From 780384484cf58939f9413d644ccdd8c40cb82ae5 Mon Sep 17 00:00:00 2001
From: Martin Kagamino Lehoux <martin@lehoux.net>
Date: Mon, 21 Jul 2025 14:37:12 +0200
Subject: feat(string): Arena base allocation for copy

---
 json.c        | 10 +++++-----
 string.c      | 11 ++++++-----
 string.h      |  2 +-
 test_json.c   | 10 ++++++----
 test_string.c |  6 +++---
 5 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/json.c b/json.c
index 0ef03a2..f170e3f 100644
--- a/json.c
+++ b/json.c
@@ -69,7 +69,7 @@ parse_array_result parse_array(Arena *a, char *src, uintptr_t pos) {
 }
 
 typedef struct {
-  Str string;
+  Str *string;
   uintptr_t pos;
 } parse_string_result;
 
@@ -81,7 +81,7 @@ parse_string_result parse_string(Arena *a, char *src, uintptr_t pos) {
     i++;
   }
   assert(src[pos + i] == '"');
-  Str s = Str_copy(a, &src[pos + 1], i - 1);
+  Str* s = Str_copy(a, &src[pos + 1], i - 1);
 
   return (parse_string_result){s, pos + i + 1};
 }
@@ -104,13 +104,13 @@ parse_object_result parse_object(Arena *a, char *src, uintptr_t pos) {
     for (;;) {
         assert(src[pos] == '"');
         parse_string_result str_result = parse_string(a, src, pos);
-        Str key = str_result.string;
+        Str *key = str_result.string;
         pos = absorb_whitespaces(src, str_result.pos);
         assert(src[pos] == ':');
         pos = absorb_whitespaces(src,  pos+1);
         parse_any_result any_result = parse_any(a, src, pos);
         object->len++;
-        Vec_push(a, &object->keys, &key);
+        Vec_push(a, &object->keys, key);
         Vec_push(a, &object->values, any_result.value);
         pos = absorb_whitespaces(src, any_result.pos);
         if (src[pos] != ',') {break;}
@@ -132,7 +132,7 @@ parse_any_result parse_any(Arena *a, char *src, uintptr_t pos) {
     pos = result.pos;
   } else if (src[pos] == '"') {
     parse_string_result result = parse_string(a, src, pos);
-    value->string = &result.string;
+    value->string = result.string;
     pos = result.pos;
   } else if (src[pos] == '{') {
     parse_object_result result = parse_object(a, src, pos);
diff --git a/string.c b/string.c
index 191059e..0fc8341 100644
--- a/string.c
+++ b/string.c
@@ -20,11 +20,12 @@ uint64_t Str_hash64(Str s) {
   return h;
 }
 
-Str Str_copy(Arena *a, char *data, uintptr_t len) {
-  Str str = {.data = NULL, .len = len};
-  str.data =  new (a, char, len);
-  if (str.len)
-    memcpy(str.data, data, len);
+Str* Str_copy(Arena *a, char *data, uintptr_t len) {
+  Str *str = new(a, Str, 1);
+  str->len = len;
+  str->data =  new (a, char, len);
+  if (str->len)
+    memcpy(str->data, data, len);
   return str;
 }
 
diff --git a/string.h b/string.h
index d8835f4..10b3869 100644
--- a/string.h
+++ b/string.h
@@ -12,6 +12,6 @@ typedef struct {
 } Str;
 int Str_equals(Str a, Str b);
 uint64_t Str_hash64(Str s);
-Str Str_copy(Arena *a, char *data, uintptr_t len);
+Str* Str_copy(Arena *a, char *data, uintptr_t len);
 void Str_print(Str s);
 #endif
diff --git a/test_json.c b/test_json.c
index e187b62..d2a4595 100644
--- a/test_json.c
+++ b/test_json.c
@@ -40,6 +40,7 @@ char test_json_nested_array() {
 
   JSON doc = JSON_parse(&perm, "[[1,\"abc\"]]");
 
+  t_assert_equal(Arena_get_used(perm), 283);
   JSON sub_array = *Vec_get(doc.array, JSON, 0);
   JSON val_1 = *Vec_get(sub_array.array, JSON, 0);
   t_assert(*val_1.integer == 1);
@@ -47,7 +48,7 @@ char test_json_nested_array() {
   Str str = *val_2.string;
   Str expected = S("abc");
   t_assert(Str_equals(str, expected));
-  t_assert_equal(Arena_get_used(perm), 267);
+  t_assert_equal(Arena_get_used(perm), 283);
 
   return 0;
 }
@@ -57,8 +58,9 @@ char test_json_string() {
 
   JSON js = JSON_parse(&perm, "\"abc\"");
 
+  t_assert_equal(Arena_get_used(perm), 51);
   t_assert(Str_equals(*js.string, S("abc")));
-  t_assert_equal(Arena_get_used(perm), 35);
+  t_assert_equal(Arena_get_used(perm), 51);
 
   return 0;
 }
@@ -79,11 +81,11 @@ char test_json_object() {
 
     JSON doc = JSON_parse(&perm, "{\"key\": \"value\"}");
 
-    t_assert_equal(Arena_get_used(perm), 261);
+    t_assert_equal(Arena_get_used(perm), 293);
     t_assert_equal(doc.object->len, 1);
     t_assert(Str_equals(*Vec_get(&doc.object->keys, Str, 0), S("key")));
     t_assert(Str_equals(*JSONObject_get(doc.object, S("key"))->string, S("value")))
-    t_assert_equal(Arena_get_used(perm), 261);
+    t_assert_equal(Arena_get_used(perm), 293);
 
     return 0;
 }
diff --git a/test_string.c b/test_string.c
index 590a30f..f62f4ab 100644
--- a/test_string.c
+++ b/test_string.c
@@ -10,10 +10,10 @@ char test_string_copy() {
   Arena perm = Arena_new(128e3);
   Str src = S("Hello");
 
-  Str cpy = Str_copy(&perm, src.data, src.len);
+  Str *cpy = Str_copy(&perm, src.data, src.len);
 
-  t_assert(Str_equals(src, cpy));
-  t_assert(Arena_get_used(perm) == 5);
+  t_assert(Str_equals(src, *cpy));
+  t_assert_equal(Arena_get_used(perm), 21);
 
   return 0;
 }
-- 
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