diff options
Diffstat (limited to 'abseil-cpp/absl/strings/string_view.cc')
| -rw-r--r-- | abseil-cpp/absl/strings/string_view.cc | 94 |
1 files changed, 50 insertions, 44 deletions
diff --git a/abseil-cpp/absl/strings/string_view.cc b/abseil-cpp/absl/strings/string_view.cc index c5f5de9..f20ff53 100644 --- a/abseil-cpp/absl/strings/string_view.cc +++ b/abseil-cpp/absl/strings/string_view.cc @@ -21,18 +21,41 @@ #include <cstring> #include <ostream> -#include "absl/strings/internal/memutil.h" - namespace absl { ABSL_NAMESPACE_BEGIN namespace { + +// This is significantly faster for case-sensitive matches with very +// few possible matches. +const char* memmatch(const char* phaystack, size_t haylen, const char* pneedle, + size_t neelen) { + if (0 == neelen) { + return phaystack; // even if haylen is 0 + } + if (haylen < neelen) return nullptr; + + const char* match; + const char* hayend = phaystack + haylen - neelen + 1; + // A static cast is used here to work around the fact that memchr returns + // a void* on Posix-compliant systems and const void* on Windows. + while ( + (match = static_cast<const char*>(memchr( + phaystack, pneedle[0], static_cast<size_t>(hayend - phaystack))))) { + if (memcmp(match, pneedle, neelen) == 0) + return match; + else + phaystack = match + 1; + } + return nullptr; +} + void WritePadding(std::ostream& o, size_t pad) { char fill_buf[32]; memset(fill_buf, o.fill(), sizeof(fill_buf)); while (pad) { size_t n = std::min(pad, sizeof(fill_buf)); - o.write(fill_buf, n); + o.write(fill_buf, static_cast<std::streamsize>(n)); pad -= n; } } @@ -63,7 +86,7 @@ std::ostream& operator<<(std::ostream& o, string_view piece) { size_t lpad = 0; size_t rpad = 0; if (static_cast<size_t>(o.width()) > piece.size()) { - size_t pad = o.width() - piece.size(); + size_t pad = static_cast<size_t>(o.width()) - piece.size(); if ((o.flags() & o.adjustfield) == o.left) { rpad = pad; } else { @@ -71,22 +94,21 @@ std::ostream& operator<<(std::ostream& o, string_view piece) { } } if (lpad) WritePadding(o, lpad); - o.write(piece.data(), piece.size()); + o.write(piece.data(), static_cast<std::streamsize>(piece.size())); if (rpad) WritePadding(o, rpad); o.width(0); } return o; } -string_view::size_type string_view::find(string_view s, size_type pos) const - noexcept { +string_view::size_type string_view::find(string_view s, + size_type pos) const noexcept { if (empty() || pos > length_) { if (empty() && pos == 0 && s.empty()) return 0; return npos; } - const char* result = - strings_internal::memmatch(ptr_ + pos, length_ - pos, s.ptr_, s.length_); - return result ? result - ptr_ : npos; + const char* result = memmatch(ptr_ + pos, length_ - pos, s.ptr_, s.length_); + return result ? static_cast<size_type>(result - ptr_) : npos; } string_view::size_type string_view::find(char c, size_type pos) const noexcept { @@ -95,21 +117,21 @@ string_view::size_type string_view::find(char c, size_type pos) const noexcept { } const char* result = static_cast<const char*>(memchr(ptr_ + pos, c, length_ - pos)); - return result != nullptr ? result - ptr_ : npos; + return result != nullptr ? static_cast<size_type>(result - ptr_) : npos; } -string_view::size_type string_view::rfind(string_view s, size_type pos) const - noexcept { +string_view::size_type string_view::rfind(string_view s, + size_type pos) const noexcept { if (length_ < s.length_) return npos; if (s.empty()) return std::min(length_, pos); const char* last = ptr_ + std::min(length_ - s.length_, pos) + s.length_; const char* result = std::find_end(ptr_, last, s.ptr_, s.ptr_ + s.length_); - return result != last ? result - ptr_ : npos; + return result != last ? static_cast<size_type>(result - ptr_) : npos; } // Search range is [0..pos] inclusive. If pos == npos, search everything. -string_view::size_type string_view::rfind(char c, size_type pos) const - noexcept { +string_view::size_type string_view::rfind(char c, + size_type pos) const noexcept { // Note: memrchr() is not available on Windows. if (empty()) return npos; for (size_type i = std::min(pos, length_ - 1);; --i) { @@ -121,9 +143,8 @@ string_view::size_type string_view::rfind(char c, size_type pos) const return npos; } -string_view::size_type string_view::find_first_of(string_view s, - size_type pos) const - noexcept { +string_view::size_type string_view::find_first_of( + string_view s, size_type pos) const noexcept { if (empty() || s.empty()) { return npos; } @@ -138,9 +159,8 @@ string_view::size_type string_view::find_first_of(string_view s, return npos; } -string_view::size_type string_view::find_first_not_of(string_view s, - size_type pos) const - noexcept { +string_view::size_type string_view::find_first_not_of( + string_view s, size_type pos) const noexcept { if (empty()) return npos; // Avoid the cost of LookupTable() for a single-character search. if (s.length_ == 1) return find_first_not_of(s.ptr_[0], pos); @@ -153,9 +173,8 @@ string_view::size_type string_view::find_first_not_of(string_view s, return npos; } -string_view::size_type string_view::find_first_not_of(char c, - size_type pos) const - noexcept { +string_view::size_type string_view::find_first_not_of( + char c, size_type pos) const noexcept { if (empty()) return npos; for (; pos < length_; ++pos) { if (ptr_[pos] != c) { @@ -180,9 +199,8 @@ string_view::size_type string_view::find_last_of(string_view s, return npos; } -string_view::size_type string_view::find_last_not_of(string_view s, - size_type pos) const - noexcept { +string_view::size_type string_view::find_last_not_of( + string_view s, size_type pos) const noexcept { if (empty()) return npos; size_type i = std::min(pos, length_ - 1); if (s.empty()) return i; @@ -198,9 +216,8 @@ string_view::size_type string_view::find_last_not_of(string_view s, return npos; } -string_view::size_type string_view::find_last_not_of(char c, - size_type pos) const - noexcept { +string_view::size_type string_view::find_last_not_of( + char c, size_type pos) const noexcept { if (empty()) return npos; size_type i = std::min(pos, length_ - 1); for (;; --i) { @@ -212,22 +229,11 @@ string_view::size_type string_view::find_last_not_of(char c, return npos; } -// MSVC has non-standard behavior that implicitly creates definitions for static -// const members. These implicit definitions conflict with explicit out-of-class -// member definitions that are required by the C++ standard, resulting in -// LNK1169 "multiply defined" errors at link time. __declspec(selectany) asks -// MSVC to choose only one definition for the symbol it decorates. See details -// at https://msdn.microsoft.com/en-us/library/34h23df8(v=vs.100).aspx -#ifdef _MSC_VER -#define ABSL_STRING_VIEW_SELECTANY __declspec(selectany) -#else -#define ABSL_STRING_VIEW_SELECTANY -#endif -ABSL_STRING_VIEW_SELECTANY +#ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL constexpr string_view::size_type string_view::npos; -ABSL_STRING_VIEW_SELECTANY constexpr string_view::size_type string_view::kMaxSize; +#endif ABSL_NAMESPACE_END } // namespace absl |