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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
//
// https://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_USES_STD_STRING_VIEW
#include <algorithm>
#include <climits>
#include <cstring>
#include <ostream>
#include "absl/strings/internal/memutil.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
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, static_cast<std::streamsize>(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 = static_cast<size_t>(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(), 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 {
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 ? static_cast<size_type>(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 ? static_cast<size_type>(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 ? 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 {
// 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;
}
#ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
constexpr string_view::size_type string_view::npos;
constexpr string_view::size_type string_view::kMaxSize;
#endif
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_USES_STD_STRING_VIEW
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