From dcbda91730a4c839844485d327ce9c7014514094 Mon Sep 17 00:00:00 2001
From: Abdelrahman <said.abdelrahman89@gmail.com>
Date: Fri, 13 Sep 2024 02:57:06 +0100
Subject: [PATCH] str8_substr returns copy of the string

---
 src/main.c    | 6 +++---
 src/str/str.c | 6 ++++--
 src/str/str.h | 2 +-
 3 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/src/main.c b/src/main.c
index d5d884b..fd79d1a 100644
--- a/src/main.c
+++ b/src/main.c
@@ -61,15 +61,15 @@ internal TinyArgs parse_args(Arena *arena, int argc, char *argv[]) {
     exit(TINY_EXIT_OBJ_NOT_EXIST);
   }
 
-  const Str8 basename = str8_substr(&args.obj, 0, args.obj.length - 4);
+  u64 substr_end = args.obj.length - 4;
 
-  args.diffuse = str8_copy(arena, &basename);
+  args.diffuse = str8_substr(arena, &args.obj, 0, substr_end);
   str8_concat(arena, &args.diffuse, "_diffuse.pnm");
   if (!file_exists(&args.diffuse)) {
     args.diffuse = (Str8){0};
   }
 
-  args.nm_tangent = str8_copy(arena, &basename);
+  args.nm_tangent = str8_substr(arena, &args.obj, 0, substr_end);
   str8_concat(arena, &args.nm_tangent, "_nm_tangent.pnm");
   if (!file_exists(&args.nm_tangent)) {
     args.nm_tangent = (Str8){0};
diff --git a/src/str/str.c b/src/str/str.c
index d82e77d..1017bd1 100644
--- a/src/str/str.c
+++ b/src/str/str.c
@@ -85,14 +85,16 @@ i32 str8_concat(Arena *arena, Str8 *dst, char *src) {
   return STR_OP_SUCEEDED;
 }
 
-const Str8 str8_substr(const Str8 *str, u64 start, u64 count) {
+Str8 str8_substr(Arena *arena, const Str8 *str, u64 start, u64 count) {
   if (start > str->length || start + count > str->length) {
     return (Str8){0};
   }
 
-  return (Str8){
+  Str8 tmp = {
       .str = str->str + start,
       .length = count,
       .capacity = count,
   };
+
+  return str8_copy(arena, &tmp);
 }
diff --git a/src/str/str.h b/src/str/str.h
index 771bdc2..b957689 100644
--- a/src/str/str.h
+++ b/src/str/str.h
@@ -21,6 +21,6 @@ struct str8 {
 Str8 str8(Arena *arena, char *str);
 Str8 str8_copy(Arena *arena, const Str8 *str);
 i32 str8_concat(Arena *arena, Str8 *dst, char *src);
-const Str8 str8_substr(const Str8 *str, u64 start, u64 count);
+Str8 str8_substr(Arena *arena, const Str8 *str, u64 start, u64 count);
 
 #endif // !STR_H