Merge pull request #75 from karl-zylinski/arena-allocator

Virtual growing arena allocator example

.github/workflows/check.yml

@@ -33,16 +33,18 @@ jobs:
         run: |
           FLAGS="-vet -strict-style -vet-tabs -disallow-do -warnings-as-errors"
 
-          odin check basics/command_line_arguments $FLAGS
-          odin check basics/dir_info $FLAGS
-          odin check basics/dynamic_arrays $FLAGS
-          odin check basics/hellope $FLAGS
-          odin check basics/raw_console $FLAGS
-          odin check basics/raw_console -target:windows_amd64 $FLAGS
-          odin check basics/read_console_input $FLAGS
-          odin check basics/strings $FLAGS
-          odin check basics/variables $FLAGS
-          odin check basics/working_directory $FLAGS
+          odin check !basics/command_line_arguments $FLAGS
+          odin check !basics/dir_info $FLAGS
+          odin check !basics/dynamic_arrays $FLAGS
+          odin check !basics/hellope $FLAGS
+          odin check !basics/raw_console $FLAGS
+          odin check !basics/raw_console -target:windows_amd64 $FLAGS
+          odin check !basics/read_console_input $FLAGS
+          odin check !basics/strings $FLAGS
+          odin check !basics/variables $FLAGS
+          odin check !basics/working_directory $FLAGS
+
+          odin check arena_allocator $FLAGS
 
           odin check directx/d3d12_triangle_sdl2 -target:windows_amd64 $FLAGS
 

arena_allocator/arena_allocator.odin

@@ -0,0 +1,51 @@
+package arena_allocator
+
+import "core:fmt"
+import "core:os"
+
+// virtual package implements a multi-purpose arena allocator. If you are on a
+// platform that does not support virtual memory, then there is also a similar
+// arena in `core:mem`.
+import vmem "core:mem/virtual"
+
+load_files :: proc() -> ([]string, vmem.Arena) {
+	// This creates a growing virtual memory arena. It uses virtual memory and
+	// can grow as things are added to it.
+	arena: vmem.Arena
+	arena_err := vmem.arena_init_growing(&arena)
+	ensure(arena_err == nil)
+	arena_alloc := vmem.arena_allocator(&arena)
+
+	// See arena_init_static for an arena that uses virtual memory, but cannot grow.
+
+	// See arena_init_buffer for an arena that does not use virtual memory,
+	// instead it relies on you feeding it a buffer.
+
+	f1, f1_ok := os.read_entire_file("file1.txt", arena_alloc)
+	ensure(f1_ok)
+
+	f2, f2_ok := os.read_entire_file("file2.txt", arena_alloc)
+	ensure(f2_ok)
+
+	f3, f3_ok := os.read_entire_file("file3.txt", arena_alloc)
+	ensure(f3_ok)
+
+	res := make([]string, 3, arena_alloc)
+	res[0] = string(f1)
+	res[1] = string(f2)
+	res[2] = string(f3)
+
+	return res, arena
+}
+
+main :: proc() {
+	files, arena := load_files()
+
+	for f in files {
+		fmt.println(f)
+	}	
+
+	// This deallocates everything that was allocated on the arena:
+	// The loaded content of the files as well as the `files` slice.
+	vmem.arena_destroy(&arena)
+}

arena_allocator/file1.txt

@@ -0,0 +1 @@
+This is from file1.txt

arena_allocator/file2.txt

@@ -0,0 +1 @@
+This is from file2.txt

arena_allocator/file3.txt

@@ -0,0 +1 @@
+This is from file3.txt