keyword.c

来自「开放源码的编译器open watcom 1.6.0版的源代码」· C语言 代码 · 共 126 行

/****************************************************************************
*
*                            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!
*
****************************************************************************/


#include "plusplus.h"
#include "initdefs.h"
#include "stats.h"
#include "preproc.h"
#include "scan.h"
#include "name.h"

#include "kwhash.h"

ExtraRptCtr( ctr_calls );
ExtraRptCtr( ctr_ids );
ExtraRptCtr( ctr_len_min );
ExtraRptCtr( ctr_len_max );
ExtraRptCtr( ctr_len_mask );


int KwLookup(           // TRANSFORM TO T_ID OR KEYWORD TOKEN
    unsigned len )      // - length of id
{
    unsigned hash;      // - hash value for KW
    unsigned mask;      // - test mask
    unsigned *s1;       // - keyword string to compare with
    unsigned *s2;       // - token string to compare against

#ifdef XTRA_RPT
    ExtraRptIncrementCtr( ctr_calls );
    if( len < LEN_MIN )
        ExtraRptIncrementCtr( ctr_len_min );
    if( len > LEN_MAX )
        ExtraRptIncrementCtr( ctr_len_max );
    if(( (1<<len) & LEN_MASK ) == 0 )
        ExtraRptIncrementCtr( ctr_len_mask );
#endif
    hash = keyword_hash( Buffer, TokValue, len ) + FIRST_KEYWORD;
    /* hash is now a token number */
    ++len;
    s1 = (unsigned*) Tokens[ hash ];
    s2 = (unsigned*) Buffer;
    if( len > sizeof( unsigned ) ) {
        do {
            if( *s1 != *s2 ) {
                // codegen can't seem to do this simple optimization
                goto is_id;
                //ExtraRptIncrementCtr( ctr_ids );
                //hash = T_ID;
                //return( hash );
            }
            ++s1;
            ++s2;
            len -= sizeof( unsigned );
        } while( len > sizeof( unsigned ) );
    }
    mask = NameCmpMask[ len ];
    if((( *s1 ^ *s2 ) & mask ) != 0 ) {
is_id:
        ExtraRptIncrementCtr( ctr_ids );
        hash = T_ID;
    }
    return( hash );
}

char KwDisable(                 // DISABLE A KEYWORD TOKEN TO T_ID
    unsigned token )            // - token id
{
    char retn = Tokens[ token ][0];
    Tokens[ token ][0] = '\0';
    return retn;
}

void KwEnable(                  // ENABLE A KEYWORD TOKEN FROM T_ID
    unsigned token,             // - token id
    char first_char )           // - first character of name
{
    DbgAssert( first_char == '_'
            || ( first_char >= 'a' && first_char <= 'z' ) );
    Tokens[ token ][0] = first_char;
}

#ifdef XTRA_RPT
static void init(               // INITIALIZATION
    INITFINI* defn )            // - definition
{
    defn = defn;
    ExtraRptRegisterCtr( &ctr_calls, "# keyword hashs" );
    ExtraRptRegisterCtr( &ctr_ids, "# keywords that are ids" );
    ExtraRptRegisterCtr( &ctr_len_mask, "# keywords that fail len mask test" );
    ExtraRptRegisterCtr( &ctr_len_min, "# keywords that fail min len test" );
    ExtraRptRegisterCtr( &ctr_len_max, "# keywords that fail max len test" );
}


INITDEFN( keyword, init, InitFiniStub );
#endif