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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
#ifndef Utils_h
#define Utils_h
#include <pthread.h>
#include <stdint.h>
#include <stddef.h>
#include <sys/mman.h>
#include <unistd.h>
#include "mozilla/Assertions.h"
#include "mozilla/Atomics.h"
/**
* On architectures that are little endian and that support unaligned reads,
* we can use direct type, but on others, we want to have a special class
* to handle conversion and alignment issues.
*/
#if !defined(DEBUG) && (defined(__i386__) || defined(__x86_64__))
typedef uint16_t le_uint16;
typedef uint32_t le_uint32;
#else
/**
* Template that allows to find an unsigned int type from a (computed) bit size
*/
template <int s>
struct UInt {};
template <>
struct UInt<16> {
typedef uint16_t Type;
};
template <>
struct UInt<32> {
typedef uint32_t Type;
};
/**
* Template to access 2 n-bit sized words as a 2*n-bit sized word, doing
* conversion from little endian and avoiding alignment issues.
*/
template <typename T>
class le_to_cpu {
public:
typedef typename UInt<16 * sizeof(T)>::Type Type;
operator Type() const { return (b << (sizeof(T) * 8)) | a; }
const le_to_cpu& operator=(const Type& v) {
a = v & ((1 << (sizeof(T) * 8)) - 1);
b = v >> (sizeof(T) * 8);
return *this;
}
le_to_cpu() {}
explicit le_to_cpu(const Type& v) { operator=(v); }
const le_to_cpu& operator+=(const Type& v) {
return operator=(operator Type() + v);
}
const le_to_cpu& operator++(int) { return operator=(operator Type() + 1); }
private:
T a, b;
};
/**
* Type definitions
*/
typedef le_to_cpu<unsigned char> le_uint16;
typedef le_to_cpu<le_uint16> le_uint32;
#endif
struct AutoCloseFD {
const int fd;
MOZ_IMPLICIT AutoCloseFD(int fd) : fd(fd) {}
~AutoCloseFD() {
if (fd != -1) close(fd);
}
operator int() const { return fd; }
};
extern mozilla::Atomic<size_t, mozilla::ReleaseAcquire> gPageSize;
/**
* Page alignment helpers
*/
static size_t PageSize() {
if (!gPageSize) {
gPageSize = sysconf(_SC_PAGESIZE);
}
return gPageSize;
}
static inline uintptr_t AlignedPtr(uintptr_t ptr, size_t alignment) {
return ptr & ~(alignment - 1);
}
template <typename T>
static inline T* AlignedPtr(T* ptr, size_t alignment) {
return reinterpret_cast<T*>(
AlignedPtr(reinterpret_cast<uintptr_t>(ptr), alignment));
}
template <typename T>
static inline T PageAlignedPtr(T ptr) {
return AlignedPtr(ptr, PageSize());
}
static inline uintptr_t AlignedEndPtr(uintptr_t ptr, size_t alignment) {
return AlignedPtr(ptr + alignment - 1, alignment);
}
template <typename T>
static inline T* AlignedEndPtr(T* ptr, size_t alignment) {
return reinterpret_cast<T*>(
AlignedEndPtr(reinterpret_cast<uintptr_t>(ptr), alignment));
}
template <typename T>
static inline T PageAlignedEndPtr(T ptr) {
return AlignedEndPtr(ptr, PageSize());
}
static inline size_t AlignedSize(size_t size, size_t alignment) {
return (size + alignment - 1) & ~(alignment - 1);
}
static inline size_t PageAlignedSize(size_t size) {
return AlignedSize(size, PageSize());
}
static inline bool IsAlignedPtr(uintptr_t ptr, size_t alignment) {
return ptr % alignment == 0;
}
template <typename T>
static inline bool IsAlignedPtr(T* ptr, size_t alignment) {
return IsAlignedPtr(reinterpret_cast<uintptr_t>(ptr), alignment);
}
template <typename T>
static inline bool IsPageAlignedPtr(T ptr) {
return IsAlignedPtr(ptr, PageSize());
}
static inline bool IsAlignedSize(size_t size, size_t alignment) {
return size % alignment == 0;
}
static inline bool IsPageAlignedSize(size_t size) {
return IsAlignedSize(size, PageSize());
}
static inline size_t PageNumber(size_t size) {
return (size + PageSize() - 1) / PageSize();
}
/**
* MemoryRange stores a pointer, size pair.
*/
class MemoryRange {
public:
MemoryRange(void* buf, size_t length) : buf(buf), length(length) {}
void Assign(void* b, size_t len) {
buf = b;
length = len;
}
void Assign(const MemoryRange& other) {
buf = other.buf;
length = other.length;
}
void* get() const { return buf; }
operator void*() const { return buf; }
operator unsigned char*() const {
return reinterpret_cast<unsigned char*>(buf);
}
bool operator==(void* ptr) const { return buf == ptr; }
bool operator==(unsigned char* ptr) const { return buf == ptr; }
void* operator+(off_t offset) const {
return reinterpret_cast<char*>(buf) + offset;
}
/**
* Returns whether the given address is within the mapped range
*/
bool Contains(void* ptr) const {
return (ptr >= buf) && (ptr < reinterpret_cast<char*>(buf) + length);
}
/**
* Returns the length of the mapped range
*/
size_t GetLength() const { return length; }
static MemoryRange mmap(void* addr, size_t length, int prot, int flags,
int fd, off_t offset) {
return MemoryRange(::mmap(addr, length, prot, flags, fd, offset), length);
}
private:
void* buf;
size_t length;
};
/**
* MappedPtr is a RAII wrapper for mmap()ed memory. It can be used as
* a simple void * or unsigned char *.
*
* It is defined as a derivative of a template that allows to use a
* different unmapping strategy.
*/
template <typename T>
class GenericMappedPtr : public MemoryRange {
public:
GenericMappedPtr(void* buf, size_t length) : MemoryRange(buf, length) {}
explicit GenericMappedPtr(const MemoryRange& other) : MemoryRange(other) {}
GenericMappedPtr() : MemoryRange(MAP_FAILED, 0) {}
void Assign(void* b, size_t len) {
if (get() != MAP_FAILED) static_cast<T*>(this)->munmap(get(), GetLength());
MemoryRange::Assign(b, len);
}
void Assign(const MemoryRange& other) {
Assign(other.get(), other.GetLength());
}
~GenericMappedPtr() {
if (get() != MAP_FAILED) static_cast<T*>(this)->munmap(get(), GetLength());
}
void release() { MemoryRange::Assign(MAP_FAILED, 0); }
};
struct MappedPtr : public GenericMappedPtr<MappedPtr> {
MappedPtr(void* buf, size_t length)
: GenericMappedPtr<MappedPtr>(buf, length) {}
MOZ_IMPLICIT MappedPtr(const MemoryRange& other)
: GenericMappedPtr<MappedPtr>(other) {}
MappedPtr() : GenericMappedPtr<MappedPtr>() {}
private:
friend class GenericMappedPtr<MappedPtr>;
void munmap(void* buf, size_t length) { ::munmap(buf, length); }
};
/**
* UnsizedArray is a way to access raw arrays of data in memory.
*
* struct S { ... };
* UnsizedArray<S> a(buf);
* UnsizedArray<S> b; b.Init(buf);
*
* This is roughly equivalent to
* const S *a = reinterpret_cast<const S *>(buf);
* const S *b = nullptr; b = reinterpret_cast<const S *>(buf);
*
* An UnsizedArray has no known length, and it's up to the caller to make
* sure the accessed memory is mapped and makes sense.
*/
template <typename T>
class UnsizedArray {
public:
typedef size_t idx_t;
/**
* Constructors and Initializers
*/
UnsizedArray() : contents(nullptr) {}
explicit UnsizedArray(const void* buf)
: contents(reinterpret_cast<const T*>(buf)) {}
void Init(const void* buf) {
MOZ_ASSERT(contents == nullptr);
contents = reinterpret_cast<const T*>(buf);
}
/**
* Returns the nth element of the array
*/
const T& operator[](const idx_t index) const {
MOZ_ASSERT(contents);
return contents[index];
}
operator const T*() const { return contents; }
/**
* Returns whether the array points somewhere
*/
explicit operator bool() const { return contents != nullptr; }
private:
const T* contents;
};
/**
* Array, like UnsizedArray, is a way to access raw arrays of data in memory.
* Unlike UnsizedArray, it has a known length, and is enumerable with an
* iterator.
*
* struct S { ... };
* Array<S> a(buf, len);
* UnsizedArray<S> b; b.Init(buf, len);
*
* In the above examples, len is the number of elements in the array. It is
* also possible to initialize an Array with the buffer size:
*
* Array<S> c; c.InitSize(buf, size);
*
* It is also possible to initialize an Array in two steps, only providing
* one data at a time:
*
* Array<S> d;
* d.Init(buf);
* d.Init(len); // or d.InitSize(size);
*
*/
template <typename T>
class Array : public UnsizedArray<T> {
public:
typedef typename UnsizedArray<T>::idx_t idx_t;
/**
* Constructors and Initializers
*/
Array() : UnsizedArray<T>(), length(0) {}
Array(const void* buf, const idx_t length)
: UnsizedArray<T>(buf), length(length) {}
void Init(const void* buf) { UnsizedArray<T>::Init(buf); }
void Init(const idx_t len) {
MOZ_ASSERT(length == 0);
length = len;
}
void InitSize(const idx_t size) { Init(size / sizeof(T)); }
void Init(const void* buf, const idx_t len) {
UnsizedArray<T>::Init(buf);
Init(len);
}
void InitSize(const void* buf, const idx_t size) {
UnsizedArray<T>::Init(buf);
InitSize(size);
}
/**
* Returns the nth element of the array
*/
const T& operator[](const idx_t index) const {
MOZ_ASSERT(index < length);
MOZ_ASSERT(operator bool());
return UnsizedArray<T>::operator[](index);
}
/**
* Returns the number of elements in the array
*/
idx_t numElements() const { return length; }
/**
* Returns whether the array points somewhere and has at least one element.
*/
explicit operator bool() const {
return (length > 0) && UnsizedArray<T>::operator bool();
}
/**
* Iterator for an Array. Use is similar to that of STL const_iterators:
*
* struct S { ... };
* Array<S> a(buf, len);
* for (Array<S>::iterator it = a.begin(); it < a.end(); ++it) {
* // Do something with *it.
* }
*/
class iterator {
public:
iterator() : item(nullptr) {}
const T& operator*() const { return *item; }
const T* operator->() const { return item; }
iterator& operator++() {
++item;
return *this;
}
bool operator<(const iterator& other) const { return item < other.item; }
protected:
friend class Array<T>;
explicit iterator(const T& item) : item(&item) {}
private:
const T* item;
};
/**
* Returns an iterator pointing at the beginning of the Array
*/
iterator begin() const {
if (length) return iterator(UnsizedArray<T>::operator[](0));
return iterator();
}
/**
* Returns an iterator pointing past the end of the Array
*/
iterator end() const {
if (length) return iterator(UnsizedArray<T>::operator[](length));
return iterator();
}
/**
* Reverse iterator for an Array. Use is similar to that of STL
* const_reverse_iterators:
*
* struct S { ... };
* Array<S> a(buf, len);
* for (Array<S>::reverse_iterator it = a.rbegin(); it < a.rend(); ++it) {
* // Do something with *it.
* }
*/
class reverse_iterator {
public:
reverse_iterator() : item(nullptr) {}
const T& operator*() const {
const T* tmp = item;
return *--tmp;
}
const T* operator->() const { return &operator*(); }
reverse_iterator& operator++() {
--item;
return *this;
}
bool operator<(const reverse_iterator& other) const {
return item > other.item;
}
protected:
friend class Array<T>;
explicit reverse_iterator(const T& item) : item(&item) {}
private:
const T* item;
};
/**
* Returns a reverse iterator pointing at the end of the Array
*/
reverse_iterator rbegin() const {
if (length) return reverse_iterator(UnsizedArray<T>::operator[](length));
return reverse_iterator();
}
/**
* Returns a reverse iterator pointing past the beginning of the Array
*/
reverse_iterator rend() const {
if (length) return reverse_iterator(UnsizedArray<T>::operator[](0));
return reverse_iterator();
}
private:
idx_t length;
};
/**
* Transforms a pointer-to-function to a pointer-to-object pointing at the
* same address.
*/
template <typename T>
void* FunctionPtr(T func) {
union {
void* ptr;
T func;
} f;
f.func = func;
return f.ptr;
}
class AutoLock {
public:
explicit AutoLock(pthread_mutex_t* mutex) : mutex(mutex) {
if (pthread_mutex_lock(mutex)) MOZ_CRASH("pthread_mutex_lock failed");
}
~AutoLock() {
if (pthread_mutex_unlock(mutex)) MOZ_CRASH("pthread_mutex_unlock failed");
}
private:
pthread_mutex_t* mutex;
};
#endif /* Utils_h */