Merge pull request #2432 from wangkuiyi/stringpiece

Add StringPiece

Author: wangkuiyi

paddle/CMakeLists.txt

@@ -8,6 +8,7 @@ add_subdirectory(gserver)
 add_subdirectory(pserver)
 add_subdirectory(trainer)
 add_subdirectory(scripts)
+add_subdirectory(strings)
 
 # Do not build go directory until go cmake is working smoothly.
 # if(CMAKE_Go_COMPILER)

paddle/strings/CMakeLists.txt

@@ -0,0 +1,2 @@
+cc_library(stringpiece SRCS stringpiece.cc)
+cc_test(stringpiece_test SRCS stringpiece_test.cc DEPS stringpiece glog gflags)

paddle/strings/stringpiece.cc

@@ -0,0 +1,135 @@
+/*
+  Copyright (c) 2016 PaddlePaddle Authors. All Rights Reserve.
+
+  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 "paddle/strings/stringpiece.h"
+
+// #include <stddef.h>
+#include <string.h>
+
+#include <algorithm>
+#include <iosfwd>
+
+namespace paddle {
+
+StringPiece::StringPiece() : data_(NULL), size_(0) {}
+
+StringPiece::StringPiece(const char* d, size_t n) : data_(d), size_(n) {
+  if (d == NULL && n != 0)
+    throw std::invalid_argument(
+        "StringPiece requires len to be 0 for NULL data");
+}
+
+StringPiece::StringPiece(const char* s) : data_(s) {
+  size_ = (s == NULL) ? 0 : strlen(s);
+}
+
+StringPiece::StringPiece(const std::string& s)
+    : data_(s.data()), size_(s.size()) {}
+
+int Compare(StringPiece a, StringPiece b) {
+  const size_t min_len = (a.len() < b.len()) ? a.len() : b.len();
+  int r = memcmp(a.data(), b.data(), min_len);
+  if (r == 0) {
+    if (a.len() < b.len())
+      return -1;
+    else if (a.len() > b.len())
+      return 1;
+  }
+  return r;
+}
+
+bool operator==(StringPiece x, StringPiece y) {
+  return ((x.len() == y.len()) &&
+          (x.data() == y.data() || memcmp(x.data(), y.data(), x.len()) == 0));
+}
+
+bool operator!=(StringPiece x, StringPiece y) { return !(x == y); }
+
+bool operator<(StringPiece x, StringPiece y) { return Compare(x, y) < 0; }
+bool operator>(StringPiece x, StringPiece y) { return Compare(x, y) > 0; }
+
+bool operator<=(StringPiece x, StringPiece y) { return Compare(x, y) <= 0; }
+bool operator>=(StringPiece x, StringPiece y) { return Compare(x, y) >= 0; }
+
+bool HasPrefix(StringPiece s, StringPiece x) {
+  return ((s.len() >= x.len()) && (memcmp(s.data(), x.data(), x.len()) == 0));
+}
+
+bool HasSuffix(StringPiece s, StringPiece x) {
+  return ((s.len() >= x.len()) &&
+          (memcmp(s.data() + (s.len() - x.len()), x.data(), x.len()) == 0));
+}
+
+StringPiece SkipPrefix(StringPiece s, size_t n) {
+  if (n > s.len())
+    throw std::invalid_argument("Skip distance larger than StringPiece length");
+  return StringPiece(s.data() + n, s.len() - n);
+}
+
+StringPiece SkipSuffix(StringPiece s, size_t n) {
+  if (n > s.len())
+    throw std::invalid_argument("Skip distance larger than StringPiece length");
+  return StringPiece(s.data(), s.len() - n);
+}
+
+StringPiece TrimPrefix(StringPiece s, StringPiece x) {
+  return HasPrefix(s, x) ? SkipPrefix(s, x.len()) : s;
+}
+
+StringPiece TrimSuffix(StringPiece s, StringPiece x) {
+  return HasSuffix(s, x) ? SkipSuffix(s, x.len()) : s;
+}
+
+bool Contains(StringPiece s, StringPiece sub) {
+  return std::search(s.begin(), s.end(), sub.begin(), sub.end()) != s.end();
+}
+
+size_t Index(StringPiece s, StringPiece sub) {
+  auto e = std::search(s.begin(), s.end(), sub.begin(), sub.end());
+  return e != s.end() ? e - s.data() : StringPiece::npos;
+}
+
+size_t Find(StringPiece s, char c, size_t pos) {
+  if (pos >= s.len()) {
+    return StringPiece::npos;
+  }
+  const char* result =
+      reinterpret_cast<const char*>(memchr(s.data() + pos, c, s.len() - pos));
+  return result != nullptr ? result - s.data() : StringPiece::npos;
+}
+
+size_t RFind(StringPiece s, char c, size_t pos) {
+  if (s.len() == 0) return StringPiece::npos;
+  for (const char* p = s.data() + std::min(pos, s.len() - 1); p >= s.data();
+       p--) {
+    if (*p == c) {
+      return p - s.data();
+    }
+  }
+  return StringPiece::npos;
+}
+
+StringPiece SubStr(StringPiece s, size_t pos, size_t n) {
+  if (pos > s.len()) pos = s.len();
+  if (n > s.len() - pos) n = s.len() - pos;
+  return StringPiece(s.data() + pos, n);
+}
+
+std::ostream& operator<<(std::ostream& o, StringPiece piece) {
+  return o << piece.ToString();
+}
+
+}  // namespace paddle

paddle/strings/stringpiece.h

@@ -0,0 +1,110 @@
+/*
+  Copyright (c) 2016 PaddlePaddle Authors. All Rights Reserve.
+
+  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.
+*/
+
+#pragma once
+
+#include <assert.h>
+
+#include <stdexcept>
+#include <string>
+
+namespace paddle {
+
+// StringPiece points into a std::string object but doesn't own the
+// string.  It is for efficient access to strings.  Like Go's string
+// type.  Not that StringPiece doesn't mutate the underlying string,
+// so it is thread-safe given that the underlying string doesn't
+// change.  Because StringPiece contains a little data members, and
+// its syntax is simple as it doesn't own/manage the string, it is
+// cheap to construct StringPieces and pass them around.
+class StringPiece {
+public:
+  static const size_t npos = static_cast<size_t>(-1);
+
+  // We provide non-explicit singleton constructors so users can
+  // pass in a "const char*" or a "string" wherever a "StringPiece"
+  // is expected.  These contructors ensure that if data_ is NULL,
+  // size_ is 0.
+  StringPiece();
+  StringPiece(const char* d, size_t n);
+  StringPiece(const char* d);
+  StringPiece(const std::string& s);
+
+  const char* data() const { return data_; }
+  size_t len() const { return size_; }
+
+  char operator[](size_t n) const {
+    assert(n < len());
+    return data_[n];
+  }
+
+  // StringPiece doesn't own the string, so both iterator and const
+  // iterator are const char* indeed.
+  typedef const char* const_iterator;
+  typedef const char* iterator;
+  iterator begin() const { return data_; }
+  iterator end() const { return data_ + size_; }
+
+  // Return a string that contains the copy of the referenced data.
+  std::string ToString() const { return std::string(data_, size_); }
+
+private:
+  const char* data_;
+  size_t size_;
+
+  // Intentionally copyable
+};
+
+int Compare(StringPiece a, StringPiece b);
+
+bool operator==(StringPiece x, StringPiece y);
+bool operator!=(StringPiece x, StringPiece y);
+bool operator<(StringPiece x, StringPiece y);
+bool operator>(StringPiece x, StringPiece y);
+bool operator<=(StringPiece x, StringPiece y);
+bool operator>=(StringPiece x, StringPiece y);
+
+bool HasPrefix(StringPiece s, StringPiece prefix);
+bool HasSuffix(StringPiece s, StringPiece suffix);
+
+StringPiece SkipPrefix(StringPiece s, size_t n);
+StringPiece SkipSuffix(StringPiece s, size_t n);
+
+// Skip the prefix (or suffix) if it matches with the string.
+StringPiece TrimPrefix(StringPiece s, StringPiece prefix);
+StringPiece TrimSuffix(StringPiece s, StringPiece suffix);
+
+// Returns if s contains sub.  Any s except for empty s contains an
+// empty sub.
+bool Contains(StringPiece s, StringPiece sub);
+
+// Return the first occurrence of sub in s, or npos.  If both s and
+// sub is empty, it returns npos; otherwise, if only sub is empty, it
+// returns 0.
+size_t Index(StringPiece s, StringPiece sub);
+
+// Return the first occurrence of c in s[pos:end], or npos.
+size_t Find(StringPiece s, char c, size_t pos);
+
+// Search range is [0..pos] inclusive.  If pos == npos, search everything.
+size_t RFind(StringPiece s, char c, size_t pos);
+
+StringPiece SubStr(StringPiece s, size_t pos, size_t n);
+
+// allow StringPiece to be logged
+std::ostream& operator<<(std::ostream& o, StringPiece piece);
+
+}  // namespace paddle