X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=folly%2FRange.h;h=c34d5cfe601efd766d7c43b3181422a02eae4686;hb=a716b86b2e1b944cb12b6efede404e1aa3964f4d;hp=0043c703233eee1fa8e20a5d1b1473ca9d23967c;hpb=6205123a736c70d73e9878939a9af5c49f3832c5;p=folly.git diff --git a/folly/Range.h b/folly/Range.h index 0043c703..c34d5cfe 100644 --- a/folly/Range.h +++ b/folly/Range.h @@ -1,5 +1,5 @@ /* - * Copyright 2014 Facebook, Inc. + * 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. @@ -20,10 +20,13 @@ #ifndef FOLLY_RANGE_H_ #define FOLLY_RANGE_H_ -#include "folly/Portability.h" -#include "folly/FBString.h" +#include +#include +#include + #include #include +#include #include #include #include @@ -42,9 +45,9 @@ #include #endif -#include "folly/CpuId.h" -#include "folly/Traits.h" -#include "folly/Likely.h" +#include +#include +#include // Ignore shadowing warnings within this file, so includers can use -Wshadow. #pragma GCC diagnostic push @@ -121,6 +124,23 @@ value_before(Iter i) { return *--i; } +/* + * Use IsCharPointer::type to enable const char* or char*. + * Use IsCharPointer::const_type to enable only const char*. + */ +template struct IsCharPointer {}; + +template <> +struct IsCharPointer { + typedef int type; +}; + +template <> +struct IsCharPointer { + typedef int const_type; + typedef int type; +}; + } // namespace detail /** @@ -144,38 +164,54 @@ public: typename std::iterator_traits::reference>::type value_type; typedef typename std::iterator_traits::reference reference; + + /** + * For MutableStringPiece and MutableByteRange we define StringPiece + * and ByteRange as const_range_type (for everything else its just + * identity). We do that to enable operations such as find with + * args which are const. + */ + typedef typename std::conditional< + std::is_same::value + || std::is_same::value, + Range, + Range>::type const_range_type; + typedef std::char_traits::type> traits_type; static const size_type npos; // Works for all iterators - Range() : b_(), e_() { + constexpr Range() : b_(), e_() { } + constexpr Range(const Range&) = default; + constexpr Range(Range&&) = default; + public: // Works for all iterators - Range(Iter start, Iter end) : b_(start), e_(end) { + constexpr Range(Iter start, Iter end) : b_(start), e_(end) { } // Works only for random-access iterators - Range(Iter start, size_t size) + constexpr Range(Iter start, size_t size) : b_(start), e_(start + size) { } #if FOLLY_HAVE_CONSTEXPR_STRLEN - // Works only for Range - /* implicit */ constexpr Range(Iter str) + template ::type = 0> + constexpr /* implicit */ Range(Iter str) : b_(str), e_(str + strlen(str)) {} #else - // Works only for Range + template ::type = 0> /* implicit */ Range(Iter str) : b_(str), e_(str + strlen(str)) {} #endif - // Works only for Range + template ::const_type = 0> /* implicit */ Range(const std::string& str) : b_(str.data()), e_(b_ + str.size()) {} - // Works only for Range + 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"); @@ -183,7 +219,8 @@ public: b_ = str.data() + startFrom; e_ = str.data() + str.size(); } - // Works only for Range + + template ::const_type = 0> Range(const std::string& str, std::string::size_type startFrom, std::string::size_type size) { @@ -197,23 +234,18 @@ public: e_ = b_ + size; } } - Range(const Range& str, - size_t startFrom, - size_t size) { - if (UNLIKELY(startFrom > str.size())) { - throw std::out_of_range("index out of range"); - } - b_ = str.b_ + startFrom; - if (str.size() - startFrom < size) { - e_ = str.e_; - } else { - e_ = b_ + size; - } - } - // Works only for Range + + Range(const Range& other, + size_type first, + size_type length = npos) + : Range(other.subpiece(first, length)) + { } + + template ::const_type = 0> /* implicit */ Range(const fbstring& str) : b_(str.data()), e_(b_ + str.size()) { } - // Works only for Range + + 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"); @@ -221,7 +253,8 @@ public: b_ = str.data() + startFrom; e_ = str.data() + str.size(); } - // Works only for Range + + template ::const_type = 0> Range(const fbstring& str, fbstring::size_type startFrom, fbstring::size_type size) { if (UNLIKELY(startFrom > str.size())) { @@ -278,7 +311,7 @@ public: template ::value && std::is_convertible::value), int>::type = 0> - /* implicit */ Range(const Range& other) + constexpr /* implicit */ Range(const Range& other) : b_(other.begin()), e_(other.end()) { } @@ -289,11 +322,14 @@ public: (!std::is_same::value && !std::is_convertible::value && std::is_constructible::value), int>::type = 0> - explicit Range(const Range& other) + constexpr explicit Range(const Range& other) : b_(other.begin()), e_(other.end()) { } + Range& operator=(const Range& rhs) & = default; + Range& operator=(Range&& rhs) & = default; + void clear() { b_ = Iter(); e_ = Iter(); @@ -345,20 +381,30 @@ public: assert(b_ < e_); return detail::value_before(e_); } - // Works only for Range + // Works only for Range and Range std::string str() const { return std::string(b_, size()); } std::string toString() const { return str(); } - // Works only for Range + // Works only for Range and Range fbstring fbstr() const { return fbstring(b_, size()); } fbstring toFbstring() const { return fbstr(); } - // Works only for Range - int compare(const Range& o) const { + const_range_type castToConst() const { + return const_range_type(*this); + }; + + // Works only for Range and Range + int compare(const const_range_type& o) const { const size_type tsize = this->size(); const size_type osize = o.size(); const size_type msize = std::min(tsize, osize); int r = traits_type::compare(data(), o.data(), msize); - if (r == 0) r = tsize - osize; + if (r == 0 && tsize != osize) { + // We check the signed bit of the subtraction and bit shift it + // to produce either 0 or 2. The subtraction yields the + // comparison values of either -1 or 1. + r = (static_cast( + (osize - tsize) >> (CHAR_BIT * sizeof(size_t) - 1)) << 1) - 1; + } return r; } @@ -382,7 +428,12 @@ public: return b_[i]; } - // Works only for Range + // Do NOT use this function, which was left behind for backwards + // compatibility. Use SpookyHashV2 instead -- it is faster, and produces + // a 64-bit hash, which means dramatically fewer collisions in large maps. + // (The above advice does not apply if you are targeting a 32-bit system.) + // + // Works only for Range and Range uint32_t hash() const { // Taken from fbi/nstring.h: // Quick and dirty bernstein hash...fine for short ascii strings @@ -417,80 +468,81 @@ public: --e_; } - Range subpiece(size_type first, - size_type length = std::string::npos) const { + 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)); + + return Range(b_ + first, std::min(length, size() - first)); } // string work-alike functions - size_type find(Range str) const { - return qfind(*this, str); + size_type find(const_range_type str) const { + return qfind(castToConst(), str); } - size_type find(Range str, size_t pos) const { + size_type find(const_range_type str, size_t pos) const { if (pos > size()) return std::string::npos; - size_t ret = qfind(subpiece(pos), str); + size_t ret = qfind(castToConst().subpiece(pos), str); return ret == npos ? ret : ret + pos; } size_type find(Iter s, size_t pos, size_t n) const { if (pos > size()) return std::string::npos; - size_t ret = qfind(pos ? subpiece(pos) : *this, Range(s, n)); + auto forFinding = castToConst(); + size_t ret = qfind( + pos ? forFinding.subpiece(pos) : forFinding, const_range_type(s, n)); return ret == npos ? ret : ret + pos; } - // Works only for Range which have Range(Iter) ctor + // Works only for Range<(const) (unsigned) char*> which have Range(Iter) ctor size_type find(const Iter s) const { - return qfind(*this, Range(s)); + return qfind(castToConst(), const_range_type(s)); } - // Works only for Range which have Range(Iter) ctor + // Works only for Range<(const) (unsigned) char*> which have Range(Iter) ctor size_type find(const Iter s, size_t pos) const { if (pos > size()) return std::string::npos; - size_type ret = qfind(subpiece(pos), Range(s)); + size_type ret = qfind(castToConst().subpiece(pos), const_range_type(s)); return ret == npos ? ret : ret + pos; } size_type find(value_type c) const { - return qfind(*this, c); + return qfind(castToConst(), c); } size_type rfind(value_type c) const { - return folly::rfind(*this, c); + return folly::rfind(castToConst(), c); } size_type find(value_type c, size_t pos) const { if (pos > size()) return std::string::npos; - size_type ret = qfind(subpiece(pos), c); + size_type ret = qfind(castToConst().subpiece(pos), c); return ret == npos ? ret : ret + pos; } - size_type find_first_of(Range needles) const { - return qfind_first_of(*this, needles); + size_type find_first_of(const_range_type needles) const { + return qfind_first_of(castToConst(), needles); } - size_type find_first_of(Range needles, size_t pos) const { + size_type find_first_of(const_range_type needles, size_t pos) const { if (pos > size()) return std::string::npos; - size_type ret = qfind_first_of(subpiece(pos), needles); + size_type ret = qfind_first_of(castToConst().subpiece(pos), needles); return ret == npos ? ret : ret + pos; } - // Works only for Range which have Range(Iter) ctor + // Works only for Range<(const) (unsigned) char*> which have Range(Iter) ctor size_type find_first_of(Iter needles) const { - return find_first_of(Range(needles)); + return find_first_of(const_range_type(needles)); } - // Works only for Range which have Range(Iter) ctor + // Works only for Range<(const) (unsigned) char*> which have Range(Iter) ctor size_type find_first_of(Iter needles, size_t pos) const { - return find_first_of(Range(needles), pos); + return find_first_of(const_range_type(needles), pos); } size_type find_first_of(Iter needles, size_t pos, size_t n) const { - return find_first_of(Range(needles, n), pos); + return find_first_of(const_range_type(needles, n), pos); } size_type find_first_of(value_type c) const { @@ -506,7 +558,7 @@ public: * * Note: Call find() directly if the index is needed. */ - bool contains(const Range& other) const { + bool contains(const const_range_type& other) const { return find(other) != std::string::npos; } @@ -522,8 +574,9 @@ public: /** * Does this Range start with another range? */ - bool startsWith(const Range& other) const { - return size() >= other.size() && subpiece(0, other.size()) == other; + bool startsWith(const const_range_type& other) const { + return size() >= other.size() + && castToConst().subpiece(0, other.size()) == other; } bool startsWith(value_type c) const { return !empty() && front() == c; @@ -532,8 +585,9 @@ public: /** * Does this Range end with another range? */ - bool endsWith(const Range& other) const { - return size() >= other.size() && subpiece(size() - other.size()) == other; + bool endsWith(const const_range_type& other) const { + return size() >= other.size() + && castToConst().subpiece(size() - other.size()) == other; } bool endsWith(value_type c) const { return !empty() && back() == c; @@ -543,7 +597,7 @@ public: * Remove the given prefix and return true if the range starts with the given * prefix; return false otherwise. */ - bool removePrefix(const Range& prefix) { + bool removePrefix(const const_range_type& prefix) { return startsWith(prefix) && (b_ += prefix.size(), true); } bool removePrefix(value_type prefix) { @@ -554,13 +608,73 @@ public: * Remove the given suffix and return true if the range ends with the given * suffix; return false otherwise. */ - bool removeSuffix(const Range& suffix) { + bool removeSuffix(const const_range_type& suffix) { return endsWith(suffix) && (e_ -= suffix.size(), true); } bool removeSuffix(value_type suffix) { return endsWith(suffix) && (--e_, true); } + /** + * Replaces the content of the range, starting at position 'pos', with + * contents of 'replacement'. Entire 'replacement' must fit into the + * range. Returns false if 'replacements' does not fit. Example use: + * + * char in[] = "buffer"; + * auto msp = MutablesStringPiece(input); + * EXPECT_TRUE(msp.replaceAt(2, "tt")); + * EXPECT_EQ(msp, "butter"); + * + * // not enough space + * EXPECT_FALSE(msp.replace(msp.size() - 1, "rr")); + * EXPECT_EQ(msp, "butter"); // unchanged + */ + bool replaceAt(size_t pos, const_range_type replacement) { + if (size() < pos + replacement.size()) { + return false; + } + + std::copy(replacement.begin(), replacement.end(), begin() + pos); + + return true; + } + + /** + * Replaces all occurences of 'source' with 'dest'. Returns number + * of replacements made. Source and dest have to have the same + * length. Throws if the lengths are different. If 'source' is a + * pattern that is overlapping with itself, we perform sequential + * replacement: "aaaaaaa".replaceAll("aa", "ba") --> "bababaa" + * + * Example use: + * + * char in[] = "buffer"; + * auto msp = MutablesStringPiece(input); + * EXPECT_EQ(msp.replaceAll("ff","tt"), 1); + * EXPECT_EQ(msp, "butter"); + */ + size_t replaceAll(const_range_type source, const_range_type dest) { + if (source.size() != dest.size()) { + throw std::invalid_argument( + "replacement must have the same size as source"); + } + + if (dest.empty()) { + return 0; + } + + size_t pos = 0; + size_t num_replaced = 0; + size_type found = std::string::npos; + while ((found = find(source, pos)) != std::string::npos) { + replaceAt(found, dest); + pos += source.size(); + ++num_replaced; + } + + return num_replaced; + } + /** * Splits this `Range` `[b, e)` in the position `i` dictated by the next * occurence of `delimiter`. @@ -611,7 +725,8 @@ public: /** * Convenience method that calls `split_step()` and passes the result to a - * functor, returning whatever the functor does. + * functor, returning whatever the functor does. Any additional arguments + * `args` passed to this function are perfectly forwarded to the functor. * * Say you have a functor with this signature: * @@ -636,17 +751,49 @@ public: * // ... * } * + * struct Foo { + * void parse(folly::StringPiece s) { + * s.split_step(' ', parse_field, bar, 10); + * s.split_step('\t', parse_field, baz, 20); + * + * auto const kludge = [](folly::StringPiece x, int &out, int def) { + * if (x == "null") { + * out = 0; + * } else { + * parse_field(x, out, def); + * } + * }; + * + * s.split_step('\t', kludge, gaz); + * s.split_step(' ', kludge, foo); + * } + * + * private: + * int bar; + * int baz; + * int gaz; + * int foo; + * + * static parse_field(folly::StringPiece s, int &out, int def) { + * try { + * out = folly::to(s); + * } catch (std::exception const &) { + * value = def; + * } + * } + * }; + * * @author: Marcelo Juchem */ - template - auto split_step(value_type delimiter, TProcess &&process) - -> decltype(process(std::declval())) - { return process(split_step(delimiter)); } + template + auto split_step(value_type delimiter, TProcess &&process, Args &&...args) + -> decltype(process(std::declval(), std::forward(args)...)) + { return process(split_step(delimiter), std::forward(args)...); } - template - auto split_step(Range delimiter, TProcess &&process) - -> decltype(process(std::declval())) - { return process(split_step(delimiter)); } + template + auto split_step(Range delimiter, TProcess &&process, Args &&...args) + -> decltype(process(std::declval(), std::forward(args)...)) + { return process(split_step(delimiter), std::forward(args)...); } private: Iter b_, e_; @@ -689,7 +836,17 @@ typedef Range MutableStringPiece; typedef Range ByteRange; typedef Range MutableByteRange; -std::ostream& operator<<(std::ostream& os, const StringPiece& piece); +inline std::ostream& operator<<(std::ostream& os, + const StringPiece piece) { + os.write(piece.start(), piece.size()); + return os; +} + +inline std::ostream& operator<<(std::ostream& os, + const MutableStringPiece piece) { + os.write(piece.start(), piece.size()); + return os; +} /** * Templated comparison operators @@ -775,8 +932,9 @@ 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 { + std::size_t operator()(const StringPiece str) const { return static_cast(str.hash()); } }; @@ -842,15 +1000,15 @@ size_t qfind(const Range& haystack, namespace detail { -size_t qfind_first_byte_of_nosse(const StringPiece& haystack, - const StringPiece& needles); +size_t qfind_first_byte_of_nosse(const StringPiece haystack, + const StringPiece needles); #if FOLLY_HAVE_EMMINTRIN_H && __GNUC_PREREQ(4, 6) -size_t qfind_first_byte_of_sse42(const StringPiece& haystack, - const StringPiece& needles); +size_t qfind_first_byte_of_sse42(const StringPiece haystack, + const StringPiece needles); -inline size_t qfind_first_byte_of(const StringPiece& haystack, - const StringPiece& needles) { +inline size_t qfind_first_byte_of(const StringPiece haystack, + const StringPiece needles) { static auto const qfind_first_byte_of_fn = folly::CpuId().sse42() ? qfind_first_byte_of_sse42 : qfind_first_byte_of_nosse; @@ -858,8 +1016,8 @@ inline size_t qfind_first_byte_of(const StringPiece& haystack, } #else -inline size_t qfind_first_byte_of(const StringPiece& haystack, - const StringPiece& needles) { +inline size_t qfind_first_byte_of(const StringPiece haystack, + const StringPiece needles) { return qfind_first_byte_of_nosse(haystack, needles); } #endif // FOLLY_HAVE_EMMINTRIN_H @@ -974,6 +1132,16 @@ inline size_t qfind_first_of(const Range& haystack, return detail::qfind_first_byte_of(StringPiece(haystack), StringPiece(needles)); } + +template +struct hasher; + +template struct hasher> { + size_t operator()(folly::Range r) const { + return hash::SpookyHashV2::Hash64(r.begin(), r.size() * sizeof(T), 0); + } +}; + } // !namespace folly #pragma GCC diagnostic pop