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/*
* Copyright 2015 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.
*/
// @author: Andrei Alexandrescu (aalexandre)
// String type.
#ifndef FOLLY_BASE_FBSTRING_H_
#define FOLLY_BASE_FBSTRING_H_
#include <atomic>
#include <limits>
#include <type_traits>
// This file appears in two locations: inside fbcode and in the
// libstdc++ source code (when embedding fbstring as std::string).
// To aid in this schizophrenic use, _LIBSTDCXX_FBSTRING is defined in
// libstdc++'s c++config.h, to gate use inside fbcode v. libstdc++.
#ifdef _LIBSTDCXX_FBSTRING
#pragma GCC system_header
// Handle the cases where the fbcode version (folly/Malloc.h) is included
// either before or after this inclusion.
#ifdef FOLLY_MALLOC_H_
#undef FOLLY_MALLOC_H_
#include "basic_fbstring_malloc.h" // nolint
#else
#include "basic_fbstring_malloc.h" // nolint
#undef FOLLY_MALLOC_H_
#endif
#else // !_LIBSTDCXX_FBSTRING
#include <folly/Portability.h>
// libc++ doesn't provide this header, nor does msvc
#ifdef FOLLY_HAVE_BITS_CXXCONFIG_H
#include <bits/c++config.h>
#endif
#include <string>
#include <cstring>
#include <cassert>
#include <algorithm>
#include <folly/Traits.h>
#include <folly/Malloc.h>
#include <folly/Hash.h>
#include <folly/ScopeGuard.h>
#if FOLLY_HAVE_DEPRECATED_ASSOC
#ifdef _GLIBCXX_SYMVER
#include <ext/hash_set>
#include <ext/hash_map>
#endif
#endif
#endif
// We defined these here rather than including Likely.h to avoid
// redefinition errors when fbstring is imported into libstdc++.
#if defined(__GNUC__) && __GNUC__ >= 4
#define FBSTRING_LIKELY(x) (__builtin_expect((x), 1))
#define FBSTRING_UNLIKELY(x) (__builtin_expect((x), 0))
#else
#define FBSTRING_LIKELY(x) (x)
#define FBSTRING_UNLIKELY(x) (x)
#endif
// Ignore shadowing warnings within this file, so includers can use -Wshadow.
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wshadow"
// FBString cannot use throw when replacing std::string, though it may still
// use std::__throw_*
// nolint
#define throw FOLLY_FBSTRING_MAY_NOT_USE_THROW
#ifdef _LIBSTDCXX_FBSTRING
namespace std _GLIBCXX_VISIBILITY(default) {
_GLIBCXX_BEGIN_NAMESPACE_VERSION
#else
namespace folly {
#endif
// Different versions of gcc/clang support different versions of
// the address sanitizer attribute. Unfortunately, this attribute
// has issues when inlining is used, so disable that as well.
#if defined(__clang__)
# if __has_feature(address_sanitizer)
# if __has_attribute(__no_address_safety_analysis__)
# define FBSTRING_DISABLE_ADDRESS_SANITIZER \
__attribute__((__no_address_safety_analysis__, __noinline__))
# elif __has_attribute(__no_sanitize_address__)
# define FBSTRING_DISABLE_ADDRESS_SANITIZER \
__attribute__((__no_sanitize_address__, __noinline__))
# endif
# endif
#elif defined (__GNUC__) && \
(__GNUC__ == 4) && \
(__GNUC_MINOR__ >= 8) && \
__SANITIZE_ADDRESS__
# define FBSTRING_DISABLE_ADDRESS_SANITIZER \
__attribute__((__no_address_safety_analysis__, __noinline__))
#endif
#ifndef FBSTRING_DISABLE_ADDRESS_SANITIZER
# define FBSTRING_DISABLE_ADDRESS_SANITIZER
#endif
namespace fbstring_detail {
template <class InIt, class OutIt>
inline
OutIt copy_n(InIt b,
typename std::iterator_traits<InIt>::difference_type n,
OutIt d) {
for (; n != 0; --n, ++b, ++d) {
*d = *b;
}
return d;
}
template <class Pod, class T>
inline void pod_fill(Pod* b, Pod* e, T c) {
assert(b && e && b <= e);
/*static*/ if (sizeof(T) == 1) {
memset(b, c, e - b);
} else {
auto const ee = b + ((e - b) & ~7u);
for (; b != ee; b += 8) {
b[0] = c;
b[1] = c;
b[2] = c;
b[3] = c;
b[4] = c;
b[5] = c;
b[6] = c;
b[7] = c;
}
// Leftovers
for (; b != e; ++b) {
*b = c;
}
}
}
/*
* Lightly structured memcpy, simplifies copying PODs and introduces
* some asserts. Unfortunately using this function may cause
* measurable overhead (presumably because it adjusts from a begin/end
* convention to a pointer/size convention, so it does some extra
* arithmetic even though the caller might have done the inverse
* adaptation outside).
*/
template <class Pod>
inline void pod_copy(const Pod* b, const Pod* e, Pod* d) {
assert(e >= b);
assert(d >= e || d + (e - b) <= b);
memcpy(d, b, (e - b) * sizeof(Pod));
}
/*
* Lightly structured memmove, simplifies copying PODs and introduces
* some asserts
*/
template <class Pod>
inline void pod_move(const Pod* b, const Pod* e, Pod* d) {
assert(e >= b);
memmove(d, b, (e - b) * sizeof(*b));
}
} // namespace fbstring_detail
/**
* Defines a special acquisition method for constructing fbstring
* objects. AcquireMallocatedString means that the user passes a
* pointer to a malloc-allocated string that the fbstring object will
* take into custody.
*/
enum class AcquireMallocatedString {};
/*
* fbstring_core_model is a mock-up type that defines all required
* signatures of a fbstring core. The fbstring class itself uses such
* a core object to implement all of the numerous member functions
* required by the standard.
*
* If you want to define a new core, copy the definition below and
* implement the primitives. Then plug the core into basic_fbstring as
* a template argument.
template <class Char>
class fbstring_core_model {
public:
fbstring_core_model();
fbstring_core_model(const fbstring_core_model &);
~fbstring_core_model();
// Returns a pointer to string's buffer (currently only contiguous
// strings are supported). The pointer is guaranteed to be valid
// until the next call to a non-const member function.
const Char * data() const;
// Much like data(), except the string is prepared to support
// character-level changes. This call is a signal for
// e.g. reference-counted implementation to fork the data. The
// pointer is guaranteed to be valid until the next call to a
// non-const member function.
Char * mutable_data();
// Returns a pointer to string's buffer and guarantees that a
// readable '\0' lies right after the buffer. The pointer is
// guaranteed to be valid until the next call to a non-const member
// function.
const Char * c_str() const;
// Shrinks the string by delta characters. Asserts that delta <=
// size().
void shrink(size_t delta);
// Expands the string by delta characters (i.e. after this call
// size() will report the old size() plus delta) but without
// initializing the expanded region. Returns a pointer to the memory
// to be initialized (the beginning of the expanded portion). The
// caller is expected to fill the expanded area appropriately.
Char* expand_noinit(size_t delta);
// Expands the string by one character and sets the last character
// to c.
void push_back(Char c);
// Returns the string's size.
size_t size() const;
// Returns the string's capacity, i.e. maximum size that the string
// can grow to without reallocation. Note that for reference counted
// strings that's technically a lie - even assigning characters
// within the existing size would cause a reallocation.
size_t capacity() const;
// Returns true if the data underlying the string is actually shared
// across multiple strings (in a refcounted fashion).
bool isShared() const;
// Makes sure that at least minCapacity characters are available for
// the string without reallocation. For reference-counted strings,
// it should fork the data even if minCapacity < size().
void reserve(size_t minCapacity);
private:
// Do not implement
fbstring_core_model& operator=(const fbstring_core_model &);
};
*/
/**
* gcc-4.7 throws what appears to be some false positive uninitialized
* warnings for the members of the MediumLarge struct. So, mute them here.
*/
#if defined(__GNUC__) && !defined(__clang__)
# pragma GCC diagnostic push
# pragma GCC diagnostic ignored "-Wuninitialized"
#endif
/**
* This is the core of the string. The code should work on 32- and
* 64-bit architectures and with any Char size. Porting to big endian
* architectures would require some changes.
*
* The storage is selected as follows (assuming we store one-byte
* characters on a 64-bit machine): (a) "small" strings between 0 and
* 23 chars are stored in-situ without allocation (the rightmost byte
* stores the size); (b) "medium" strings from 24 through 254 chars
* are stored in malloc-allocated memory that is copied eagerly; (c)
* "large" strings of 255 chars and above are stored in a similar
* structure as medium arrays, except that the string is
* reference-counted and copied lazily. the reference count is
* allocated right before the character array.
*
* The discriminator between these three strategies sits in the two
* most significant bits of the rightmost char of the storage. If
* neither is set, then the string is small (and its length sits in
* the lower-order bits of that rightmost character). If the MSb is
* set, the string is medium width. If the second MSb is set, then the
* string is large.
*/
template <class Char> class fbstring_core {
public:
fbstring_core() noexcept {
// Only initialize the tag, will set the MSBs (i.e. the small
// string size) to zero too
ml_.capacity_ = maxSmallSize << (8 * (sizeof(size_t) - sizeof(Char)));
// or: setSmallSize(0);
writeTerminator();
assert(category() == Category::isSmall && size() == 0);
}
fbstring_core(const fbstring_core & rhs) {
assert(&rhs != this);
// Simplest case first: small strings are bitblitted
if (rhs.category() == Category::isSmall) {
static_assert(offsetof(MediumLarge, data_) == 0,
"fbstring layout failure");
static_assert(offsetof(MediumLarge, size_) == sizeof(ml_.data_),
"fbstring layout failure");
static_assert(offsetof(MediumLarge, capacity_) == 2 * sizeof(ml_.data_),
"fbstring layout failure");
const size_t size = rhs.smallSize();
if (size == 0) {
ml_.capacity_ = rhs.ml_.capacity_;
writeTerminator();
} else {
// Just write the whole thing, don't look at details. In
// particular we need to copy capacity anyway because we want
// to set the size (don't forget that the last character,
// which stores a short string's length, is shared with the
// ml_.capacity field).
ml_ = rhs.ml_;
}
assert(category() == Category::isSmall && this->size() == rhs.size());
} else if (rhs.category() == Category::isLarge) {
// Large strings are just refcounted
ml_ = rhs.ml_;
RefCounted::incrementRefs(ml_.data_);
assert(category() == Category::isLarge && size() == rhs.size());
} else {
// Medium strings are copied eagerly. Don't forget to allocate
// one extra Char for the null terminator.
auto const allocSize =
goodMallocSize((1 + rhs.ml_.size_) * sizeof(Char));
ml_.data_ = static_cast<Char*>(checkedMalloc(allocSize));
fbstring_detail::pod_copy(rhs.ml_.data_,
// 1 for terminator
rhs.ml_.data_ + rhs.ml_.size_ + 1,
ml_.data_);
// No need for writeTerminator() here, we copied one extra
// element just above.
ml_.size_ = rhs.ml_.size_;
ml_.capacity_ = (allocSize / sizeof(Char) - 1)
| static_cast<category_type>(Category::isMedium);
assert(category() == Category::isMedium);
}
assert(size() == rhs.size());
assert(memcmp(data(), rhs.data(), size() * sizeof(Char)) == 0);
}
fbstring_core(fbstring_core&& goner) noexcept {
if (goner.category() == Category::isSmall) {
// Just copy, leave the goner in peace
new(this) fbstring_core(goner.small_, goner.smallSize());
} else {
// Take goner's guts
ml_ = goner.ml_;
// Clean goner's carcass
goner.setSmallSize(0);
}
}
// NOTE(agallagher): The word-aligned copy path copies bytes which are
// outside the range of the string, and makes address sanitizer unhappy,
// so just disable it on this function.
fbstring_core(const Char *const data, const size_t size)
FBSTRING_DISABLE_ADDRESS_SANITIZER {
#ifndef NDEBUG
#ifndef _LIBSTDCXX_FBSTRING
SCOPE_EXIT {
assert(this->size() == size);
assert(memcmp(this->data(), data, size * sizeof(Char)) == 0);
};
#endif
#endif
// Simplest case first: small strings are bitblitted
if (size <= maxSmallSize) {
// Layout is: Char* data_, size_t size_, size_t capacity_
static_assert(sizeof(*this) == sizeof(Char*) + 2 * sizeof(size_t),
"fbstring has unexpected size");
static_assert(sizeof(Char*) == sizeof(size_t),
"fbstring size assumption violation");
// sizeof(size_t) must be a power of 2
static_assert((sizeof(size_t) & (sizeof(size_t) - 1)) == 0,
"fbstring size assumption violation");
// If data is aligned, use fast word-wise copying. Otherwise,
// use conservative memcpy.
if (reinterpret_cast<size_t>(data) & (sizeof(size_t) - 1)) {
fbstring_detail::pod_copy(data, data + size, small_);
} else {
// Copy one word (64 bits) at a time
const size_t byteSize = size * sizeof(Char);
if (byteSize > 2 * sizeof(size_t)) {
// Copy three words
ml_.capacity_ = reinterpret_cast<const size_t*>(data)[2];
copyTwo:
ml_.size_ = reinterpret_cast<const size_t*>(data)[1];
copyOne:
ml_.data_ = *reinterpret_cast<Char**>(const_cast<Char*>(data));
} else if (byteSize > sizeof(size_t)) {
// Copy two words
goto copyTwo;
} else if (size > 0) {
// Copy one word
goto copyOne;
}
}
setSmallSize(size);
return;
} else if (size <= maxMediumSize) {
// Medium strings are allocated normally. Don't forget to
// allocate one extra Char for the terminating null.
auto const allocSize = goodMallocSize((1 + size) * sizeof(Char));
ml_.data_ = static_cast<Char*>(checkedMalloc(allocSize));
fbstring_detail::pod_copy(data, data + size, ml_.data_);
ml_.size_ = size;
ml_.capacity_ = (allocSize / sizeof(Char) - 1)
| static_cast<category_type>(Category::isMedium);
} else {
// Large strings are allocated differently
size_t effectiveCapacity = size;
auto const newRC = RefCounted::create(data, & effectiveCapacity);
ml_.data_ = newRC->data_;
ml_.size_ = size;
ml_.capacity_ = effectiveCapacity
| static_cast<category_type>(Category::isLarge);
}
writeTerminator();
}
~fbstring_core() noexcept {
auto const c = category();
if (c == Category::isSmall) {
return;
}
if (c == Category::isMedium) {
free(ml_.data_);
return;
}
RefCounted::decrementRefs(ml_.data_);
}
// Snatches a previously mallocated string. The parameter "size"
// is the size of the string, and the parameter "allocatedSize"
// is the size of the mallocated block. The string must be
// \0-terminated, so allocatedSize >= size + 1 and data[size] == '\0'.
//
// So if you want a 2-character string, pass malloc(3) as "data",
// pass 2 as "size", and pass 3 as "allocatedSize".
fbstring_core(Char * const data,
const size_t size,
const size_t allocatedSize,
AcquireMallocatedString) {
if (size > 0) {
assert(allocatedSize >= size + 1);
assert(data[size] == '\0');
// Use the medium string storage
ml_.data_ = data;
ml_.size_ = size;
// Don't forget about null terminator
ml_.capacity_ = (allocatedSize - 1)
| static_cast<category_type>(Category::isMedium);
} else {
// No need for the memory
free(data);
setSmallSize(0);
}
}
// swap below doesn't test whether &rhs == this (and instead
// potentially does extra work) on the premise that the rarity of
// that situation actually makes the check more expensive than is
// worth.
void swap(fbstring_core & rhs) {
auto const t = ml_;
ml_ = rhs.ml_;
rhs.ml_ = t;
}
// In C++11 data() and c_str() are 100% equivalent.
const Char * data() const {
return c_str();
}
Char * mutable_data() {
auto const c = category();
if (c == Category::isSmall) {
return small_;
}
assert(c == Category::isMedium || c == Category::isLarge);
if (c == Category::isLarge && RefCounted::refs(ml_.data_) > 1) {
// Ensure unique.
size_t effectiveCapacity = ml_.capacity();
auto const newRC = RefCounted::create(& effectiveCapacity);
// If this fails, someone placed the wrong capacity in an
// fbstring.
assert(effectiveCapacity >= ml_.capacity());
fbstring_detail::pod_copy(ml_.data_, ml_.data_ + ml_.size_ + 1,
newRC->data_);
RefCounted::decrementRefs(ml_.data_);
ml_.data_ = newRC->data_;
// No need to call writeTerminator(), we have + 1 above.
}
return ml_.data_;
}
const Char * c_str() const {
auto const c = category();
if (c == Category::isSmall) {
assert(small_[smallSize()] == '\0');
return small_;
}
assert(c == Category::isMedium || c == Category::isLarge);
assert(ml_.data_[ml_.size_] == '\0');
return ml_.data_;
}
void shrink(const size_t delta) {
if (category() == Category::isSmall) {
// Check for underflow
assert(delta <= smallSize());
setSmallSize(smallSize() - delta);
} else if (category() == Category::isMedium ||
RefCounted::refs(ml_.data_) == 1) {
// Medium strings and unique large strings need no special
// handling.
assert(ml_.size_ >= delta);
ml_.size_ -= delta;
writeTerminator();
} else {
assert(ml_.size_ >= delta);
// Shared large string, must make unique. This is because of the
// durn terminator must be written, which may trample the shared
// data.
if (delta) {
fbstring_core(ml_.data_, ml_.size_ - delta).swap(*this);
}
// No need to write the terminator.
}
}
void reserve(size_t minCapacity) {
if (category() == Category::isLarge) {
// Ensure unique
if (RefCounted::refs(ml_.data_) > 1) {
// We must make it unique regardless; in-place reallocation is
// useless if the string is shared. In order to not surprise
// people, reserve the new block at current capacity or
// more. That way, a string's capacity never shrinks after a
// call to reserve.
minCapacity = std::max(minCapacity, ml_.capacity());
auto const newRC = RefCounted::create(& minCapacity);
fbstring_detail::pod_copy(ml_.data_, ml_.data_ + ml_.size_ + 1,
newRC->data_);
// Done with the old data. No need to call writeTerminator(),
// we have + 1 above.
RefCounted::decrementRefs(ml_.data_);
ml_.data_ = newRC->data_;
ml_.capacity_ = minCapacity
| static_cast<category_type>(Category::isLarge);
// size remains unchanged
} else {
// String is not shared, so let's try to realloc (if needed)
if (minCapacity > ml_.capacity()) {
// Asking for more memory
auto const newRC =
RefCounted::reallocate(ml_.data_, ml_.size_,
ml_.capacity(), minCapacity);
ml_.data_ = newRC->data_;
ml_.capacity_ = minCapacity
| static_cast<category_type>(Category::isLarge);
writeTerminator();
}
assert(capacity() >= minCapacity);
}
} else if (category() == Category::isMedium) {
// String is not shared
if (minCapacity <= ml_.capacity()) {
return; // nothing to do, there's enough room
}
if (minCapacity <= maxMediumSize) {
// Keep the string at medium size. Don't forget to allocate
// one extra Char for the terminating null.
size_t capacityBytes = goodMallocSize((1 + minCapacity) * sizeof(Char));
ml_.data_ = static_cast<Char *>(
smartRealloc(
ml_.data_,
ml_.size_ * sizeof(Char),
(ml_.capacity() + 1) * sizeof(Char),
capacityBytes));
writeTerminator();
ml_.capacity_ = (capacityBytes / sizeof(Char) - 1)
| static_cast<category_type>(Category::isMedium);
} else {
// Conversion from medium to large string
fbstring_core nascent;
// Will recurse to another branch of this function
nascent.reserve(minCapacity);
nascent.ml_.size_ = ml_.size_;
fbstring_detail::pod_copy(ml_.data_, ml_.data_ + ml_.size_,
nascent.ml_.data_);
nascent.swap(*this);
writeTerminator();
assert(capacity() >= minCapacity);
}
} else {
assert(category() == Category::isSmall);
if (minCapacity > maxMediumSize) {
// large
auto const newRC = RefCounted::create(& minCapacity);
auto const size = smallSize();
fbstring_detail::pod_copy(small_, small_ + size + 1, newRC->data_);
// No need for writeTerminator(), we wrote it above with + 1.
ml_.data_ = newRC->data_;
ml_.size_ = size;
ml_.capacity_ = minCapacity
| static_cast<category_type>(Category::isLarge);
assert(capacity() >= minCapacity);
} else if (minCapacity > maxSmallSize) {
// medium
// Don't forget to allocate one extra Char for the terminating null
auto const allocSizeBytes =
goodMallocSize((1 + minCapacity) * sizeof(Char));
auto const data = static_cast<Char*>(checkedMalloc(allocSizeBytes));
auto const size = smallSize();
fbstring_detail::pod_copy(small_, small_ + size + 1, data);
// No need for writeTerminator(), we wrote it above with + 1.
ml_.data_ = data;
ml_.size_ = size;
ml_.capacity_ = (allocSizeBytes / sizeof(Char) - 1)
| static_cast<category_type>(Category::isMedium);
} else {
// small
// Nothing to do, everything stays put
}
}
assert(capacity() >= minCapacity);
}
Char * expand_noinit(const size_t delta) {
// Strategy is simple: make room, then change size
assert(capacity() >= size());
size_t sz, newSz;
if (category() == Category::isSmall) {
sz = smallSize();
newSz = sz + delta;
if (newSz <= maxSmallSize) {
setSmallSize(newSz);
return small_ + sz;
}
reserve(newSz);
} else {
sz = ml_.size_;
newSz = ml_.size_ + delta;
if (newSz > capacity()) {
reserve(newSz);
}
}
assert(capacity() >= newSz);
// Category can't be small - we took care of that above
assert(category() == Category::isMedium || category() == Category::isLarge);
ml_.size_ = newSz;
writeTerminator();
assert(size() == newSz);
return ml_.data_ + sz;
}
void push_back(Char c) {
assert(capacity() >= size());
size_t sz;
if (category() == Category::isSmall) {
sz = smallSize();
if (sz < maxSmallSize) {
small_[sz] = c;
setSmallSize(sz + 1);
return;
}
reserve(maxSmallSize * 2);
} else {
sz = ml_.size_;
if (sz == capacity()) { // always true for isShared()
reserve(1 + sz * 3 / 2); // ensures not shared
}
}
assert(!isShared());
assert(capacity() >= sz + 1);
// Category can't be small - we took care of that above
assert(category() == Category::isMedium || category() == Category::isLarge);
ml_.size_ = sz + 1;
ml_.data_[sz] = c;
writeTerminator();
}
size_t size() const {
return category() == Category::isSmall ? smallSize() : ml_.size_;
}
size_t capacity() const {
switch (category()) {
case Category::isSmall:
return maxSmallSize;
case Category::isLarge:
// For large-sized strings, a multi-referenced chunk has no
// available capacity. This is because any attempt to append
// data would trigger a new allocation.
if (RefCounted::refs(ml_.data_) > 1) return ml_.size_;
default: {}
}
return ml_.capacity();
}
bool isShared() const {
return category() == Category::isLarge && RefCounted::refs(ml_.data_) > 1;
}
void writeTerminator() {
if (category() == Category::isSmall) {
const auto s = smallSize();
if (s != maxSmallSize) {
small_[s] = '\0';
}
} else {
ml_.data_[ml_.size_] = '\0';
}
}
private:
// Disabled
fbstring_core & operator=(const fbstring_core & rhs);
struct MediumLarge {
Char * data_;
size_t size_;
size_t capacity_;
size_t capacity() const {
return capacity_ & capacityExtractMask;
}
};
struct RefCounted {
std::atomic<size_t> refCount_;
Char data_[1];
static RefCounted * fromData(Char * p) {
return static_cast<RefCounted*>(
static_cast<void*>(
static_cast<unsigned char*>(static_cast<void*>(p))
- sizeof(refCount_)));
}
static size_t refs(Char * p) {
return fromData(p)->refCount_.load(std::memory_order_acquire);
}
static void incrementRefs(Char * p) {
fromData(p)->refCount_.fetch_add(1, std::memory_order_acq_rel);
}
static void decrementRefs(Char * p) {
auto const dis = fromData(p);
size_t oldcnt = dis->refCount_.fetch_sub(1, std::memory_order_acq_rel);
assert(oldcnt > 0);
if (oldcnt == 1) {
free(dis);
}
}
static RefCounted * create(size_t * size) {
// Don't forget to allocate one extra Char for the terminating
// null. In this case, however, one Char is already part of the
// struct.
const size_t allocSize = goodMallocSize(
sizeof(RefCounted) + *size * sizeof(Char));
auto result = static_cast<RefCounted*>(checkedMalloc(allocSize));
result->refCount_.store(1, std::memory_order_release);
*size = (allocSize - sizeof(RefCounted)) / sizeof(Char);
return result;
}
static RefCounted * create(const Char * data, size_t * size) {
const size_t effectiveSize = *size;
auto result = create(size);
fbstring_detail::pod_copy(data, data + effectiveSize, result->data_);
return result;
}
static RefCounted * reallocate(Char *const data,
const size_t currentSize,
const size_t currentCapacity,
const size_t newCapacity) {
assert(newCapacity > 0 && newCapacity > currentSize);
auto const dis = fromData(data);
assert(dis->refCount_.load(std::memory_order_acquire) == 1);
// Don't forget to allocate one extra Char for the terminating
// null. In this case, however, one Char is already part of the
// struct.
auto result = static_cast<RefCounted*>(
smartRealloc(dis,
sizeof(RefCounted) + currentSize * sizeof(Char),
sizeof(RefCounted) + currentCapacity * sizeof(Char),
sizeof(RefCounted) + newCapacity * sizeof(Char)));
assert(result->refCount_.load(std::memory_order_acquire) == 1);
return result;
}
};
union {
Char small_[sizeof(MediumLarge) / sizeof(Char)];
MediumLarge ml_;
};
enum : size_t {
lastChar = sizeof(MediumLarge) - 1,
maxSmallSize = lastChar / sizeof(Char),
maxMediumSize = 254 / sizeof(Char), // coincides with the small
// bin size in dlmalloc
categoryExtractMask = sizeof(size_t) == 4 ? 0xC0000000 : 0xC000000000000000,
capacityExtractMask = ~categoryExtractMask,
};
static_assert(!(sizeof(MediumLarge) % sizeof(Char)),
"Corrupt memory layout for fbstring.");
typedef std::conditional<sizeof(size_t) == 4, uint32_t, uint64_t>::type
category_type;
enum class Category : category_type {
isSmall = 0,
isMedium = sizeof(size_t) == 4 ? 0x80000000 : 0x8000000000000000,
isLarge = sizeof(size_t) == 4 ? 0x40000000 : 0x4000000000000000,
};
Category category() const {
// Assumes little endian
return static_cast<Category>(ml_.capacity_ & categoryExtractMask);
}
size_t smallSize() const {
assert(category() == Category::isSmall &&
static_cast<size_t>(small_[maxSmallSize])
<= static_cast<size_t>(maxSmallSize));
return static_cast<size_t>(maxSmallSize)
- static_cast<size_t>(small_[maxSmallSize]);
}
void setSmallSize(size_t s) {
// Warning: this should work with uninitialized strings too,
// so don't assume anything about the previous value of
// small_[maxSmallSize].
assert(s <= maxSmallSize);
small_[maxSmallSize] = maxSmallSize - s;
writeTerminator();
}
};
#if defined(__GNUC__) && !defined(__clang__)
# pragma GCC diagnostic pop
#endif
#ifndef _LIBSTDCXX_FBSTRING
/**
* Dummy fbstring core that uses an actual std::string. This doesn't
* make any sense - it's just for testing purposes.
*/
template <class Char>
class dummy_fbstring_core {
public:
dummy_fbstring_core() {
}
dummy_fbstring_core(const dummy_fbstring_core& another)
: backend_(another.backend_) {
}
dummy_fbstring_core(const Char * s, size_t n)
: backend_(s, n) {
}
void swap(dummy_fbstring_core & rhs) {
backend_.swap(rhs.backend_);
}
const Char * data() const {
return backend_.data();
}
Char * mutable_data() {
//assert(!backend_.empty());
return &*backend_.begin();
}
void shrink(size_t delta) {
assert(delta <= size());
backend_.resize(size() - delta);
}
Char * expand_noinit(size_t delta) {
auto const sz = size();
backend_.resize(size() + delta);
return backend_.data() + sz;
}
void push_back(Char c) {
backend_.push_back(c);
}
size_t size() const {
return backend_.size();
}
size_t capacity() const {
return backend_.capacity();
}
bool isShared() const {
return false;
}
void reserve(size_t minCapacity) {
backend_.reserve(minCapacity);
}
private:
std::basic_string<Char> backend_;
};
#endif // !_LIBSTDCXX_FBSTRING
/**
* This is the basic_string replacement. For conformity,
* basic_fbstring takes the same template parameters, plus the last
* one which is the core.
*/
#ifdef _LIBSTDCXX_FBSTRING
template <typename E, class T, class A, class Storage>
#else
template <typename E,
class T = std::char_traits<E>,
class A = std::allocator<E>,
class Storage = fbstring_core<E> >
#endif
class basic_fbstring {
static void enforce(
bool condition,
void (*throw_exc)(const char*),
const char* msg) {
if (!condition) throw_exc(msg);
}
bool isSane() const {
return
begin() <= end() &&
empty() == (size() == 0) &&
empty() == (begin() == end()) &&
size() <= max_size() &&
capacity() <= max_size() &&
size() <= capacity() &&
begin()[size()] == '\0';
}
struct Invariant;
friend struct Invariant;
struct Invariant {
#ifndef NDEBUG
explicit Invariant(const basic_fbstring& s) : s_(s) {
assert(s_.isSane());
}
~Invariant() {
assert(s_.isSane());
}
private:
const basic_fbstring& s_;
#else
explicit Invariant(const basic_fbstring&) {}
#endif
Invariant& operator=(const Invariant&);
};
public:
// types
typedef T traits_type;
typedef typename traits_type::char_type value_type;
typedef A allocator_type;
typedef typename A::size_type size_type;
typedef typename A::difference_type difference_type;
typedef typename A::reference reference;
typedef typename A::const_reference const_reference;
typedef typename A::pointer pointer;
typedef typename A::const_pointer const_pointer;
typedef E* iterator;
typedef const E* const_iterator;
typedef std::reverse_iterator<iterator
#ifdef NO_ITERATOR_TRAITS
, value_type
#endif
> reverse_iterator;
typedef std::reverse_iterator<const_iterator
#ifdef NO_ITERATOR_TRAITS
, const value_type
#endif
> const_reverse_iterator;
static const size_type npos; // = size_type(-1)
private:
static void procrustes(size_type& n, size_type nmax) {
if (n > nmax) n = nmax;
}
public:
// C++11 21.4.2 construct/copy/destroy
explicit basic_fbstring(const A& /*a*/ = A()) noexcept {
}
basic_fbstring(const basic_fbstring& str)
: store_(str.store_) {
}
// Move constructor
basic_fbstring(basic_fbstring&& goner) noexcept
: store_(std::move(goner.store_)) {
}
#ifndef _LIBSTDCXX_FBSTRING
// This is defined for compatibility with std::string
/* implicit */ basic_fbstring(const std::string& str)
: store_(str.data(), str.size()) {
}
#endif
basic_fbstring(const basic_fbstring& str, size_type pos,
size_type n = npos, const A& a = A()) {
assign(str, pos, n);
}
/* implicit */ basic_fbstring(const value_type* s, const A& /*a*/ = A())
: store_(s, s
? traits_type::length(s)
: (std::__throw_logic_error(
"basic_fbstring: null pointer initializer not valid"),
0)) {
}
basic_fbstring(const value_type* s, size_type n, const A& /*a*/ = A())
: store_(s, n) {
}
basic_fbstring(size_type n, value_type c, const A& /*a*/ = A()) {
auto const data = store_.expand_noinit(n);
fbstring_detail::pod_fill(data, data + n, c);
store_.writeTerminator();
}
template <class InIt>
basic_fbstring(InIt begin, InIt end,
typename std::enable_if<
!std::is_same<typename std::remove_const<InIt>::type,
value_type*>::value, const A>::type & /*a*/ = A()) {
assign(begin, end);
}
// Specialization for const char*, const char*
basic_fbstring(const value_type* b, const value_type* e)
: store_(b, e - b) {
}
// Nonstandard constructor
basic_fbstring(value_type *s, size_type n, size_type c,
AcquireMallocatedString a)
: store_(s, n, c, a) {
}
// Construction from initialization list
basic_fbstring(std::initializer_list<value_type> il) {
assign(il.begin(), il.end());
}
~basic_fbstring() noexcept {
}
basic_fbstring& operator=(const basic_fbstring& lhs) {
if (FBSTRING_UNLIKELY(&lhs == this)) {
return *this;
}
auto const oldSize = size();
auto const srcSize = lhs.size();
if (capacity() >= srcSize && !store_.isShared()) {
// great, just copy the contents
if (oldSize < srcSize)
store_.expand_noinit(srcSize - oldSize);
else
store_.shrink(oldSize - srcSize);
assert(size() == srcSize);
fbstring_detail::pod_copy(lhs.begin(), lhs.end(), begin());
store_.writeTerminator();
} else {
// need to reallocate, so we may as well create a brand new string
basic_fbstring(lhs).swap(*this);
}
return *this;
}
// Move assignment
basic_fbstring& operator=(basic_fbstring&& goner) noexcept {
if (FBSTRING_UNLIKELY(&goner == this)) {
// Compatibility with std::basic_string<>,
// C++11 21.4.2 [string.cons] / 23 requires self-move-assignment support.
return *this;
}
// No need of this anymore
this->~basic_fbstring();
// Move the goner into this
new(&store_) fbstring_core<E>(std::move(goner.store_));
return *this;
}
#ifndef _LIBSTDCXX_FBSTRING
// Compatibility with std::string
basic_fbstring & operator=(const std::string & rhs) {
return assign(rhs.data(), rhs.size());
}
// Compatibility with std::string
std::string toStdString() const {
return std::string(data(), size());
}
#else
// A lot of code in fbcode still uses this method, so keep it here for now.
const basic_fbstring& toStdString() const {
return *this;
}
#endif
basic_fbstring& operator=(const value_type* s) {
return assign(s);
}
basic_fbstring& operator=(value_type c) {
if (empty()) {
store_.expand_noinit(1);
} else if (store_.isShared()) {
basic_fbstring(1, c).swap(*this);
return *this;
} else {
store_.shrink(size() - 1);
}
*store_.mutable_data() = c;
store_.writeTerminator();
return *this;
}
basic_fbstring& operator=(std::initializer_list<value_type> il) {
return assign(il.begin(), il.end());
}
// C++11 21.4.3 iterators:
iterator begin() { return store_.mutable_data(); }
const_iterator begin() const { return store_.data(); }
const_iterator cbegin() const { return begin(); }
iterator end() {
return store_.mutable_data() + store_.size();
}
const_iterator end() const {
return store_.data() + store_.size();
}
const_iterator cend() const { return end(); }
reverse_iterator rbegin() {
return reverse_iterator(end());
}
const_reverse_iterator rbegin() const {
return const_reverse_iterator(end());
}
const_reverse_iterator crbegin() const { return rbegin(); }
reverse_iterator rend() {
return reverse_iterator(begin());
}
const_reverse_iterator rend() const {
return const_reverse_iterator(begin());
}
const_reverse_iterator crend() const { return rend(); }
// Added by C++11
// C++11 21.4.5, element access:
const value_type& front() const { return *begin(); }
const value_type& back() const {
assert(!empty());
// Should be begin()[size() - 1], but that branches twice
return *(end() - 1);
}
value_type& front() { return *begin(); }
value_type& back() {
assert(!empty());
// Should be begin()[size() - 1], but that branches twice
return *(end() - 1);
}
void pop_back() {
assert(!empty());
store_.shrink(1);
}
// C++11 21.4.4 capacity:
size_type size() const { return store_.size(); }
size_type length() const { return size(); }
size_type max_size() const {
return std::numeric_limits<size_type>::max();
}
void resize(const size_type n, const value_type c = value_type()) {
auto size = this->size();
if (n <= size) {
store_.shrink(size - n);
} else {
// Do this in two steps to minimize slack memory copied (see
// smartRealloc).
auto const capacity = this->capacity();
assert(capacity >= size);
if (size < capacity) {
auto delta = std::min(n, capacity) - size;
store_.expand_noinit(delta);
fbstring_detail::pod_fill(begin() + size, end(), c);
size += delta;
if (size == n) {
store_.writeTerminator();
return;
}
assert(size < n);
}
auto const delta = n - size;
store_.expand_noinit(delta);
fbstring_detail::pod_fill(end() - delta, end(), c);
store_.writeTerminator();
}
assert(this->size() == n);
}
size_type capacity() const { return store_.capacity(); }
void reserve(size_type res_arg = 0) {
enforce(res_arg <= max_size(), std::__throw_length_error, "");
store_.reserve(res_arg);
}
void shrink_to_fit() {
// Shrink only if slack memory is sufficiently large
if (capacity() < size() * 3 / 2) {
return;
}
basic_fbstring(cbegin(), cend()).swap(*this);
}
void clear() { resize(0); }
bool empty() const { return size() == 0; }
// C++11 21.4.5 element access:
const_reference operator[](size_type pos) const {
return *(begin() + pos);
}
reference operator[](size_type pos) {
return *(begin() + pos);
}
const_reference at(size_type n) const {
enforce(n <= size(), std::__throw_out_of_range, "");
return (*this)[n];
}
reference at(size_type n) {
enforce(n < size(), std::__throw_out_of_range, "");
return (*this)[n];
}
// C++11 21.4.6 modifiers:
basic_fbstring& operator+=(const basic_fbstring& str) {
return append(str);
}
basic_fbstring& operator+=(const value_type* s) {
return append(s);
}
basic_fbstring& operator+=(const value_type c) {
push_back(c);
return *this;
}
basic_fbstring& operator+=(std::initializer_list<value_type> il) {
append(il);
return *this;
}
basic_fbstring& append(const basic_fbstring& str) {
#ifndef NDEBUG
auto desiredSize = size() + str.size();
#endif
append(str.data(), str.size());
assert(size() == desiredSize);
return *this;
}
basic_fbstring& append(const basic_fbstring& str, const size_type pos,
size_type n) {
const size_type sz = str.size();
enforce(pos <= sz, std::__throw_out_of_range, "");
procrustes(n, sz - pos);
return append(str.data() + pos, n);
}
basic_fbstring& append(const value_type* s, size_type n) {
#ifndef NDEBUG
Invariant checker(*this);
(void) checker;
#endif
if (FBSTRING_UNLIKELY(!n)) {
// Unlikely but must be done
return *this;
}
auto const oldSize = size();
auto const oldData = data();
// Check for aliasing (rare). We could use "<=" here but in theory
// those do not work for pointers unless the pointers point to
// elements in the same array. For that reason we use
// std::less_equal, which is guaranteed to offer a total order
// over pointers. See discussion at http://goo.gl/Cy2ya for more
// info.
std::less_equal<const value_type*> le;
if (FBSTRING_UNLIKELY(le(oldData, s) && !le(oldData + oldSize, s))) {
assert(le(s + n, oldData + oldSize));
const size_type offset = s - oldData;
store_.reserve(oldSize + n);
// Restore the source
s = data() + offset;
}
// Warning! Repeated appends with short strings may actually incur
// practically quadratic performance. Avoid that by pushing back
// the first character (which ensures exponential growth) and then
// appending the rest normally. Worst case the append may incur a
// second allocation but that will be rare.
push_back(*s++);
--n;
memcpy(store_.expand_noinit(n), s, n * sizeof(value_type));
assert(size() == oldSize + n + 1);
return *this;
}
basic_fbstring& append(const value_type* s) {
return append(s, traits_type::length(s));
}
basic_fbstring& append(size_type n, value_type c) {
resize(size() + n, c);
return *this;
}
template<class InputIterator>
basic_fbstring& append(InputIterator first, InputIterator last) {
insert(end(), first, last);
return *this;
}
basic_fbstring& append(std::initializer_list<value_type> il) {
return append(il.begin(), il.end());
}
void push_back(const value_type c) { // primitive
store_.push_back(c);
}
basic_fbstring& assign(const basic_fbstring& str) {
if (&str == this) return *this;
return assign(str.data(), str.size());
}
basic_fbstring& assign(basic_fbstring&& str) {
return *this = std::move(str);
}
basic_fbstring& assign(const basic_fbstring& str, const size_type pos,
size_type n) {
const size_type sz = str.size();
enforce(pos <= sz, std::__throw_out_of_range, "");
procrustes(n, sz - pos);
return assign(str.data() + pos, n);
}
basic_fbstring& assign(const value_type* s, const size_type n) {
Invariant checker(*this);
(void) checker;
if (size() >= n) {
std::copy(s, s + n, begin());
resize(n);
assert(size() == n);
} else {
const value_type *const s2 = s + size();
std::copy(s, s2, begin());
append(s2, n - size());
assert(size() == n);
}
store_.writeTerminator();
assert(size() == n);
return *this;
}
basic_fbstring& assign(const value_type* s) {
return assign(s, traits_type::length(s));
}
basic_fbstring& assign(std::initializer_list<value_type> il) {
return assign(il.begin(), il.end());
}
template <class ItOrLength, class ItOrChar>
basic_fbstring& assign(ItOrLength first_or_n, ItOrChar last_or_c) {
return replace(begin(), end(), first_or_n, last_or_c);
}
basic_fbstring& insert(size_type pos1, const basic_fbstring& str) {
return insert(pos1, str.data(), str.size());
}
basic_fbstring& insert(size_type pos1, const basic_fbstring& str,
size_type pos2, size_type n) {
enforce(pos2 <= str.length(), std::__throw_out_of_range, "");
procrustes(n, str.length() - pos2);
return insert(pos1, str.data() + pos2, n);
}
basic_fbstring& insert(size_type pos, const value_type* s, size_type n) {
enforce(pos <= length(), std::__throw_out_of_range, "");
insert(begin() + pos, s, s + n);
return *this;
}
basic_fbstring& insert(size_type pos, const value_type* s) {
return insert(pos, s, traits_type::length(s));
}
basic_fbstring& insert(size_type pos, size_type n, value_type c) {
enforce(pos <= length(), std::__throw_out_of_range, "");
insert(begin() + pos, n, c);
return *this;
}
iterator insert(const_iterator p, const value_type c) {
const size_type pos = p - begin();
insert(p, 1, c);
return begin() + pos;
}
private:
template <int i> class Selector {};
iterator insertImplDiscr(const_iterator p,
size_type n, value_type c, Selector<1>) {
Invariant checker(*this);
(void) checker;
auto const pos = p - begin();
assert(p >= begin() && p <= end());
if (capacity() - size() < n) {
const size_type sz = p - begin();
reserve(size() + n);
p = begin() + sz;
}
const iterator oldEnd = end();
if (n < size_type(oldEnd - p)) {
append(oldEnd - n, oldEnd);
//std::copy(
// reverse_iterator(oldEnd - n),
// reverse_iterator(p),
// reverse_iterator(oldEnd));
fbstring_detail::pod_move(&*p, &*oldEnd - n,
begin() + pos + n);
std::fill(begin() + pos, begin() + pos + n, c);
} else {
append(n - (end() - p), c);
append(iterator(p), oldEnd);
std::fill(iterator(p), oldEnd, c);
}
store_.writeTerminator();
return begin() + pos;
}
template<class InputIter>
iterator insertImplDiscr(const_iterator i,
InputIter b, InputIter e, Selector<0>) {
return insertImpl(i, b, e,
typename std::iterator_traits<InputIter>::iterator_category());
}
template <class FwdIterator>
iterator insertImpl(const_iterator i,
FwdIterator s1, FwdIterator s2, std::forward_iterator_tag) {
Invariant checker(*this);
(void) checker;
const size_type pos = i - begin();
const typename std::iterator_traits<FwdIterator>::difference_type n2 =
std::distance(s1, s2);
assert(n2 >= 0);
using namespace fbstring_detail;
assert(pos <= size());
const typename std::iterator_traits<FwdIterator>::difference_type maxn2 =
capacity() - size();
if (maxn2 < n2) {
// realloc the string
reserve(size() + n2);
i = begin() + pos;
}
if (pos + n2 <= size()) {
const iterator tailBegin = end() - n2;
store_.expand_noinit(n2);
fbstring_detail::pod_copy(tailBegin, tailBegin + n2, end() - n2);
std::copy(const_reverse_iterator(tailBegin), const_reverse_iterator(i),
reverse_iterator(tailBegin + n2));
std::copy(s1, s2, begin() + pos);
} else {
FwdIterator t = s1;
const size_type old_size = size();
std::advance(t, old_size - pos);
const size_t newElems = std::distance(t, s2);
store_.expand_noinit(n2);
std::copy(t, s2, begin() + old_size);
fbstring_detail::pod_copy(data() + pos, data() + old_size,
begin() + old_size + newElems);
std::copy(s1, t, begin() + pos);
}
store_.writeTerminator();
return begin() + pos;
}
template <class InputIterator>
iterator insertImpl(const_iterator i,
InputIterator b, InputIterator e,
std::input_iterator_tag) {
const auto pos = i - begin();
basic_fbstring temp(begin(), i);
for (; b != e; ++b) {
temp.push_back(*b);
}
temp.append(i, cend());
swap(temp);
return begin() + pos;
}
public:
template <class ItOrLength, class ItOrChar>
iterator insert(const_iterator p, ItOrLength first_or_n, ItOrChar last_or_c) {
Selector<std::numeric_limits<ItOrLength>::is_specialized> sel;
return insertImplDiscr(p, first_or_n, last_or_c, sel);
}
iterator insert(const_iterator p, std::initializer_list<value_type> il) {
return insert(p, il.begin(), il.end());
}
basic_fbstring& erase(size_type pos = 0, size_type n = npos) {
Invariant checker(*this);
(void) checker;
enforce(pos <= length(), std::__throw_out_of_range, "");
procrustes(n, length() - pos);
std::copy(begin() + pos + n, end(), begin() + pos);
resize(length() - n);
return *this;
}
iterator erase(iterator position) {
const size_type pos(position - begin());
enforce(pos <= size(), std::__throw_out_of_range, "");
erase(pos, 1);
return begin() + pos;
}
iterator erase(iterator first, iterator last) {
const size_type pos(first - begin());
erase(pos, last - first);
return begin() + pos;
}
// Replaces at most n1 chars of *this, starting with pos1 with the
// content of str
basic_fbstring& replace(size_type pos1, size_type n1,
const basic_fbstring& str) {
return replace(pos1, n1, str.data(), str.size());
}
// Replaces at most n1 chars of *this, starting with pos1,
// with at most n2 chars of str starting with pos2
basic_fbstring& replace(size_type pos1, size_type n1,
const basic_fbstring& str,
size_type pos2, size_type n2) {
enforce(pos2 <= str.length(), std::__throw_out_of_range, "");
return replace(pos1, n1, str.data() + pos2,
std::min(n2, str.size() - pos2));
}
// Replaces at most n1 chars of *this, starting with pos, with chars from s
basic_fbstring& replace(size_type pos, size_type n1, const value_type* s) {
return replace(pos, n1, s, traits_type::length(s));
}
// Replaces at most n1 chars of *this, starting with pos, with n2
// occurrences of c
//
// consolidated with
//
// Replaces at most n1 chars of *this, starting with pos, with at
// most n2 chars of str. str must have at least n2 chars.
template <class StrOrLength, class NumOrChar>
basic_fbstring& replace(size_type pos, size_type n1,
StrOrLength s_or_n2, NumOrChar n_or_c) {
Invariant checker(*this);
(void) checker;
enforce(pos <= size(), std::__throw_out_of_range, "");
procrustes(n1, length() - pos);
const iterator b = begin() + pos;
return replace(b, b + n1, s_or_n2, n_or_c);
}
basic_fbstring& replace(iterator i1, iterator i2, const basic_fbstring& str) {
return replace(i1, i2, str.data(), str.length());
}
basic_fbstring& replace(iterator i1, iterator i2, const value_type* s) {
return replace(i1, i2, s, traits_type::length(s));
}
private:
basic_fbstring& replaceImplDiscr(iterator i1, iterator i2,
const value_type* s, size_type n,
Selector<2>) {
assert(i1 <= i2);
assert(begin() <= i1 && i1 <= end());
assert(begin() <= i2 && i2 <= end());
return replace(i1, i2, s, s + n);
}
basic_fbstring& replaceImplDiscr(iterator i1, iterator i2,
size_type n2, value_type c, Selector<1>) {
const size_type n1 = i2 - i1;
if (n1 > n2) {
std::fill(i1, i1 + n2, c);
erase(i1 + n2, i2);
} else {
std::fill(i1, i2, c);
insert(i2, n2 - n1, c);
}
assert(isSane());
return *this;
}
template <class InputIter>
basic_fbstring& replaceImplDiscr(iterator i1, iterator i2,
InputIter b, InputIter e,
Selector<0>) {
replaceImpl(i1, i2, b, e,
typename std::iterator_traits<InputIter>::iterator_category());
return *this;
}
private:
template <class FwdIterator>
bool replaceAliased(iterator i1, iterator i2,
FwdIterator s1, FwdIterator s2, std::false_type) {
return false;
}
template <class FwdIterator>
bool replaceAliased(iterator i1, iterator i2,
FwdIterator s1, FwdIterator s2, std::true_type) {
static const std::less_equal<const value_type*> le =
std::less_equal<const value_type*>();
const bool aliased = le(&*begin(), &*s1) && le(&*s1, &*end());
if (!aliased) {
return false;
}
// Aliased replace, copy to new string
basic_fbstring temp;
temp.reserve(size() - (i2 - i1) + std::distance(s1, s2));
temp.append(begin(), i1).append(s1, s2).append(i2, end());
swap(temp);
return true;
}
template <class FwdIterator>
void replaceImpl(iterator i1, iterator i2,
FwdIterator s1, FwdIterator s2, std::forward_iterator_tag) {
Invariant checker(*this);
(void) checker;
// Handle aliased replace
if (replaceAliased(i1, i2, s1, s2,
std::integral_constant<bool,
std::is_same<FwdIterator, iterator>::value ||
std::is_same<FwdIterator, const_iterator>::value>())) {
return;
}
auto const n1 = i2 - i1;
assert(n1 >= 0);
auto const n2 = std::distance(s1, s2);
assert(n2 >= 0);
if (n1 > n2) {
// shrinks
std::copy(s1, s2, i1);
erase(i1 + n2, i2);
} else {
// grows
fbstring_detail::copy_n(s1, n1, i1);
std::advance(s1, n1);
insert(i2, s1, s2);
}
assert(isSane());
}
template <class InputIterator>
void replaceImpl(iterator i1, iterator i2,
InputIterator b, InputIterator e, std::input_iterator_tag) {
basic_fbstring temp(begin(), i1);
temp.append(b, e).append(i2, end());
swap(temp);
}
public:
template <class T1, class T2>
basic_fbstring& replace(iterator i1, iterator i2,
T1 first_or_n_or_s, T2 last_or_c_or_n) {
const bool
num1 = std::numeric_limits<T1>::is_specialized,
num2 = std::numeric_limits<T2>::is_specialized;
return replaceImplDiscr(
i1, i2, first_or_n_or_s, last_or_c_or_n,
Selector<num1 ? (num2 ? 1 : -1) : (num2 ? 2 : 0)>());
}
size_type copy(value_type* s, size_type n, size_type pos = 0) const {
enforce(pos <= size(), std::__throw_out_of_range, "");
procrustes(n, size() - pos);
fbstring_detail::pod_copy(
data() + pos,
data() + pos + n,
s);
return n;
}
void swap(basic_fbstring& rhs) {
store_.swap(rhs.store_);
}
const value_type* c_str() const {
return store_.c_str();
}
const value_type* data() const { return c_str(); }
allocator_type get_allocator() const {
return allocator_type();
}
size_type find(const basic_fbstring& str, size_type pos = 0) const {
return find(str.data(), pos, str.length());
}
size_type find(const value_type* needle, const size_type pos,
const size_type nsize) const {
if (!nsize) return pos;
auto const size = this->size();
// nsize + pos can overflow (eg pos == npos), guard against that by checking
// that nsize + pos does not wrap around.
if (nsize + pos > size || nsize + pos < pos) return npos;
// Don't use std::search, use a Boyer-Moore-like trick by comparing
// the last characters first
auto const haystack = data();
auto const nsize_1 = nsize - 1;
auto const lastNeedle = needle[nsize_1];
// Boyer-Moore skip value for the last char in the needle. Zero is
// not a valid value; skip will be computed the first time it's
// needed.
size_type skip = 0;
const E * i = haystack + pos;
auto iEnd = haystack + size - nsize_1;
while (i < iEnd) {
// Boyer-Moore: match the last element in the needle
while (i[nsize_1] != lastNeedle) {
if (++i == iEnd) {
// not found
return npos;
}
}
// Here we know that the last char matches
// Continue in pedestrian mode
for (size_t j = 0; ; ) {
assert(j < nsize);
if (i[j] != needle[j]) {
// Not found, we can skip
// Compute the skip value lazily
if (skip == 0) {
skip = 1;
while (skip <= nsize_1 && needle[nsize_1 - skip] != lastNeedle) {
++skip;
}
}
i += skip;
break;
}
// Check if done searching
if (++j == nsize) {
// Yay
return i - haystack;
}
}
}
return npos;
}
size_type find(const value_type* s, size_type pos = 0) const {
return find(s, pos, traits_type::length(s));
}
size_type find (value_type c, size_type pos = 0) const {
return find(&c, pos, 1);
}
size_type rfind(const basic_fbstring& str, size_type pos = npos) const {
return rfind(str.data(), pos, str.length());
}
size_type rfind(const value_type* s, size_type pos, size_type n) const {
if (n > length()) return npos;
pos = std::min(pos, length() - n);
if (n == 0) return pos;
const_iterator i(begin() + pos);
for (; ; --i) {
if (traits_type::eq(*i, *s)
&& traits_type::compare(&*i, s, n) == 0) {
return i - begin();
}
if (i == begin()) break;
}
return npos;
}
size_type rfind(const value_type* s, size_type pos = npos) const {
return rfind(s, pos, traits_type::length(s));
}
size_type rfind(value_type c, size_type pos = npos) const {
return rfind(&c, pos, 1);
}
size_type find_first_of(const basic_fbstring& str, size_type pos = 0) const {
return find_first_of(str.data(), pos, str.length());
}
size_type find_first_of(const value_type* s,
size_type pos, size_type n) const {
if (pos > length() || n == 0) return npos;
const_iterator i(begin() + pos),
finish(end());
for (; i != finish; ++i) {
if (traits_type::find(s, n, *i) != 0) {
return i - begin();
}
}
return npos;
}
size_type find_first_of(const value_type* s, size_type pos = 0) const {
return find_first_of(s, pos, traits_type::length(s));
}
size_type find_first_of(value_type c, size_type pos = 0) const {
return find_first_of(&c, pos, 1);
}
size_type find_last_of (const basic_fbstring& str,
size_type pos = npos) const {
return find_last_of(str.data(), pos, str.length());
}
size_type find_last_of (const value_type* s, size_type pos,
size_type n) const {
if (!empty() && n > 0) {
pos = std::min(pos, length() - 1);
const_iterator i(begin() + pos);
for (;; --i) {
if (traits_type::find(s, n, *i) != 0) {
return i - begin();
}
if (i == begin()) break;
}
}
return npos;
}
size_type find_last_of (const value_type* s,
size_type pos = npos) const {
return find_last_of(s, pos, traits_type::length(s));
}
size_type find_last_of (value_type c, size_type pos = npos) const {
return find_last_of(&c, pos, 1);
}
size_type find_first_not_of(const basic_fbstring& str,
size_type pos = 0) const {
return find_first_not_of(str.data(), pos, str.size());
}
size_type find_first_not_of(const value_type* s, size_type pos,
size_type n) const {
if (pos < length()) {
const_iterator
i(begin() + pos),
finish(end());
for (; i != finish; ++i) {
if (traits_type::find(s, n, *i) == 0) {
return i - begin();
}
}
}
return npos;
}
size_type find_first_not_of(const value_type* s,
size_type pos = 0) const {
return find_first_not_of(s, pos, traits_type::length(s));
}
size_type find_first_not_of(value_type c, size_type pos = 0) const {
return find_first_not_of(&c, pos, 1);
}
size_type find_last_not_of(const basic_fbstring& str,
size_type pos = npos) const {
return find_last_not_of(str.data(), pos, str.length());
}
size_type find_last_not_of(const value_type* s, size_type pos,
size_type n) const {
if (!this->empty()) {
pos = std::min(pos, size() - 1);
const_iterator i(begin() + pos);
for (;; --i) {
if (traits_type::find(s, n, *i) == 0) {
return i - begin();
}
if (i == begin()) break;
}
}
return npos;
}
size_type find_last_not_of(const value_type* s,
size_type pos = npos) const {
return find_last_not_of(s, pos, traits_type::length(s));
}
size_type find_last_not_of (value_type c, size_type pos = npos) const {
return find_last_not_of(&c, pos, 1);
}
basic_fbstring substr(size_type pos = 0, size_type n = npos) const& {
enforce(pos <= size(), std::__throw_out_of_range, "");
return basic_fbstring(data() + pos, std::min(n, size() - pos));
}
basic_fbstring substr(size_type pos = 0, size_type n = npos) && {
enforce(pos <= size(), std::__throw_out_of_range, "");
erase(0, pos);
if (n < size()) resize(n);
return std::move(*this);
}
int compare(const basic_fbstring& str) const {
// FIX due to Goncalo N M de Carvalho July 18, 2005
return compare(0, size(), str);
}
int compare(size_type pos1, size_type n1,
const basic_fbstring& str) const {
return compare(pos1, n1, str.data(), str.size());
}
int compare(size_type pos1, size_type n1,
const value_type* s) const {
return compare(pos1, n1, s, traits_type::length(s));
}
int compare(size_type pos1, size_type n1,
const value_type* s, size_type n2) const {
enforce(pos1 <= size(), std::__throw_out_of_range, "");
procrustes(n1, size() - pos1);
// The line below fixed by Jean-Francois Bastien, 04-23-2007. Thanks!
const int r = traits_type::compare(pos1 + data(), s, std::min(n1, n2));
return r != 0 ? r : n1 > n2 ? 1 : n1 < n2 ? -1 : 0;
}
int compare(size_type pos1, size_type n1,
const basic_fbstring& str,
size_type pos2, size_type n2) const {
enforce(pos2 <= str.size(), std::__throw_out_of_range, "");
return compare(pos1, n1, str.data() + pos2,
std::min(n2, str.size() - pos2));
}
// Code from Jean-Francois Bastien (03/26/2007)
int compare(const value_type* s) const {
// Could forward to compare(0, size(), s, traits_type::length(s))
// but that does two extra checks
const size_type n1(size()), n2(traits_type::length(s));
const int r = traits_type::compare(data(), s, std::min(n1, n2));
return r != 0 ? r : n1 > n2 ? 1 : n1 < n2 ? -1 : 0;
}
private:
// Data
Storage store_;
};
// non-member functions
// C++11 21.4.8.1/1
template <typename E, class T, class A, class S>
inline
basic_fbstring<E, T, A, S> operator+(const basic_fbstring<E, T, A, S>& lhs,
const basic_fbstring<E, T, A, S>& rhs) {
basic_fbstring<E, T, A, S> result;
result.reserve(lhs.size() + rhs.size());
result.append(lhs).append(rhs);
return std::move(result);
}
// C++11 21.4.8.1/2
template <typename E, class T, class A, class S>
inline
basic_fbstring<E, T, A, S> operator+(basic_fbstring<E, T, A, S>&& lhs,
const basic_fbstring<E, T, A, S>& rhs) {
return std::move(lhs.append(rhs));
}
// C++11 21.4.8.1/3
template <typename E, class T, class A, class S>
inline
basic_fbstring<E, T, A, S> operator+(const basic_fbstring<E, T, A, S>& lhs,
basic_fbstring<E, T, A, S>&& rhs) {
if (rhs.capacity() >= lhs.size() + rhs.size()) {
// Good, at least we don't need to reallocate
return std::move(rhs.insert(0, lhs));
}
// Meh, no go. Forward to operator+(const&, const&).
auto const& rhsC = rhs;
return lhs + rhsC;
}
// C++11 21.4.8.1/4
template <typename E, class T, class A, class S>
inline
basic_fbstring<E, T, A, S> operator+(basic_fbstring<E, T, A, S>&& lhs,
basic_fbstring<E, T, A, S>&& rhs) {
return std::move(lhs.append(rhs));
}
// C++11 21.4.8.1/5
template <typename E, class T, class A, class S>
inline
basic_fbstring<E, T, A, S> operator+(
const E* lhs,
const basic_fbstring<E, T, A, S>& rhs) {
//
basic_fbstring<E, T, A, S> result;
const auto len = basic_fbstring<E, T, A, S>::traits_type::length(lhs);
result.reserve(len + rhs.size());
result.append(lhs, len).append(rhs);
return result;
}
// C++11 21.4.8.1/6
template <typename E, class T, class A, class S>
inline
basic_fbstring<E, T, A, S> operator+(
const E* lhs,
basic_fbstring<E, T, A, S>&& rhs) {
//
const auto len = basic_fbstring<E, T, A, S>::traits_type::length(lhs);
if (rhs.capacity() >= len + rhs.size()) {
// Good, at least we don't need to reallocate
return std::move(rhs.insert(rhs.begin(), lhs, lhs + len));
}
// Meh, no go. Do it by hand since we have len already.
basic_fbstring<E, T, A, S> result;
result.reserve(len + rhs.size());
result.append(lhs, len).append(rhs);
return result;
}
// C++11 21.4.8.1/7
template <typename E, class T, class A, class S>
inline
basic_fbstring<E, T, A, S> operator+(
E lhs,
const basic_fbstring<E, T, A, S>& rhs) {
basic_fbstring<E, T, A, S> result;
result.reserve(1 + rhs.size());
result.push_back(lhs);
result.append(rhs);
return result;
}
// C++11 21.4.8.1/8
template <typename E, class T, class A, class S>
inline
basic_fbstring<E, T, A, S> operator+(
E lhs,
basic_fbstring<E, T, A, S>&& rhs) {
//
if (rhs.capacity() > rhs.size()) {
// Good, at least we don't need to reallocate
return std::move(rhs.insert(rhs.begin(), lhs));
}
// Meh, no go. Forward to operator+(E, const&).
auto const& rhsC = rhs;
return lhs + rhsC;
}
// C++11 21.4.8.1/9
template <typename E, class T, class A, class S>
inline
basic_fbstring<E, T, A, S> operator+(
const basic_fbstring<E, T, A, S>& lhs,
const E* rhs) {
typedef typename basic_fbstring<E, T, A, S>::size_type size_type;
typedef typename basic_fbstring<E, T, A, S>::traits_type traits_type;
basic_fbstring<E, T, A, S> result;
const size_type len = traits_type::length(rhs);
result.reserve(lhs.size() + len);
result.append(lhs).append(rhs, len);
return result;
}
// C++11 21.4.8.1/10
template <typename E, class T, class A, class S>
inline
basic_fbstring<E, T, A, S> operator+(
basic_fbstring<E, T, A, S>&& lhs,
const E* rhs) {
//
return std::move(lhs += rhs);
}
// C++11 21.4.8.1/11
template <typename E, class T, class A, class S>
inline
basic_fbstring<E, T, A, S> operator+(
const basic_fbstring<E, T, A, S>& lhs,
E rhs) {
basic_fbstring<E, T, A, S> result;
result.reserve(lhs.size() + 1);
result.append(lhs);
result.push_back(rhs);
return result;
}
// C++11 21.4.8.1/12
template <typename E, class T, class A, class S>
inline
basic_fbstring<E, T, A, S> operator+(
basic_fbstring<E, T, A, S>&& lhs,
E rhs) {
//
return std::move(lhs += rhs);
}
template <typename E, class T, class A, class S>
inline
bool operator==(const basic_fbstring<E, T, A, S>& lhs,
const basic_fbstring<E, T, A, S>& rhs) {
return lhs.size() == rhs.size() && lhs.compare(rhs) == 0; }
template <typename E, class T, class A, class S>
inline
bool operator==(const typename basic_fbstring<E, T, A, S>::value_type* lhs,
const basic_fbstring<E, T, A, S>& rhs) {
return rhs == lhs; }
template <typename E, class T, class A, class S>
inline
bool operator==(const basic_fbstring<E, T, A, S>& lhs,
const typename basic_fbstring<E, T, A, S>::value_type* rhs) {
return lhs.compare(rhs) == 0; }
template <typename E, class T, class A, class S>
inline
bool operator!=(const basic_fbstring<E, T, A, S>& lhs,
const basic_fbstring<E, T, A, S>& rhs) {
return !(lhs == rhs); }
template <typename E, class T, class A, class S>
inline
bool operator!=(const typename basic_fbstring<E, T, A, S>::value_type* lhs,
const basic_fbstring<E, T, A, S>& rhs) {
return !(lhs == rhs); }
template <typename E, class T, class A, class S>
inline
bool operator!=(const basic_fbstring<E, T, A, S>& lhs,
const typename basic_fbstring<E, T, A, S>::value_type* rhs) {
return !(lhs == rhs); }
template <typename E, class T, class A, class S>
inline
bool operator<(const basic_fbstring<E, T, A, S>& lhs,
const basic_fbstring<E, T, A, S>& rhs) {
return lhs.compare(rhs) < 0; }
template <typename E, class T, class A, class S>
inline
bool operator<(const basic_fbstring<E, T, A, S>& lhs,
const typename basic_fbstring<E, T, A, S>::value_type* rhs) {
return lhs.compare(rhs) < 0; }
template <typename E, class T, class A, class S>
inline
bool operator<(const typename basic_fbstring<E, T, A, S>::value_type* lhs,
const basic_fbstring<E, T, A, S>& rhs) {
return rhs.compare(lhs) > 0; }
template <typename E, class T, class A, class S>
inline
bool operator>(const basic_fbstring<E, T, A, S>& lhs,
const basic_fbstring<E, T, A, S>& rhs) {
return rhs < lhs; }
template <typename E, class T, class A, class S>
inline
bool operator>(const basic_fbstring<E, T, A, S>& lhs,
const typename basic_fbstring<E, T, A, S>::value_type* rhs) {
return rhs < lhs; }
template <typename E, class T, class A, class S>
inline
bool operator>(const typename basic_fbstring<E, T, A, S>::value_type* lhs,
const basic_fbstring<E, T, A, S>& rhs) {
return rhs < lhs; }
template <typename E, class T, class A, class S>
inline
bool operator<=(const basic_fbstring<E, T, A, S>& lhs,
const basic_fbstring<E, T, A, S>& rhs) {
return !(rhs < lhs); }
template <typename E, class T, class A, class S>
inline
bool operator<=(const basic_fbstring<E, T, A, S>& lhs,
const typename basic_fbstring<E, T, A, S>::value_type* rhs) {
return !(rhs < lhs); }
template <typename E, class T, class A, class S>
inline
bool operator<=(const typename basic_fbstring<E, T, A, S>::value_type* lhs,
const basic_fbstring<E, T, A, S>& rhs) {
return !(rhs < lhs); }
template <typename E, class T, class A, class S>
inline
bool operator>=(const basic_fbstring<E, T, A, S>& lhs,
const basic_fbstring<E, T, A, S>& rhs) {
return !(lhs < rhs); }
template <typename E, class T, class A, class S>
inline
bool operator>=(const basic_fbstring<E, T, A, S>& lhs,
const typename basic_fbstring<E, T, A, S>::value_type* rhs) {
return !(lhs < rhs); }
template <typename E, class T, class A, class S>
inline
bool operator>=(const typename basic_fbstring<E, T, A, S>::value_type* lhs,
const basic_fbstring<E, T, A, S>& rhs) {
return !(lhs < rhs);
}
// C++11 21.4.8.8
template <typename E, class T, class A, class S>
void swap(basic_fbstring<E, T, A, S>& lhs, basic_fbstring<E, T, A, S>& rhs) {
lhs.swap(rhs);
}
// TODO: make this faster.
template <typename E, class T, class A, class S>
inline
std::basic_istream<
typename basic_fbstring<E, T, A, S>::value_type,
typename basic_fbstring<E, T, A, S>::traits_type>&
operator>>(
std::basic_istream<typename basic_fbstring<E, T, A, S>::value_type,
typename basic_fbstring<E, T, A, S>::traits_type>& is,
basic_fbstring<E, T, A, S>& str) {
typename std::basic_istream<E, T>::sentry sentry(is);
typedef std::basic_istream<typename basic_fbstring<E, T, A, S>::value_type,
typename basic_fbstring<E, T, A, S>::traits_type>
__istream_type;
typedef typename __istream_type::ios_base __ios_base;
size_t extracted = 0;
auto err = __ios_base::goodbit;
if (sentry) {
auto n = is.width();
if (n <= 0) {
n = str.max_size();
}
str.erase();
for (auto got = is.rdbuf()->sgetc(); extracted != size_t(n); ++extracted) {
if (got == T::eof()) {
err |= __ios_base::eofbit;
is.width(0);
break;
}
if (isspace(got)) break;
str.push_back(got);
got = is.rdbuf()->snextc();
}
}
if (!extracted) {
err |= __ios_base::failbit;
}
if (err) {
is.setstate(err);
}
return is;
}
template <typename E, class T, class A, class S>
inline
std::basic_ostream<typename basic_fbstring<E, T, A, S>::value_type,
typename basic_fbstring<E, T, A, S>::traits_type>&
operator<<(
std::basic_ostream<typename basic_fbstring<E, T, A, S>::value_type,
typename basic_fbstring<E, T, A, S>::traits_type>& os,
const basic_fbstring<E, T, A, S>& str) {
#if _LIBCPP_VERSION
typename std::basic_ostream<
typename basic_fbstring<E, T, A, S>::value_type,
typename basic_fbstring<E, T, A, S>::traits_type>::sentry __s(os);
if (__s) {
typedef std::ostreambuf_iterator<
typename basic_fbstring<E, T, A, S>::value_type,
typename basic_fbstring<E, T, A, S>::traits_type> _Ip;
size_t __len = str.size();
bool __left =
(os.flags() & std::ios_base::adjustfield) == std::ios_base::left;
if (__pad_and_output(_Ip(os),
str.data(),
__left ? str.data() + __len : str.data(),
str.data() + __len,
os,
os.fill()).failed()) {
os.setstate(std::ios_base::badbit | std::ios_base::failbit);
}
}
#elif defined(_MSC_VER)
// MSVC doesn't define __ostream_insert
os.write(str.data(), str.size());
#else
std::__ostream_insert(os, str.data(), str.size());
#endif
return os;
}
#ifndef _LIBSTDCXX_FBSTRING
template <typename E, class T, class A, class S>
inline
std::basic_istream<typename basic_fbstring<E, T, A, S>::value_type,
typename basic_fbstring<E, T, A, S>::traits_type>&
getline(
std::basic_istream<typename basic_fbstring<E, T, A, S>::value_type,
typename basic_fbstring<E, T, A, S>::traits_type>& is,
basic_fbstring<E, T, A, S>& str,
typename basic_fbstring<E, T, A, S>::value_type delim) {
// Use the nonstandard getdelim()
char * buf = nullptr;
size_t size = 0;
for (;;) {
// This looks quadratic but it really depends on realloc
auto const newSize = size + 128;
buf = static_cast<char*>(checkedRealloc(buf, newSize));
is.getline(buf + size, newSize - size, delim);
if (is.bad() || is.eof() || !is.fail()) {
// done by either failure, end of file, or normal read
size += std::strlen(buf + size);
break;
}
// Here we have failed due to too short a buffer
// Minus one to discount the terminating '\0'
size = newSize - 1;
assert(buf[size] == 0);
// Clear the error so we can continue reading
is.clear();
}
basic_fbstring<E, T, A, S> result(buf, size, size + 1,
AcquireMallocatedString());
result.swap(str);
return is;
}
template <typename E, class T, class A, class S>
inline
std::basic_istream<typename basic_fbstring<E, T, A, S>::value_type,
typename basic_fbstring<E, T, A, S>::traits_type>&
getline(
std::basic_istream<typename basic_fbstring<E, T, A, S>::value_type,
typename basic_fbstring<E, T, A, S>::traits_type>& is,
basic_fbstring<E, T, A, S>& str) {
// Just forward to the version with a delimiter
return getline(is, str, '\n');
}
#endif
template <typename E1, class T, class A, class S>
const typename basic_fbstring<E1, T, A, S>::size_type
basic_fbstring<E1, T, A, S>::npos =
static_cast<typename basic_fbstring<E1, T, A, S>::size_type>(-1);
#ifndef _LIBSTDCXX_FBSTRING
// basic_string compatibility routines
template <typename E, class T, class A, class S>
inline
bool operator==(const basic_fbstring<E, T, A, S>& lhs,
const std::string& rhs) {
return lhs.compare(0, lhs.size(), rhs.data(), rhs.size()) == 0;
}
template <typename E, class T, class A, class S>
inline
bool operator==(const std::string& lhs,
const basic_fbstring<E, T, A, S>& rhs) {
return rhs == lhs;
}
template <typename E, class T, class A, class S>
inline
bool operator!=(const basic_fbstring<E, T, A, S>& lhs,
const std::string& rhs) {
return !(lhs == rhs);
}
template <typename E, class T, class A, class S>
inline
bool operator!=(const std::string& lhs,
const basic_fbstring<E, T, A, S>& rhs) {
return !(lhs == rhs);
}
#if !defined(_LIBSTDCXX_FBSTRING)
typedef basic_fbstring<char> fbstring;
#endif
// fbstring is relocatable
template <class T, class R, class A, class S>
FOLLY_ASSUME_RELOCATABLE(basic_fbstring<T, R, A, S>);
#else
_GLIBCXX_END_NAMESPACE_VERSION
#endif
} // namespace folly
#ifndef _LIBSTDCXX_FBSTRING
// Hash functions to make fbstring usable with e.g. hash_map