vec_h.c

[Game.Programming].Academic - Graphics Gems (6 books source code)

char *getsuffix(s)
char *s;
{
    static char buf[100];
    int i;
    for (i = 0; !strchr(" ,)", s[i]); ++i)
	buf[i] = s[i];
    buf[i] = 0;
    return buf;
}

/*
 * Print the string s with the following substitutions:
 * 	%d turns into d
 *	%i turns into i
 *	%- turns into "-" if i is odd, " " otherwise
 *	%-- turns into "-" if i is even, " " otherwise
 *	%_ turns into "_" if i is odd, " " otherwise
 *	%-%- turns into "-" if d+i is even, " " otherwise (sorry this is stupid)
 *	%i+1 turns into (i+1)%d etc.
 *	%d-1 turns into d-1 etc.
 *	%% turns into %
 *	blah%0..d-1bleh turns into blah0bleh,blah1bleh,...,blahd-1bleh
 *	blah%~ibleh  is same as blah%0..d-1bleh but excluding i
 *	%XV turns into VXVX...XV with d-1 V's (or XV if d==2)
 *	%VXV turns into VXVX...XV with d V's 
 */
void printformatted_to(s, tochar, d, i)
char *s;
int tochar, d, i;
{
    char *prefix, *suffix;
    int num, j, lastj;

    for (; *s != tochar; s++) {
	if (*s == '%') {
	    ++s;

	    prefix = NULL;
	    if (isdigit(*s) && !strncmp(s+1, "..d-1", 5)) {
		prefix = getprefix(s-2);	/* one char before the % */
		suffix = getsuffix(s+6);
	    } else if (!strncmp(s, "~i", 2)) {
		prefix = getprefix(s-2);	/* one char before the % */
		suffix = getsuffix(s+2);
	    }
	    if (prefix) {
		lastj = d-1 - (*s == '~');
		for (j = atoi(s); j <= lastj; ++j) {
		    printf("%d", j + (*s == '~' && j >= i));
		    printf("%s", suffix);
		    if (j < lastj)
			printf(",%s", prefix);
		}
		s += (*s == '~' ? 2 : 6) + strlen(suffix) - 1;
	    } else {
		switch(*s) {
		    case '-': case '_':
			if (!strncmp(s, "-%-", 3)) {
			    printf("%c", (i+d)%2==0 ? *s : ' ');
			    s += 2;
			} else if (!strncmp(s, "--", 2)) {
			    printf("%c", i%2==0 ? *s : ' ');
			    s++;
			} else {
			    printf("%c", i%2==1 ? *s : ' ');
			}
			break;
		    case 'i': case 'd':
			num = (*s == 'i' ? i : d);
			if (strchr("+-", s[1])) {
			    num += (s[1] == '-' ? -1 : 1) * atoi(s+2);
			    if (*s == 'i')
				num = (num+d) % d;
			    s += 2;
			    /* s is now pointing to the first digit */
			    while (isdigit(s[1]))
				s++;
			    /* s is now pointing to the last digit */
			}
			printf("%d", num);
			break;
		    case 'X': case 'V':
			if (*s == 'X' && d == 2)
			    printf("X");
			for (j = 0; j < d-2; ++j)
			    printf("VX");
			if (*s == 'V')
			    printf("V");
			break;
		    case '%':
			    printf("%%");
			break;
		    default:
			assert(0);
		}
	    }
	} else
	    putchar(*s);
    }
}

void printformatted(s, d, i)
char *s;
int d, i;
{
    printformatted_to(s, '\0', d, i);
}

void define(d, name_and_args, all_but_last, sep, last)
int d;
char *name_and_args, *all_but_last, *sep, *last;
{
    int i;

    printf("#define ");
    printformatted(name_and_args, d, 0);
    printf("\t\\\n\t\t");
    printf("(");

	if (sep)
	    for (i = 0; i < d-1; ++i) {		/* loop for all but last */
		printformatted(all_but_last, d, i);
		printformatted(sep, d, i);
		printf(" \\\n\t\t ");
	    }
	printformatted(last, d, i);

    printf(")\n");
}

int is_substring(a,b)
char *a, *b;
{
    for (; *b; b++)
	if (strncmp(a, b, strlen(a)) == 0)
	    return 1;
    return 0;
}


/*
 * Hack utility routines...
 */
void print_name_and_args_with_stuff_inserted(name_and_arg, suff, arg0, d)
char *name_and_arg, *suff, *arg0;
int d;
{
    printformatted_to(name_and_arg, '(', d, 0);
    printformatted(suff, d, 0);
    printf("(");
    if (arg0) {
	printformatted(arg0, d, 0);
	printf(",");
    }
    printformatted(strchr(name_and_arg, '(' /*)*/ ) + 1, d, 0);
}

void print_name_and_args_with_first_arg_changed(name_and_arg, arg0, d)
char *name_and_arg, *arg0;
int d;
{
    printformatted_to(name_and_arg, '(', d, 0);
    printf("(");
    printformatted(arg0, d, 0);
    printformatted(strchr(name_and_arg, ','), d, 0);
}

void print_first_arg(name_and_arg, d)
char *name_and_arg;
int d;
{
    printformatted_to(strchr(name_and_arg, '(' /*)*/ ) + 1, ',', d, 0);
}


#define MINDIM 2

main(argc, argv)
char **argv;
{
    int i, d, maxdim;

    if (argc != 2 || ! (maxdim = atoi(argv[argc-1])))
	fprintf(stderr, "Usage: %s [<maxdim>]\n", argv[0]), exit(1);


    printf("/*\n");
    for (i  = 0; intro[i]; ++i) {
	printf(" *");
	printformatted(intro[i], maxdim, 0);
	printf("\n");
    }
    printf(" */\n\n");

    printf("#ifndef VEC_H\n");
    printf("#define VEC_H %d\n", maxdim);
    printf("#include <math.h>	/* for definition of floor() */\n");

    for (d = MINDIM; d <= maxdim; ++d)
	for (i = 0; i < numberof(defs); ++i) {
	    if (is_substring("%d-1", defs[i].name_and_args) && d-1 < MINDIM
	     || is_substring("%d+1", defs[i].name_and_args) && d+1 > maxdim)
		continue;
	    if (!is_substring("%d", defs[i].name_and_args) && d != MINDIM)
		continue;	/* don't redefine if it's the same */
	    define(d, defs[i].name_and_args,
		      defs[i].all_but_last,
		      defs[i].sep,
		      defs[i].last ? defs[i].last : defs[i].all_but_last);
	}
    for (d = MINDIM; d <= maxdim; ++d)
	for (i = 0; i < numberof(defs); ++i) {
	    if (is_substring("%d-1", defs[i].name_and_args) && d-1 < MINDIM
	     || is_substring("%d+1", defs[i].name_and_args) && d+1 > maxdim)
		continue;
	    if (!is_substring("%d", defs[i].name_and_args) && d != MINDIM)
		continue;	/* don't redefine if it's the same */
	    if (defs[i].safety > 0) {
		int t;
		printf("#define ");
		print_name_and_args_with_stuff_inserted(defs[i].name_and_args,
							    "safe", "type", d);
		printf(" \\\n\t\t");
		printformatted("do {type _vec_h_temp_[%d]", d, 0);
		if (defs[i].safety > 1)
		    printformatted("[%d]", d, 0);
		printf("; \\\n\t\t    ");

		print_name_and_args_with_first_arg_changed(
			defs[i].name_and_args, "_vec_h_temp_", d);
		printf("; \\\n\t\t    ");

		if (defs[i].safety > 1)
		    printformatted("SETMAT%d(", d, 0);
		else
		    printformatted("SET%d(", d, 0);
		print_first_arg(defs[i].name_and_args, d);
		printf(", _vec_h_temp_); \\\n\t\t} while (0)\n");

		for (t = 0; t < numberof(types); ++t) {
		    printf("#define ");
		    print_name_and_args_with_stuff_inserted(
			defs[i].name_and_args, types[t].abbr, (char *)NULL, d);
		    printf(" ");
		    print_name_and_args_with_stuff_inserted(
			defs[i].name_and_args, "safe", types[t].full, d);
		    printf("\n");
		}
	    }
	}

    printf("#endif /* VEC_H */\n");

    return 0;
}