From e2250e5cb71c9a06bf75d59e9c0369efd65b1206 Mon Sep 17 00:00:00 2001
From: "B. Watson" <urchlay@slackware.uk>
Date: Sun, 16 Jun 2024 17:33:22 -0400
Subject: cxrefbas: added.

---
 cxrefbas.c | 198 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 198 insertions(+)
 create mode 100644 cxrefbas.c

(limited to 'cxrefbas.c')

diff --git a/cxrefbas.c b/cxrefbas.c
new file mode 100644
index 0000000..45369d4
--- /dev/null
+++ b/cxrefbas.c
@@ -0,0 +1,198 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+#include <time.h>
+
+#include "bas.h"
+#include "bcdfp.h"
+
+unsigned short *linerefs[32769];
+int refcounts[32769];
+int lines_exist[32769];
+int last_cmd;
+int last_cmd_pos;
+
+void add_lineref(unsigned short from, unsigned short to) {
+	unsigned short *p;
+	int c;
+
+	if(to > 32767) return;
+
+	p = linerefs[to];
+	c = refcounts[to];
+
+	if(c) {
+		p = realloc(p, sizeof(unsigned short) * (c + 1));
+	} else {
+		p = malloc(sizeof(unsigned short));
+	}
+
+	if(!p) die("Out of memory.");
+
+	linerefs[to] = p;
+	p[c] = from;
+	c++;
+	refcounts[to] = c;
+}
+
+/* makes sure a numeric constant isn't start of an expression. */
+int is_standalone_num(unsigned short pos) {
+	if(program[pos] != OP_NUMCONST) return 0;
+	switch(program[pos + 7]) {
+		case OP_EOS:
+		case OP_EOL:
+		case OP_COMMA:
+			return 1;
+		default:
+			return 0;
+	}
+}
+
+CALLBACK(start_stmt) {
+	lines_exist[lineno] = 1;
+}
+
+CALLBACK(got_cmd) {
+	last_cmd = tok;
+	last_cmd_pos = pos;
+}
+
+void computed_msg(unsigned char tok, unsigned short lineno) {
+	static int last_lineno = -1;
+	char *cmd;
+
+	/* avoid duplicate warnings */
+	if(lineno == last_lineno) return;
+	last_lineno = lineno;
+
+	switch(tok) {
+		case CMD_GOTO:
+			cmd = "GOTO"; break;
+		case CMD_GO_TO:
+			cmd = "GO TO"; break;
+		case CMD_GOSUB:
+			cmd = "GOSUB"; break;
+		case CMD_RESTORE:
+			cmd = "RESTORE"; break;
+		case CMD_TRAP:
+			cmd = "TRAP"; break;
+		case CMD_ON:
+			cmd = "ON"; break;
+		default: /* should never happen! */
+			cmd = "???"; break;
+	}
+
+	fprintf(stderr, "Computed %s at line %d\n", cmd, lineno);
+}
+
+CALLBACK(got_var) {
+	switch(last_cmd) {
+		case CMD_GOTO:
+		case CMD_GO_TO:
+		case CMD_GOSUB:
+		case CMD_RESTORE:
+		case CMD_TRAP:
+			computed_msg(last_cmd, lineno);
+			break;
+		default:
+			break;
+	}
+}
+
+CALLBACK(got_exp) {
+	int standalone;
+
+	if(tok != OP_NUMCONST) return;
+	standalone = is_standalone_num(pos);
+
+	switch(last_cmd) {
+		case CMD_GOTO:
+		case CMD_GO_TO:
+		case CMD_GOSUB:
+		case CMD_RESTORE:
+		case CMD_TRAP:
+			if((pos == last_cmd_pos + 1) && standalone) {
+				add_lineref(lineno, fp2int(program + pos + 1));
+			} else {
+				computed_msg(last_cmd, lineno);
+			}
+			break;
+		case CMD_ON: {
+				unsigned char last_tok = program[pos - 1];
+				switch(last_tok) {
+					case OP_GOTO:
+					case OP_GOSUB:
+					case OP_COMMA:
+						if(standalone)
+							add_lineref(lineno, fp2int(program + pos + 1));
+						else
+							computed_msg(last_cmd, lineno);
+						break;
+					default:
+						break;
+				}
+			}
+			break;
+		default:
+			break;
+	}
+}
+
+void build_ref_table(void) {
+	on_start_stmt = start_stmt;
+	on_cmd_token = got_cmd;
+	on_exp_token = got_exp;
+	on_var_token = got_var;
+	walk_all_code();
+}
+
+void print_ref_table(void) {
+	int i, j;
+	for(i = 0; i < 32768; i++) {
+		if(refcounts[i]) {
+			if(!lines_exist[i]) putchar('!');
+			printf("%d: ", i);
+			for(j = 0; j < refcounts[i]; j++) {
+				printf("%d ", linerefs[i][j]);
+			}
+			putchar('\n');
+		}
+	}
+}
+
+void print_help(void) {
+	fprintf(stderr, "Usage: %s [-v] program.bas\n", self);
+	exit(0);
+}
+
+void parse_args(int argc, char **argv) {
+	int opt;
+
+	while( (opt = getopt(argc, argv, "v")) != -1) {
+		switch(opt) {
+			case 'v': verbose = 1; break;
+			default: print_help(); exit(1);
+		}
+	}
+
+	if(optind >= argc)
+		die("No input file given (use - for stdin).");
+	else
+		open_input(argv[optind]);
+}
+
+int main(int argc, char **argv) {
+	set_self(*argv);
+	parse_general_args(argc, argv, print_help);
+	parse_args(argc, argv);
+
+	readfile();
+	parse_header();
+
+	build_ref_table();
+	print_ref_table();
+
+	return 0;
+}
-- 
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