Enhacnementsand toolchain

bin/tl_alloc.v

@@ -0,0 +1,52 @@
+// toolchain alloc
+// A tiny byte arena for toolchain scratch memory: allocate fixed-size blocks
+// from a pre-sized arena and release them all at once.
+// Run standalone with:  v run bin/tl_alloc.v
+
+module main
+
+struct Arena {
+mut:
+	data []u8
+	used int
+}
+
+// new_arena reserves `cap` bytes of scratch memory.
+fn new_arena(cap int) Arena {
+	return Arena{
+		data: []u8{len: cap}
+		used: 0
+	}
+}
+
+// alloc returns an offset into the arena for a block of `n` bytes.
+fn (mut a Arena) alloc(n int) !int {
+	if a.used + n > a.data.len {
+		return error('arena out of memory: need ${n} bytes, ${a.data.len - a.used} left')
+	}
+	off := a.used
+	a.used += n
+	return off
+}
+
+// free_all releases everything allocated so far.
+fn (mut a Arena) free_all() {
+	a.used = 0
+}
+
+fn (a Arena) stats() string {
+	return 'arena: ${a.used} / ${a.data.len} bytes used'
+}
+
+fn main() {
+	mut arena := new_arena(1024 * 1024) // 1 MiB
+	println('toolchain alloc: arena ready')
+	println(arena.stats())
+	off1 := arena.alloc(64) or { eprintln(err); exit(1) }
+	off2 := arena.alloc(4096) or { eprintln(err); exit(1) }
+	println('allocated 64 bytes  at offset ${off1}')
+	println('allocated 4096 bytes at offset ${off2}')
+	println(arena.stats())
+	arena.free_all()
+	println('after free_all: ${arena.stats()}')
+}