allow passing NULL for all arrays in functions that return the array length

This eschews the need to allocate a zero-sized array on the Java side.

Signed-off-by: Aram Hăvărneanu <[email protected]>

Author: 4ad

alloc.c

@@ -21,6 +21,10 @@ size_t
 cue_cgo_handle_slice_len(uintptr_t *p) {
 	size_t len = 0;
 
+	if (p == NULL) {
+		return 0;
+	}
+
 	while(*p != 0) {
 		p++;
 		len++;

build.c

@@ -19,6 +19,10 @@ size_t
 cue_bopt_len(cue_bopt *opts) {
 	size_t len = 0;
 
+	if (opts == NULL) {
+		return 0;
+	}
+
 	while(opts->tag != CUE_BUILD_NONE) {
 		opts++;
 		len++;

option.c

@@ -19,6 +19,10 @@ size_t
 cue_eopt_len(cue_eopt *opts) {
 	size_t len = 0;
 
+	if (opts == NULL) {
+		return 0;
+	}
+
 	while(opts->tag != CUE_OPT_NONE) {
 		opts++;
 		len++;