C: Add hb_buffer_init_arena for allocating a buffer using the arena allocator

src/include/util/hb_buffer.h

@@ -1,18 +1,21 @@
 #ifndef HERB_BUFFER_H
 #define HERB_BUFFER_H
 
+#include "hb_arena.h"
 #include "hb_string.h"
 
 #include <stdbool.h>
 #include <stdlib.h>
 
 typedef struct HB_BUFFER_STRUCT {
+  hb_arena_T* allocator;
   char* value;
   size_t length;
   size_t capacity;
 } hb_buffer_T;
 
 bool hb_buffer_init(hb_buffer_T* buffer, size_t capacity);
+bool hb_buffer_init_arena(hb_buffer_T* buffer, hb_arena_T* allocator, size_t capacity);
 
 void hb_buffer_append(hb_buffer_T* buffer, const char* text);
 void hb_buffer_append_with_length(hb_buffer_T* buffer, const char* text, size_t length);

src/util/hb_buffer.c

@@ -22,8 +22,14 @@ static bool hb_buffer_resize(hb_buffer_T* buffer, const size_t new_capacity) {
     fprintf(stderr, "Error: Buffer capacity would overflow system limits.\n");
     exit(1);
   }
+  char* new_value = NULL;
 
-  char* new_value = realloc(buffer->value, new_capacity + 1);
+  if (buffer->allocator == NULL) {
+    new_value = realloc(buffer->value, new_capacity + 1);
+  } else {
+    new_value = hb_arena_alloc(buffer->allocator, new_capacity + 1);
+    memcpy(new_value, buffer->value, buffer->capacity + 1);
+  }
 
   if (unlikely(new_value == NULL)) {
     fprintf(stderr, "Error: Failed to resize buffer to %zu.\n", new_capacity);
@@ -61,6 +67,7 @@ static bool hb_buffer_expand_if_needed(hb_buffer_T* buffer, const size_t require
 }
 
 bool hb_buffer_init(hb_buffer_T* buffer, const size_t capacity) {
+  buffer->allocator = NULL;
   buffer->capacity = capacity;
   buffer->length = 0;
   buffer->value = malloc(sizeof(char) * (buffer->capacity + 1));
@@ -76,6 +83,16 @@ bool hb_buffer_init(hb_buffer_T* buffer, const size_t capacity) {
   return true;
 }
 
+bool hb_buffer_init_arena(hb_buffer_T* buffer, hb_arena_T* allocator, size_t capacity) {
+  buffer->allocator = allocator;
+  buffer->capacity = capacity;
+  buffer->length = 0;
+  buffer->value = hb_arena_alloc(allocator, sizeof(char) * (buffer->capacity + 1));
+  buffer->value[0] = '\0';
+
+  return true;
+}
+
 char* hb_buffer_value(const hb_buffer_T* buffer) {
   return buffer->value;
 }