From 279c233cb1f32ed42419ed6a9c2e14c1c1bc80e7 Mon Sep 17 00:00:00 2001
From: Micha White <botahamec@outlook.com>
Date: Wed, 8 Nov 2023 14:09:17 -0500
Subject: Create a script system

---
 scripts/src/libs/allocate.rs | 76 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 76 insertions(+)
 create mode 100644 scripts/src/libs/allocate.rs

(limited to 'scripts/src/libs/allocate.rs')

diff --git a/scripts/src/libs/allocate.rs b/scripts/src/libs/allocate.rs
new file mode 100644
index 0000000..7f2825d
--- /dev/null
+++ b/scripts/src/libs/allocate.rs
@@ -0,0 +1,76 @@
+use wasmtime::Caller;
+
+use crate::{ScriptManager, WasmScriptState};
+
+use super::{
+	system::{_alloc, _get_memory},
+	LIBRARY_NAME,
+};
+
+fn allocate_zeroed(mut caller: Caller<'_, WasmScriptState>, size: u32, align: u32) -> u32 {
+	let Some((ptr, data)) = _alloc(&mut caller, size, align) else {
+		return 0;
+	};
+
+	data.fill(0);
+	ptr
+}
+
+fn reallocate(
+	mut caller: Caller<'_, WasmScriptState>,
+	ptr: u32,
+	size: u32,
+	new_size: u32,
+	align: u32,
+) -> u32 {
+	if new_size < size {
+		return ptr;
+	}
+
+	let bump_pointer = &mut caller.data_mut().bump_pointer;
+	if *bump_pointer == ptr + size {
+		*bump_pointer = ptr;
+		let Some((new_ptr, _)) = _alloc(&mut caller, new_size, align) else {
+			return 4;
+		};
+		return new_ptr;
+	}
+
+	let (_, original) = _get_memory(&mut caller);
+	let Some(original) = original.get(ptr as usize..(ptr + size) as usize) else {
+		return 4;
+	};
+	let original = original.to_vec();
+
+	let Some((new_ptr, data)) = _alloc(&mut caller, new_size, align) else {
+		return 0;
+	};
+
+	data.get_mut(..size as usize)
+		.unwrap()
+		.clone_from_slice(&original);
+	new_ptr
+}
+
+fn duplicate(mut caller: Caller<'_, WasmScriptState>, ptr: u32, size: u32, align: u32) -> u32 {
+	let (_, original) = _get_memory(&mut caller);
+	let Some(original) = original.get(ptr as usize..(ptr + size) as usize) else {
+		return 4;
+	};
+	let original = original.to_vec();
+
+	let Some((new_ptr, data)) = _alloc(&mut caller, size, align) else {
+		return 0;
+	};
+
+	data.clone_from_slice(&original);
+	new_ptr
+}
+
+pub fn library(manager: &mut ScriptManager) -> Option<()> {
+	manager.add_library_function(LIBRARY_NAME, "calloc", allocate_zeroed)?;
+	manager.add_library_function(LIBRARY_NAME, "realloc", reallocate)?;
+	manager.add_library_function(LIBRARY_NAME, "memdup", duplicate)?;
+
+	Some(())
+}
-- 
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