/****************************************************************************
*
*                            Open Watcom Project
*
*    Portions Copyright (c) 1983-2002 Sybase, Inc. All Rights Reserved.
*
*  ========================================================================
*
*    This file contains Original Code and/or Modifications of Original
*    Code as defined in and that are subject to the Sybase Open Watcom
*    Public License version 1.0 (the 'License'). You may not use this file
*    except in compliance with the License. BY USING THIS FILE YOU AGREE TO
*    ALL TERMS AND CONDITIONS OF THE LICENSE. A copy of the License is
*    provided with the Original Code and Modifications, and is also
*    available at www.sybase.com/developer/opensource.
*
*    The Original Code and all software distributed under the License are
*    distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
*    EXPRESS OR IMPLIED, AND SYBASE AND ALL CONTRIBUTORS HEREBY DISCLAIM
*    ALL SUCH WARRANTIES, INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF
*    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR
*    NON-INFRINGEMENT. Please see the License for the specific language
*    governing rights and limitations under the License.
*
*  ========================================================================
*
* Description:  WHEN YOU FIGURE OUT WHAT THIS FILE DOES, PLEASE
*               DESCRIBE IT HERE!
*
****************************************************************************/


// %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
// %     Copyright (C) 1992, by WATCOM International Inc.  All rights    %
// %     reserved.  No part of this software may be reproduced or        %
// %     used in any form or by any means - graphic, electronic or       %
// %     mechanical, including photocopying, recording, taping or        %
// %     information storage and retrieval systems - except with the     %
// %     written permission of WATCOM International Inc.                 %
// %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
//
//  Modified    By              Reason
//  ========    ==              ======
//  92/02/10    Steve McDowell  Initial implementation.
//  92/02/28    ...             Modified to delay allocation of buffers
//                              until overflow/underflow called.
//  92/09/08    Greg Bentz      Cleanup.
//  93/10/21    Raymond Tang    Split into separate files.
//  94/04/06    Greg Bentz      combine header files
//  94/08/09    A.F.Scian       fixed delete of base() to be delete []

#ifdef __SW_FH
#include "iost.h"
#else
#include "variety.h"
#include <string.h>
#include <strstrea.h>
#endif
#include "ioutil.h"

int strstreambuf::doallocate() {
/******************************/
// Do the allocation required if allocate() thinks it's needed.
// If the allocation fails, return EOF.
// Copy the old buffer into the new buffer.
// Free the old buffer.
// Return __NOT_EOF if everything succeeds.

    char   *oldbuf;
    int     oldbufsize;
    char   *newbuf;
    int     newbufsize;
    size_t  base_offset, ptr_offset, end_offset;

    __lock_it( __b_lock );
    if( !__dynamic || __frozen ) {
        return( EOF );
    }
    oldbuf     = base();
    oldbufsize = blen();
    if( __allocation_size <= oldbufsize ) {
        newbufsize = oldbufsize + DEFAULT_MAINBUF_SIZE;
    } else {
        newbufsize = __allocation_size;
    }
    if( __alloc_fn == NULL ) {
        newbuf = new char [newbufsize];
    } else {
        newbuf = (char *) __alloc_fn( newbufsize );
    }
    if( newbuf == NULL ) {
        return( EOF );
    }
    setb( newbuf, newbuf + newbufsize, FALSE );

    // Copy the get area.
    // This can be done directly by copying bytes and setting new pointers.
    // The size of the get area does not change.
    if( eback() != NULL ) {
        base_offset = (__huge_ptr_int)(eback() - oldbuf);
        ptr_offset  = (__huge_ptr_int)(gptr()  - oldbuf);
        end_offset  = (__huge_ptr_int)(egptr() - oldbuf);
        ::memcpy( newbuf+base_offset, eback(), end_offset-base_offset );
        setg( newbuf+base_offset, newbuf+ptr_offset, newbuf+end_offset );
    }

    // Copy the put area.
    // This can be done directly by copying bytes and setting new pointers.
    // Add the extra bytes allocated above to the end of the put area.
    if( pbase() == NULL ) {
        setp( newbuf, newbuf + newbufsize );
    } else {
        base_offset = (__huge_ptr_int)(pbase() - oldbuf);
        ptr_offset  = (__huge_ptr_int)(pptr()  - oldbuf);
        end_offset  = (__huge_ptr_int)(epptr() - oldbuf);
        ::memcpy( newbuf+base_offset, pbase(), end_offset-base_offset );
        end_offset += newbufsize - oldbufsize;    // grow the put area
        setp( newbuf+base_offset, newbuf+end_offset );
        pbump( ptr_offset - base_offset );
    }

    // Free the old buffer.
    if( oldbuf != NULL ) {
        if( __free_fn == NULL ) {
            delete [] oldbuf;
        } else {
            __free_fn( oldbuf );
        }
    }
    return( __NOT_EOF );
}
