reftable/basics: fix return type of `binsearch()` to be `size_t`

The `binsearch()` function can be used to find the first element for
which a callback functions returns a truish value. But while the array
size is of type `size_t`, the function in fact returns an `int` that is
supposed to index into that array.

Fix the function signature to return a `size_t`. This conversion does
not change any semantics given that the function would only ever return
a value in the range `[0, sz]` anyway.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

reftable/basics.c

@@ -27,7 +27,7 @@ void put_be16(uint8_t *out, uint16_t i)
 	out[1] = (uint8_t)(i & 0xff);
 }
 
-int binsearch(size_t sz, int (*f)(size_t k, void *args), void *args)
+size_t binsearch(size_t sz, int (*f)(size_t k, void *args), void *args)
 {
 	size_t lo = 0;
 	size_t hi = sz;

reftable/basics.h

@@ -28,7 +28,7 @@ void put_be16(uint8_t *out, uint16_t i);
  * Contrary to bsearch(3), this returns something useful if the argument is not
  * found.
  */
-int binsearch(size_t sz, int (*f)(size_t k, void *args), void *args);
+size_t binsearch(size_t sz, int (*f)(size_t k, void *args), void *args);
 
 /*
  * Frees a NULL terminated array of malloced strings. The array itself is also

reftable/basics_test.c

@@ -34,15 +34,15 @@ static void test_binsearch(void)
 
 	int i = 0;
 	for (i = 1; i < 11; i++) {
-		int res;
+		size_t res;
+
 		args.key = i;
 		res = binsearch(sz, &binsearch_func, &args);
 
 		if (res < sz) {
 			EXPECT(args.key < arr[res]);
-			if (res > 0) {
+			if (res > 0)
 				EXPECT(args.key >= arr[res - 1]);
-			}
 		} else {
 			EXPECT(args.key == 10 || args.key == 11);
 		}

reftable/block.c

@@ -382,7 +382,8 @@ int block_reader_seek(struct block_reader *br, struct block_iter *it,
 	};
 	struct block_iter next = BLOCK_ITER_INIT;
 	struct reftable_record rec;
-	int err = 0, i;
+	int err = 0;
+	size_t i;
 
 	if (args.error) {
 		err = REFTABLE_FORMAT_ERROR;

reftable/refname.c

@@ -33,10 +33,9 @@ static int modification_has_ref(struct modification *mod, const char *name)
 			.names = mod->add,
 			.want = name,
 		};
-		int idx = binsearch(mod->add_len, find_name, &arg);
+		size_t idx = binsearch(mod->add_len, find_name, &arg);
-		if (idx < mod->add_len && !strcmp(mod->add[idx], name)) {
+		if (idx < mod->add_len && !strcmp(mod->add[idx], name))
 			return 0;
-		}
 	}
 
 	if (mod->del_len > 0) {
@@ -44,10 +43,9 @@ static int modification_has_ref(struct modification *mod, const char *name)
 			.names = mod->del,
 			.want = name,
 		};
-		int idx = binsearch(mod->del_len, find_name, &arg);
+		size_t idx = binsearch(mod->del_len, find_name, &arg);
-		if (idx < mod->del_len && !strcmp(mod->del[idx], name)) {
+		if (idx < mod->del_len && !strcmp(mod->del[idx], name))
 			return 1;
-		}
 	}
 
 	err = reftable_table_read_ref(&mod->tab, name, &ref);
@@ -77,7 +75,7 @@ static int modification_has_ref_with_prefix(struct modification *mod,
 			.names = mod->add,
 			.want = prefix,
 		};
-		int idx = binsearch(mod->add_len, find_name, &arg);
+		size_t idx = binsearch(mod->add_len, find_name, &arg);
 		if (idx < mod->add_len &&
 		    !strncmp(prefix, mod->add[idx], strlen(prefix)))
 			goto done;
@@ -96,11 +94,10 @@ static int modification_has_ref_with_prefix(struct modification *mod,
 				.names = mod->del,
 				.want = ref.refname,
 			};
-			int idx = binsearch(mod->del_len, find_name, &arg);
+			size_t idx = binsearch(mod->del_len, find_name, &arg);
 			if (idx < mod->del_len &&
-			    !strcmp(ref.refname, mod->del[idx])) {
+			    !strcmp(ref.refname, mod->del[idx]))
 				continue;
-			}
 		}
 
 		if (strncmp(ref.refname, prefix, strlen(prefix))) {