arena helper for dealing with buffer preallocation for workers

src/linker/base_ext/base_arena.c

@@ -25,13 +25,32 @@ push_array_copy_u64(Arena *arena, U64 *v, U64 count)
   return result;
 }
 
-internal U64 **
-push_matrix_u64(Arena *arena, U64 rows, U64 columns)
+internal Arena **
+alloc_arena_many(Arena *arena, U64 count, U64 *sizes)
 {
-  U64 **result = push_array_no_zero(arena, U64 *, rows);
-  for (U64 row_idx = 0; row_idx < rows; row_idx += 1) {
-    result[row_idx] = push_array(arena, U64, columns);
+  Arena **result = push_array(arena, Arena *, count);
+  U64  total_size = sum_array_u64(count, sizes);
+  U8  *buffer     = push_array(arena, U8, total_size + (ARENA_HEADER_SIZE * count));
+  U64  offset     = 0;
+  for EachIndex(i, count) {
+    if (sizes[i] > 0) {
+      void *backing_buffer = buffer + offset;
+      result[i] = arena_alloc_(&(ArenaParams){ .flags = ArenaFlag_NoChain, .optional_backing_buffer = backing_buffer, .reserve_size = ARENA_HEADER_SIZE + sizes[i], .commit_size = ARENA_HEADER_SIZE + sizes[i] });
+      offset += ARENA_HEADER_SIZE;
+      offset += sizes[i];
     }
+  }
+  return result;
+}
+
+internal Arena **
+alloc_arena_array_(Arena *arena, U64 count, U64 *counts, U64 element_size)
+{
+  Temp scratch = scratch_begin(&arena, 1);
+  U64 *sizes = push_array(scratch.arena, U64, count);
+  for EachIndex(i, count) { sizes[i] = counts[i] * element_size; }
+  Arena **result = alloc_arena_many(arena, count, sizes);
+  scratch_end(scratch);
   return result;
 }
 
@@ -44,26 +63,11 @@ alloc_fixed_size_arena_array(Arena *arena, U64 count, U64 res, U64 cmt)
   Arena **arr = (Arena **)(count_ptr + 1);
   *count_ptr = count;
 
-  ArenaParams params  = {0};
-  params.reserve_size = res;
-  params.commit_size  = cmt;
-
-  for (U64 i = 0; i < count; i += 1) {
-    Arena *fixed_arena = arena_alloc_(&params);
+  for EachIndex(i, count) {
+    Arena *fixed_arena = arena_alloc_(&(ArenaParams){ .reserve_size = res, .commit_size = cmt });
     arr[i] = fixed_arena;
   }
 
   return arr;
 }
 
-internal void
-release_arena_array(Arena **arr)
-{
-  U64 *count_ptr = (U64 *)arr - 1;
-  U64 count = *count_ptr;
-  for (U64 i = 0; i < count; i += 1) {
-    arena_release(arr[i]);
-    arr[i] = 0;
-  }
-}
-

src/linker/base_ext/base_arena.h

@@ -6,8 +6,6 @@
 internal U64 *    push_u64           (Arena *arena, U64 value);
 internal U32 *    push_array_copy_u32(Arena *arena, U32 *v, U64 count);
 internal U64 *    push_array_copy_u64(Arena *arena, U64 *v, U64 count);
-internal U64 **  push_matrix_u64    (Arena *arena, U64 rows, U64 columns);
-
 internal Arena ** alloc_fixed_size_arena_array(Arena *arena, U64 count, U64 res, U64 cmt);
-internal void     release_arena_array(Arena **arr);
+#define alloc_arena_array(_arena_, _arena_count_, _counts_, T) alloc_arena_array_(_arena_, _arena_count_, _counts_, sizeof(T))