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/*
* Copyright 1993-2002 Christopher Seiwald and Perforce Software, Inc.
*
* This file is part of Jam - see jam.c for Copyright information.
*/
/*
* scan.c - the jam yacc scanner
*
* 12/26/93 (seiwald) - bump buf in yylex to 10240 - yuk.
* 09/16/94 (seiwald) - check for overflows, unmatched {}'s, etc.
* Also handle tokens abutting EOF by remembering
* to return EOF now matter how many times yylex()
* reinvokes yyline().
* 02/11/95 (seiwald) - honor only punctuation keywords if SCAN_PUNCT.
* 07/27/95 (seiwald) - Include jamgram.h after scan.h, so that YYSTYPE is
* defined before Linux's yacc tries to redefine it.
* 01/10/01 (seiwald) - \ can now escape any whitespace char
* 11/04/02 (seiwald) - const-ing for string literals
*/
# include "jam.h"
# include "lists.h"
# include "parse.h"
# include "scan.h"
# include "jamgram.h"
# include "jambase.h"
# include "newstr.h"
struct keyword {
const char *word;
int type;
} keywords[] = {
# include "jamgramtab.h"
{ 0, 0 }
} ;
struct include {
struct include *next; /* next serial include file */
const char *string; /* pointer into current line */
char **strings; /* for yyfparse() -- text to parse */
FILE *file; /* for yyfparse() -- file being read */
const char *fname; /* for yyfparse() -- file name */
int line; /* line counter for error messages */
char buf[ 512 ]; /* for yyfparse() -- line buffer */
} ;
static struct include *incp = 0; /* current file; head of chain */
static int scanmode = SCAN_NORMAL;
static int anyerrors = 0;
static char *symdump( YYSTYPE *s );
# define BIGGEST_TOKEN 10240 /* no single token can be larger */
/*
* Set parser mode: normal, string, or keyword
*/
void
yymode( int n )
{
scanmode = n;
}
void
yyerror( const char *s )
{
if( incp )
printf( "%s: line %d: ", incp->fname, incp->line );
printf( "%s at %s\n", s, symdump( &yylval ) );
++anyerrors;
}
int
yyanyerrors()
{
return anyerrors != 0;
}
void
yyfparse( const char *s )
{
struct include *i = (struct include *)malloc( sizeof( *i ) );
/* Push this onto the incp chain. */
i->string = "";
i->strings = 0;
i->file = 0;
i->fname = copystr( s );
i->line = 0;
i->next = incp;
incp = i;
/* If the filename is "+", it means use the internal jambase. */
if( !strcmp( s, "+" ) )
i->strings = jambase;
}
/*
* yyline() - read new line and return first character
*
* Fabricates a continuous stream of characters across include files,
* returning EOF at the bitter end.
*/
int
yyline()
{
struct include *i = incp;
if( !incp )
return EOF;
/* Once we start reading from the input stream, we reset the */
/* include insertion point so that the next include file becomes */
/* the head of the list. */
/* If there is more data in this line, return it. */
if( *i->string )
return *i->string++;
/* If we're reading from an internal string list, go to the */
/* next string. */
if( i->strings )
{
if( !*i->strings )
goto next;
i->line++;
i->string = *(i->strings++);
return *i->string++;
}
/* If necessary, open the file */
if( !i->file )
{
FILE *f = stdin;
if( strcmp( i->fname, "-" ) && !( f = fopen( i->fname, "r" ) ) )
perror( i->fname );
i->file = f;
}
/* If there's another line in this file, start it. */
if( i->file && fgets( i->buf, sizeof( i->buf ), i->file ) )
{
i->line++;
i->string = i->buf;
return *i->string++;
}
next:
/* This include is done. */
/* Free it up and return EOF so yyparse() returns to parse_file(). */
incp = i->next;
/* Close file, free name */
if( i->file && i->file != stdin )
fclose( i->file );
freestr( i->fname );
free( (char *)i );
return EOF;
}
/*
* yylex() - set yylval to current token; return its type
*
* Macros to move things along:
*
* yychar() - return and advance character; invalid after EOF
* yyprev() - back up one character; invalid before yychar()
*
* yychar() returns a continuous stream of characters, until it hits
* the EOF of the current include file.
*/
# define yychar() ( *incp->string ? *incp->string++ : yyline() )
# define yyprev() ( incp->string-- )
int
yylex()
{
int c;
char buf[BIGGEST_TOKEN];
char *b = buf;
if( !incp )
goto eof;
/* Get first character (whitespace or of token) */
c = yychar();
if( scanmode == SCAN_STRING )
{
/* If scanning for a string (action's {}'s), look for the */
/* closing brace. We handle matching braces, if they match! */
int nest = 1;
while( c != EOF && b < buf + sizeof( buf ) )
{
if( c == '{' )
nest++;
if( c == '}' && !--nest )
break;
*b++ = c;
c = yychar();
}
/* We ate the ending brace -- regurgitate it. */
if( c != EOF )
yyprev();
/* Check obvious errors. */
if( b == buf + sizeof( buf ) )
{
yyerror( "action block too big" );
goto eof;
}
if( nest )
{
yyerror( "unmatched {} in action block" );
goto eof;
}
*b = 0;
yylval.type = STRING;
yylval.string = newstr( buf );
}
else
{
char *b = buf;
struct keyword *k;
int inquote = 0;
int notkeyword;
/* Eat white space */
for( ;; )
{
/* Skip past white space */
while( c != EOF && isspace( c ) )
c = yychar();
/* Not a comment? Swallow up comment line. */
if( c != '#' )
break;
while( ( c = yychar() ) != EOF && c != '\n' )
;
}
/* c now points to the first character of a token. */
if( c == EOF )
goto eof;
/* While scanning the word, disqualify it for (expensive) */
/* keyword lookup when we can: $anything, "anything", \anything */
notkeyword = c == '$';
/* look for white space to delimit word */
/* "'s get stripped but preserve white space */
/* \ protects next character */
while(
c != EOF &&
b < buf + sizeof( buf ) &&
( inquote || !isspace( c ) ) )
{
if( c == '"' )
{
/* begin or end " */
inquote = !inquote;
notkeyword = 1;
}
else if( c != '\\' )
{
/* normal char */
*b++ = c;
}
else if( ( c = yychar()) != EOF )
{
/* \c */
*b++ = c;
notkeyword = 1;
}
else
{
/* \EOF */
break;
}
c = yychar();
}
/* Check obvious errors. */
if( b == buf + sizeof( buf ) )
{
yyerror( "string too big" );
goto eof;
}
if( inquote )
{
yyerror( "unmatched \" in string" );
goto eof;
}
/* We looked ahead a character - back up. */
if( c != EOF )
yyprev();
/* scan token table */
/* don't scan if it's obviously not a keyword or if its */
/* an alphabetic when were looking for punctuation */
*b = 0;
yylval.type = ARG;
if( !notkeyword && !( isalpha( *buf ) && scanmode == SCAN_PUNCT ) )
{
for( k = keywords; k->word; k++ )
if( *buf == *k->word && !strcmp( k->word, buf ) )
{
yylval.type = k->type;
yylval.string = k->word; /* used by symdump */
break;
}
}
if( yylval.type == ARG )
yylval.string = newstr( buf );
}
if( DEBUG_SCAN )
printf( "scan %s\n", symdump( &yylval ) );
return yylval.type;
eof:
yylval.type = EOF;
return yylval.type;
}
static char *
symdump( YYSTYPE *s )
{
static char buf[ BIGGEST_TOKEN + 20 ];
switch( s->type )
{
case EOF:
sprintf( buf, "EOF" );
break;
case 0:
sprintf( buf, "unknown symbol %s", s->string );
break;
case ARG:
sprintf( buf, "argument %s", s->string );
break;
case STRING:
sprintf( buf, "string \"%s\"", s->string );
break;
default:
sprintf( buf, "keyword %s", s->string );
break;
}
return buf;
}
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