/****************************************************************************
**
** Copyright (C) 1992-2004 Trolltech AS. All rights reserved.
**
** This file is part of the compatibility classes of the Qt Toolkit.
**
** Licensees holding valid Qt Preview licenses may use this file in
** accordance with the Qt Preview License Agreement provided with the
** Software.
**
** See http://www.trolltech.com/pricing.html or email sales@trolltech.com for
** information about Qt Commercial License Agreements.
**
** Contact info@trolltech.com if any conditions of this licensing are
** not clear to you.
**
** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
**
****************************************************************************/

#include "qglobal.h"
#if defined(Q_CC_BOR)
    // needed for qsort() because of a std namespace problem on Borland
#   include "qplatformdefs.h"
#elif defined(Q_WS_WIN)
    // needed for bsearch on some platforms
#   include "qt_windows.h"
#endif

#define         QGARRAY_CPP
#include "qgarray.h"
#include <stdlib.h>
#include <string.h>

#ifdef QT_THREAD_SUPPORT
#  include <private/qmutexpool_p.h>
#endif // QT_THREAD_SUPPORT

/*
  If USE_MALLOC isn't defined, we use new[] and delete[] to allocate
  memory. The documentation for QMemArray<T>::assign() explicitly
  mentions that the array is freed using free(), so don't mess around
  with USE_MALLOC unless you know what you're doing.
*/
#define USE_MALLOC

#undef NEW
#undef DELETE

#if defined(USE_MALLOC)
#define NEW(type,size)        ((type*)malloc(size*sizeof(type)))
#define DELETE(array)        (free((char*)array))
#else
#define NEW(type,size)        (new type[size])
#define DELETE(array)        (delete[] array)
#define DONT_USE_REALLOC                        // comment to use realloc()
#endif

/*!
  \class QGArray qgarray.h
  \reentrant
  \brief The QGArray class is an internal class for implementing the QMemArray class.

  \internal

  QGArray is a strictly internal class that acts as base class for the
  QMemArray template array.

  It contains an array of bytes and has no notion of an array element.
*/


/*!
  Constructs a null array.
*/

QGArray::QGArray()
{
    shd = newData();
    Q_CHECK_PTR(shd);
}

/*!
  Dummy constructor; does not allocate any data.

  This constructor does not initialize any array data so subclasses
  must do it. The intention is to make the code more efficient.
*/

QGArray::QGArray(int, int)
{
}

/*!
  Constructs an array with room for \a size bytes.
*/

QGArray::QGArray(int size)
{
    if (size < 0) {
        qWarning("QGArray: Cannot allocate array with negative length");
        size = 0;
    }
    shd = newData();
    Q_CHECK_PTR(shd);
    if (size == 0)                                // zero length
        return;
    shd->data = NEW(char,size);
    Q_CHECK_PTR(shd->data);
    shd->len =
#ifdef QT_QGARRAY_SPEED_OPTIM
        shd->maxl =
#endif
        size;
}

/*!
  Constructs a shallow copy of \a a.
*/

QGArray::QGArray(const QGArray &a)
{
    shd = a.shd;
    shd->ref();
}

/*!
  Dereferences the array data and deletes it if this was the last
  reference.
*/

QGArray::~QGArray()
{
    if (shd && shd->deref()) {                // delete when last reference
        if (shd->data)                        // is lost
            DELETE(shd->data);
        deleteData(shd);
        shd = 0;
    }
}


/*!
  \fn QGArray &QGArray::operator=(const QGArray &a)

  Assigns a shallow copy of \a a to this array and returns a reference to
  this array.  Equivalent to assign().
*/

/*!
  \fn void QGArray::detach()

  Detaches this array from shared array data.
*/

/*!
  \fn char *QGArray::data() const

  Returns a pointer to the actual array data.
*/

/*!
  \fn uint QGArray::nrefs() const

  Returns the reference count.
*/

/*!
  \fn uint QGArray::size() const

  Returns the size of the array, in bytes.
*/


/*!
  Returns true if this array is equal to \a a, otherwise false.
  The comparison is bitwise, of course.
*/

bool QGArray::isEqual(const QGArray &a) const
{
    if (size() != a.size())                        // different size
        return false;
    if (data() == a.data())                        // has same data
        return true;
    return (size() ? memcmp(data(), a.data(), size()) : 0) == 0;
}


/*!
  Resizes the array to \a newsize bytes. \a optim is either
  MemOptim (the default) or SpeedOptim.
*/
bool QGArray::resize(uint newsize, Optimization optim)
{
#ifndef QT_QGARRAY_SPEED_OPTIM
    Q_UNUSED(optim);
#endif

    if (newsize == shd->len
#ifdef QT_QGARRAY_SPEED_OPTIM
         && newsize == shd->maxl
#endif
       ) // nothing to do
        return true;
    if (newsize == 0) {                        // remove array
        if (shd->data)
            DELETE(shd->data);
        shd->data = 0;
        shd->len = 0;
#ifdef QT_QGARRAY_SPEED_OPTIM
        shd->maxl = 0;
#endif
        return true;
    }

    uint newmaxl = newsize;
#ifdef QT_QGARRAY_SPEED_OPTIM
    if (optim == SpeedOptim) {
        if (newsize <= shd->maxl &&
             (newsize * 4 > shd->maxl || shd->maxl <= 4)) {
            shd->len = newsize;
            return true;
        }
        newmaxl = 4;
        while (newmaxl < newsize)
            newmaxl *= 2;
        // try to spare some memory
        if (newmaxl >= 1024 * 1024 && newsize <= newmaxl - (newmaxl >> 2))
            newmaxl -= newmaxl >> 2;
    }
    shd->maxl = newmaxl;
#endif

    if (shd->data) {                                // existing data
#if defined(DONT_USE_REALLOC)
        char *newdata = NEW(char,newsize);        // manual realloc
        memcpy(newdata, shd->data, qMin(shd->len,newmaxl));
        DELETE(shd->data);
        shd->data = newdata;
#else
        shd->data = (char *)realloc(shd->data, newmaxl);
#endif
    } else {
        shd->data = NEW(char,newmaxl);
    }
    if (!shd->data)                                // no memory
        return false;
    shd->len = newsize;
    return true;
}

/*!\overload
*/
bool QGArray::resize(uint newsize)
{
    return resize(newsize, MemOptim);
}


/*!
  Fills the array with the repeated occurrences of \a d, which is
  \a sz bytes long.
  If \a len is specified as different from -1, then the array will be
  resized to \a len*sz before it is filled.

  Returns true if successful, or false if the memory cannot be allocated
  (only when \a len != -1).

  \sa resize()
*/

bool QGArray::fill(const char *d, int len, uint sz)
{
    if (len < 0)
        len = shd->len/sz;                        // default: use array length
    else if (!resize(len*sz))
        return false;
    if (sz == 1)                                // 8 bit elements
        memset(data(), *d, len);
    else if (sz == 4) {                        // 32 bit elements
        register Q_INT32 *x = (Q_INT32*)data();
        Q_INT32 v = *((Q_INT32*)d);
        while (len--)
            *x++ = v;
    } else if (sz == 2) {                        // 16 bit elements
        register Q_INT16 *x = (Q_INT16*)data();
        Q_INT16 v = *((Q_INT16*)d);
        while (len--)
            *x++ = v;
    } else {                                        // any other size elements
        register char *x = data();
        while (len--) {                        // more complicated
            memcpy(x, d, sz);
            x += sz;
        }
    }
    return true;
}

/*!
    \overload
  Shallow copy. Dereference the current array and references the data
  contained in \a a instead. Returns a reference to this array.
  \sa operator=()
*/

QGArray &QGArray::assign(const QGArray &a)
{
    a.shd->ref();                                // avoid 'a = a'
    if (shd->deref()) {                        // delete when last reference
        if (shd->data)                        // is lost
            DELETE(shd->data);
        deleteData(shd);
    }
    shd = a.shd;
    return *this;
}

/*!
  Shallow copy. Dereference the current array and references the
  array data \a d, which contains \a len bytes.
  Returns a reference to this array.

  Do not delete \a d later, because QGArray takes care of that.
*/

QGArray &QGArray::assign(const char *d, uint len)
{
    if (shd->count > 1) {                        // disconnect this
        shd->count--;
        shd = newData();
        Q_CHECK_PTR(shd);
    } else {
        if (shd->data)
            DELETE(shd->data);
    }
    shd->data = (char *)d;
    shd->len =
#ifdef QT_QGARRAY_SPEED_OPTIM
        shd->maxl =
#endif
        len;
    return *this;
}

/*!
  Deep copy. Dereference the current array and obtains a copy of the data
  contained in \a a instead. Returns a reference to this array.
  \sa assign(), operator=()
*/

QGArray &QGArray::duplicate(const QGArray &a)
{
    if (a.shd == shd) {                        // a.duplicate(a) !
        if (shd->count > 1) {
            shd->count--;
            register array_data *n = newData();
            Q_CHECK_PTR(n);
            if ((n->len=shd->len)) {
                n->data = NEW(char,n->len);
                Q_CHECK_PTR(n->data);
                if (n->data)
                    memcpy(n->data, shd->data, n->len);
            } else {
                n->data = 0;
            }
            shd = n;
        }
        return *this;
    }
    char *oldptr = 0;
    if (shd->count > 1) {                        // disconnect this
        shd->count--;
        shd = newData();
        Q_CHECK_PTR(shd);
    } else {                                        // delete after copy was made
        oldptr = shd->data;
    }
    if (a.shd->len) {                                // duplicate data
        shd->data = NEW(char,a.shd->len);
        Q_CHECK_PTR(shd->data);
        if (shd->data)
            memcpy(shd->data, a.shd->data, a.shd->len);
    } else {
        shd->data = 0;
    }
    shd->len =
#ifdef QT_QGARRAY_SPEED_OPTIM
        shd->maxl =
#endif
        a.shd->len;
    if (oldptr)
        DELETE(oldptr);
    return *this;
}

/*!
    \overload
  Deep copy. Dereferences the current array and obtains a copy of
  \a len characters from array data \a d instead.  Returns a reference
  to this array.
  \sa assign(), operator=()
*/

QGArray &QGArray::duplicate(const char *d, uint len)
{
    char *data;
    if (d == 0 || len == 0) {
        data = 0;
        len  = 0;
    } else {
        if (shd->count == 1 && shd->len == len) {
            if (shd->data != d)                // avoid self-assignment
                memcpy(shd->data, d, len);        // use same buffer
            return *this;
        }
        data = NEW(char,len);
        Q_CHECK_PTR(data);
        memcpy(data, d, len);
    }
    if (shd->count > 1) {                        // detach
        shd->count--;
        shd = newData();
        Q_CHECK_PTR(shd);
    } else {                                        // just a single reference
        if (shd->data)
            DELETE(shd->data);
    }
    shd->data = data;
    shd->len =
#ifdef QT_QGARRAY_SPEED_OPTIM
        shd->maxl =
#endif
        len;
    return *this;
}

/*!
  Resizes this array to \a len bytes and copies the \a len bytes at
  address \a d into it.

  \warning This function disregards the reference count mechanism.  If
  other QGArrays reference the same data as this, all will be updated.
*/

void QGArray::store(const char *d, uint len)
{                                                // store, but not deref
    resize(len);
    memcpy(shd->data, d, len);
}


/*!
  \fn array_data *QGArray::sharedBlock() const

  Returns a pointer to the shared array block.

  \warning

  Do not use this function.  Using it is begging for trouble.  We dare
  not remove it, for fear of breaking code, but we \e strongly
  discourage new use of it.
*/

/*!
  \fn void QGArray::setSharedBlock(array_data *p)

  Sets the shared array block to \a p.

  \warning

  Do not use this function.  Using it is begging for trouble.  We dare
  not remove it, for fear of breaking code, but we \e strongly
  discourage new use of it.
*/


/*!
  Sets raw data and returns a reference to the array.

  Dereferences the current array and sets the new array data to \a d and
  the new array size to \a len.         Do not attempt to resize or re-assign the
  array data when raw data has been set.
  Call resetRawData(d,len) to reset the array.

  Setting raw data is useful because it sets QMemArray data without
  allocating memory or copying data.

  Example of intended use:
  \code
    static uchar bindata[] = { 231, 1, 44, ... };
    QByteArray        a;
    a.setRawData(bindata, sizeof(bindata));        // a points to bindata
    QDataStream s(a, IO_ReadOnly);                // open on a's data
    s >> <something>;                                // read raw bindata
    s.close();
    a.resetRawData(bindata, sizeof(bindata)); // finished
  \endcode

  Example of misuse (do not do this):
  \code
    static uchar bindata[] = { 231, 1, 44, ... };
    QByteArray        a, b;
    a.setRawData(bindata, sizeof(bindata));        // a points to bindata
    a.resize(8);                                // will crash
    b = a;                                        // will crash
    a[2] = 123;                                        // might crash
      // forget to resetRawData - will crash
  \endcode

  \warning If you do not call resetRawData(), QGArray will attempt to
  deallocate or reallocate the raw data, which might not be too good.
  Be careful.
*/

QGArray &QGArray::setRawData(const char *d, uint len)
{
    duplicate(0, 0);                                // set null data
    shd->data = (char *)d;
    shd->len  = len;
    return *this;
}

/*!
  Resets raw data.

  The arguments must be the data, \a d, and length \a len, that were
  passed to setRawData().  This is for consistency checking.
*/

void QGArray::resetRawData(const char *d, uint len)
{
    if (d != shd->data || len != shd->len) {
        qWarning("QGArray::resetRawData: Inconsistent arguments");
        return;
    }
    shd->data = 0;
    shd->len  = 0;
}


/*!
  Finds the first occurrence of \a d in the array from position \a index,
  where \a sz is the size of the \a d element.

  Note that \a index is given in units of \a sz, not bytes.

  This function only compares whole cells, not bytes.
*/

int QGArray::find(const char *d, uint index, uint sz) const
{
    index *= sz;
    if (index >= shd->len) {
        qWarning("QGArray::find: Index %d out of range", index/sz);
        return -1;
    }
    register uint i;
    uint ii;
    switch (sz) {
        case 1: {                                // 8 bit elements
            register char *x = data() + index;
            char v = *d;
            for (i=index; i<shd->len; i++) {
                if (*x++ == v)
                    break;
            }
            ii = i;
            }
            break;
        case 2: {                                // 16 bit elements
            register Q_INT16 *x = (Q_INT16*)(data() + index);
            Q_INT16 v = *((Q_INT16*)d);
            for (i=index; i<shd->len; i+=2) {
                if (*x++ == v)
                    break;
            }
            ii = i/2;
            }
            break;
        case 4: {                                // 32 bit elements
            register Q_INT32 *x = (Q_INT32*)(data() + index);
            Q_INT32 v = *((Q_INT32*)d);
            for (i=index; i<shd->len; i+=4) {
                if (*x++ == v)
                    break;
            }
            ii = i/4;
            }
            break;
        default: {                                // any size elements
            for (i=index; i<shd->len; i+=sz) {
                if (memcmp(d, &shd->data[i], sz) == 0)
                    break;
            }
            ii = i/sz;
            }
            break;
    }
    return i<shd->len ? (int)ii : -1;
}

/*!
  Returns the number of occurrences of \a d in the array, where \a sz is
  the size of the \a d element.

  This function only compares whole cells, not bytes.
*/

int QGArray::contains(const char *d, uint sz) const
{
    register uint i = shd->len;
    int count = 0;
    switch (sz) {
        case 1: {                                // 8 bit elements
            register char *x = data();
            char v = *d;
            while (i--) {
                if (*x++ == v)
                    count++;
            }
            }
            break;
        case 2: {                                // 16 bit elements
            register Q_INT16 *x = (Q_INT16*)data();
            Q_INT16 v = *((Q_INT16*)d);
            i /= 2;
            while (i--) {
                if (*x++ == v)
                    count++;
            }
            }
            break;
        case 4: {                                // 32 bit elements
            register Q_INT32 *x = (Q_INT32*)data();
            Q_INT32 v = *((Q_INT32*)d);
            i /= 4;
            while (i--) {
                if (*x++ == v)
                    count++;
            }
            }
            break;
        default: {                                // any size elements
            for (i=0; i<shd->len; i+=sz) {
                if (memcmp(d, &shd->data[i], sz) == 0)
                    count++;
            }
            }
            break;
    }
    return count;
}

static int cmp_item_size = 0;

#if defined(Q_C_CALLBACKS)
extern "C" {
#endif

#ifdef Q_OS_TEMP
static int __cdecl cmp_arr(const void *n1, const void *n2)
#else
static int cmp_arr(const void *n1, const void *n2)
#endif
{
    return (n1 && n2) ? memcmp(n1, n2, cmp_item_size)
                        : (n1 ? 1 : (n2 ? -1 : 0));
}

#if defined(Q_C_CALLBACKS)
}
#endif

/*!
  Sorts the first \a sz items of the array.
*/

void QGArray::sort(uint sz)
{
    int numItems = size() / sz;
    if (numItems < 2)
        return;

#ifdef QT_THREAD_SUPPORT
    QMutexLocker locker(qt_global_mutexpool ?
                         qt_global_mutexpool->get(&cmp_item_size) : 0);
#endif // QT_THREAD_SUPPORT

    cmp_item_size = sz;
    qsort(shd->data, numItems, sz, cmp_arr);
}

/*!
  Binary search; assumes that \a d is a sorted array of size \a sz.
*/

int QGArray::bsearch(const char *d, uint sz) const
{
    int numItems = size() / sz;
    if (!numItems)
        return -1;

#ifdef QT_THREAD_SUPPORT
    QMutexLocker locker(qt_global_mutexpool ?
                         qt_global_mutexpool->get(&cmp_item_size) : 0);
#endif // QT_THREAD_SUPPORT

    cmp_item_size = sz;
    char* r = (char*)::bsearch(d, shd->data, numItems, sz, cmp_arr);
    if (!r)
        return -1;
    while((r >= shd->data + sz) && (cmp_arr(r - sz, d) == 0))
        r -= sz;        // search to first of equal elements; bsearch is undef
    return (int)((r - shd->data) / sz);
}


/*!
  \fn char *QGArray::at(uint index) const

  Returns a pointer to the byte at offset \a index in the array.
*/

/*!
  Expand the array if necessary, and copies (the first part of) its
  contents from the \a index * \a sz bytes at \a d.

  Returns true if the operation succeeds, false if it runs out of
  memory.

  \warning This function disregards the reference count mechanism.  If
  other QGArrays reference the same data as this, all will be changed.
*/

bool QGArray::setExpand(uint index, const char *d, uint sz)
{
    index *= sz;
    if (index >= shd->len) {
        if (!resize(index+sz))                // no memory
            return false;
    }
    memcpy(data() + index, d, sz);
    return true;
}


/*!
  Returns a new shared array block.
*/

QGArray::array_data * QGArray::newData()
{
    return new array_data;
}


/*!
  Deletes the shared array block \a p.
*/

void QGArray::deleteData(array_data *p)
{
    delete p;
}
