lib: fix negative uc_index() return value on 32bit systems

The numeric return value was incorrectly stored in an unsigned size_t
variable which got later wrapped in an ucode signed 64bit integer value.

This worked by accident on 64bit systems since (int64_t)(size_t)(-1) == -1,
but it failed on 32bit ones where (int64_t)(size_t)(-1) yields 4294967295
due to the different sizes of the size_t and int64_t types.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

1 files changed, 4 insertions, 3 deletions

diff --git a/lib.c b/lib.c
index 98307f6..f0f934d 100644
--- a/lib.c
+++ b/lib.c
@@ -321,14 +321,15 @@ uc_index(uc_vm *vm, size_t nargs, bool right)
 {
 	uc_value_t *stack = uc_get_arg(0);
 	uc_value_t *needle = uc_get_arg(1);
-	size_t arridx, len, ret = -1;
 	const char *sstr, *nstr, *p;
+	size_t arridx, len;
+	ssize_t ret = -1;
 
 	switch (ucv_type(stack)) {
 	case UC_ARRAY:
 		for (arridx = 0, len = ucv_array_length(stack); arridx < len; arridx++) {
 			if (uc_cmp(TK_EQ, ucv_array_get(stack, arridx), needle)) {
-				ret = arridx;
+				ret = (ssize_t)arridx;
 
 				if (!right)
 					break;
@@ -344,7 +345,7 @@ uc_index(uc_vm *vm, size_t nargs, bool right)
 
 		for (p = sstr; *p && len; p++) {
 			if (!strncmp(p, nstr, len)) {
-				ret = p - sstr;
+				ret = (ssize_t)(p - sstr);
 
 				if (!right)
 					break;