asterisk/ast_expr2.fl

%{
/*! \file
 *
 * \brief Dialplan Expression Parser
 */

#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <locale.h>
#include <ctype.h>
#if !defined(SOLARIS) && !defined(__CYGWIN__)
#include <err.h>
#else
#define quad_t int64_t
#endif
#include <errno.h>
#include <regex.h>
#include <limits.h>
#include <asterisk/ast_expr.h>
#include <asterisk/logger.h>
#include <asterisk/strings.h>

enum valtype {
	AST_EXPR_integer, AST_EXPR_numeric_string, AST_EXPR_string
} ;

struct val {
	enum valtype type;
	union {
		char *s;
		quad_t i;
	} u;
} ;

#include "ast_expr2.h" /* the o/p of the bison on ast_expr2.y */

#define SET_COLUMNS yylloc_param->first_column = (int)(yyg->yytext_r - YY_CURRENT_BUFFER_LVALUE->yy_ch_buf);yylloc_param->last_column = yylloc_param->last_column + yyleng - 1; yylloc_param->first_line = yylloc_param->last_line = 1
#define SET_STRING yylval_param->val = (struct val *)calloc(sizeof(struct val),1); yylval_param->val->type = AST_EXPR_string; yylval_param->val->u.s = strdup(yytext);
#define SET_NUMERIC_STRING yylval_param->val = (struct val *)calloc(sizeof(struct val),1); yylval_param->val->type = AST_EXPR_numeric_string; yylval_param->val->u.s = strdup(yytext);

struct parse_io
{
	char *string;
	struct val *val;
	yyscan_t scanner;
};
 
void ast_yyset_column(int column_no, yyscan_t yyscanner);
int ast_yyget_column(yyscan_t yyscanner);
static int curlycount = 0;
%}

%option prefix="ast_yy"
%option batch
%option outfile="ast_expr2f.c"
%option reentrant
%option bison-bridge
%option bison-locations
%option noyywrap
%x var trail

%%

\|	{ SET_COLUMNS; SET_STRING; return TOK_OR;}
\&	{ SET_COLUMNS; SET_STRING; return TOK_AND;}
\=	{ SET_COLUMNS; SET_STRING; return TOK_EQ;}
\>	{ SET_COLUMNS; SET_STRING; return TOK_GT;}
\<	{ SET_COLUMNS; SET_STRING; return TOK_LT;}
\>\=	{ SET_COLUMNS; SET_STRING; return TOK_GE;}
\<\=	{ SET_COLUMNS; SET_STRING; return TOK_LE;}
\!\=	{ SET_COLUMNS; SET_STRING; return TOK_NE;}
\+	{ SET_COLUMNS; SET_STRING; return TOK_PLUS;}
\-	{ SET_COLUMNS; SET_STRING; return TOK_MINUS;}
\*	{ SET_COLUMNS; SET_STRING; return TOK_MULT;}
\/	{ SET_COLUMNS; SET_STRING; return TOK_DIV;}
\%	{ SET_COLUMNS; SET_STRING; return TOK_MOD;}
\?	{ SET_COLUMNS; SET_STRING; return TOK_COND;}
\:	{ SET_COLUMNS; SET_STRING; return TOK_COLON;}
\:\:	{ SET_COLUMNS; SET_STRING; return TOK_COLONCOLON;}
\(	{ SET_COLUMNS; SET_STRING; return TOK_LP;}
\)	{ SET_COLUMNS; SET_STRING; return TOK_RP;}
\$\{   {/* gather the contents of ${} expressions, with trailing stuff, into a single TOKEN. They are much more complex now than they used to be */
                       curlycount = 0; BEGIN(var); yymore();}

[ 	\r]		{}
\"[^"]*\"   {SET_COLUMNS; SET_STRING; return TOKEN;}

[\n]	{/* what to do with eol */}
[0-9]+		{   SET_COLUMNS;  /* the original behavior of the expression parser was to bring in numbers as a numeric string */
				SET_NUMERIC_STRING;
				return TOKEN;}
[a-zA-Z0-9,.';\\_^%$#@!]+	{SET_COLUMNS; SET_STRING; return TOKEN;}

<var>[^{}]*\}  {curlycount--; if(curlycount < 0){ BEGIN(trail);  yymore();} else {  yymore();}}
<var>[^{}]*\{  {curlycount++; yymore();  }
<trail>[^-\t\r \n$():?%/+=*<>!|&]* {BEGIN(0); SET_COLUMNS; SET_STRING; return TOKEN;}
<trail>[-\t\r \n$():?%/+=*<>!|&]        {char c = yytext[yyleng-1]; BEGIN(0); unput(c); SET_COLUMNS; SET_STRING; return TOKEN;}
<trail>\$\{            {curlycount = 0; BEGIN(var); yymore();  }
<trail><<EOF>>		{BEGIN(0); SET_COLUMNS; SET_STRING; return TOKEN; /* actually, if an expr is only a variable ref, this could happen a LOT */}

%%

/* I'm putting the interface routine to the whole parse here in the flexer input file
   mainly because of all the flexer initialization that has to be done. Shouldn't matter
   where it is, as long as it's somewhere. I didn't want to define a prototype for the
   ast_yy_scan_string in the .y file, because then, I'd have to define YY_BUFFER_STATE there...
	UGH! that would be inappropriate. */

int ast_yyparse(void *); /* need to/should define this prototype for the call to yyparse */
int ast_yyerror(const char *, YYLTYPE *, struct parse_io *); /* likewise */

int ast_expr(char *expr, char *buf, int length)
{
	struct parse_io io;
	int return_value = 0;
	
	memset(&io, 0, sizeof(io));
	io.string = expr;  /* to pass to the error routine */
	
	ast_yylex_init(&io.scanner);
	
	ast_yy_scan_string(expr, io.scanner);
	
	ast_yyparse ((void *) &io);

	ast_yylex_destroy(io.scanner);

	if (!io.val) {
		if (length > 1) {
			strcpy(buf, "0");
			return_value = 1;
		}
	} else {
		if (io.val->type == AST_EXPR_integer) {
			int res_length;

			res_length = snprintf(buf, length, "%ld", (long int) io.val->u.i);
			return_value = (res_length <= length) ? res_length : length;
		} else {
#ifdef STANDALONE
			strncpy(buf, io.val->u.s, length - 1);
#else /* !STANDALONE */
			ast_copy_string(buf, io.val->u.s, length);
#endif /* STANDALONE */
			return_value = strlen(buf);
			free(io.val->u.s);
		}
		free(io.val);
	}
	return return_value;
}

int ast_yyerror (const char *s,  yyltype *loc, struct parse_io *parseio )
{	
	struct yyguts_t * yyg = (struct yyguts_t*)(parseio->scanner);
	char spacebuf[8000]; /* best safe than sorry */
	char spacebuf2[8000]; /* best safe than sorry */
	int i=0;
	spacebuf[0] = 0;
	
	for(i=0;i< (int)(yytext - YY_CURRENT_BUFFER_LVALUE->yy_ch_buf);i++) spacebuf2[i] = ' ';  /* uh... assuming yyg is defined, then I can use the yycolumn macro,
													which is the same thing as... get this:
													yyg->yy_buffer_stack[yyg->yy_buffer_stack_top]->yy_bs_column
													I was tempted to just use yy_buf_pos in the STATE, but..., well:
														a. the yy_buf_pos is the current position in the buffer, which
															may not relate to the entire string/buffer because of the
															buffering.
														b. but, analysis of the situation is that when you use the
															yy_scan_string func, it creates a single buffer the size of
															string, so the two would be the same... 
													so, in the end, the yycolumn macro is available, shorter, therefore easier. */
	spacebuf2[i++]='^';
	spacebuf2[i]= 0;

#ifdef STANDALONE3
	/* easier to read in the standalone version */
	printf("ast_yyerror(): syntax error: %s; Input:\n%s\n%s\n",  
			s, parseio->string,spacebuf2);
#else
	ast_log(LOG_WARNING,"ast_yyerror(): syntax error: %s; Input:\n%s\n%s\n",  
			s, parseio->string,spacebuf2);
#endif
#ifndef STANDALONE
	ast_log(LOG_WARNING,"If you have questions, please refer to doc/README.variables in the asterisk source.\n");
#endif
	return(0);
}