// © 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 == NULL) ? 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 != NULL)

    length_ = static_cast<int32_t>(uprv_strlen(str));

  else

    length_ = 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