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+// Copyright 2017 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "absl/strings/string_view.h"
+
+#ifndef ABSL_HAVE_STD_STRING_VIEW
+
+#include <algorithm>
+#include <climits>
+#include <cstring>
+#include <ostream>
+#include <string>
+
+#include "absl/strings/internal/memutil.h"
+#include "absl/strings/internal/resize_uninitialized.h"
+#include "absl/strings/match.h"
+
+namespace absl {
+
+namespace {
+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);
+ pad -= n;
+ }
+}
+
+class LookupTable {
+ public:
+ // For each character in wanted, sets the index corresponding
+ // to the ASCII code of that character. This is used by
+ // the find_.*_of methods below to tell whether or not a character is in
+ // the lookup table in constant time.
+ explicit LookupTable(string_view wanted) {
+ for (char c : wanted) {
+ table_[Index(c)] = true;
+ }
+ }
+ bool operator[](char c) const { return table_[Index(c)]; }
+
+ private:
+ static unsigned char Index(char c) { return static_cast<unsigned char>(c); }
+ bool table_[UCHAR_MAX + 1] = {};
+};
+
+} // namespace
+
+std::ostream& operator<<(std::ostream& o, string_view piece) {
+ std::ostream::sentry sentry(o);
+ if (sentry) {
+ size_t lpad = 0;
+ size_t rpad = 0;
+ if (static_cast<size_t>(o.width()) > piece.size()) {
+ size_t pad = o.width() - piece.size();
+ if ((o.flags() & o.adjustfield) == o.left) {
+ rpad = pad;
+ } else {
+ lpad = pad;
+ }
+ }
+ if (lpad) WritePadding(o, lpad);
+ o.write(piece.data(), piece.size());
+ if (rpad) WritePadding(o, rpad);
+ o.width(0);
+ }
+ return o;
+}
+
+string_view::size_type string_view::copy(char* buf, size_type n,
+ size_type pos) const {
+ size_type ulen = length_;
+ assert(pos <= ulen);
+ size_type rlen = std::min(ulen - pos, n);
+ if (rlen > 0) {
+ const char* start = ptr_ + pos;
+ std::copy(start, start + rlen, buf);
+ }
+ return rlen;
+}
+
+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;
+}
+
+string_view::size_type string_view::find(char c, size_type pos) const noexcept {
+ if (empty() || pos >= length_) {
+ return npos;
+ }
+ const char* result =
+ static_cast<const char*>(memchr(ptr_ + pos, c, length_ - pos));
+ return result != nullptr ? result - ptr_ : npos;
+}
+
+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;
+}
+
+// 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 {
+ // Note: memrchr() is not available on Windows.
+ if (empty()) return npos;
+ for (size_type i = std::min(pos, length_ - 1);; --i) {
+ if (ptr_[i] == c) {
+ return i;
+ }
+ if (i == 0) break;
+ }
+ return npos;
+}
+
+string_view::size_type string_view::find_first_of(string_view s,
+ size_type pos) const
+ noexcept {
+ if (empty() || s.empty()) {
+ return npos;
+ }
+ // Avoid the cost of LookupTable() for a single-character search.
+ if (s.length_ == 1) return find_first_of(s.ptr_[0], pos);
+ LookupTable tbl(s);
+ for (size_type i = pos; i < length_; ++i) {
+ if (tbl[ptr_[i]]) {
+ return i;
+ }
+ }
+ return npos;
+}
+
+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);
+ LookupTable tbl(s);
+ for (size_type i = pos; i < length_; ++i) {
+ if (!tbl[ptr_[i]]) {
+ return i;
+ }
+ }
+ return npos;
+}
+
+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) {
+ return pos;
+ }
+ }
+ return npos;
+}
+
+string_view::size_type string_view::find_last_of(string_view s,
+ size_type pos) const noexcept {
+ if (empty() || s.empty()) return npos;
+ // Avoid the cost of LookupTable() for a single-character search.
+ if (s.length_ == 1) return find_last_of(s.ptr_[0], pos);
+ LookupTable tbl(s);
+ for (size_type i = std::min(pos, length_ - 1);; --i) {
+ if (tbl[ptr_[i]]) {
+ return i;
+ }
+ if (i == 0) break;
+ }
+ return npos;
+}
+
+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;
+ // Avoid the cost of LookupTable() for a single-character search.
+ if (s.length_ == 1) return find_last_not_of(s.ptr_[0], pos);
+ LookupTable tbl(s);
+ for (;; --i) {
+ if (!tbl[ptr_[i]]) {
+ return i;
+ }
+ if (i == 0) break;
+ }
+ return npos;
+}
+
+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) {
+ if (ptr_[i] != c) {
+ return i;
+ }
+ if (i == 0) break;
+ }
+ 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 http://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
+constexpr string_view::size_type string_view::npos;
+ABSL_STRING_VIEW_SELECTANY
+constexpr string_view::size_type string_view::kMaxSize;
+
+} // namespace absl
+
+#endif // ABSL_HAVE_STD_STRING_VIEW