Replaced num_traits::FromPrimitive with a inline implementation using…

… transmute
patbuc · Nov 20, 2023 · 6ecff6d · 6ecff6d
1 parent 05c9553
commit 6ecff6d
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Showing 5 changed files with 13 additions and 12 deletions.
diff --git a/Cargo.toml b/Cargo.toml
@@ -7,8 +7,6 @@ edition = "2021"
 
 [dependencies]
 colored = "2.0.4"
-enum-primitive-derive = "0.2.2"
-num-traits = "0.2.17"
 
 [features]
 disassemble = []
diff --git a/src/vm/block/block.rs b/src/vm/block/block.rs
@@ -106,7 +106,6 @@ impl Block {
 mod tests {
     use crate::vm::opcodes::OpCode;
     use crate::vm::Block;
-    use num_traits::FromPrimitive;
 
     #[test]
     fn new_block_is_empty() {
@@ -136,14 +135,13 @@ mod tests {
         assert_eq!(2 * 256 + 6, block.instructions.len());
         assert_eq!(
             OpCode::Constant2,
-            OpCode::from_u8(block.instructions[2 * 256]).unwrap()
+            OpCode::from_u8(block.instructions[2 * 256])
         );
 
         assert_eq!(256, block.read_u16(2 * 256 + 1));
-
         assert_eq!(
             OpCode::Constant2,
-            OpCode::from_u8(block.instructions[2 * 256 + 3]).unwrap()
+            OpCode::from_u8(block.instructions[2 * 256 + 3])
         );
         let constant_index = block.read_u16(2 * 256 + 4) as usize;
         assert_eq!(257, constant_index);

diff --git a/src/vm/block/disassembler.rs b/src/vm/block/disassembler.rs
@@ -1,6 +1,5 @@
 use crate::vm::opcodes::OpCode;
 use crate::vm::Block;
-use num_traits::FromPrimitive;
 
 #[cfg(feature = "disassemble")]
 impl Block {
@@ -27,7 +26,7 @@ impl Block {
             print!("{:6} ", line.unwrap());
         }
 
-        let instruction = OpCode::from_u8(self.instructions[offset]).unwrap();
+        let instruction = OpCode::from_u8(self.instructions[offset]);
         return match instruction {
             OpCode::Return => self.simple_instruction(OpCode::Return, offset),
             OpCode::Constant => self.constant_instruction(instruction, offset),

diff --git a/src/vm/opcodes.rs b/src/vm/opcodes.rs
@@ -1,7 +1,7 @@
-use enum_primitive_derive::Primitive;
+use std::mem::transmute;
 
 #[repr(u8)]
-#[derive(Debug, PartialEq, Primitive)]
+#[derive(Debug, PartialEq)]
 pub(in crate::vm) enum OpCode {
     Return = 0x00,
     Constant = 0x01,
@@ -13,3 +13,10 @@ pub(in crate::vm) enum OpCode {
     Multiply = 0x07,
     Divide = 0x08,
 }
+
+impl OpCode {
+    #[inline(always)]
+    pub(in crate::vm) fn from_u8(value: u8) -> OpCode {
+        unsafe { transmute(value) }
+    }
+}
diff --git a/src/vm/virtual_machine.rs b/src/vm/virtual_machine.rs
@@ -1,7 +1,6 @@
 use crate::compiler::Compiler;
 use crate::vm::opcodes::OpCode;
 use crate::vm::{Block, Result, Value, VirtualMachine};
-use num_traits::FromPrimitive;
 
 impl VirtualMachine {
     pub fn new() -> Self {
@@ -23,7 +22,7 @@ impl VirtualMachine {
         loop {
             #[cfg(feature = "disassemble")]
             self.block.disassemble_instruction(self.ip);
-            match OpCode::from_u8(self.block.read_u8(self.ip)).unwrap() {
+            match OpCode::from_u8(self.block.read_u8(self.ip)) {
                 OpCode::Return => {
                     let value = self.pop();
                     VirtualMachine::print(value);