/*
* Copyright (c) Facebook, Inc. and its affiliates.
*
* 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/Portability.h>
#include <folly/Range.h>
#include <folly/ScopeGuard.h>
#include <folly/Traits.h>
namespace folly {
/**
* C-Escape a string, making it suitable for representation as a C string
* literal. Appends the result to the output string.
*
* Backslashes all occurrences of backslash and double-quote:
* " -> \"
* \ -> \\
*
* Replaces all non-printable ASCII characters with backslash-octal
* representation:
* <ASCII 254> -> \376
*
* Note that we use backslash-octal instead of backslash-hex because the octal
* representation is guaranteed to consume no more than 3 characters; "\3760"
* represents two characters, one with value 254, and one with value 48 ('0'),
* whereas "\xfe0" represents only one character (with value 4064, which leads
* to implementation-defined behavior).
*/
template <class String>
void cEscape(StringPiece str, String& out);
/**
* Similar to cEscape above, but returns the escaped string.
*/
template <class String>
String cEscape(StringPiece str) {
String out;
cEscape(str, out);
return out;
}
/**
* C-Unescape a string; the opposite of cEscape above. Appends the result
* to the output string.
*
* Recognizes the standard C escape sequences:
*
* \' \" \? \\ \a \b \f \n \r \t \v
* \[0-7]+
* \x[0-9a-fA-F]+
*
* In strict mode (default), throws std::invalid_argument if it encounters
* an unrecognized escape sequence. In non-strict mode, it leaves
* the escape sequence unchanged.
*/
template <class String>
void cUnescape(StringPiece str, String& out, bool strict = true);
/**
* Similar to cUnescape above, but returns the escaped string.
*/
template <class String>
String cUnescape(StringPiece str, bool strict = true) {
String out;
cUnescape(str, out, strict);
return out;
}
/**
* URI-escape a string. Appends the result to the output string.
*
* Alphanumeric characters and other characters marked as "unreserved" in RFC
* 3986 ( -_.~ ) are left unchanged. In PATH mode, the forward slash (/) is
* also left unchanged. In QUERY mode, spaces are replaced by '+'. All other
* characters are percent-encoded.
*/
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);
/**
* Similar to uriEscape above, but returns the escaped string.
*/
template <class String>
String uriEscape(StringPiece str, UriEscapeMode mode = UriEscapeMode::ALL) {
String out;
uriEscape(str, out, mode);
return out;
}
/**
* URI-unescape a string. Appends the result to the output string.
*
* In QUERY mode, '+' are replaced by space. %XX sequences are decoded if
* XX is a valid hex sequence, otherwise we throw invalid_argument.
*/
template <class String>
void uriUnescape(
StringPiece str,
String& out,
UriEscapeMode mode = UriEscapeMode::ALL);
/**
* Similar to uriUnescape above, but returns the unescaped string.
*/
template <class String>
String uriUnescape(StringPiece str, UriEscapeMode mode = UriEscapeMode::ALL) {
String out;
uriUnescape(str, out, mode);
return out;
}
/**
* stringPrintf is much like printf but deposits its result into a
* string. Two signatures are supported: the first simply returns the
* resulting string, and the second appends the produced characters to
* the specified string and returns a reference to it.
*/
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* format, ...)
FOLLY_PRINTF_FORMAT_ATTR(2, 3);
std::string& stringAppendf(
std::string* output,
FOLLY_PRINTF_FORMAT const char* format,
...) FOLLY_PRINTF_FORMAT_ATTR(2, 3);
/**
* Similar to stringPrintf, but accepts a va_list argument.
*
* As with vsnprintf() itself, the value of ap is undefined after the call.
* These functions do not call va_end() on ap.
*/
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);
/**
* Backslashify a string, that is, replace non-printable characters
* with C-style (but NOT C compliant) "\xHH" encoding. If hex_style
* is false, then shorthand notations like "\0" will be used instead
* of "\x00" for the most common backslash cases.
*
* There are two forms, one returning the input string, and one
* creating output in the specified output string.
*
* This is mainly intended for printing to a terminal, so it is not
* particularly optimized.
*
* Do *not* use this in situations where you expect to be able to feed
* the string to a C or C++ compiler, as there are nuances with how C
* parses such strings that lead to failures. This is for display
* purposed only. If you want a string you can embed for use in C or
* C++, use cEscape instead. This function is for display purposes
* only.
*/
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;
}
/**
* Take a string and "humanify" it -- that is, make it look better.
* Since "better" is subjective, caveat emptor. The basic approach is
* to count the number of unprintable characters. If there are none,
* then the output is the input. If there are relatively few, or if
* there is a long "enough" prefix of printable characters, use
* backslashify. If it is mostly binary, then simply hex encode.
*
* This is an attempt to make a computer smart, and so likely is wrong
* most of the time.
*/
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;
}
/**
* Same functionality as Python's binascii.hexlify. Returns true
* on successful conversion.
*
* If append_output is true, append data to the output rather than
* replace it.
*/
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_exception<std::runtime_error>("hexlify failed");
}
return output;
}
template <class OutputString = std::string>
OutputString hexlify(StringPiece input) {
return hexlify<OutputString>(ByteRange{input});
}
/**
* Same functionality as Python's binascii.unhexlify. Returns true
* on successful conversion.
*/
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_exception<std::domain_error>("unhexlify() called with non-hex input");
}
return output;
}
/**
* A pretty-printer for numbers that appends suffixes of units of the
* given type. It prints 4 sig-figs of value with the most
* appropriate unit.
*
* If `addSpace' is true, we put a space between the units suffix and
* the value.
*
* Current types are:
* PRETTY_TIME - s, ms, us, ns, etc.
* PRETTY_TIME_HMS - h, m, s, ms, us, ns, etc.
* PRETTY_BYTES_METRIC - kB, MB, GB, etc (goes up by 10^3 = 1000 each time)
* PRETTY_BYTES - kB, MB, GB, etc (goes up by 2^10 = 1024 each time)
* PRETTY_BYTES_IEC - KiB, MiB, GiB, etc
* PRETTY_UNITS_METRIC - k, M, G, etc (goes up by 10^3 = 1000 each time)
* PRETTY_UNITS_BINARY - k, M, G, etc (goes up by 2^10 = 1024 each time)
* PRETTY_UNITS_BINARY_IEC - Ki, Mi, Gi, etc
* PRETTY_SI - full SI metric prefixes from yocto to Yotta
* http://en.wikipedia.org/wiki/Metric_prefix
*
* @author Mark Rabkin <mrabkin@fb.com>
*/
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);
/**
* This utility converts StringPiece in pretty format (look above) to double,
* with progress information. Alters the StringPiece parameter
* to get rid of the already-parsed characters.
* Expects string in form <floating point number> {space}* [<suffix>]
* If string is not in correct format, utility finds longest valid prefix and
* if there at least one, returns double value based on that prefix and
* modifies string to what is left after parsing. Throws and std::range_error
* exception if there is no correct parse.
* Examples(for PRETTY_UNITS_METRIC):
* '10M' => 10 000 000
* '10 M' => 10 000 000
* '10' => 10
* '10 Mx' => 10 000 000, prettyString == "x"
* 'abc' => throws std::range_error
*/
double prettyToDouble(
folly::StringPiece* const prettyString,
const PrettyType type);
/**
* Same as prettyToDouble(folly::StringPiece*, PrettyType), but
* expects whole string to be correctly parseable. Throws std::range_error
* otherwise
*/
double prettyToDouble(folly::StringPiece prettyString, const PrettyType type);
/**
* Write a hex dump of size bytes starting at ptr to out.
*
* The hex dump is formatted as follows:
*
* for the string "abcdefghijklmnopqrstuvwxyz\x02"
00000000 61 62 63 64 65 66 67 68 69 6a 6b 6c 6d 6e 6f 70 |abcdefghijklmnop|
00000010 71 72 73 74 75 76 77 78 79 7a 02 |qrstuvwxyz. |
*
* that is, we write 16 bytes per line, both as hex bytes and as printable
* characters. Non-printable characters are replaced with '.'
* Lines are written to out one by one (one StringPiece at a time) without
* delimiters.
*/
template <class OutIt>
void hexDump(const void* ptr, size_t size, OutIt out);
/**
* Return the hex dump of size bytes starting at ptr as a string.
*/
std::string hexDump(const void* ptr, size_t size);
/**
* Return a string containing the description of the given errno value.
* Takes care not to overwrite the actual system errno, so calling
* errnoStr(errno) is valid.
*/
std::string 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 T, class Allocator>
class fbvector;
template <class Delim, class String, class OutputType>
void split(
const Delim& delimiter,
const String& input,
folly::fbvector<OutputType, std::allocator<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;
}
/**
* Returns a subpiece with all whitespace removed from the front of @sp.
* Whitespace means any of [' ', '\n', '\r', '\t'].
*/
StringPiece ltrimWhitespace(StringPiece sp);
/**
* Returns a subpiece with all whitespace removed from the back of @sp.
* Whitespace means any of [' ', '\n', '\r', '\t'].
*/
StringPiece rtrimWhitespace(StringPiece sp);
/**
* Returns a subpiece with all whitespace removed from the back and front of
* @sp. Whitespace means any of [' ', '\n', '\r', '\t'].
*/
inline StringPiece trimWhitespace(StringPiece sp) {
return ltrimWhitespace(rtrimWhitespace(sp));
}
/**
* Returns a subpiece with all whitespace removed from the front of @sp.
* Whitespace means any of [' ', '\n', '\r', '\t'].
* DEPRECATED: @see ltrimWhitespace @see rtrimWhitespace
*/
inline StringPiece skipWhitespace(StringPiece sp) {
return ltrimWhitespace(sp);
}
/**
* Returns a subpiece with all characters the provided @toTrim returns true
* for removed from the front of @sp.
*/
template <typename ToTrim>
StringPiece ltrim(StringPiece sp, ToTrim toTrim) {
while (!sp.empty() && toTrim(sp.front())) {
sp.pop_front();
}
return sp;
}
/**
* Returns a subpiece with all characters the provided @toTrim returns true
* for removed from the back of @sp.
*/
template <typename ToTrim>
StringPiece rtrim(StringPiece sp, ToTrim toTrim) {
while (!sp.empty() && toTrim(sp.back())) {
sp.pop_back();
}
return sp;
}
/**
* Returns a subpiece with all characters the provided @toTrim returns true
* for removed from the back and front of @sp.
*/
template <typename ToTrim>
StringPiece trim(StringPiece sp, ToTrim toTrim) {
return ltrim(rtrim(sp, std::ref(toTrim)), std::ref(toTrim));
}
/**
* Strips the leading and the trailing whitespace-only lines. Then looks for
* the least indented non-whitespace-only line and removes its amount of
* leading whitespace from every line. Assumes leading whitespace is either all
* spaces or all tabs.
*
* Purpose: including a multiline string literal in source code, indented to
* the level expected from context.
*/
std::string stripLeftMargin(std::string s);
/**
* Fast, in-place lowercasing of ASCII alphabetic characters in strings.
* Leaves all other characters unchanged, including those with the 0x80
* bit set.
* @param str String to convert
* @param length Length of str, in bytes
*/
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>