shell.c

vxworks源码源码解读是学习vxworks的最佳途径

** user known globals
*/
int yydebug;			/* set to 1 to get debugging */

/*
** driver internal defines
*/
#define YYFLAG		(-1000)

/*
** static variables used by the parser
*/
static YYSTYPE *yyv;			/* value stack */
static int *yys;			/* state stack */

static YYSTYPE *yypv;			/* top of value stack */
static int *yyps;			/* top of state stack */

static int yystate;			/* current state */
static int yytmp;			/* extra var (lasts between blocks) */

int yynerrs;			/* number of errors */

int yyerrflag;			/* error recovery flag */
int yychar;			/* current input token number */


/*
** yyparse - return 0 if worked, 1 if syntax error not recovered from
*/
int
yyparse()
{
	register YYSTYPE *yypvt;	/* top of value stack for $vars */
	unsigned yymaxdepth = YYMAXDEPTH;

	/*
	** Initialize externals - yyparse may be called more than once
	*/
	yyv = (YYSTYPE*)malloc(yymaxdepth*sizeof(YYSTYPE));
	yys = (int*)malloc(yymaxdepth*sizeof(int));
	if (!yyv || !yys)
	{
		yyerror( "out of memory" );
		return(1);
	}
	yypv = &yyv[-1];
	yyps = &yys[-1];
	yystate = 0;
	yytmp = 0;
	yynerrs = 0;
	yyerrflag = 0;
	yychar = -1;

	goto yystack;
	{
		register YYSTYPE *yy_pv;	/* top of value stack */
		register int *yy_ps;		/* top of state stack */
		register int yy_state;		/* current state */
		register int  yy_n;		/* internal state number info */

		/*
		** get globals into registers.
		** branch to here only if YYBACKUP was called.
		*/
	yynewstate:
		yy_pv = yypv;
		yy_ps = yyps;
		yy_state = yystate;
		goto yy_newstate;

		/*
		** get globals into registers.
		** either we just started, or we just finished a reduction
		*/
	yystack:
		yy_pv = yypv;
		yy_ps = yyps;
		yy_state = yystate;

		/*
		** top of for (;;) loop while no reductions done
		*/
	yy_stack:
		/*
		** put a state and value onto the stacks
		*/
#if YYDEBUG
		/*
		** if debugging, look up token value in list of value vs.
		** name pairs.  0 and negative (-1) are special values.
		** Note: linear search is used since time is not a real
		** consideration while debugging.
		*/
		if ( yydebug )
		{
			register int yy_i;

			(void)printf( "State %d, token ", yy_state );
			if ( yychar == 0 )
				(void)printf( "end-of-file\n" );
			else if ( yychar < 0 )
				(void)printf( "-none-\n" );
			else
			{
				for ( yy_i = 0; yytoks[yy_i].t_val >= 0;
					yy_i++ )
				{
					if ( yytoks[yy_i].t_val == yychar )
						break;
				}
				(void)printf( "%s\n", yytoks[yy_i].t_name );
			}
		}
#endif /* YYDEBUG */
		if ( ++yy_ps >= &yys[ yymaxdepth ] )	/* room on stack? */
		{
			/*
			** reallocate and recover.  Note that pointers
			** have to be reset, or bad things will happen
			*/
			int yyps_index = (yy_ps - yys);
			int yypv_index = (yy_pv - yyv);
			int yypvt_index = (yypvt - yyv);
			yymaxdepth += YYMAXDEPTH;
			yyv = (YYSTYPE*)realloc((char*)yyv,
				yymaxdepth * sizeof(YYSTYPE));
			yys = (int*)realloc((char*)yys,
				yymaxdepth * sizeof(int));
			if (!yyv || !yys)
			{
				yyerror( "yacc stack overflow" );
				return(1);
			}
			yy_ps = yys + yyps_index;
			yy_pv = yyv + yypv_index;
			yypvt = yyv + yypvt_index;
		}
		*yy_ps = yy_state;
		*++yy_pv = yyval;

		/*
		** we have a new state - find out what to do
		*/
	yy_newstate:
		if ( ( yy_n = yypact[ yy_state ] ) <= YYFLAG )
			goto yydefault;		/* simple state */
#if YYDEBUG
		/*
		** if debugging, need to mark whether new token grabbed
		*/
		yytmp = yychar < 0;
#endif
		if ( ( yychar < 0 ) && ( ( yychar = yylex() ) < 0 ) )
			yychar = 0;		/* reached EOF */
#if YYDEBUG
		if ( yydebug && yytmp )
		{
			register int yy_i;

			(void)printf( "Received token " );
			if ( yychar == 0 )
				(void)printf( "end-of-file\n" );
			else if ( yychar < 0 )
				(void)printf( "-none-\n" );
			else
			{
				for ( yy_i = 0; yytoks[yy_i].t_val >= 0;
					yy_i++ )
				{
					if ( yytoks[yy_i].t_val == yychar )
						break;
				}
				(void)printf( "%s\n", yytoks[yy_i].t_name );
			}
		}
#endif /* YYDEBUG */
		if ( ( ( yy_n += yychar ) < 0 ) || ( yy_n >= YYLAST ) )
			goto yydefault;
		if ( yychk[ yy_n = yyact[ yy_n ] ] == yychar )	/*valid shift*/
		{
			yychar = -1;
			yyval = yylval;
			yy_state = yy_n;
			if ( yyerrflag > 0 )
				yyerrflag--;
			goto yy_stack;
		}

	yydefault:
		if ( ( yy_n = yydef[ yy_state ] ) == -2 )
		{
#if YYDEBUG
			yytmp = yychar < 0;
#endif
			if ( ( yychar < 0 ) && ( ( yychar = yylex() ) < 0 ) )
				yychar = 0;		/* reached EOF */
#if YYDEBUG
			if ( yydebug && yytmp )
			{
				register int yy_i;

				(void)printf( "Received token " );
				if ( yychar == 0 )
					(void)printf( "end-of-file\n" );
				else if ( yychar < 0 )
					(void)printf( "-none-\n" );
				else
				{
					for ( yy_i = 0;
						yytoks[yy_i].t_val >= 0;
						yy_i++ )
					{
						if ( yytoks[yy_i].t_val
							== yychar )
						{
							break;
						}
					}
					(void)printf( "%s\n", yytoks[yy_i].t_name );
				}
			}
#endif /* YYDEBUG */
			/*
			** look through exception table
			*/
			{
				register int *yyxi = yyexca;

				while ( ( *yyxi != -1 ) ||
					( yyxi[1] != yy_state ) )
				{
					yyxi += 2;
				}
				while ( ( *(yyxi += 2) >= 0 ) &&
					( *yyxi != yychar ) )
					;
				if ( ( yy_n = yyxi[1] ) < 0 )
					YYACCEPT;
			}
		}

		/*
		** check for syntax error
		*/
		if ( yy_n == 0 )	/* have an error */
		{
			/* no worry about speed here! */
			switch ( yyerrflag )
			{
			case 0:		/* new error */
				yyerror( "syntax error" );
				goto skip_init;
			yyerrlab:
				/*
				** get globals into registers.
				** we have a user generated syntax type error
				*/
				yy_pv = yypv;
				yy_ps = yyps;
				yy_state = yystate;
				yynerrs++;
			skip_init:
			case 1:
			case 2:		/* incompletely recovered error */
					/* try again... */
				yyerrflag = 3;
				/*
				** find state where "error" is a legal
				** shift action
				*/
				while ( yy_ps >= yys )
				{
					yy_n = yypact[ *yy_ps ] + YYERRCODE;
					if ( yy_n >= 0 && yy_n < YYLAST &&
						yychk[yyact[yy_n]] == YYERRCODE)					{
						/*
						** simulate shift of "error"
						*/
						yy_state = yyact[ yy_n ];
						goto yy_stack;
					}
					/*
					** current state has no shift on
					** "error", pop stack
					*/
#if YYDEBUG
#	define _POP_ "Error recovery pops state %d, uncovers state %d\n"
					if ( yydebug )
						(void)printf( _POP_, *yy_ps,
							yy_ps[-1] );
#	undef _POP_
#endif
					yy_ps--;
					yy_pv--;
				}
				/*
				** there is no state on stack with "error" as
				** a valid shift.  give up.
				*/
				YYABORT;
			case 3:		/* no shift yet; eat a token */
#if YYDEBUG
				/*
				** if debugging, look up token in list of
				** pairs.  0 and negative shouldn't occur,
				** but since timing doesn't matter when
				** debugging, it doesn't hurt to leave the
				** tests here.
				*/
				if ( yydebug )
				{
					register int yy_i;

					(void)printf( "Error recovery discards " );
					if ( yychar == 0 )
						(void)printf( "token end-of-file\n" );
					else if ( yychar < 0 )
						(void)printf( "token -none-\n" );
					else
					{
						for ( yy_i = 0;
							yytoks[yy_i].t_val >= 0;
							yy_i++ )
						{
							if ( yytoks[yy_i].t_val
								== yychar )
							{
								break;
							}
						}
						(void)printf( "token %s\n",
							yytoks[yy_i].t_name );
					}
				}
#endif /* YYDEBUG */
				if ( yychar == 0 )	/* reached EOF. quit */
					YYABORT;
				yychar = -1;
				goto yy_newstate;
			}
		}/* end if ( yy_n == 0 ) */
		/*
		** reduction by production yy_n
		** put stack tops, etc. so things right after switch
		*/
#if YYDEBUG
		/*
		** if debugging, print the string that is the user's
		** specification of the reduction which is just about
		** to be done.
		*/
		if ( yydebug )
			(void)printf( "Reduce by (%d) \"%s\"\n",
				yy_n, yyreds[ yy_n ] );
#endif
		yytmp = yy_n;			/* value to switch over */
		yypvt = yy_pv;			/* $vars top of value stack */
		/*
		** Look in goto table for next state
		** Sorry about using yy_state here as temporary
		** register variable, but why not, if it works...
		** If yyr2[ yy_n ] doesn't have the low order bit
		** set, then there is no action to be done for
		** this reduction.  So, no saving & unsaving of
		** registers done.  The only difference between the
		** code just after the if and the body of the if is
		** the goto yy_stack in the body.  This way the test
		** can be made before the choice of what to do is needed.
		*/
		{
			/* length of production doubled with extra bit */
			register int yy_len = yyr2[ yy_n ];

			if ( !( yy_len & 01 ) )
			{
				yy_len >>= 1;
				yyval = ( yy_pv -= yy_len )[1];	/* $$ = $1 */
				yy_state = yypgo[ yy_n = yyr1[ yy_n ] ] +
					*( yy_ps -= yy_len ) + 1;
				if ( yy_state >= YYLAST ||
					yychk[ yy_state =
					yyact[ yy_state ] ] != -yy_n )
				{
					yy_state = yyact[ yypgo[ yy_n ] ];
				}
				goto yy_stack;
			}
			yy_len >>= 1;
			yyval = ( yy_pv -= yy_len )[1];	/* $$ = $1 */
			yy_state = yypgo[ yy_n = yyr1[ yy_n ] ] +
				*( yy_ps -= yy_len ) + 1;
			if ( yy_state >= YYLAST ||
				yychk[ yy_state = yyact[ yy_state ] ] != -yy_n )
			{
				yy_state = yyact[ yypgo[ yy_n ] ];
			}
		}
					/* save until reenter driver code */
		yystate = yy_state;
		yyps = yy_ps;
		yypv = yy_pv;
	}
	/*
	** code supplied by user is placed in this switch
	*/
	switch( yytmp )
	{
		
case 4:
# line 214 "shell.yacc"
{ printValue (&yypvt[-0]); CHECK; } break;
case 6:
# line 218 "shell.yacc"
{ yypvt[-0].side = RHS; setRv (&yyval, &yypvt[-0]); } break;
case 7:
# line 219 "shell.yacc"
{ yyval = yypvt[-0]; yyval.value.rv = newString((char*)yypvt[-0].value.rv);
			   CHECK; } break;
case 11:
# line 224 "shell.yacc"
{ yyval = yypvt[-1]; } break;
case 12:
# line 226 "shell.yacc"
{ yyval = funcCall (&yypvt[-3], &yypvt[-1]); CHECK; } break;
case 13:
# line 228 "shell.yacc"
{ 
			typeConvert (&yypvt[-0], yypvt[-1].type, yypvt[-1].side); yyval = yypvt[-0];
			CHECK;
			} break;
case 14:
# line 232 "shell.yacc"
{ VALUE tmp;
					  (void)getRv (&yypvt[-0], &tmp);
					  setLv (&yyval, &tmp);
					  CHECK;
					} break;
case 15:
# line 237 "shell.yacc"
{ yyval.value.rv = (int)getLv (&yypvt[-0]);
					  yyval.type = T_INT; yyval.side = RHS; } break;
case 16:
# line 239 "shell.yacc"
{ rvOp (RV(yypvt[-0]), UMINUS, NULLVAL); } break;
case 17:
# line 240 "shell.yacc"
{ rvOp (RV(yypvt[-0]), '!', NULLVAL); } break;
case 18:
# line 241 "shell.yacc"
{ rvOp (RV(yypvt[-0]), '~', NULLVAL); } break;
case 19:
# line 242 "shell.yacc"
{ setRv (&yyval, RV(yypvt[-4])->value.rv ? &yypvt[-2]
								       : &yypvt[-0]); } break;
case 20:
# line 244 "shell.yacc"
{ BIN_OP ('+');
					  typeConvert (&yyval, T_INT, RHS);
					  setLv (&yyval, &yyval); } break;
case 21:
# line 247 "shell.yacc"
{ BIN_OP ('+');
					  typeConvert (&yyval, T_INT, RHS);
					  setLv (&yyval, &yyval); } break;
case 22:
# line 250 "shell.yacc"
{ BIN_OP ('+'); } break;
case 23:
# line 251 "shell.yacc"
{ BIN_OP ('-'); } break;
case 24:
# line 252 "shell.yacc"
{ BIN_OP ('*'); } break;
case 25:
# line 253 "shell.yacc"
{ BIN_OP ('/'); } break;
case 26:
# line 254 "shell.yacc"
{ BIN_OP ('%'); } break;
case 27:
# line 255 "shell.yacc"
{ BIN_OP (ROT_RIGHT); } break;
case 28:
# line 256 "shell.yacc"
{ BIN_OP (ROT_LEFT); } break;
case 29:
# line 257 "shell.yacc"
{ BIN_OP ('&'); } break;
case 30:
# line 258 "shell.yacc"
{ BIN_OP ('^'); } break;
case 31:
# line 259 "shell.yacc"
{ BIN_OP ('|'); } break;
case 32:
# line 260 "shell.yacc"
{ BIN_OP (AND); } break;
case 33:
# line 261 "shell.yacc"
{ BIN_OP (OR); } break;
case 34:
# line 262 "shell.yacc"
{ BIN_OP (EQ); } break;
case 35:
# line 263 "shell.yacc"
{ BIN_OP (NE); } break;
case 36:
# line 264 "shell.yacc"
{ BIN_OP (GE); } break;
case 37:
# line 265 "shell.yacc"
{ BIN_OP (LE); } break;
case 38:
# line 266 "shell.yacc"
{ BIN_OP ('>'); } break;
case 39:
# line 267 "shell.yacc"
{ BIN_OP ('<'); } break;
case 40:
# line 268 "shell.yacc"
{ rvOp (RV(yypvt[-0]), INCR, NULLVAL);
						  assign (&yypvt[-0], &yyval); CHECK; } break;
case 41:
# line 270 "shell.yacc"
{ rvOp (RV(yypvt[-0]), DECR, NULLVAL);
						  assign (&yypvt[-0], &yyval); CHECK; } break;
case 42:
# line 272 "shell.yacc"
{ VALUE tmp;
						  tmp = yypvt[-1];
						  rvOp (RV(yypvt[-1]), INCR, NULLVAL);
						  assign (&yypvt[-1], &yyval); CHECK;
						  yyval = tmp; } break;
case 43:
# line 277 "shell.yacc"
{ VALUE tmp;
						  tmp = yypvt[-1];
						  rvOp (RV(yypvt[-1]), DECR, NULLVAL);
						  assign (&yypvt[-1], &yyval); CHECK;
						  yyval = tmp; } break;
case 44:
# line 282 "shell.yacc"
{ BIN_OP (ADDA); assign (&yypvt[-2], &yyval); CHECK;} break;
case 45:
# line 283 "shell.yacc"
{ BIN_OP (SUBA); assign (&yypvt[-2], &yyval); CHECK;} break;
case 46:
# line 284 "shell.yacc"
{ BIN_OP (ANDA); assign (&yypvt[-2], &yyval); CHECK;} break;
case 47:
# line 285 "shell.yacc"
{ BIN_OP (ORA);  assign (&yypvt[-2], &yyval); CHECK;} break;
case 48:
# line 286 "shell.yacc"
{ BIN_OP (MODA); assign (&yypvt[-2], &yyval); CHECK;} break;
case 49:
# line 287 "shell.yacc"
{ BIN_OP (XORA); assign (&yypvt[-2], &yyval); CHECK;} break;
case 50:
# line 288 "shell.yacc"
{ BIN_OP (MULA); assign (&yypvt[-2], &yyval); CHECK;} break;
case 51:
# line 289 "shell.yacc"
{ BIN_OP (DIVA); assign (&yypvt[-2], &yyval); CHECK;} break;
case 52:
# line 290 "shell.yacc"
{ BIN_OP (SHLA); assign (&yypvt[-2], &yyval); CHECK;} break;
case 53:
# line 291 "shell.yacc"
{ BIN_OP (SHRA); assign (&yypvt[-2], &yyval); CHECK;} break;
case 54:
# line 292 "shell.yacc"
{ assign (&yypvt[-2], &yypvt[-0]); yyval = yypvt[-2]; } break;
case 55:
# line 297 "shell.yacc"
{ usymFlag = TRUE; usymVal = yypvt[-0]; } break;
case 56:
# line 299 "shell.yacc"
{
			if (yypvt[-3].type != T_UNKNOWN)
			    {
			    printf ("typecast of lhs not allowed.\n");
			    YYERROR;
			    }
			else
			    {
			    yyval = newSym ((char *)yypvt[-3].value.rv, yypvt[-0].type); CHECK;
			    assign (&yyval, &yypvt[-0]); CHECK;
			    }
			usymFlag = FALSE;
			} break;
case 57:
# line 315 "shell.yacc"
{ yyval = newArgList (); } break;
case 59:
# line 320 "shell.yacc"
{ yyval = newArgList (); addArg (&yyval, &yypvt[-0]); CHECK; } break;
case 60:
# line 322 "shell.yacc"
{ addArg (&yypvt[-2], &yypvt[-0]); CHECK; } break;
case 61:
# line 325 "shell.yacc"
{ yypvt[-1].side = RHS; yyval = yypvt[-1]; } break;
case 62:
# line 326 "shell.yacc"
{ yypvt[-3].side = FHS; yyval = yypvt[-3]; } break;
	}
	goto yystack;		/* reset registers in driver code */
}