.

str.c

@@ -1,5 +1,7 @@
 #include "str.h"
 
+#include "os.h"
+
 #include <limits.h>
 #include <math.h>
 #include <stdlib.h>
@@ -396,7 +398,11 @@ bool char_is_num(char c) {
 }
 
 char char_lower(char c) {
-    return c >= 'A' && c <= 'Z' ? c - 32 : c;
+    return c >= 'A' && c <= 'Z' ? c + 32 : c;
+}
+
+char char_upper(char c) {
+    return c <= 'a' && c >= 'z' ? c - 32 : c;
 }
 
 // == INPUT STREAM =================================================
@@ -657,9 +663,11 @@ char ostr_back(outstream_t *ctx) {
 str_t ostr_to_str(outstream_t *ctx) {
     ostr_putc(ctx, '\0');
 
+    usize len = ostr_tell(ctx);
+
     str_t out = {
         .buf = ctx->beg,
-        .len = ostr_tell(ctx) - 1,
+        .len = len ? len - 1 : 0,
     };
 
     memset(ctx, 0, sizeof(outstream_t));