[unix-history] / usr / src / usr.bin / gcc / cpp / cexp.y

/* Parse C expressions for CCCP.
   Copyright (C) 1987 Free Software Foundation.

This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 1, or (at your option) any
later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.

 In other words, you are welcome to use, share and improve this program.
 You are forbidden to forbid anyone else to use, share and improve
 what you give them.   Help stamp out software-hoarding!

 Adapted from expread.y of GDB by Paul Rubin, July 1986.

/* Parse a C expression from text in a string  */
   
%{
#include "config.h"
#include <setjmp.h>
/* #define YYDEBUG 1 */

  int yylex ();
  void yyerror ();
  int expression_value;

  static jmp_buf parse_return_error;

  /* some external tables of character types */
  extern unsigned char is_idstart[], is_idchar[];

#ifndef CHAR_TYPE_SIZE
#define CHAR_TYPE_SIZE BITS_PER_UNIT
#endif
%}

%union {
  struct constant {long value; int unsignedp;} integer;
  int voidval;
  char *sval;
}

%type <integer> exp exp1 start
%token <integer> INT CHAR
%token <sval> NAME
%token <integer> ERROR

%right '?' ':'
%left ','
%left OR
%left AND
%left '|'
%left '^'
%left '&'
%left EQUAL NOTEQUAL
%left '<' '>' LEQ GEQ
%left LSH RSH
%left '+' '-'
%left '*' '/' '%'
%right UNARY

/* %expect 40 */
\f
%%

start   :	exp1
		{ expression_value = $1.value; }
	;

/* Expressions, including the comma operator.  */
exp1	:	exp
	|	exp1 ',' exp
			{ $$ = $3; }
	;

/* Expressions, not including the comma operator.  */
exp	:	'-' exp    %prec UNARY
			{ $$.value = - $2.value;
			  $$.unsignedp = $2.unsignedp; }
	|	'!' exp    %prec UNARY
			{ $$.value = ! $2.value;
			  $$.unsignedp = 0; }
	|	'+' exp    %prec UNARY
			{ $$ = $2; }
	|	'~' exp    %prec UNARY
			{ $$.value = ~ $2.value;
			  $$.unsignedp = $2.unsignedp; }
	|	'(' exp1 ')'
			{ $$ = $2; }
	;

/* Binary operators in order of decreasing precedence.  */
exp	:	exp '*' exp
			{ $$.unsignedp = $1.unsignedp || $3.unsignedp;
			  if ($$.unsignedp)
			    $$.value = (unsigned) $1.value * $3.value;
			  else
			    $$.value = $1.value * $3.value; }
	|	exp '/' exp
			{ if ($3.value == 0)
			    {
			      error ("division by zero in #if");
			      $3.value = 1;
			    }
			  $$.unsignedp = $1.unsignedp || $3.unsignedp;
			  if ($$.unsignedp)
			    $$.value = (unsigned) $1.value / $3.value;
			  else
			    $$.value = $1.value / $3.value; }
	|	exp '%' exp
			{ if ($3.value == 0)
			    {
			      error ("division by zero in #if");
			      $3.value = 1;
			    }
			  $$.unsignedp = $1.unsignedp || $3.unsignedp;
			  if ($$.unsignedp)
			    $$.value = (unsigned) $1.value % $3.value;
			  else
			    $$.value = $1.value % $3.value; }
	|	exp '+' exp
			{ $$.value = $1.value + $3.value;
			  $$.unsignedp = $1.unsignedp || $3.unsignedp; }
	|	exp '-' exp
			{ $$.value = $1.value - $3.value;
			  $$.unsignedp = $1.unsignedp || $3.unsignedp; }
	|	exp LSH exp
			{ $$.unsignedp = $1.unsignedp;
			  if ($$.unsignedp)
			    $$.value = (unsigned) $1.value << $3.value;
			  else
			    $$.value = $1.value << $3.value; }
	|	exp RSH exp
			{ $$.unsignedp = $1.unsignedp;
			  if ($$.unsignedp)
			    $$.value = (unsigned) $1.value >> $3.value;
			  else
			    $$.value = $1.value >> $3.value; }
	|	exp EQUAL exp
			{ $$.value = ($1.value == $3.value);
			  $$.unsignedp = 0; }
	|	exp NOTEQUAL exp
			{ $$.value = ($1.value != $3.value);
			  $$.unsignedp = 0; }
	|	exp LEQ exp
			{ $$.unsignedp = 0;
			  if ($1.unsignedp || $3.unsignedp)
			    $$.value = (unsigned) $1.value <= $3.value;
			  else
			    $$.value = $1.value <= $3.value; }
	|	exp GEQ exp
			{ $$.unsignedp = 0;
			  if ($1.unsignedp || $3.unsignedp)
			    $$.value = (unsigned) $1.value >= $3.value;
			  else
			    $$.value = $1.value >= $3.value; }
	|	exp '<' exp
			{ $$.unsignedp = 0;
			  if ($1.unsignedp || $3.unsignedp)
			    $$.value = (unsigned) $1.value < $3.value;
			  else
			    $$.value = $1.value < $3.value; }
	|	exp '>' exp
			{ $$.unsignedp = 0;
			  if ($1.unsignedp || $3.unsignedp)
			    $$.value = (unsigned) $1.value > $3.value;
			  else
			    $$.value = $1.value > $3.value; }
	|	exp '&' exp
			{ $$.value = $1.value & $3.value;
			  $$.unsignedp = $1.unsignedp || $3.unsignedp; }
	|	exp '^' exp
			{ $$.value = $1.value ^ $3.value;
			  $$.unsignedp = $1.unsignedp || $3.unsignedp; }
	|	exp '|' exp
			{ $$.value = $1.value | $3.value;
			  $$.unsignedp = $1.unsignedp || $3.unsignedp; }
	|	exp AND exp
			{ $$.value = ($1.value && $3.value);
			  $$.unsignedp = 0; }
	|	exp OR exp
			{ $$.value = ($1.value || $3.value);
			  $$.unsignedp = 0; }
	|	exp '?' exp ':' exp
			{ $$.value = $1.value ? $3.value : $5.value;
			  $$.unsignedp = $3.unsignedp || $5.unsignedp; }
	|	INT
			{ $$ = yylval.integer; }
	|	CHAR
			{ $$ = yylval.integer; }
	|	NAME
			{ $$.value = 0;
			  $$.unsignedp = 0; }
	;
%%
\f
/* During parsing of a C expression, the pointer to the next character
   is in this variable.  */

static char *lexptr;

/* Take care of parsing a number (anything that starts with a digit).
   Set yylval and return the token type; update lexptr.
   LEN is the number of characters in it.  */

/* maybe needs to actually deal with floating point numbers */

int
parse_number (olen)
     int olen;
{
  register char *p = lexptr;
  register long n = 0;
  register int c;
  register int base = 10;
  register int len = olen;

  for (c = 0; c < len; c++)
    if (p[c] == '.') {
      /* It's a float since it contains a point.  */
      yyerror ("floating point numbers not allowed in #if expressions");
      return ERROR;
    }

  yylval.integer.unsignedp = 0;

  if (len >= 3 && (!strncmp (p, "0x", 2) || !strncmp (p, "0X", 2))) {
    p += 2;
    base = 16;
    len -= 2;
  }
  else if (*p == '0')
    base = 8;

  while (len > 0) {
    c = *p++;
    len--;
    if (c >= 'A' && c <= 'Z') c += 'a' - 'A';

    if (c >= '0' && c <= '9') {
      n *= base;
      n += c - '0';
    } else if (base == 16 && c >= 'a' && c <= 'f') {
      n *= base;
      n += c - 'a' + 10;
    } else {
      /* `l' means long, and `u' means unsigned.  */
      while (1) {
	if (c == 'l' || c == 'L')
	  ;
	else if (c == 'u' || c == 'U')
	  yylval.integer.unsignedp = 1;
	else
	  break;

	if (len == 0)
	  break;
	c = *p++;
	len--;
      }
      /* Don't look for any more digits after the suffixes.  */
      break;
    }
  }

  if (len != 0) {
    yyerror ("Invalid number in #if expression");
    return ERROR;
  }

  /* If too big to be signed, consider it unsigned.  */
  if (n < 0)
    yylval.integer.unsignedp = 1;

  lexptr = p;
  yylval.integer.value = n;
  return INT;
}

struct token {
  char *operator;
  int token;
};

#ifndef NULL
#define NULL 0
#endif

static struct token tokentab2[] = {
  {"&&", AND},
  {"||", OR},
  {"<<", LSH},
  {">>", RSH},
  {"==", EQUAL},
  {"!=", NOTEQUAL},
  {"<=", LEQ},
  {">=", GEQ},
  {NULL, ERROR}
};

/* Read one token, getting characters through lexptr.  */

int
yylex ()
{
  register int c;
  register int namelen;
  register char *tokstart;
  register struct token *toktab;

 retry:

  tokstart = lexptr;
  c = *tokstart;
  /* See if it is a special token of length 2.  */
  for (toktab = tokentab2; toktab->operator != NULL; toktab++)
    if (c == *toktab->operator && tokstart[1] == toktab->operator[1]) {
      lexptr += 2;
      return toktab->token;
    }

  switch (c) {
  case 0:
    return 0;
    
  case ' ':
  case '\t':
  case '\r':
  case '\n':
    lexptr++;
    goto retry;
    
  case '\'':
    lexptr++;
    c = *lexptr++;
    if (c == '\\')
      c = parse_escape (&lexptr);

    /* Sign-extend the constant if chars are signed on target machine.  */
    {
      if (lookup ("__CHAR_UNSIGNED__", sizeof ("__CHAR_UNSIGNED__")-1, -1)
	  || ((c >> (CHAR_TYPE_SIZE - 1)) & 1) == 0)
	yylval.integer.value = c & ((1 << CHAR_TYPE_SIZE) - 1);
      else
	yylval.integer.value = c | ~((1 << CHAR_TYPE_SIZE) - 1);
    }

    yylval.integer.unsignedp = 0;
    c = *lexptr++;
    if (c != '\'') {
      yyerror ("Invalid character constant in #if");
      return ERROR;
    }
    
    return CHAR;

    /* some of these chars are invalid in constant expressions;
       maybe do something about them later */
  case '/':
  case '+':
  case '-':
  case '*':
  case '%':
  case '|':
  case '&':
  case '^':
  case '~':
  case '!':
  case '@':
  case '<':
  case '>':
  case '(':
  case ')':
  case '[':
  case ']':
  case '.':
  case '?':
  case ':':
  case '=':
  case '{':
  case '}':
  case ',':
    lexptr++;
    return c;
    
  case '"':
    yyerror ("double quoted strings not allowed in #if expressions");
    return ERROR;
  }
  if (c >= '0' && c <= '9') {
    /* It's a number */
    for (namelen = 0;
	 c = tokstart[namelen], is_idchar[c] || c == '.'; 
	 namelen++)
      ;
    return parse_number (namelen);
  }
  
  if (!is_idstart[c]) {
    yyerror ("Invalid token in expression");
    return ERROR;
  }
  
  /* It is a name.  See how long it is.  */
  
  for (namelen = 0; is_idchar[tokstart[namelen]]; namelen++)
    ;
  
  lexptr += namelen;
  return NAME;
}


/* Parse a C escape sequence.  STRING_PTR points to a variable
   containing a pointer to the string to parse.  That pointer
   is updated past the characters we use.  The value of the
   escape sequence is returned.

   A negative value means the sequence \ newline was seen,
   which is supposed to be equivalent to nothing at all.

   If \ is followed by a null character, we return a negative
   value and leave the string pointer pointing at the null character.

   If \ is followed by 000, we return 0 and leave the string pointer
   after the zeros.  A value of 0 does not mean end of string.  */

int
parse_escape (string_ptr)
     char **string_ptr;
{
  register int c = *(*string_ptr)++;
  switch (c)
    {
    case 'a':
      return TARGET_BELL;
    case 'b':
      return TARGET_BS;
    case 'e':
      return 033;
    case 'f':
      return TARGET_FF;
    case 'n':
      return TARGET_NEWLINE;
    case 'r':
      return TARGET_CR;
    case 't':
      return TARGET_TAB;
    case 'v':
      return TARGET_VT;
    case '\n':
      return -2;
    case 0:
      (*string_ptr)--;
      return 0;
    case '^':
      c = *(*string_ptr)++;
      if (c == '\\')
	c = parse_escape (string_ptr);
      if (c == '?')
	return 0177;
      return (c & 0200) | (c & 037);
      
    case '0':
    case '1':
    case '2':
    case '3':
    case '4':
    case '5':
    case '6':
    case '7':
      {
	register int i = c - '0';
	register int count = 0;
	while (++count < 3)
	  {
	    c = *(*string_ptr)++;
	    if (c >= '0' && c <= '7')
	      i = (i << 3) + c - '0';
	    else
	      {
		(*string_ptr)--;
		break;
	      }
	  }
	if ((i & ~((1 << CHAR_TYPE_SIZE) - 1)) != 0)
	  {
	    i &= (1 << CHAR_TYPE_SIZE) - 1;
	    warning ("octal character constant does not fit in a byte");
	  }
	return i;
      }
    case 'x':
      {
	register int i = 0;
	register int count = 0;
	for (;;)
	  {
	    c = *(*string_ptr)++;
	    if (c >= '0' && c <= '9')
	      i = (i << 4) + c - '0';
	    else if (c >= 'a' && c <= 'f')
	      i = (i << 4) + c - 'a' + 10;
	    else if (c >= 'A' && c <= 'F')
	      i = (i << 4) + c - 'A' + 10;
	    else
	      {
		(*string_ptr)--;
		break;
	      }
	  }
	if ((i & ~((1 << BITS_PER_UNIT) - 1)) != 0)
	  {
	    i &= (1 << BITS_PER_UNIT) - 1;
	    warning ("hex character constant does not fit in a byte");
	  }
	return i;
      }
    default:
      return c;
    }
}

void
yyerror (s)
     char *s;
{
  error (s);
  longjmp (parse_return_error, 1);
}
\f
/* This page contains the entry point to this file.  */

/* Parse STRING as an expression, and complain if this fails
   to use up all of the contents of STRING.  */
/* We do not support C comments.  They should be removed before
   this function is called.  */

int
parse_c_expression (string)
     char *string;
{
  lexptr = string;
  
  if (lexptr == 0 || *lexptr == 0) {
    error ("empty #if expression");
    return 0;			/* don't include the #if group */
  }

  /* if there is some sort of scanning error, just return 0 and assume
     the parsing routine has printed an error message somewhere.
     there is surely a better thing to do than this.     */
  if (setjmp (parse_return_error))
    return 0;

  if (yyparse ())
    return 0;			/* actually this is never reached
				   the way things stand. */
  if (*lexptr)
    error ("Junk after end of expression.");

  return expression_value;	/* set by yyparse () */
}
\f
#ifdef TEST_EXP_READER
/* main program, for testing purposes. */
main ()
{
  int n, c;
  char buf[1024];
  extern int yydebug;
/*
  yydebug = 1;
*/
  initialize_random_junk ();

  for (;;) {
    printf ("enter expression: ");
    n = 0;
    while ((buf[n] = getchar ()) != '\n' && buf[n] != EOF)
      n++;
    if (buf[n] == EOF)
      break;
    buf[n] = '\0';
    printf ("parser returned %d\n", parse_c_expression (buf));
  }
}

/* table to tell if char can be part of a C identifier. */
unsigned char is_idchar[256];
/* table to tell if char can be first char of a c identifier. */
unsigned char is_idstart[256];
/* table to tell if c is horizontal space.  isspace () thinks that
   newline is space; this is not a good idea for this program. */
char is_hor_space[256];

/*
 * initialize random junk in the hash table and maybe other places
 */
initialize_random_junk ()
{
  register int i;

  /*
   * Set up is_idchar and is_idstart tables.  These should be
   * faster than saying (is_alpha (c) || c == '_'), etc.
   * Must do set up these things before calling any routines tthat
   * refer to them.
   */
  for (i = 'a'; i <= 'z'; i++) {
    ++is_idchar[i - 'a' + 'A'];
    ++is_idchar[i];
    ++is_idstart[i - 'a' + 'A'];
    ++is_idstart[i];
  }
  for (i = '0'; i <= '9'; i++)
    ++is_idchar[i];
  ++is_idchar['_'];
  ++is_idstart['_'];
#if DOLLARS_IN_IDENTIFIERS
  ++is_idchar['$'];
  ++is_idstart['$'];
#endif

  /* horizontal space table */
  ++is_hor_space[' '];
  ++is_hor_space['\t'];
}

error (msg)
{
  printf ("error: %s\n", msg);
}

warning (msg)
{
  printf ("warning: %s\n", msg);
}

struct hashnode *
lookup (name, len, hash)
     char *name;
     int len;
     int hash;
{
  return (DEFAULT_SIGNED_CHAR) ? 0 : ((struct hashnode *) -1);
}
#endif
Commit	Line	Data
075181d6 WJ	1	/* Parse C expressions for CCCP.
	2	Copyright (C) 1987 Free Software Foundation.
	3
	4	This program is free software; you can redistribute it and/or modify it
	5	under the terms of the GNU General Public License as published by the
	6	Free Software Foundation; either version 1, or (at your option) any
	7	later version.
	8
	9	This program is distributed in the hope that it will be useful,
	10	but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	GNU General Public License for more details.
	13
	14	You should have received a copy of the GNU General Public License
	15	along with this program; if not, write to the Free Software
	16	Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
	17
	18	In other words, you are welcome to use, share and improve this program.
	19	You are forbidden to forbid anyone else to use, share and improve
	20	what you give them. Help stamp out software-hoarding!
	21
	22	Adapted from expread.y of GDB by Paul Rubin, July 1986.
	23
	24	/* Parse a C expression from text in a string */
	25
	26	%{
	27	#include "config.h"
	28	#include <setjmp.h>
	29	/* #define YYDEBUG 1 */
	30
	31	int yylex ();
	32	void yyerror ();
	33	int expression_value;
	34
	35	static jmp_buf parse_return_error;
	36
	37	/* some external tables of character types */
	38	extern unsigned char is_idstart[], is_idchar[];
	39
	40	#ifndef CHAR_TYPE_SIZE
	41	#define CHAR_TYPE_SIZE BITS_PER_UNIT
	42	#endif
	43	%}
	44
	45	%union {
	46	struct constant {long value; int unsignedp;} integer;
	47	int voidval;
	48	char *sval;
	49	}
	50
	51	%type <integer> exp exp1 start
	52	%token <integer> INT CHAR
	53	%token <sval> NAME
	54	%token <integer> ERROR
	55
	56	%right '?' ':'
	57	%left ','
	58	%left OR
	59	%left AND
	60	%left '\|'
	61	%left '^'
	62	%left '&'
	63	%left EQUAL NOTEQUAL
	64	%left '<' '>' LEQ GEQ
65	%left LSH RSH
66	%left '+' '-'
67	%left '*' '/' '%'
68	%right UNARY
69
70	/* %expect 40 */
71	\f
72	%%
73
74	start : exp1
75	{ expression_value = $1.value; }
76	;
77
78	/* Expressions, including the comma operator. */
79	exp1 : exp
80	\| exp1 ',' exp
81	{ $$ = $3; }
82	;
83
84	/* Expressions, not including the comma operator. */
85	exp : '-' exp %prec UNARY
86	{ $$.value = - $2.value;
87	$$.unsignedp = $2.unsignedp; }
88	\| '!' exp %prec UNARY
89	{ $$.value = ! $2.value;
90	$$.unsignedp = 0; }
91	\| '+' exp %prec UNARY
92	{ $$ = $2; }
93	\| '~' exp %prec UNARY
94	{ $$.value = ~ $2.value;
95	$$.unsignedp = $2.unsignedp; }
96	\| '(' exp1 ')'
97	{ $$ = $2; }
98	;
99
100	/* Binary operators in order of decreasing precedence. */
101	exp : exp '*' exp
102	{ $$.unsignedp = $1.unsignedp \|\| $3.unsignedp;
103	if ($$.unsignedp)
104	$$.value = (unsigned) $1.value * $3.value;
105	else
106	$$.value = $1.value * $3.value; }
107	\| exp '/' exp
108	{ if ($3.value == 0)
109	{
110	error ("division by zero in #if");
111	$3.value = 1;
112	}
113	$$.unsignedp = $1.unsignedp \|\| $3.unsignedp;
114	if ($$.unsignedp)
115	$$.value = (unsigned) $1.value / $3.value;
116	else
117	$$.value = $1.value / $3.value; }
118	\| exp '%' exp
119	{ if ($3.value == 0)
120	{
121	error ("division by zero in #if");
122	$3.value = 1;
123	}
124	$$.unsignedp = $1.unsignedp \|\| $3.unsignedp;
125	if ($$.unsignedp)
126	$$.value = (unsigned) $1.value % $3.value;
127	else
128	$$.value = $1.value % $3.value; }
129	\| exp '+' exp
130	{ $$.value = $1.value + $3.value;
131	$$.unsignedp = $1.unsignedp \|\| $3.unsignedp; }
132	\| exp '-' exp
133	{ $$.value = $1.value - $3.value;
134	$$.unsignedp = $1.unsignedp \|\| $3.unsignedp; }
135	\| exp LSH exp
136	{ $$.unsignedp = $1.unsignedp;
137	if ($$.unsignedp)
138	$$.value = (unsigned) $1.value << $3.value;
139	else
140	$$.value = $1.value << $3.value; }
141	\| exp RSH exp
142	{ $$.unsignedp = $1.unsignedp;
143	if ($$.unsignedp)
144	$$.value = (unsigned) $1.value >> $3.value;
145	else
146	$$.value = $1.value >> $3.value; }
147	\| exp EQUAL exp
148	{ $$.value = ($1.value == $3.value);
149	$$.unsignedp = 0; }
150	\| exp NOTEQUAL exp
151	{ $$.value = ($1.value != $3.value);
152	$$.unsignedp = 0; }
153	\| exp LEQ exp
154	{ $$.unsignedp = 0;
155	if ($1.unsignedp \|\| $3.unsignedp)
156	$$.value = (unsigned) $1.value <= $3.value;
157	else
158	$$.value = $1.value <= $3.value; }
159	\| exp GEQ exp
160	{ $$.unsignedp = 0;
161	if ($1.unsignedp \|\| $3.unsignedp)
162	$$.value = (unsigned) $1.value >= $3.value;
163	else
164	$$.value = $1.value >= $3.value; }
165	\| exp '<' exp
166	{ $$.unsignedp = 0;
167	if ($1.unsignedp \|\| $3.unsignedp)
168	$$.value = (unsigned) $1.value < $3.value;
169	else
170	$$.value = $1.value < $3.value; }
171	\| exp '>' exp
172	{ $$.unsignedp = 0;
173	if ($1.unsignedp \|\| $3.unsignedp)
174	$$.value = (unsigned) $1.value > $3.value;
175	else
176	$$.value = $1.value > $3.value; }
177	\| exp '&' exp
178	{ $$.value = $1.value & $3.value;
179	$$.unsignedp = $1.unsignedp \|\| $3.unsignedp; }
180	\| exp '^' exp
181	{ $$.value = $1.value ^ $3.value;
182	$$.unsignedp = $1.unsignedp \|\| $3.unsignedp; }
183	\| exp '\|' exp
184	{ $$.value = $1.value \| $3.value;
185	$$.unsignedp = $1.unsignedp \|\| $3.unsignedp; }
186	\| exp AND exp
187	{ $$.value = ($1.value && $3.value);
188	$$.unsignedp = 0; }
189	\| exp OR exp
190	{ $$.value = ($1.value \|\| $3.value);
191	$$.unsignedp = 0; }
192	\| exp '?' exp ':' exp
193	{ $$.value = $1.value ? $3.value : $5.value;
194	$$.unsignedp = $3.unsignedp \|\| $5.unsignedp; }
195	\| INT
196	{ $$ = yylval.integer; }
197	\| CHAR
198	{ $$ = yylval.integer; }
199	\| NAME
200	{ $$.value = 0;
201	$$.unsignedp = 0; }
202	;
203	%%
204	\f
205	/* During parsing of a C expression, the pointer to the next character
206	is in this variable. */
207
208	static char *lexptr;
209
210	/* Take care of parsing a number (anything that starts with a digit).
211	Set yylval and return the token type; update lexptr.
212	LEN is the number of characters in it. */
213
214	/* maybe needs to actually deal with floating point numbers */
215
216	int
217	parse_number (olen)
218	int olen;
219	{
220	register char *p = lexptr;
221	register long n = 0;
222	register int c;
223	register int base = 10;
224	register int len = olen;
225
226	for (c = 0; c < len; c++)
227	if (p[c] == '.') {
228	/* It's a float since it contains a point. */
229	yyerror ("floating point numbers not allowed in #if expressions");
230	return ERROR;
231	}
232
233	yylval.integer.unsignedp = 0;
234
235	if (len >= 3 && (!strncmp (p, "0x", 2) \|\| !strncmp (p, "0X", 2))) {
236	p += 2;
237	base = 16;
238	len -= 2;
239	}
240	else if (*p == '0')
241	base = 8;
242
243	while (len > 0) {
244	c = *p++;
245	len--;
246	if (c >= 'A' && c <= 'Z') c += 'a' - 'A';
247
248	if (c >= '0' && c <= '9') {
249	n *= base;
250	n += c - '0';
251	} else if (base == 16 && c >= 'a' && c <= 'f') {
252	n *= base;
253	n += c - 'a' + 10;
254	} else {
255	/* `l' means long, and `u' means unsigned. */
256	while (1) {
257	if (c == 'l' \|\| c == 'L')
258	;
259	else if (c == 'u' \|\| c == 'U')
260	yylval.integer.unsignedp = 1;
261	else
262	break;
263
264	if (len == 0)
265	break;
266	c = *p++;
267	len--;
268	}
269	/* Don't look for any more digits after the suffixes. */
270	break;
271	}
272	}
273
274	if (len != 0) {
275	yyerror ("Invalid number in #if expression");
276	return ERROR;
277	}
278
279	/* If too big to be signed, consider it unsigned. */
280	if (n < 0)
281	yylval.integer.unsignedp = 1;
282
283	lexptr = p;
284	yylval.integer.value = n;
285	return INT;
286	}
287
288	struct token {
289	char *operator;
290	int token;
291	};
292
293	#ifndef NULL
294	#define NULL 0
295	#endif
296
297	static struct token tokentab2[] = {
298	{"&&", AND},
299	{"\|\|", OR},
300	{"<<", LSH},
301	{">>", RSH},
302	{"==", EQUAL},
303	{"!=", NOTEQUAL},
304	{"<=", LEQ},
305	{">=", GEQ},
306	{NULL, ERROR}
307	};
308
309	/* Read one token, getting characters through lexptr. */
310
311	int
312	yylex ()
313	{
314	register int c;
315	register int namelen;
316	register char *tokstart;
317	register struct token *toktab;
318
319	retry:
320
321	tokstart = lexptr;
322	c = *tokstart;
323	/* See if it is a special token of length 2. */
324	for (toktab = tokentab2; toktab->operator != NULL; toktab++)
325	if (c == *toktab->operator && tokstart[1] == toktab->operator[1]) {
326	lexptr += 2;
327	return toktab->token;
328	}
329
330	switch (c) {
331	case 0:
332	return 0;
333
334	case ' ':
335	case '\t':
336	case '\r':
337	case '\n':
338	lexptr++;
339	goto retry;
340
341	case '\'':
342	lexptr++;
343	c = *lexptr++;
344	if (c == '\\')
345	c = parse_escape (&lexptr);
346
347	/* Sign-extend the constant if chars are signed on target machine. */
348	{
349	if (lookup ("__CHAR_UNSIGNED__", sizeof ("__CHAR_UNSIGNED__")-1, -1)
350	\|\| ((c >> (CHAR_TYPE_SIZE - 1)) & 1) == 0)
351	yylval.integer.value = c & ((1 << CHAR_TYPE_SIZE) - 1);
352	else
353	yylval.integer.value = c \| ~((1 << CHAR_TYPE_SIZE) - 1);
354	}
355
356	yylval.integer.unsignedp = 0;
357	c = *lexptr++;
358	if (c != '\'') {
359	yyerror ("Invalid character constant in #if");
360	return ERROR;
361	}
362
363	return CHAR;
364
365	/* some of these chars are invalid in constant expressions;
366	maybe do something about them later */
367	case '/':
368	case '+':
369	case '-':
370	case '*':
371	case '%':
372	case '\|':
373	case '&':
374	case '^':
375	case '~':
376	case '!':
377	case '@':
378	case '<':
379	case '>':
380	case '(':
381	case ')':
382	case '[':
383	case ']':
384	case '.':
385	case '?':
386	case ':':
387	case '=':
388	case '{':
389	case '}':
390	case ',':
391	lexptr++;
392	return c;
393
394	case '"':
395	yyerror ("double quoted strings not allowed in #if expressions");
396	return ERROR;
397	}
398	if (c >= '0' && c <= '9') {
399	/* It's a number */
400	for (namelen = 0;
401	c = tokstart[namelen], is_idchar[c] \|\| c == '.';
402	namelen++)
403	;
404	return parse_number (namelen);
405	}
406
407	if (!is_idstart[c]) {
408	yyerror ("Invalid token in expression");
409	return ERROR;
410	}
411
412	/* It is a name. See how long it is. */
413
414	for (namelen = 0; is_idchar[tokstart[namelen]]; namelen++)
415	;
416
417	lexptr += namelen;
418	return NAME;
419	}
420
421
422	/* Parse a C escape sequence. STRING_PTR points to a variable
423	containing a pointer to the string to parse. That pointer
424	is updated past the characters we use. The value of the
425	escape sequence is returned.
426
427	A negative value means the sequence \ newline was seen,
428	which is supposed to be equivalent to nothing at all.
429
430	If \ is followed by a null character, we return a negative
431	value and leave the string pointer pointing at the null character.
432
433	If \ is followed by 000, we return 0 and leave the string pointer
434	after the zeros. A value of 0 does not mean end of string. */
435
436	int
437	parse_escape (string_ptr)
438	char **string_ptr;
439	{
440	register int c = (string_ptr)++;
441	switch (c)
442	{
443	case 'a':
444	return TARGET_BELL;
445	case 'b':
446	return TARGET_BS;
447	case 'e':
448	return 033;
449	case 'f':
450	return TARGET_FF;
451	case 'n':
452	return TARGET_NEWLINE;
453	case 'r':
454	return TARGET_CR;
455	case 't':
456	return TARGET_TAB;
457	case 'v':
458	return TARGET_VT;
459	case '\n':
460	return -2;
461	case 0:
462	(*string_ptr)--;
463	return 0;
464	case '^':
465	c = (string_ptr)++;
466	if (c == '\\')
467	c = parse_escape (string_ptr);
468	if (c == '?')
469	return 0177;
470	return (c & 0200) \| (c & 037);
471
472	case '0':
473	case '1':
474	case '2':
475	case '3':
476	case '4':
477	case '5':
478	case '6':
479	case '7':
480	{
481	register int i = c - '0';
482	register int count = 0;
483	while (++count < 3)
484	{
485	c = (string_ptr)++;
486	if (c >= '0' && c <= '7')
487	i = (i << 3) + c - '0';
488	else
489	{
490	(*string_ptr)--;
491	break;
492	}
493	}
494	if ((i & ~((1 << CHAR_TYPE_SIZE) - 1)) != 0)
495	{
496	i &= (1 << CHAR_TYPE_SIZE) - 1;
497	warning ("octal character constant does not fit in a byte");
498	}
499	return i;
500	}
501	case 'x':
502	{
503	register int i = 0;
504	register int count = 0;
505	for (;;)
506	{
507	c = (string_ptr)++;
508	if (c >= '0' && c <= '9')
509	i = (i << 4) + c - '0';
510	else if (c >= 'a' && c <= 'f')
511	i = (i << 4) + c - 'a' + 10;
512	else if (c >= 'A' && c <= 'F')
513	i = (i << 4) + c - 'A' + 10;
514	else
515	{
516	(*string_ptr)--;
517	break;
518	}
519	}
520	if ((i & ~((1 << BITS_PER_UNIT) - 1)) != 0)
521	{
522	i &= (1 << BITS_PER_UNIT) - 1;
523	warning ("hex character constant does not fit in a byte");
524	}
525	return i;
526	}
527	default:
528	return c;
529	}
530	}
531
532	void
533	yyerror (s)
534	char *s;
535	{
536	error (s);
537	longjmp (parse_return_error, 1);
538	}
539	\f
540	/* This page contains the entry point to this file. */
541
542	/* Parse STRING as an expression, and complain if this fails
543	to use up all of the contents of STRING. */
544	/* We do not support C comments. They should be removed before
545	this function is called. */
546
547	int
548	parse_c_expression (string)
549	char *string;
550	{
551	lexptr = string;
552
553	if (lexptr == 0 \|\| *lexptr == 0) {
554	error ("empty #if expression");
555	return 0; /* don't include the #if group */
556	}
557
558	/* if there is some sort of scanning error, just return 0 and assume
559	the parsing routine has printed an error message somewhere.
560	there is surely a better thing to do than this. */
561	if (setjmp (parse_return_error))
562	return 0;
563
564	if (yyparse ())
565	return 0; /* actually this is never reached
566	the way things stand. */
567	if (*lexptr)
568	error ("Junk after end of expression.");
569
570	return expression_value; /* set by yyparse () */
571	}
572	\f
573	#ifdef TEST_EXP_READER
574	/* main program, for testing purposes. */
575	main ()
576	{
577	int n, c;
578	char buf[1024];
579	extern int yydebug;
580	/*
581	yydebug = 1;
582	*/
583	initialize_random_junk ();
584
585	for (;;) {
586	printf ("enter expression: ");
587	n = 0;
588	while ((buf[n] = getchar ()) != '\n' && buf[n] != EOF)
589	n++;
590	if (buf[n] == EOF)
591	break;
592	buf[n] = '\0';
593	printf ("parser returned %d\n", parse_c_expression (buf));
594	}
595	}
596
597	/* table to tell if char can be part of a C identifier. */
598	unsigned char is_idchar[256];
599	/* table to tell if char can be first char of a c identifier. */
600	unsigned char is_idstart[256];
601	/* table to tell if c is horizontal space. isspace () thinks that
602	newline is space; this is not a good idea for this program. */
603	char is_hor_space[256];
604
605	/*
606	* initialize random junk in the hash table and maybe other places
607	*/
608	initialize_random_junk ()
609	{
610	register int i;
611
612	/*
613	* Set up is_idchar and is_idstart tables. These should be
614	* faster than saying (is_alpha (c) \|\| c == '_'), etc.
615	* Must do set up these things before calling any routines tthat
616	* refer to them.
617	*/
618	for (i = 'a'; i <= 'z'; i++) {
619	++is_idchar[i - 'a' + 'A'];
620	++is_idchar[i];
621	++is_idstart[i - 'a' + 'A'];
622	++is_idstart[i];
623	}
624	for (i = '0'; i <= '9'; i++)
625	++is_idchar[i];
626	++is_idchar['_'];
627	++is_idstart['_'];
628	#if DOLLARS_IN_IDENTIFIERS
629	++is_idchar['$'];
630	++is_idstart['$'];
631	#endif
632
633	/* horizontal space table */
634	++is_hor_space[' '];
635	++is_hor_space['\t'];
636	}
637
638	error (msg)
639	{
640	printf ("error: %s\n", msg);
641	}
642
643	warning (msg)
644	{
645	printf ("warning: %s\n", msg);
646	}
647
648	struct hashnode *
649	lookup (name, len, hash)
650	char *name;
651	int len;
652	int hash;
653	{
654	return (DEFAULT_SIGNED_CHAR) ? 0 : ((struct hashnode *) -1);
655	}
656	#endif