initial commit, 4.5 stable

thirdparty/icu4c/common/stringpiece.cpp

@@ -0,0 +1,116 @@
+// © 2016 and later: Unicode, Inc. and others.
+// License & terms of use: http://www.unicode.org/copyright.html
+// Copyright (C) 2009-2013, International Business Machines
+// Corporation and others. All Rights Reserved.
+//
+// Copyright 2004 and onwards Google Inc.
+//
+// Author: wilsonh@google.com (Wilson Hsieh)
+//
+
+#include "unicode/utypes.h"
+#include "unicode/stringpiece.h"
+#include "cstring.h"
+#include "cmemory.h"
+
+U_NAMESPACE_BEGIN
+
+StringPiece::StringPiece(const char* str)
+    : ptr_(str), length_((str == nullptr) ? 0 : static_cast<int32_t>(uprv_strlen(str))) { }
+
+StringPiece::StringPiece(const StringPiece& x, int32_t pos) {
+  if (pos < 0) {
+    pos = 0;
+  } else if (pos > x.length_) {
+    pos = x.length_;
+  }
+  ptr_ = x.ptr_ + pos;
+  length_ = x.length_ - pos;
+}
+
+StringPiece::StringPiece(const StringPiece& x, int32_t pos, int32_t len) {
+  if (pos < 0) {
+    pos = 0;
+  } else if (pos > x.length_) {
+    pos = x.length_;
+  }
+  if (len < 0) {
+    len = 0;
+  } else if (len > x.length_ - pos) {
+    len = x.length_ - pos;
+  }
+  ptr_ = x.ptr_ + pos;
+  length_ = len;
+}
+
+void StringPiece::set(const char* str) {
+  ptr_ = str;
+  if (str != nullptr)
+    length_ = static_cast<int32_t>(uprv_strlen(str));
+  else
+    length_ = 0;
+}
+
+int32_t StringPiece::find(StringPiece needle, int32_t offset) {
+  if (length() == 0 && needle.length() == 0) {
+    return 0;
+  }
+  // TODO: Improve to be better than O(N^2)?
+  for (int32_t i = offset; i < length(); i++) {
+    int32_t j = 0;
+    for (; j < needle.length(); i++, j++) {
+      if (data()[i] != needle.data()[j]) {
+        i -= j;
+        goto outer_end;
+      }
+    }
+    return i - j;
+    outer_end: void();
+  }
+  return -1;
+}
+
+int32_t StringPiece::compare(StringPiece other) {
+  int32_t i = 0;
+  for (; i < length(); i++) {
+    if (i == other.length()) {
+      // this is longer
+      return 1;
+    }
+    char a = data()[i];
+    char b = other.data()[i];
+    if (a < b) {
+      return -1;
+    } else if (a > b) {
+      return 1;
+    }
+  }
+  if (i < other.length()) {
+    // other is longer
+    return -1;
+  }
+  return 0;
+}
+
+U_EXPORT UBool U_EXPORT2
+operator==(const StringPiece& x, const StringPiece& y) {
+  int32_t len = x.size();
+  if (len != y.size()) {
+    return false;
+  }
+  if (len == 0) {
+    return true;
+  }
+  const char* p = x.data();
+  const char* p2 = y.data();
+  // Test last byte in case strings share large common prefix
+  --len;
+  if (p[len] != p2[len]) return false;
+  // At this point we can, but don't have to, ignore the last byte.
+  return uprv_memcmp(p, p2, len) == 0;
+}
+
+
+const int32_t StringPiece::npos = 0x7fffffff;
+
+U_NAMESPACE_END