mirror of
git://xwords.git.sourceforge.net/gitroot/xwords/xwords
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133 lines
2.9 KiB
C
133 lines
2.9 KiB
C
/* -*-mode: C; compile-command: "cd ../linux && make MEMDEBUG=TRUE"; -*- */
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/*
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* Copyright 2009 by Eric House (xwords@eehouse.org). All rights reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#ifdef USE_BUFQUEUE
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#include "bufqueue.h"
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#ifdef CPLUS
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extern "C" {
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#endif
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static XP_U16
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roundUp( XP_U16 num )
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{
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/* Keep ptrs word-aligned so can case to XP_U16* */
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return (num + 1) & 0xFFFE;
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}
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#ifdef DEBUG
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static void
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printQueue( const BufQueue* bq )
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{
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XP_U16 head = bq->head;
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XP_U16 counter;
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for ( counter = 0; head < bq->tail; ++counter ) {
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XP_U16 len = *(XP_U16*)&bq->base[head];
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XP_LOGF( "item %d, len %d", counter, len );
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head += roundUp( len + 2 );
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}
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}
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#else
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# define printQueue( bq )
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#endif
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static XP_Bool
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haveSpace( const BufQueue* bq, XP_U16 len )
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{
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return (bq->tail + len + 2) < bq->bufSize;
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}
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static void
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shiftDown( BufQueue* bq )
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{
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if ( bq->head > 0 ) {
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XP_ASSERT( bq->tail > bq->head );
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XP_MEMMOVE( bq->base, &bq->base[bq->head], bq->tail - bq->head );
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bq->tail -= bq->head;
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bq->head = 0;
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}
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}
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void
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bqInit( BufQueue* bq, XP_U8* buf, XP_U16 buflen )
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{
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bq->base = buf;
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bq->bufSize = buflen;
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bq->head = bq->tail = 0;
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}
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XP_Bool
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bqAdd( BufQueue* bq, const XP_U8* buf, XP_U16 len )
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{
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XP_Bool success = XP_FALSE;
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if ( !haveSpace( bq, len ) ) {
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shiftDown( bq );
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}
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success = haveSpace( bq, len );
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if ( success ) {
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XP_U8* tailp = &bq->base[bq->tail];
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*(XP_U16*)tailp = len;
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XP_MEMCPY( tailp+2, buf, len );
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bq->tail += roundUp(len + 2);
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}
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printQueue( bq );
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return success;
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}
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XP_Bool
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bqGet( BufQueue* bq, const XP_U8** buf, XP_U16* len )
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{
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XP_Bool have = bq->head < bq->tail;
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if ( have ) {
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*len = *(XP_U16*)&bq->base[bq->head];
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*buf = &bq->base[bq->head+2];
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}
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return have;
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}
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void
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bqRemoveOne( BufQueue* bq )
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{
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XP_U16 len;
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XP_ASSERT( bq->head != bq->tail );
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len = *(XP_U16*)&bq->base[bq->head];
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bq->head += roundUp( len + 2 );
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XP_ASSERT( bq->head <= bq->tail );
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/* can we reset for free */
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if ( bq->head == bq->tail ) {
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bq->head = bq->tail = 0;
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}
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}
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void
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bqRemoveAll( BufQueue* bq )
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{
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bq->head = bq->tail = 0;
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}
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#ifdef CPLUS
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}
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#endif
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#endif /* USE_BUFQUEUE */
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