From c6f4a231743738c3a5afcddfa64f3d21c26fb661 Mon Sep 17 00:00:00 2001
From: Jur van den Berg <Jurl.berg@gmail.com>
Date: Sat, 2 Jun 2018 16:26:21 +0200
Subject: [PATCH] Add next_instruction helper and bump version

---
 Cargo.toml      |  2 +-
 src/bin/ijvm.rs | 18 ++++++++----------
 src/machine.rs  | 41 ++++++++++++++++++++++++++++++++++++++++-
 3 files changed, 49 insertions(+), 12 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index 888ca5f..b587d3f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "rustijvm"
-version = "0.1.0"
+version = "1.0.0"
 authors = ["Jur van den Berg <Jurl.berg@gmail.com>"]
 
 [dependencies]
diff --git a/src/bin/ijvm.rs b/src/bin/ijvm.rs
index faa1087..553a2ac 100644
--- a/src/bin/ijvm.rs
+++ b/src/bin/ijvm.rs
@@ -15,16 +15,14 @@ fn main() {
     let ijvmfile = &args[1];
 
     let mut machine = Machine::new_from_file(ijvmfile).unwrap();
-    while machine.has_step() {
-        match machine.step() {
-            Ok(_) => (),
-            Err(str) => {
-                println!("\n\nERROR: pc=0x{:x} fp=0x{:x}: {}\nProgram exit",
-                         machine.get_program_counter(),
-                         machine.frame.len() - 1,
-                         str);
-                return;
-            }
+    match machine.run() {
+        Ok(_) => (),
+        Err(str) => {
+            println!("\n\nERROR: pc=0x{:x} fp=0x{:x}: {}\nProgram exit",
+                     machine.get_program_counter(),
+                     machine.frame.len() - 1,
+                     str);
+            return;
         }
     }
 }
\ No newline at end of file
diff --git a/src/machine.rs b/src/machine.rs
index 5a74f64..cb77740 100644
--- a/src/machine.rs
+++ b/src/machine.rs
@@ -3,7 +3,7 @@ use std::sync::{Mutex, Arc};
 
 use Result;
 use block::Block;
-use ops::Operation;
+use ops::{Operation, Args, num_to_op};
 use ijvmreader::IJVMReader;
 use binread::{BinRead, BinReadable};
 use frame::Frame;
@@ -135,6 +135,45 @@ impl Machine {
         self.block[self.get_program_counter()]
     }
 
+    pub fn next_instruction(&mut self) -> Result<(String, Vec<i32>)> {
+        let checkpoint = self.block.cur();
+
+        let mut opcode = self.block.read_u8()?;
+        let mut params = Vec::new();
+        let mut wide = false;
+
+        // WIDE
+        if opcode == 0xC4 {
+            wide = true;
+            opcode = self.block.read_u8()?;
+        }
+
+        let (name, args) = match num_to_op(opcode) {
+            Operation::Invalid(_) => return Err("Invalid  operation"),
+            Operation::Op(name, _, args) => (name, args),
+        };
+
+        for arg in &args {
+            let v = match arg {
+                Args::Byte => self.block.read_i8()? as i32,
+                Args::Short => self.block.read_i16()? as i32,
+                Args::Var => {
+                    if wide {
+                        self.block.read_u16()? as i32
+                    } else {
+                        self.block.read_u8()? as i32
+                    }
+                },
+                Args::Label => self.block.read_i16()? as i32,
+                Args::Constant => self.block.read_u16()? as i32,
+            };
+            params.push(v);
+        }
+
+        self.block.seek(checkpoint).unwrap();
+        Ok((name.to_string(), params))
+    }
+
 //    pub fn get_stack_pointer(&self) -> usize {
 //        return self.frame.last().unwrap().stack.len();
 //    }