X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=folly%2FRange.h;h=7872383ce8b46a1239b66338e034101f16a367e3;hb=cc0ca971057edb5e4c8f78946b0c5508395ecc48;hp=4913aef403580330a3609e474ff315791913273e;hpb=8ff7c8b8270a20fd768b57ea6c1b6dd48d849e9f;p=folly.git diff --git a/folly/Range.h b/folly/Range.h index 4913aef4..7872383c 100644 --- a/folly/Range.h +++ b/folly/Range.h @@ -1,5 +1,5 @@ /* - * Copyright 2016 Facebook, Inc. + * Copyright 2017 Facebook, Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. @@ -17,12 +17,12 @@ // @author Mark Rabkin (mrabkin@fb.com) // @author Andrei Alexandrescu (andrei.alexandrescu@fb.com) -#ifndef FOLLY_RANGE_H_ -#define FOLLY_RANGE_H_ +#pragma once #include #include #include +#include #include #include @@ -218,7 +218,7 @@ public: template ::const_type = 0> Range(const std::string& str, std::string::size_type startFrom) { if (UNLIKELY(startFrom > str.size())) { - throw std::out_of_range("index out of range"); + std::__throw_out_of_range("index out of range"); } b_ = str.data() + startFrom; e_ = str.data() + str.size(); @@ -229,7 +229,7 @@ public: std::string::size_type startFrom, std::string::size_type size) { if (UNLIKELY(startFrom > str.size())) { - throw std::out_of_range("index out of range"); + std::__throw_out_of_range("index out of range"); } b_ = str.data() + startFrom; if (str.size() - startFrom < size) { @@ -252,7 +252,7 @@ public: template ::const_type = 0> Range(const fbstring& str, fbstring::size_type startFrom) { if (UNLIKELY(startFrom > str.size())) { - throw std::out_of_range("index out of range"); + std::__throw_out_of_range("index out of range"); } b_ = str.data() + startFrom; e_ = str.data() + str.size(); @@ -262,7 +262,7 @@ public: Range(const fbstring& str, fbstring::size_type startFrom, fbstring::size_type size) { if (UNLIKELY(startFrom > str.size())) { - throw std::out_of_range("index out of range"); + std::__throw_out_of_range("index out of range"); } b_ = str.data() + startFrom; if (str.size() - startFrom < size) { @@ -354,20 +354,39 @@ public: reset(str.data(), str.size()); } - size_type size() const { - assert(b_ <= e_); - return e_ - b_; + constexpr size_type size() const { + // It would be nice to assert(b_ <= e_) here. This can be achieved even + // in a C++11 compatible constexpr function: + // http://ericniebler.com/2014/09/27/assert-and-constexpr-in-cxx11/ + // Unfortunately current gcc versions have a bug causing it to reject + // this check in a constexpr function: + // https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71448 + return size_type(e_ - b_); } - size_type walk_size() const { + constexpr size_type walk_size() const { return std::distance(b_, e_); } - bool empty() const { return b_ == e_; } - Iter data() const { return b_; } - Iter start() const { return b_; } - Iter begin() const { return b_; } - Iter end() const { return e_; } - Iter cbegin() const { return b_; } - Iter cend() const { return e_; } + constexpr bool empty() const { + return b_ == e_; + } + constexpr Iter data() const { + return b_; + } + constexpr Iter start() const { + return b_; + } + constexpr Iter begin() const { + return b_; + } + constexpr Iter end() const { + return e_; + } + constexpr Iter cbegin() const { + return b_; + } + constexpr Iter cend() const { + return e_; + } value_type& front() { assert(b_ < e_); return *b_; @@ -393,7 +412,7 @@ public: const_range_type castToConst() const { return const_range_type(*this); - }; + } // Works only for Range and Range int compare(const const_range_type& o) const { @@ -422,12 +441,12 @@ public: } value_type& at(size_t i) { - if (i >= size()) throw std::out_of_range("index out of range"); + if (i >= size()) std::__throw_out_of_range("index out of range"); return b_[i]; } const value_type& at(size_t i) const { - if (i >= size()) throw std::out_of_range("index out of range"); + if (i >= size()) std::__throw_out_of_range("index out of range"); return b_[i]; } @@ -437,6 +456,19 @@ public: // (The above advice does not apply if you are targeting a 32-bit system.) // // Works only for Range and Range + // + // + // ** WANT TO GET RID OF THIS LINT? ** + // + // A) Use a better hash function (*cough*folly::Hash*cough*), but + // only if you don't serialize data in a format that depends on + // this formula (ie the writer and reader assume this exact hash + // function is used). + // + // B) If you have to use this exact function then make your own hasher + // object and copy the body over (see thrift example: D3972362). + // https://github.com/facebook/fbthrift/commit/f8ed502e24ab4a32a9d5f266580 + FOLLY_DEPRECATED("Replace with folly::Hash if the hash is not serialized") uint32_t hash() const { // Taken from fbi/nstring.h: // Quick and dirty bernstein hash...fine for short ascii strings @@ -449,18 +481,42 @@ public: void advance(size_type n) { if (UNLIKELY(n > size())) { - throw std::out_of_range("index out of range"); + std::__throw_out_of_range("index out of range"); } b_ += n; } void subtract(size_type n) { if (UNLIKELY(n > size())) { - throw std::out_of_range("index out of range"); + std::__throw_out_of_range("index out of range"); + } + e_ -= n; + } + + Range subpiece(size_type first, size_type length = npos) const { + if (UNLIKELY(first > size())) { + std::__throw_out_of_range("index out of range"); } + + return Range(b_ + first, std::min(length, size() - first)); + } + + // unchecked versions + void uncheckedAdvance(size_type n) { + DCHECK_LE(n, size()); + b_ += n; + } + + void uncheckedSubtract(size_type n) { + DCHECK_LE(n, size()); e_ -= n; } + Range uncheckedSubpiece(size_type first, size_type length = npos) const { + DCHECK_LE(first, size()); + return Range(b_ + first, std::min(length, size() - first)); + } + void pop_front() { assert(b_ < e_); ++b_; @@ -471,14 +527,6 @@ public: --e_; } - Range subpiece(size_type first, size_type length = npos) const { - if (UNLIKELY(first > size())) { - throw std::out_of_range("index out of range"); - } - - return Range(b_ + first, std::min(length, size() - first)); - } - // string work-alike functions size_type find(const_range_type str) const { return qfind(castToConst(), str); @@ -608,7 +656,7 @@ public: } else if (e == e_) { e_ = b; } else { - throw std::out_of_range("index out of range"); + std::__throw_out_of_range("index out of range"); } } @@ -830,7 +878,7 @@ void swap(Range& lhs, Range& rhs) { * Create a range from two iterators, with type deduction. */ template -Range range(Iter first, Iter last) { +constexpr Range range(Iter first, Iter last) { return Range(first, last); } @@ -838,18 +886,25 @@ Range range(Iter first, Iter last) { * Creates a range to reference the contents of a contiguous-storage container. */ // Use pointers for types with '.data()' member -template ().data())>::type> -Range range(Collection&& v) { +template < + class Collection, + class T = typename std::remove_pointer< + decltype(std::declval().data())>::type> +constexpr Range range(Collection&& v) { return Range(v.data(), v.data() + v.size()); } template -Range range(T (&array)[n]) { +constexpr Range range(T (&array)[n]) { return Range(array, array + n); } +template +constexpr Range range(const std::array& array) { + using r = Range; + return array.empty() ? r{} : r(&array.at(0), &array.at(0) + n); +} + typedef Range StringPiece; typedef Range MutableStringPiece; typedef Range ByteRange; @@ -857,13 +912,13 @@ typedef Range MutableByteRange; inline std::ostream& operator<<(std::ostream& os, const StringPiece piece) { - os.write(piece.start(), piece.size()); + os.write(piece.start(), std::streamsize(piece.size())); return os; } inline std::ostream& operator<<(std::ostream& os, const MutableStringPiece piece) { - os.write(piece.start(), piece.size()); + os.write(piece.start(), std::streamsize(piece.size())); return os; } @@ -951,13 +1006,6 @@ operator>=(const T& lhs, const U& rhs) { return StringPiece(lhs) >= StringPiece(rhs); } -// Do NOT use this, use SpookyHashV2 instead, see commment on hash() above. -struct StringPieceHash { - std::size_t operator()(const StringPiece str) const { - return static_cast(str.hash()); - } -}; - /** * Finds substrings faster than brute force by borrowing from Boyer-Moore */ @@ -1010,7 +1058,7 @@ size_t qfind(const Range& haystack, // Check if done searching if (++j == nsize) { // Yay - return i - haystack.begin(); + return size_t(i - haystack.begin()); } } } @@ -1081,6 +1129,10 @@ size_t rfind(const Range& haystack, // specialization for StringPiece template <> inline size_t qfind(const Range& haystack, const char& needle) { + // memchr expects a not-null pointer, early return if the range is empty. + if (haystack.empty()) { + return std::string::npos; + } auto pos = static_cast( ::memchr(haystack.data(), needle, haystack.size())); return pos == nullptr ? std::string::npos : pos - haystack.data(); @@ -1088,6 +1140,10 @@ inline size_t qfind(const Range& haystack, const char& needle) { template <> inline size_t rfind(const Range& haystack, const char& needle) { + // memchr expects a not-null pointer, early return if the range is empty. + if (haystack.empty()) { + return std::string::npos; + } auto pos = static_cast( ::memrchr(haystack.data(), needle, haystack.size())); return pos == nullptr ? std::string::npos : pos - haystack.data(); @@ -1097,6 +1153,10 @@ inline size_t rfind(const Range& haystack, const char& needle) { template <> inline size_t qfind(const Range& haystack, const unsigned char& needle) { + // memchr expects a not-null pointer, early return if the range is empty. + if (haystack.empty()) { + return std::string::npos; + } auto pos = static_cast( ::memchr(haystack.data(), needle, haystack.size())); return pos == nullptr ? std::string::npos : pos - haystack.data(); @@ -1105,6 +1165,10 @@ inline size_t qfind(const Range& haystack, template <> inline size_t rfind(const Range& haystack, const unsigned char& needle) { + // memchr expects a not-null pointer, early return if the range is empty. + if (haystack.empty()) { + return std::string::npos; + } auto pos = static_cast( ::memrchr(haystack.data(), needle, haystack.size())); return pos == nullptr ? std::string::npos : pos - haystack.data(); @@ -1142,10 +1206,16 @@ struct hasher, } }; +/** + * Ubiquitous helper template for knowing what's a string + */ +template struct IsSomeString { + enum { value = std::is_same::value + || std::is_same::value }; +}; + } // !namespace folly #pragma GCC diagnostic pop FOLLY_ASSUME_FBVECTOR_COMPATIBLE_1(folly::Range); - -#endif // FOLLY_RANGE_H_