String out;
  uriUnescape(str, out, mode);
  return out;
}

std::string stringPrintf(FOLLY_PRINTF_FORMAT const char* format, ...)
    FOLLY_PRINTF_FORMAT_ATTR(1, 2);

/* Similar to stringPrintf, with different signature. */
void stringPrintf(std::string* out, FOLLY_PRINTF_FORMAT const char* fmt, ...)
    FOLLY_PRINTF_FORMAT_ATTR(2, 3);

std::string& stringAppendf(
    std::string* output,
    FOLLY_PRINTF_FORMAT const char* format,
    ...) FOLLY_PRINTF_FORMAT_ATTR(2, 3);

std::string stringVPrintf(const char* format, va_list ap);
void stringVPrintf(std::string* out, const char* format, va_list ap);
std::string& stringVAppendf(std::string* out, const char* format, va_list ap);

template <class OutputString>
void backslashify(
    folly::StringPiece input,
    OutputString& output,
    bool hex_style = false);

template <class OutputString = std::string>
OutputString backslashify(StringPiece input, bool hex_style = false) {
  OutputString output;
  backslashify(input, output, hex_style);
  return output;
}

template <class String1, class String2>
void humanify(const String1& input, String2& output);

template <class String>
String humanify(const String& input) {
  String output;
  humanify(input, output);
  return output;
}

template <class InputString, class OutputString>
bool hexlify(
    const InputString& input,
    OutputString& output,
    bool append = false);

template <class OutputString = std::string>
OutputString hexlify(ByteRange input) {
  OutputString output;
  if (!hexlify(input, output)) {
    // hexlify() currently always returns true, so this can't really happen
    throw std::runtime_error("hexlify failed");
  }
  return output;
}

template <class OutputString = std::string>
OutputString hexlify(StringPiece input) {
  return hexlify<OutputString>(ByteRange{input});
}

template <class InputString, class OutputString>
bool unhexlify(const InputString& input, OutputString& output);

template <class OutputString = std::string>
OutputString unhexlify(StringPiece input) {
  OutputString output;
  if (!unhexlify(input, output)) {
    // unhexlify() fails if the input has non-hexidecimal characters,
    // or if it doesn't consist of a whole number of bytes
    throw std::domain_error("unhexlify() called with non-hex input");
  }
  return output;
}

enum PrettyType {
  PRETTY_TIME,
  PRETTY_TIME_HMS,

  PRETTY_BYTES_METRIC,
  PRETTY_BYTES_BINARY,
  PRETTY_BYTES = PRETTY_BYTES_BINARY,
  PRETTY_BYTES_BINARY_IEC,
  PRETTY_BYTES_IEC = PRETTY_BYTES_BINARY_IEC,

  PRETTY_UNITS_METRIC,
  PRETTY_UNITS_BINARY,
  PRETTY_UNITS_BINARY_IEC,

  PRETTY_SI,
  PRETTY_NUM_TYPES,
};

std::string prettyPrint(double val, PrettyType, bool addSpace = true);

double prettyToDouble(
    folly::StringPiece* const prettyString,
    const PrettyType type);

double prettyToDouble(folly::StringPiece prettyString, const PrettyType type);

template <class OutIt>
void hexDump(const void* ptr, size_t size, OutIt out);

std::string hexDump(const void* ptr, size_t size);

fbstring errnoStr(int err);

/*
 * Split a string into a list of tokens by delimiter.
 *
 * The split interface here supports different output types, selected
 * at compile time: StringPiece, fbstring, or std::string.  If you are
 * using a vector to hold the output, it detects the type based on
 * what your vector contains.  If the output vector is not empty, split
 * will append to the end of the vector.
 *
 * You can also use splitTo() to write the output to an arbitrary
 * OutputIterator (e.g. std::inserter() on a std::set<>), in which
 * case you have to tell the function the type.  (Rationale:
 * OutputIterators don't have a value_type, so we can't detect the
 * type in splitTo without being told.)
 *
 * Examples:
 *
 *   std::vector<folly::StringPiece> v;
 *   folly::split(":", "asd:bsd", v);
 *
 *   std::set<StringPiece> s;
 *   folly::splitTo<StringPiece>(":", "asd:bsd:asd:csd",
 *    std::inserter(s, s.begin()));
 *
 * Split also takes a flag (ignoreEmpty) that indicates whether adjacent
 * delimiters should be treated as one single separator (ignoring empty tokens)
 * or not (generating empty tokens).
 */

template <class Delim, class String, class OutputType>
void split(
    const Delim& delimiter,
    const String& input,
    std::vector<OutputType>& out,
    const bool ignoreEmpty = false);

template <class Delim, class String, class OutputType>
void split(
    const Delim& delimiter,
    const String& input,
    folly::fbvector<OutputType>& out,
    const bool ignoreEmpty = false);

template <
    class OutputValueType,
    class Delim,
    class String,
    class OutputIterator>
void splitTo(
    const Delim& delimiter,
    const String& input,
    OutputIterator out,
    const bool ignoreEmpty = false);

/*
 * Split a string into a fixed number of string pieces and/or numeric types
 * by delimiter. Conversions are supported for any type which folly:to<> can
 * target, including all overloads of parseTo(). Returns 'true' if the fields
 * were all successfully populated.  Returns 'false' if there were too few
 * fields in the input, or too many fields if exact=true.  Casting exceptions
 * will not be caught.
 *
 * Examples:
 *
 *  folly::StringPiece name, key, value;
 *  if (folly::split('\t', line, name, key, value))
 *    ...
 *
 *  folly::StringPiece name;
 *  double value;
 *  int id;
 *  if (folly::split('\t', line, name, value, id))
 *    ...
 *
 * The 'exact' template parameter specifies how the function behaves when too
 * many fields are present in the input string. When 'exact' is set to its
 * default value of 'true', a call to split will fail if the number of fields in
 * the input string does not exactly match the number of output parameters
 * passed. If 'exact' is overridden to 'false', all remaining fields will be
 * stored, unsplit, in the last field, as shown below:
 *
 *  folly::StringPiece x, y.
 *  if (folly::split<false>(':', "a:b:c", x, y))
 *    assert(x == "a" && y == "b:c");
 *
 * Note that this will likely not work if the last field's target is of numeric
 * type, in which case folly::to<> will throw an exception.
 */
namespace detail {
template <typename Void, typename OutputType>
struct IsConvertible : std::false_type {};

template <>
struct IsConvertible<void, decltype(std::ignore)> : std::true_type {};

template <typename OutputType>
struct IsConvertible<
    void_t<decltype(parseTo(StringPiece{}, std::declval<OutputType&>()))>,
    OutputType> : std::true_type {};
} // namespace detail
template <typename OutputType>
struct IsConvertible : detail::IsConvertible<void, OutputType> {};

template <bool exact = true, class Delim, class... OutputTypes>
typename std::enable_if<
    StrictConjunction<IsConvertible<OutputTypes>...>::value &&
        sizeof...(OutputTypes) >= 1,
    bool>::type
split(const Delim& delimiter, StringPiece input, OutputTypes&... outputs);

/*
 * Join list of tokens.
 *
 * Stores a string representation of tokens in the same order with
 * deliminer between each element.
 */

template <class Delim, class Iterator, class String>
void join(const Delim& delimiter, Iterator begin, Iterator end, String& output);

template <class Delim, class Container, class String>
void join(const Delim& delimiter, const Container& container, String& output) {
  join(delimiter, container.begin(), container.end(), output);
}

template <class Delim, class Value, class String>
void join(
    const Delim& delimiter,
    const std::initializer_list<Value>& values,
    String& output) {
  join(delimiter, values.begin(), values.end(), output);
}

template <class Delim, class Container>
std::string join(const Delim& delimiter, const Container& container) {
  std::string output;
  join(delimiter, container.begin(), container.end(), output);
  return output;
}

template <class Delim, class Value>
std::string join(
    const Delim& delimiter,
    const std::initializer_list<Value>& values) {
  std::string output;
  join(delimiter, values.begin(), values.end(), output);
  return output;
}

template <
    class Delim,
    class Iterator,
    typename std::enable_if<std::is_base_of<
        std::forward_iterator_tag,
        typename std::iterator_traits<Iterator>::iterator_category>::value>::
        type* = nullptr>
std::string join(const Delim& delimiter, Iterator begin, Iterator end) {
  std::string output;
  join(delimiter, begin, end, output);
  return output;
}

StringPiece ltrimWhitespace(StringPiece sp);

StringPiece rtrimWhitespace(StringPiece sp);

inline StringPiece trimWhitespace(StringPiece sp) {
  return ltrimWhitespace(rtrimWhitespace(sp));
}

inline StringPiece skipWhitespace(StringPiece sp) {
  return ltrimWhitespace(sp);
}

std::string stripLeftMargin(std::string s);

void toLowerAscii(char* str, size_t length);

inline void toLowerAscii(MutableStringPiece str) {
  toLowerAscii(str.begin(), str.size());
}

inline void toLowerAscii(std::string& str) {
  // str[0] is legal also if the string is empty.
  toLowerAscii(&str[0], str.size());
}

} // namespace folly

#include <folly/String-inl.h>