2024-10-10

core/sim/sim_3_01/idf.c

@@ -0,0 +1,87 @@
+/*	This file is part of the software similarity tester SIM.
+	Written by Dick Grune, Vrije Universiteit, Amsterdam.
+	$Id: idf.c,v 2.19 2015-01-17 10:20:40 dick Exp $
+*/
+
+#include	<string.h>
+
+#include	"system.par"
+#include	"token.h"
+#include	"idf.h"
+
+Token
+idf_in_list(
+	const char *str,
+	const struct idf list[],
+	size_t listsize,
+	Token default_token
+) {
+	int first = 0;
+	int last = (int) (listsize / sizeof (struct idf)) - 1;
+
+	while (first < last) {
+		int middle = (first + last) / 2;
+
+		if (strcmp(str, list[middle].id_tag) > 0) {
+			first = middle + 1;
+		}
+		else {
+			last = middle;
+		}
+	}
+	return (strcmp(str, list[first].id_tag) == 0
+	?	list[first].id_tr
+	:	default_token
+	);
+}
+
+#define	HASH(h,ch)	(((h) * 8209) + (ch)*613)
+
+Token
+idf_hashed(const char *str) {
+	int32 h = 0;
+
+	/* let's be careful about ranges; if done wrong it's hard to debug */
+	while (*str) {
+		int ch = *str++ & 0377;
+
+		/* ignore spaces in spaced words */
+		if (ch == ' ') continue;
+
+		/* -1 <= h <= 2^31-1 */
+		h = HASH(h, ch);
+		/* -2^31 <= h <= 2^31-1 */
+		if (h < 0) {
+			/* -2^31 <= h <= -1 */
+			h += 2147483647;	/* 2^31-1 */
+			/* -1 <= h <= 2^31-2 */
+		}
+		else {
+			/* 0 <= h <= 2^31-1 */
+		}
+		/* -1 <= h <= 2^31-1 */
+	}
+	/* -1 <= h <= 2^31-1 */
+	if (h < 0) {
+		/* h = -1 */
+		h = 0;
+	}
+	/* 0 <= h <= 2^31-1 */
+	h %= (N_TOKENS - N_REGULAR_TOKENS - 1);
+	/* 0 <= h < N_TOKENS - N_REGULAR_TOKENS - 1 */
+	h += N_REGULAR_TOKENS;
+	/* N_REGULAR_TOKENS <= h < N_TOKENS - 1 */
+	return int2Token(h);
+	/* this avoids the regular tokens and End_Of_Line */
+}
+
+void
+lower_case(char *str) {
+	char *s;
+
+	for (s = str; *s; s++) {
+		if ('A' <= *s && *s <= 'Z') {
+			*s += (-'A' + 'a');
+		}
+	}
+}