summaryrefslogtreecommitdiff
path: root/klm/util/string_piece.cc
diff options
context:
space:
mode:
Diffstat (limited to 'klm/util/string_piece.cc')
-rw-r--r--klm/util/string_piece.cc193
1 files changed, 193 insertions, 0 deletions
diff --git a/klm/util/string_piece.cc b/klm/util/string_piece.cc
new file mode 100644
index 00000000..ec394b96
--- /dev/null
+++ b/klm/util/string_piece.cc
@@ -0,0 +1,193 @@
+// Copyright 2004 The RE2 Authors. All Rights Reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in string_piece.hh.
+
+#include "util/string_piece.hh"
+
+#include <algorithm>
+
+#include <limits.h>
+
+#ifndef HAVE_ICU
+
+typedef StringPiece::size_type size_type;
+
+void StringPiece::CopyToString(std::string* target) const {
+ target->assign(ptr_, length_);
+}
+
+size_type StringPiece::find(const StringPiece& s, size_type pos) const {
+ // Not sure why length_ < 0 was here since it's std::size_t.
+ if (/*length_ < 0 || */pos > static_cast<size_type>(length_))
+ return npos;
+
+ const char* result = std::search(ptr_ + pos, ptr_ + length_,
+ s.ptr_, s.ptr_ + s.length_);
+ const size_type xpos = result - ptr_;
+ return xpos + s.length_ <= length_ ? xpos : npos;
+}
+
+size_type StringPiece::find(char c, size_type pos) const {
+ if (length_ <= 0 || pos >= static_cast<size_type>(length_)) {
+ return npos;
+ }
+ const char* result = std::find(ptr_ + pos, ptr_ + length_, c);
+ return result != ptr_ + length_ ? result - ptr_ : npos;
+}
+
+size_type StringPiece::rfind(const StringPiece& s, size_type pos) const {
+ if (length_ < s.length_) return npos;
+ const size_t ulen = length_;
+ if (s.length_ == 0) return std::min(ulen, pos);
+
+ const char* last = ptr_ + std::min(ulen - 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;
+}
+
+size_type StringPiece::rfind(char c, size_type pos) const {
+ if (length_ <= 0) return npos;
+ for (int i = std::min(pos, static_cast<size_type>(length_ - 1));
+ i >= 0; --i) {
+ if (ptr_[i] == c) {
+ return i;
+ }
+ }
+ return npos;
+}
+
+// For each character in characters_wanted, sets the index corresponding
+// to the ASCII code of that character to 1 in table. This is used by
+// the find_.*_of methods below to tell whether or not a character is in
+// the lookup table in constant time.
+// The argument `table' must be an array that is large enough to hold all
+// the possible values of an unsigned char. Thus it should be be declared
+// as follows:
+// bool table[UCHAR_MAX + 1]
+static inline void BuildLookupTable(const StringPiece& characters_wanted,
+ bool* table) {
+ const size_type length = characters_wanted.length();
+ const char* const data = characters_wanted.data();
+ for (size_type i = 0; i < length; ++i) {
+ table[static_cast<unsigned char>(data[i])] = true;
+ }
+}
+
+size_type StringPiece::find_first_of(const StringPiece& s,
+ size_type pos) const {
+ if (length_ == 0 || s.length_ == 0)
+ return npos;
+
+ // Avoid the cost of BuildLookupTable() for a single-character search.
+ if (s.length_ == 1)
+ return find_first_of(s.ptr_[0], pos);
+
+ bool lookup[UCHAR_MAX + 1] = { false };
+ BuildLookupTable(s, lookup);
+ for (size_type i = pos; i < length_; ++i) {
+ if (lookup[static_cast<unsigned char>(ptr_[i])]) {
+ return i;
+ }
+ }
+ return npos;
+}
+
+size_type StringPiece::find_first_not_of(const StringPiece& s,
+ size_type pos) const {
+ if (length_ == 0)
+ return npos;
+
+ if (s.length_ == 0)
+ return 0;
+
+ // Avoid the cost of BuildLookupTable() for a single-character search.
+ if (s.length_ == 1)
+ return find_first_not_of(s.ptr_[0], pos);
+
+ bool lookup[UCHAR_MAX + 1] = { false };
+ BuildLookupTable(s, lookup);
+ for (size_type i = pos; i < length_; ++i) {
+ if (!lookup[static_cast<unsigned char>(ptr_[i])]) {
+ return i;
+ }
+ }
+ return npos;
+}
+
+size_type StringPiece::find_first_not_of(char c, size_type pos) const {
+ if (length_ == 0)
+ return npos;
+
+ for (; pos < length_; ++pos) {
+ if (ptr_[pos] != c) {
+ return pos;
+ }
+ }
+ return npos;
+}
+
+size_type StringPiece::find_last_of(const StringPiece& s, size_type pos) const {
+ if (length_ == 0 || s.length_ == 0)
+ return npos;
+
+ // Avoid the cost of BuildLookupTable() for a single-character search.
+ if (s.length_ == 1)
+ return find_last_of(s.ptr_[0], pos);
+
+ bool lookup[UCHAR_MAX + 1] = { false };
+ BuildLookupTable(s, lookup);
+ for (size_type i = std::min(pos, length_ - 1); ; --i) {
+ if (lookup[static_cast<unsigned char>(ptr_[i])])
+ return i;
+ if (i == 0)
+ break;
+ }
+ return npos;
+}
+
+size_type StringPiece::find_last_not_of(const StringPiece& s,
+ size_type pos) const {
+ if (length_ == 0)
+ return npos;
+
+ size_type i = std::min(pos, length_ - 1);
+ if (s.length_ == 0)
+ return i;
+
+ // Avoid the cost of BuildLookupTable() for a single-character search.
+ if (s.length_ == 1)
+ return find_last_not_of(s.ptr_[0], pos);
+
+ bool lookup[UCHAR_MAX + 1] = { false };
+ BuildLookupTable(s, lookup);
+ for (; ; --i) {
+ if (!lookup[static_cast<unsigned char>(ptr_[i])])
+ return i;
+ if (i == 0)
+ break;
+ }
+ return npos;
+}
+
+size_type StringPiece::find_last_not_of(char c, size_type pos) const {
+ if (length_ == 0)
+ return npos;
+
+ for (size_type i = std::min(pos, length_ - 1); ; --i) {
+ if (ptr_[i] != c)
+ return i;
+ if (i == 0)
+ break;
+ }
+ return npos;
+}
+
+StringPiece StringPiece::substr(size_type pos, size_type n) const {
+ if (pos > length_) pos = length_;
+ if (n > length_ - pos) n = length_ - pos;
+ return StringPiece(ptr_ + pos, n);
+}
+
+const size_type StringPiece::npos = size_type(-1);
+
+#endif // !HAVE_ICU