reader.c

含有BACKTARACKING的編譯軟體

#include "defs.h"

/*  The line size must be a positive integer.  One hundred was chosen	*/
/*  because few lines in Yacc input grammars exceed 100 characters.	*/
/*  Note that if a line exceeds LINESIZE characters, the line buffer	*/
/*  will be expanded to accomodate it.					*/

#define LINESIZE 100

char *cache;
int cinc, cache_size;

int ntags, tagmax;
char **tag_table;

char saw_eof, unionized;
char *cptr, *line;
int linesize;

bucket *goal;
int prec;
int gensym;
char last_was_action;

int maxitems;
bucket **pitem;

int maxrules;
bucket **plhs;

int name_pool_size;
char *name_pool;

char line_format[] = "#line %d \"%s\"\n";


void cachec(int c)
{
    assert(cinc >= 0);
    if (cinc >= cache_size)
    {
	cache_size += 256;
	cache = REALLOC(cache, cache_size);
	if (cache == 0) no_space();
    }
    cache[cinc] = c;
    ++cinc;
}


void get_line(void)
{
    register FILE *f = input_file;
    register int c;
    register int i;

    if (saw_eof || (c = getc(f)) == EOF)
    {
	if (line) { FREE(line); line = 0; }
	cptr = 0;
	saw_eof = 1;
	return;
    }

    if (line == 0 || linesize != (LINESIZE + 1))
    {
	if (line) FREE(line);
	linesize = LINESIZE + 1;
	line = MALLOC(linesize);
	if (line == 0) no_space();
    }

    i = 0;
    ++lineno;
    for (;;)
    {
	line[i]  =  c;
	if (c == '\n') { cptr = line; return; }
	if (++i >= linesize)
	{
	    linesize += LINESIZE;
	    line = REALLOC(line, linesize);
	    if (line ==  0) no_space();
	}
	c = getc(f);
	if (c ==  EOF)
	{
	    line[i] = '\n';
	    saw_eof = 1;
	    cptr = line;
	    return;
	}
    }
}


char *
dup_line(void)
{
    register char *p, *s, *t;

    if (line == 0) return (0);
    s = line;
    while (*s != '\n') ++s;
    p = MALLOC(s - line + 1);
    if (p == 0) no_space();

    s = line;
    t = p;
    while ((*t++ = *s++) != '\n') continue;
    return (p);
}


void skip_comment(void)
{
    register char *s;

    int st_lineno = lineno;
    char *st_line = dup_line();
    char *st_cptr = st_line + (cptr - line);

    s = cptr + 2;
    for (;;)
    {
	if (*s == '*' && s[1] == '/')
	{
	    cptr = s + 2;
	    FREE(st_line);
	    return;
	}
	if (*s == '\n')
	{
	    get_line();
	    if (line == 0)
		unterminated_comment(st_lineno, st_line, st_cptr);
	    s = cptr;
	}
	else
	    ++s;
    }
}


int
nextc(void)
{
    register char *s;

    if (line == 0)
    {
	get_line();
	if (line == 0)
	    return (EOF);
    }

    s = cptr;
    for (;;)
    {
	switch (*s)
	{
	case '\n':
	    get_line();
	    if (line == 0) return (EOF);
	    s = cptr;
	    break;

	case ' ':
	case '\t':
	case '\f':
	case '\r':
	case '\v':
	case ',':
	case ';':
	    ++s;
	    break;

	case '\\':
	    cptr = s;
	    return ('%');

	case '/':
	    if (s[1] == '*')
	    {
		cptr = s;
		skip_comment();
		s = cptr;
		break;
	    }
	    else if (s[1] == '/')
	    {
		get_line();
		if (line == 0) return (EOF);
		s = cptr;
		break;
	    }
	    /* fall through */

	default:
	    cptr = s;
	    return (*s);
	}
    }
}


int
keyword(void)
{
    register int c;
    char *t_cptr = cptr;

    c = *++cptr;
    if (isalpha(c))
    {
	cinc = 0;
	for (;;)
	{
	    if (isalpha(c))
	    {
		if (isupper(c)) c = tolower(c);
		cachec(c);
	    }
	    else if (isdigit(c) || c == '_' || c == '.' || c == '$')
		cachec(c);
	    else
		break;
	    c = *++cptr;
	}
	cachec(NUL);

	if (strcmp(cache, "token") == 0 || strcmp(cache, "term") == 0)
	    return (TOKEN);
	if (strcmp(cache, "type") == 0)
	    return (TYPE);
	if (strcmp(cache, "left") == 0)
	    return (LEFT);
	if (strcmp(cache, "right") == 0)
	    return (RIGHT);
	if (strcmp(cache, "nonassoc") == 0 || strcmp(cache, "binary") == 0)
	    return (NONASSOC);
	if (strcmp(cache, "start") == 0)
	    return (START);
	if (strcmp(cache, "union") == 0)
	    return (UNION);
	if (strcmp(cache, "ident") == 0)
	    return (IDENT);
    }
    else
    {
	++cptr;
	if (c == '{')
	    return (TEXT);
	if (c == '%' || c == '\\')
	    return (MARK);
	if (c == '<')
	    return (LEFT);
	if (c == '>')
	    return (RIGHT);
	if (c == '0')
	    return (TOKEN);
	if (c == '2')
	    return (NONASSOC);
    }
    syntax_error(lineno, line, t_cptr);
    /*NOTREACHED*/
}


void copy_ident(void)
{
    register int c;
    register FILE *f = output_file;

    c = nextc();
    if (c == EOF) unexpected_EOF();
    if (c != '"') syntax_error(lineno, line, cptr);
    ++outline;
    fprintf(f, "#ident \"");
    for (;;)
    {
	c = *++cptr;
	if (c == '\n')
	{
	    fprintf(f, "\"\n");
	    return;
	}
	putc(c, f);
	if (c == '"')
	{
	    putc('\n', f);
	    ++cptr;
	    return;
	}
    }
}


void copy_text(void)
{
    register int c;
    int quote;
    register FILE *f = text_file;
    int need_newline = 0;
    int t_lineno = lineno;
    char *t_line = dup_line();
    char *t_cptr = t_line + (cptr - line - 2);

    if (*cptr == '\n')
    {
	get_line();
	if (line == 0)
	    unterminated_text(t_lineno, t_line, t_cptr);
    }
    if (!lflag) fprintf(f, line_format, lineno, input_file_name);

loop:
    c = *cptr++;
    switch (c)
    {
    case '\n':
    next_line:
	putc('\n', f);
	need_newline = 0;
	get_line();
	if (line) goto loop;
	unterminated_text(t_lineno, t_line, t_cptr);

    case '\'':
    case '"':
	{
	    int s_lineno = lineno;
	    char *s_line = dup_line();
	    char *s_cptr = s_line + (cptr - line - 1);

	    quote = c;
	    putc(c, f);
	    for (;;)
	    {
		c = *cptr++;
		putc(c, f);
		if (c == quote)
		{
		    need_newline = 1;
		    FREE(s_line);
		    goto loop;
		}
		if (c == '\n')
		    unterminated_string(s_lineno, s_line, s_cptr);
		if (c == '\\')
		{
		    c = *cptr++;
		    putc(c, f);
		    if (c == '\n')
		    {
			get_line();
			if (line == 0)
			    unterminated_string(s_lineno, s_line, s_cptr);
		    }
		}
	    }
	}

    case '/':
	putc(c, f);
	need_newline = 1;
	c = *cptr;
	if (c == '/')
	{
	    putc('*', f);
	    while ((c = *++cptr) != '\n')
	    {
		if (c == '*' && cptr[1] == '/')
		    fprintf(f, "* ");
		else
		    putc(c, f);
	    }
	    fprintf(f, "*/");
	    goto next_line;
	}
	if (c == '*')
	{
	    int c_lineno = lineno;
	    char *c_line = dup_line();
	    char *c_cptr = c_line + (cptr - line - 1);

	    putc('*', f);
	    ++cptr;
	    for (;;)
	    {
		c = *cptr++;
		putc(c, f);
		if (c == '*' && *cptr == '/')
		{
		    putc('/', f);
		    ++cptr;
		    FREE(c_line);
		    goto loop;
		}
		if (c == '\n')
		{
		    get_line();
		    if (line == 0)
			unterminated_comment(c_lineno, c_line, c_cptr);
		}
	    }
	}
	need_newline = 1;
	goto loop;

    case '%':
    case '\\':
	if (*cptr == '}')
	{
	    if (need_newline) putc('\n', f);
	    ++cptr;
	    FREE(t_line);
	    return;
	}
	/* fall through */

    default:
	putc(c, f);
	need_newline = 1;
	goto loop;
    }
}


void copy_union(void)
{
    register int c;
    int quote;
    int depth;
    int u_lineno = lineno;
    char *u_line = dup_line();
    char *u_cptr = u_line + (cptr - line - 6);

    if (unionized) over_unionized(cptr - 6);
    unionized = 1;

    if (!lflag)
	fprintf(text_file, line_format, lineno, input_file_name);

    fprintf(text_file, "typedef union");
    if (dflag) fprintf(union_file, "typedef union");

    depth = 0;
loop:
    c = *cptr++;
    putc(c, text_file);
    if (dflag) putc(c, union_file);
    switch (c)
    {
    case '\n':
    next_line:
	get_line();
	if (line == 0) unterminated_union(u_lineno, u_line, u_cptr);
	goto loop;

    case '{':
	++depth;
	goto loop;

    case '}':
	if (--depth == 0)
	{
	    fprintf(text_file, " YYSTYPE;\n");
	    FREE(u_line);
	    return;
	}
	goto loop;

    case '\'':
    case '"':
	{
	    int s_lineno = lineno;
	    char *s_line = dup_line();
	    char *s_cptr = s_line + (cptr - line - 1);

	    quote = c;
	    for (;;)
	    {
		c = *cptr++;
		putc(c, text_file);
		if (dflag) putc(c, union_file);
		if (c == quote)
		{
		    FREE(s_line);
		    goto loop;
		}
		if (c == '\n')
		    unterminated_string(s_lineno, s_line, s_cptr);
		if (c == '\\')
		{
		    c = *cptr++;
		    putc(c, text_file);
		    if (dflag) putc(c, union_file);
		    if (c == '\n')
		    {
			get_line();
			if (line == 0)
			    unterminated_string(s_lineno, s_line, s_cptr);
		    }
		}
	    }
	}

    case '/':
	c = *cptr;
	if (c == '/')
	{
	    putc('*', text_file);
	    if (dflag) putc('*', union_file);
	    while ((c = *++cptr) != '\n')
	    {
		if (c == '*' && cptr[1] == '/')
		{
		    fprintf(text_file, "* ");
		    if (dflag) fprintf(union_file, "* ");
		}
		else
		{
		    putc(c, text_file);
		    if (dflag) putc(c, union_file);
		}
	    }
	    fprintf(text_file, "*/\n");
	    if (dflag) fprintf(union_file, "*/\n");
	    goto next_line;
	}
	if (c == '*')
	{
	    int c_lineno = lineno;
	    char *c_line = dup_line();
	    char *c_cptr = c_line + (cptr - line - 1);

	    putc('*', text_file);
	    if (dflag) putc('*', union_file);
	    ++cptr;
	    for (;;)
	    {
		c = *cptr++;
		putc(c, text_file);
		if (dflag) putc(c, union_file);
		if (c == '*' && *cptr == '/')
		{
		    putc('/', text_file);
		    if (dflag) putc('/', union_file);
		    ++cptr;
		    FREE(c_line);
		    goto loop;
		}
		if (c == '\n')
		{
		    get_line();
		    if (line == 0)
			unterminated_comment(c_lineno, c_line, c_cptr);
		}
	    }
	}
	goto loop;

    default:
	goto loop;
    }
}


int
hexval(int c)
{
    if (c >= '0' && c <= '9')
	return (c - '0');
    if (c >= 'A' && c <= 'F')
	return (c - 'A' + 10);
    if (c >= 'a' && c <= 'f')
	return (c - 'a' + 10);
    return (-1);
}


bucket *
get_literal(void)
{
    register int c, quote;
    register int i;
    register int n;
    register char *s;