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str.cpp

/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * $URL: https://scummvm.svn.sourceforge.net/svnroot/scummvm/scummvm/tags/release-0-11-1/common/str.cpp $
 * $Id: str.cpp 30944 2008-02-23 22:50:18Z sev $
 */

#include "common/str.h"
#include "common/hash-str.h"
#include "common/util.h"

namespace Common {

#if !(defined(PALMOS_ARM) || defined(PALMOS_DEBUG) || defined(__GP32__))
const String String::emptyString;
#else
const char *String::emptyString = "";
#endif

static int computeCapacity(int len) {
      // By default, for the capacity we use the nearest multiple of 32
      // that leaves at least 16 chars of extra space (in case the string
      // grows a bit).
      // Finally, we subtract 1 to compensate for the trailing zero byte.
      len += 16;
      return ((len + 32 - 1) & ~0x1F) - 1;
}

String::String(const char *str, uint32 len)
: _len(0), _str(_storage) {

      // Init _storage member explicitly (ie. without calling its constructor)
      // for GCC 2.95.x compatibility (see also tracker item #1602879).
      _storage[0] = 0;

      if (str && *str) {
            const uint32 tmp = strlen(str);
            assert(len <= tmp);
            if (len <= 0)
                  len = tmp;
            _len = len;

            if (len >= _builtinCapacity) {
                  // Not enough internal storage, so allocate more
                  _extern._capacity = computeCapacity(len);
                  _extern._refCount = 0;
                  _str = (char *)malloc(_extern._capacity+1);
                  assert(_str != 0);
            }

            // Copy the string into the storage area
            memcpy(_str, str, len);
            _str[len] = 0;
      }
}

String::String(const String &str)
 : _len(str._len), _str(str.isStorageIntern() ? _storage : str._str) {
      if (str.isStorageIntern()) {
            // String in internal storage: just copy it
            memcpy(_storage, str._storage, _builtinCapacity);
      } else {
            // String in external storage: use refcount mechanism
            str.incRefCount();
            _extern._refCount = str._extern._refCount;
            _extern._capacity = str._extern._capacity;
      }
      assert(_str != 0);
}

String::String(char c)
: _len(0), _str(_storage) {

      _storage[0] = c;
      _storage[1] = 0;

      _len = (c == 0) ? 0 : 1;
}

String::~String() {
      decRefCount(_extern._refCount);
}

void String::incRefCount() const {
      assert(!isStorageIntern());
      if (_extern._refCount == 0) {
            _extern._refCount = new int(2);
      } else {
            ++(*_extern._refCount);
      }
}

void String::decRefCount(int *oldRefCount) {
      if (isStorageIntern())
            return;

      if (oldRefCount) {
            --(*oldRefCount);
      }
      if (!oldRefCount || *oldRefCount <= 0) {
            // The ref count reached zero, so we free the string storage
            // and the ref count storage.
            delete oldRefCount;
            free(_str);

            // Even though _str points to a freed memory block now,
            // we do not change its value, because any code that calls
            // decRefCount will have to do this afterwards anyway.
      }
}

String& String::operator  =(const char *str) {
      uint32 len = strlen(str);
      ensureCapacity(len, false);
      _len = len;
      memcpy(_str, str, len + 1);
      return *this;
}

String &String::operator  =(const String &str) {
      if (str.isStorageIntern()) {
            decRefCount(_extern._refCount);
            _len = str._len;
            _str = _storage;
            memcpy(_str, str._str, _len + 1);
      } else {
            str.incRefCount();
            decRefCount(_extern._refCount);

            _extern._refCount = str._extern._refCount;
            _extern._capacity = str._extern._capacity;
            _len = str._len;
            _str = str._str;
      }

      return *this;
}

String& String::operator  =(char c) {
      ensureCapacity(1, false);
      _len = 1;
      _str[0] = c;
      _str[1] = 0;
      return *this;
}

String &String::operator +=(const char *str) {
      int len = strlen(str);
      if (len > 0) {
            ensureCapacity(_len + len, true);

            memcpy(_str + _len, str, len + 1);
            _len += len;
      }
      return *this;
}

String &String::operator +=(const String &str) {
      int len = str._len;
      if (len > 0) {
            ensureCapacity(_len + len, true);

            memcpy(_str + _len, str._str, len + 1);
            _len += len;
      }
      return *this;
}

String &String::operator +=(char c) {
      ensureCapacity(_len + 1, true);

      _str[_len++] = c;
      _str[_len] = 0;

      return *this;
}

bool String::hasPrefix(const char *x) const {
      assert(x != 0);
      // Compare x with the start of _str.
      const char *y = c_str();
      while (*x && *x == *y) {
            ++x;
            ++y;
      }
      // It's a prefix, if and only if all letters in x are 'used up' before
      // _str ends.
      return *x == 0;
}

bool String::hasSuffix(const char *x) const {
      assert(x != 0);
      // Compare x with the end of _str.
      const uint32 x_len = strlen(x);
      if (x_len > _len)
            return false;
      const char *y = c_str() + _len - x_len;
      while (*x && *x == *y) {
            ++x;
            ++y;
      }
      // It's a suffix, if and only if all letters in x are 'used up' before
      // _str ends.
      return *x == 0;
}

bool String::contains(const char *x) const {
      assert(x != 0);
      return strstr(c_str(), x) != NULL;
}

void String::deleteLastChar() {
      deleteChar(_len - 1);
}

void String::deleteChar(uint32 p) {
      assert(p < _len);

      // Call ensureCapacity to make sure we actually *own* the storage
      // to which _str points to -- we wouldn't want to modify a storage
      // which other string objects are sharing, after all.
      ensureCapacity(_len, true);
      while (p++ < _len)
            _str[p-1] = _str[p];
      _len--;
}

void String::clear() {
      decRefCount(_extern._refCount);

      _len = 0;
      _str = _storage;
      _storage[0] = 0;
}

void String::insertChar(char c, uint32 p) {
      assert(p <= _len);

      ensureCapacity(_len + 1, true);
      _len++;
      for (uint32 i = _len; i > p; --i)
            _str[i] = _str[i-1];
      _str[p] = c;
}

void String::toLowercase() {
      ensureCapacity(_len, true);
      for (uint32 i = 0; i < _len; ++i)
            _str[i] = tolower(_str[i]);
}

void String::toUppercase() {
      ensureCapacity(_len, true);
      for (uint32 i = 0; i < _len; ++i)
            _str[i] = toupper(_str[i]);
}

/**
 * Ensure that enough storage is available to store at least new_len
 * characters plus a null byte. In addition, if we currently share
 * the storage with another string, unshare it, so that we can safely
 * write to the storage.
 */
00281 void String::ensureCapacity(uint32 new_len, bool keep_old) {
      bool isShared;
      uint32 curCapacity, newCapacity;
      char *newStorage;
      int *oldRefCount = _extern._refCount;

      if (isStorageIntern()) {
            isShared = false;
            curCapacity = _builtinCapacity - 1;
      } else {
            isShared = (oldRefCount && *oldRefCount > 1);
            curCapacity = _extern._capacity;
      }

      // Special case: If there is enough space, and we do not share
      // the storage, then there is nothing to do.
      if (!isShared && new_len <= curCapacity)
            return;

      if (isShared && new_len <= _builtinCapacity - 1) {
            // We share the storage, but there is enough internal storage: Use that.
            newStorage = _storage;
            newCapacity = _builtinCapacity - 1;
      } else {
            // We need to allocate storage on the heap!

            // Compute a suitable new capacity limit
            newCapacity = computeCapacity(new_len);

            // Allocate new storage
            newStorage = (char *)malloc(newCapacity+1);
            assert(newStorage);
      }

      // Copy old data if needed, elsewise reset the new storage.
      if (keep_old) {
            assert(_len <= newCapacity);
            memcpy(newStorage, _str, _len + 1);
      } else {
            _len = 0;
            newStorage[0] = 0;
      }

      // Release hold on the old storage ...
      decRefCount(oldRefCount);

      // ... in favor of the new storage
      _str = newStorage;

      if (!isStorageIntern()) {
            // Set the ref count & capacity if we use an external storage.
            // It is important to do this *after* copying any old content,
            // else we would override data that has not yet been copied!
            _extern._refCount = 0;
            _extern._capacity = newCapacity;
      }
}

uint String::hash() const {
      return hashit(c_str());
}

#pragma mark -

bool String::operator ==(const String &x) const {
      return equals(x);
}

bool String::operator ==(const char *x) const {
      assert(x != 0);
      return equals(x);
}

bool String::operator !=(const String &x) const {
      return !equals(x);
}

bool String::operator !=(const char *x) const {
      assert(x != 0);
      return !equals(x);
}

bool String::operator < (const String &x) const {
      return compareTo(x) < 0;
}

bool String::operator <= (const String &x) const {
      return compareTo(x) <= 0;
}

bool String::operator > (const String &x) const {
      return compareTo(x) > 0;
}

bool String::operator >= (const String &x) const {
      return compareTo(x) >= 0;
}

#pragma mark -

bool operator == (const char* y, const String &x) {
      return (x == y);
}

bool operator != (const char* y, const String &x) {
      return x != y;
}

#pragma mark -

bool String::equals(const String &x) const {
      return (0 == compareTo(x));
}

bool String::equals(const char *x) const {
      assert(x != 0);
      return (0 == compareTo(x));
}

bool String::equalsIgnoreCase(const String &x) const {
      return (0 == compareToIgnoreCase(x));
}

bool String::equalsIgnoreCase(const char *x) const {
      assert(x != 0);
      return (0 == compareToIgnoreCase(x));
}

int String::compareTo(const String &x) const {
      return compareTo(x.c_str());
}

int String::compareTo(const char *x) const {
      assert(x != 0);
      return strcmp(c_str(), x);
}

int String::compareToIgnoreCase(const String &x) const {
      return compareToIgnoreCase(x.c_str());
}

int String::compareToIgnoreCase(const char *x) const {
      assert(x != 0);
      return scumm_stricmp(c_str(), x);
}

#pragma mark -

String operator +(const String &x, const String &y) {
      String temp(x);
      temp += y;
      return temp;
}

String operator +(const char *x, const String &y) {
      String temp(x);
      temp += y;
      return temp;
}

String operator +(const String &x, const char *y) {
      String temp(x);
      temp += y;
      return temp;
}

String operator +(char x, const String &y) {
      String temp(x);
      temp += y;
      return temp;
}

String operator +(const String &x, char y) {
      String temp(x);
      temp += y;
      return temp;
}

char *ltrim(char *t) {
      while (isspace(*t))
            t++;
      return t;
}

char *rtrim(char *t) {
      int l = strlen(t) - 1;
      while (l >= 0 && isspace(t[l]))
            t[l--] = 0;
      return t;
}

char *trim(char *t) {
      return rtrim(ltrim(t));
}

}     // End of namespace Common

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