StringView.cc

/*
 * Copyright (c) 2008-2014, Pedigree Developers
 *
 * Please see the CONTRIB file in the root of the source tree for a full
 * list of contributors.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
 
#include "pedigree/kernel/Log.h"
#include "pedigree/kernel/utilities/String.h"
#include "pedigree/kernel/utilities/StringView.h"
#include "pedigree/kernel/utilities/assert.h"
#include "pedigree/kernel/utilities/utility.h"
 
StringView::StringView()
    : m_String(nullptr), m_Length(0), m_HashingEnabled(HASH_STRINGVIEWS_BY_DEFAULT) {
  m_Hash = 0;
}
 
StringView::StringView(const char* s)
    : m_String(s),
      m_Length(StringLength(s)),
      m_Hash(0),
      m_HashingEnabled(HASH_STRINGVIEWS_BY_DEFAULT) {
  setHashingEnable(m_HashingEnabled);
}
 
StringView::StringView(const char* s, size_t length)
    : m_String(s), m_Length(length), m_Hash(0), m_HashingEnabled(HASH_STRINGVIEWS_BY_DEFAULT) {
  setHashingEnable(m_HashingEnabled);
}
 
StringView::StringView(const char* s, size_t length, uint32_t hash, bool hashingEnabled)
    : m_String(s), m_Length(length), m_Hash(hash), m_HashingEnabled(hashingEnabled) {}
 
StringView::StringView(const StringView& other)
    : m_String(other.m_String),
      m_Length(other.m_Length),
      m_Hash(other.m_Hash),
      m_HashingEnabled(other.m_HashingEnabled) {}
 
StringView::StringView(const String& other) : StringView(other.view()) {}
 
StringView::~StringView() = default;
 
StringView& StringView::operator=(const StringView& s) {
  m_String = s.m_String;
  m_Length = s.m_Length;
  m_Hash = s.m_Hash;
  m_HashingEnabled = s.m_HashingEnabled;
  return *this;
}
 
bool StringView::operator==(const char* s) const {
  return compare(s, StringLength(s));
}
 
bool StringView::operator==(const String& s) const {
  if (m_Length != s.length()) {
    return false;
  } else if (!compareHash(s)) {
    return false;
  }
 
  return compare(static_cast<const char*>(s), s.length());
}
 
bool StringView::operator==(const StringView& s) const {
  if (m_Length != s.m_Length) {
    return false;
  } else if (!(m_Length && s.m_Length)) {
    return true;
  } else if (!compareHash(s)) {
    return false;
  }
 
  return !StringMatchN(m_String, s.m_String, m_Length);
}
 
bool StringView::compare(const char* s, size_t length) const {
  if (UNLIKELY(!m_Length)) {
    if (!s || !*s) {
      // empty strings match
      return true;
    }
    return false;
  }
 
  if (length != m_Length) {
    return false;
  } else if (!s) {
    return false;
  }
 
  return !StringMatchN(s, m_String, m_Length);
}
 
size_t StringView::length() const {
  return m_Length;
}
 
StringView StringView::substring(size_t start, size_t end, bool hashed) const {
  if (start == 0 && end == m_Length) {
    return StringView(m_String, m_Length, hashed ? hash() : 0, hashed);
  }
 
  if (end > m_Length) {
    end = m_Length;
  }
 
  if ((start > m_Length) || (start >= end)) {
    return StringView();
  }
 
  StringView result(m_String + start, end - start);
  result.setHashingEnable(hashed);
  return result;
}
 
String StringView::toString() const {
  return String(m_String, m_Length, true);
}
 
char StringView::operator[](size_t index) const {
#if ADDITIONAL_CHECKS
  if (UNLIKELY(index >= m_Length)) {
    ERROR("operator[] - index " << index << " exceeds length " << m_Length);
    assert(index < m_Length);
  }
#endif
  return m_String[index];
}
 
size_t StringView::nextCharacter(size_t c) const {
  return ::nextCharacter(m_String, c);
}
 
size_t StringView::prevCharacter(size_t c) const {
  return ::prevCharacter(m_String, c);
}
 
uint32_t StringView::hash() const {
  if (m_Hash) {
    return m_Hash;
  } else {
    return computeHash();
  }
}
 
uint32_t StringView::hash() {
  // Just-in-time hashing (something clearly needs it).
  if (!m_HashingEnabled) {
    setHashingEnable(true);
  }
  return m_Hash;
}
 
const char* StringView::str() const {
  return m_String;
}
 
void StringView::setHashingEnable(bool enabled) {
  m_HashingEnabled = enabled;
 
  if (!enabled) {
    m_Hash = 0;
  } else if (!m_Hash) {
    m_Hash = computeHash();
  }
}
 
bool StringView::compareHash(const StringView& other) const {
  if (!(m_HashingEnabled && other.m_HashingEnabled)) {
    return true;
  } else {
    return hash() == other.hash();
  }
}
 
bool StringView::compareHash(const String& other) const {
  if (!m_HashingEnabled) {
    return true;
  } else {
    return hash() == other.hash();
  }
}
 
uint32_t StringView::computeHash() const {
  if (!m_Length) {
    return 0;
  } else {
    return spookyHash(m_String, m_Length);
  }
}
 
bool StringView::defaultHashingEnabled() const {
  return HASH_STRINGVIEWS_BY_DEFAULT;
}
 
HashedStringView::HashedStringView(const char* s) : StringView(s) {
  setHashingEnable(true);
}
 
HashedStringView::HashedStringView(const char* s, size_t length) : StringView(s, length) {
  setHashingEnable(true);
}
 
HashedStringView::HashedStringView(const StringView& other) : StringView(other) {
  setHashingEnable(true);
}
 
HashedStringView::HashedStringView(const HashedStringView& other) : StringView(other) {
  setHashingEnable(true);
}
 
HashedStringView::HashedStringView(const String& other) : HashedStringView(other.view()) {
  setHashingEnable(true);
}
 
bool HashedStringView::defaultHashingEnabled() const {
  return true;
}