| // Copyright 2006-2008 the V8 project authors. All rights reserved. |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are |
| // met: |
| // |
| // * Redistributions of source code must retain the above copyright |
| // notice, this list of conditions and the following disclaimer. |
| // * Redistributions in binary form must reproduce the above |
| // copyright notice, this list of conditions and the following |
| // disclaimer in the documentation and/or other materials provided |
| // with the distribution. |
| // * Neither the name of Google Inc. nor the names of its |
| // contributors may be used to endorse or promote products derived |
| // from this software without specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| |
| #ifndef V8_UTILS_H_ |
| #define V8_UTILS_H_ |
| |
| #include <stdlib.h> |
| |
| namespace v8 { |
| namespace internal { |
| |
| // ---------------------------------------------------------------------------- |
| // General helper functions |
| |
| // Returns true iff x is a power of 2. Does not work for zero. |
| template <typename T> |
| static inline bool IsPowerOf2(T x) { |
| return (x & (x - 1)) == 0; |
| } |
| |
| |
| // The C++ standard leaves the semantics of '>>' undefined for |
| // negative signed operands. Most implementations do the right thing, |
| // though. |
| static inline int ArithmeticShiftRight(int x, int s) { |
| return x >> s; |
| } |
| |
| |
| // Compute the 0-relative offset of some absolute value x of type T. |
| // This allows conversion of Addresses and integral types into |
| // 0-relative int offsets. |
| template <typename T> |
| static inline intptr_t OffsetFrom(T x) { |
| return x - static_cast<T>(0); |
| } |
| |
| |
| // Compute the absolute value of type T for some 0-relative offset x. |
| // This allows conversion of 0-relative int offsets into Addresses and |
| // integral types. |
| template <typename T> |
| static inline T AddressFrom(intptr_t x) { |
| return static_cast<T>(0) + x; |
| } |
| |
| |
| // Return the largest multiple of m which is <= x. |
| template <typename T> |
| static inline T RoundDown(T x, int m) { |
| ASSERT(IsPowerOf2(m)); |
| return AddressFrom<T>(OffsetFrom(x) & -m); |
| } |
| |
| |
| // Return the smallest multiple of m which is >= x. |
| template <typename T> |
| static inline T RoundUp(T x, int m) { |
| return RoundDown(x + m - 1, m); |
| } |
| |
| |
| template <typename T> |
| static int Compare(const T& a, const T& b) { |
| if (a == b) |
| return 0; |
| else if (a < b) |
| return -1; |
| else |
| return 1; |
| } |
| |
| |
| template <typename T> |
| static int PointerValueCompare(const T* a, const T* b) { |
| return Compare<T>(*a, *b); |
| } |
| |
| |
| // Returns the smallest power of two which is >= x. If you pass in a |
| // number that is already a power of two, it is returned as is. |
| uint32_t RoundUpToPowerOf2(uint32_t x); |
| |
| |
| template <typename T> |
| static inline bool IsAligned(T value, T alignment) { |
| ASSERT(IsPowerOf2(alignment)); |
| return (value & (alignment - 1)) == 0; |
| } |
| |
| |
| // Returns true if (addr + offset) is aligned. |
| static inline bool IsAddressAligned(Address addr, int alignment, int offset) { |
| int offs = OffsetFrom(addr + offset); |
| return IsAligned(offs, alignment); |
| } |
| |
| |
| // Returns the maximum of the two parameters. |
| template <typename T> |
| static T Max(T a, T b) { |
| return a < b ? b : a; |
| } |
| |
| |
| // Returns the minimum of the two parameters. |
| template <typename T> |
| static T Min(T a, T b) { |
| return a < b ? a : b; |
| } |
| |
| |
| // ---------------------------------------------------------------------------- |
| // BitField is a help template for encoding and decode bitfield with |
| // unsigned content. |
| template<class T, int shift, int size> |
| class BitField { |
| public: |
| // Tells whether the provided value fits into the bit field. |
| static bool is_valid(T value) { |
| return (static_cast<uint32_t>(value) & ~((1U << (size)) - 1)) == 0; |
| } |
| |
| // Returns a uint32_t mask of bit field. |
| static uint32_t mask() { |
| return (1U << (size + shift)) - (1U << shift); |
| } |
| |
| // Returns a uint32_t with the bit field value encoded. |
| static uint32_t encode(T value) { |
| ASSERT(is_valid(value)); |
| return static_cast<uint32_t>(value) << shift; |
| } |
| |
| // Extracts the bit field from the value. |
| static T decode(uint32_t value) { |
| return static_cast<T>((value >> shift) & ((1U << (size)) - 1)); |
| } |
| }; |
| |
| |
| // ---------------------------------------------------------------------------- |
| // Support for compressed, machine-independent encoding |
| // and decoding of integer values of arbitrary size. |
| |
| // Encoding and decoding from/to a buffer at position p; |
| // the result is the position after the encoded integer. |
| // Small signed integers in the range -64 <= x && x < 64 |
| // are encoded in 1 byte; larger values are encoded in 2 |
| // or more bytes. At most sizeof(int) + 1 bytes are used |
| // in the worst case. |
| byte* EncodeInt(byte* p, int x); |
| byte* DecodeInt(byte* p, int* x); |
| |
| |
| // Encoding and decoding from/to a buffer at position p - 1 |
| // moving backward; the result is the position of the last |
| // byte written. These routines are useful to read/write |
| // into a buffer starting at the end of the buffer. |
| byte* EncodeUnsignedIntBackward(byte* p, unsigned int x); |
| |
| // The decoding function is inlined since its performance is |
| // important to mark-sweep garbage collection. |
| inline byte* DecodeUnsignedIntBackward(byte* p, unsigned int* x) { |
| byte b = *--p; |
| if (b >= 128) { |
| *x = static_cast<unsigned int>(b) - 128; |
| return p; |
| } |
| unsigned int r = static_cast<unsigned int>(b); |
| unsigned int s = 7; |
| b = *--p; |
| while (b < 128) { |
| r |= static_cast<unsigned int>(b) << s; |
| s += 7; |
| b = *--p; |
| } |
| // b >= 128 |
| *x = r | ((static_cast<unsigned int>(b) - 128) << s); |
| return p; |
| } |
| |
| |
| // ---------------------------------------------------------------------------- |
| // Hash function. |
| |
| uint32_t ComputeIntegerHash(uint32_t key); |
| |
| |
| // ---------------------------------------------------------------------------- |
| // I/O support. |
| |
| // Our version of printf(). Avoids compilation errors that we get |
| // with standard printf when attempting to print pointers, etc. |
| // (the errors are due to the extra compilation flags, which we |
| // want elsewhere). |
| void PrintF(const char* format, ...); |
| |
| // Our version of fflush. |
| void Flush(); |
| |
| |
| // Read a line of characters after printing the prompt to stdout. The resulting |
| // char* needs to be disposed off with DeleteArray by the caller. |
| char* ReadLine(const char* prompt); |
| |
| |
| // Read and return the raw bytes in a file. the size of the buffer is returned |
| // in size. |
| // The returned buffer must be freed by the caller. |
| byte* ReadBytes(const char* filename, int* size, bool verbose = true); |
| |
| |
| // Write size chars from str to the file given by filename. |
| // The file is overwritten. Returns the number of chars written. |
| int WriteChars(const char* filename, |
| const char* str, |
| int size, |
| bool verbose = true); |
| |
| |
| // Write size bytes to the file given by filename. |
| // The file is overwritten. Returns the number of bytes written. |
| int WriteBytes(const char* filename, |
| const byte* bytes, |
| int size, |
| bool verbose = true); |
| |
| |
| // Write the C code |
| // const char* <varname> = "<str>"; |
| // const int <varname>_len = <len>; |
| // to the file given by filename. Only the first len chars are written. |
| int WriteAsCFile(const char* filename, const char* varname, |
| const char* str, int size, bool verbose = true); |
| |
| |
| // ---------------------------------------------------------------------------- |
| // Miscellaneous |
| |
| // A static resource holds a static instance that can be reserved in |
| // a local scope using an instance of Access. Attempts to re-reserve |
| // the instance will cause an error. |
| template <typename T> |
| class StaticResource { |
| public: |
| StaticResource() : is_reserved_(false) {} |
| |
| private: |
| template <typename S> friend class Access; |
| T instance_; |
| bool is_reserved_; |
| }; |
| |
| |
| // Locally scoped access to a static resource. |
| template <typename T> |
| class Access { |
| public: |
| explicit Access(StaticResource<T>* resource) |
| : resource_(resource) |
| , instance_(&resource->instance_) { |
| ASSERT(!resource->is_reserved_); |
| resource->is_reserved_ = true; |
| } |
| |
| ~Access() { |
| resource_->is_reserved_ = false; |
| resource_ = NULL; |
| instance_ = NULL; |
| } |
| |
| T* value() { return instance_; } |
| T* operator -> () { return instance_; } |
| |
| private: |
| StaticResource<T>* resource_; |
| T* instance_; |
| }; |
| |
| |
| template <typename T> |
| class Vector { |
| public: |
| Vector() : start_(NULL), length_(0) {} |
| Vector(T* data, int length) : start_(data), length_(length) { |
| ASSERT(length == 0 || (length > 0 && data != NULL)); |
| } |
| |
| static Vector<T> New(int length) { |
| return Vector<T>(NewArray<T>(length), length); |
| } |
| |
| // Returns a vector using the same backing storage as this one, |
| // spanning from and including 'from', to but not including 'to'. |
| Vector<T> SubVector(int from, int to) { |
| ASSERT(from < length_); |
| ASSERT(to <= length_); |
| ASSERT(from < to); |
| return Vector<T>(start() + from, to - from); |
| } |
| |
| // Returns the length of the vector. |
| int length() const { return length_; } |
| |
| // Returns whether or not the vector is empty. |
| bool is_empty() const { return length_ == 0; } |
| |
| // Returns the pointer to the start of the data in the vector. |
| T* start() const { return start_; } |
| |
| // Access individual vector elements - checks bounds in debug mode. |
| T& operator[](int index) const { |
| ASSERT(0 <= index && index < length_); |
| return start_[index]; |
| } |
| |
| T& first() { return start_[0]; } |
| |
| T& last() { return start_[length_ - 1]; } |
| |
| // Returns a clone of this vector with a new backing store. |
| Vector<T> Clone() const { |
| T* result = NewArray<T>(length_); |
| for (int i = 0; i < length_; i++) result[i] = start_[i]; |
| return Vector<T>(result, length_); |
| } |
| |
| void Sort(int (*cmp)(const T*, const T*)) { |
| typedef int (*RawComparer)(const void*, const void*); |
| qsort(start(), |
| length(), |
| sizeof(T), |
| reinterpret_cast<RawComparer>(cmp)); |
| } |
| |
| void Sort() { |
| Sort(PointerValueCompare<T>); |
| } |
| |
| // Releases the array underlying this vector. Once disposed the |
| // vector is empty. |
| void Dispose() { |
| if (is_empty()) return; |
| DeleteArray(start_); |
| start_ = NULL; |
| length_ = 0; |
| } |
| |
| inline Vector<T> operator+(int offset) { |
| ASSERT(offset < length_); |
| return Vector<T>(start_ + offset, length_ - offset); |
| } |
| |
| // Factory method for creating empty vectors. |
| static Vector<T> empty() { return Vector<T>(NULL, 0); } |
| |
| protected: |
| void set_start(T* start) { start_ = start; } |
| |
| private: |
| T* start_; |
| int length_; |
| }; |
| |
| |
| // A temporary assignment sets a (non-local) variable to a value on |
| // construction and resets it the value on destruction. |
| template <typename T> |
| class TempAssign { |
| public: |
| TempAssign(T* var, T value): var_(var), old_value_(*var) { |
| *var = value; |
| } |
| |
| ~TempAssign() { *var_ = old_value_; } |
| |
| private: |
| T* var_; |
| T old_value_; |
| }; |
| |
| |
| template <typename T, int kSize> |
| class EmbeddedVector : public Vector<T> { |
| public: |
| EmbeddedVector() : Vector<T>(buffer_, kSize) { } |
| |
| // When copying, make underlying Vector to reference our buffer. |
| EmbeddedVector(const EmbeddedVector& rhs) |
| : Vector<T>(rhs) { |
| memcpy(buffer_, rhs.buffer_, sizeof(T) * kSize); |
| set_start(buffer_); |
| } |
| |
| EmbeddedVector& operator=(const EmbeddedVector& rhs) { |
| if (this == &rhs) return *this; |
| Vector<T>::operator=(rhs); |
| memcpy(buffer_, rhs.buffer_, sizeof(T) * kSize); |
| set_start(buffer_); |
| return *this; |
| } |
| |
| private: |
| T buffer_[kSize]; |
| }; |
| |
| |
| template <typename T> |
| class ScopedVector : public Vector<T> { |
| public: |
| explicit ScopedVector(int length) : Vector<T>(NewArray<T>(length), length) { } |
| ~ScopedVector() { |
| DeleteArray(this->start()); |
| } |
| }; |
| |
| |
| inline Vector<const char> CStrVector(const char* data) { |
| return Vector<const char>(data, strlen(data)); |
| } |
| |
| inline Vector<char> MutableCStrVector(char* data) { |
| return Vector<char>(data, strlen(data)); |
| } |
| |
| inline Vector<char> MutableCStrVector(char* data, int max) { |
| int length = strlen(data); |
| return Vector<char>(data, (length < max) ? length : max); |
| } |
| |
| template <typename T> |
| inline Vector< Handle<Object> > HandleVector(v8::internal::Handle<T>* elms, |
| int length) { |
| return Vector< Handle<Object> >( |
| reinterpret_cast<v8::internal::Handle<Object>*>(elms), length); |
| } |
| |
| |
| // Simple support to read a file into a 0-terminated C-string. |
| // The returned buffer must be freed by the caller. |
| // On return, *exits tells whether the file existed. |
| Vector<const char> ReadFile(const char* filename, |
| bool* exists, |
| bool verbose = true); |
| |
| |
| // Simple wrapper that allows an ExternalString to refer to a |
| // Vector<const char>. Doesn't assume ownership of the data. |
| class AsciiStringAdapter: public v8::String::ExternalAsciiStringResource { |
| public: |
| explicit AsciiStringAdapter(Vector<const char> data) : data_(data) {} |
| |
| virtual const char* data() const { return data_.start(); } |
| |
| virtual size_t length() const { return data_.length(); } |
| |
| private: |
| Vector<const char> data_; |
| }; |
| |
| |
| // Helper class for building result strings in a character buffer. The |
| // purpose of the class is to use safe operations that checks the |
| // buffer bounds on all operations in debug mode. |
| class StringBuilder { |
| public: |
| // Create a string builder with a buffer of the given size. The |
| // buffer is allocated through NewArray<char> and must be |
| // deallocated by the caller of Finalize(). |
| explicit StringBuilder(int size); |
| |
| StringBuilder(char* buffer, int size) |
| : buffer_(buffer, size), position_(0) { } |
| |
| ~StringBuilder() { if (!is_finalized()) Finalize(); } |
| |
| int size() const { return buffer_.length(); } |
| |
| // Get the current position in the builder. |
| int position() const { |
| ASSERT(!is_finalized()); |
| return position_; |
| } |
| |
| // Reset the position. |
| void Reset() { position_ = 0; } |
| |
| // Add a single character to the builder. It is not allowed to add |
| // 0-characters; use the Finalize() method to terminate the string |
| // instead. |
| void AddCharacter(char c) { |
| ASSERT(c != '\0'); |
| ASSERT(!is_finalized() && position_ < buffer_.length()); |
| buffer_[position_++] = c; |
| } |
| |
| // Add an entire string to the builder. Uses strlen() internally to |
| // compute the length of the input string. |
| void AddString(const char* s); |
| |
| // Add the first 'n' characters of the given string 's' to the |
| // builder. The input string must have enough characters. |
| void AddSubstring(const char* s, int n); |
| |
| // Add formatted contents to the builder just like printf(). |
| void AddFormatted(const char* format, ...); |
| |
| // Add character padding to the builder. If count is non-positive, |
| // nothing is added to the builder. |
| void AddPadding(char c, int count); |
| |
| // Finalize the string by 0-terminating it and returning the buffer. |
| char* Finalize(); |
| |
| private: |
| Vector<char> buffer_; |
| int position_; |
| |
| bool is_finalized() const { return position_ < 0; } |
| |
| DISALLOW_IMPLICIT_CONSTRUCTORS(StringBuilder); |
| }; |
| |
| |
| // Copy from ASCII/16bit chars to ASCII/16bit chars. |
| template <typename sourcechar, typename sinkchar> |
| static inline void CopyChars(sinkchar* dest, const sourcechar* src, int chars) { |
| sinkchar* limit = dest + chars; |
| #ifdef V8_HOST_CAN_READ_UNALIGNED |
| if (sizeof(*dest) == sizeof(*src)) { |
| // Number of characters in a uint32_t. |
| static const int kStepSize = sizeof(uint32_t) / sizeof(*dest); // NOLINT |
| while (dest <= limit - kStepSize) { |
| *reinterpret_cast<uint32_t*>(dest) = |
| *reinterpret_cast<const uint32_t*>(src); |
| dest += kStepSize; |
| src += kStepSize; |
| } |
| } |
| #endif |
| while (dest < limit) { |
| *dest++ = static_cast<sinkchar>(*src++); |
| } |
| } |
| |
| |
| } } // namespace v8::internal |
| |
| #endif // V8_UTILS_H_ |