commit 1b3c582ee24b21ea5aa66a9b60c937ce92dc0ffe
Author: Jur van den Berg <Jurl.berg@gmail.com>
Date:   Tue Jun 6 14:19:35 2017 +0200

    Passing all `tests` i guess

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..623ee40
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,5 @@
+target
+*.jas
+*.ijvm
+*.conf
+goJASM
diff --git a/Cargo.lock b/Cargo.lock
new file mode 100644
index 0000000..005e0c7
--- /dev/null
+++ b/Cargo.lock
@@ -0,0 +1,4 @@
+[root]
+name = "rustijvm"
+version = "0.1.0"
+
diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..545e5b7
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "rustijvm"
+version = "0.1.0"
+authors = ["Jur van den Berg <Jurl.berg@gmail.com>"]
+
+[dependencies]
diff --git a/src/ijvm/binread.rs b/src/ijvm/binread.rs
new file mode 100644
index 0000000..f8e83c0
--- /dev/null
+++ b/src/ijvm/binread.rs
@@ -0,0 +1,82 @@
+use ijvm::Result;
+use ijvm::block::Block;
+use ijvm::ops::{Operation,num_to_op};
+
+pub trait BinReadable {
+    fn get(&mut self) -> Result<u8>;
+    fn cur(&self) -> usize;
+    fn len(&self) -> usize;
+    fn slice(&mut self, len: usize) -> &[u8];
+}
+
+pub trait BinRead {
+    fn has_i8(&self) -> bool;
+    fn has_i16(&self) -> bool;
+    fn has_i32(&self) -> bool;
+
+    fn read_u8(&mut self) -> Result<u8>;
+    fn read_u16(&mut self) -> Result<u16>;
+    fn read_u32(&mut self) -> Result<u32>;
+
+    fn read_i8(&mut self) -> Result<i8>;
+    fn read_i16(&mut self) -> Result<i16>;
+    fn read_i32(&mut self) -> Result<i32>;
+
+    fn read_block(&mut self) -> Result<Block>;
+    fn read_op(&mut self) -> Result<Operation>;
+}
+
+impl<T: BinReadable> BinRead for T {
+    fn has_i8(&self) -> bool {
+        self.cur() < self.len()
+    }
+
+    fn has_i16(&self) -> bool {
+        self.cur() + 1 < self.len()
+    }
+
+    fn has_i32(&self) -> bool {
+        self.cur() + 3 < self.len()
+    }
+
+    fn read_u8(&mut self) -> Result<u8> {
+        self.get()
+    }
+
+    fn read_u16(&mut self) -> Result<u16> {
+        let a = self.read_u8()? as u16;
+        let b = self.read_u8()? as u16;
+        Ok(a << 8 | b)
+    }
+
+    fn read_u32(&mut self) -> Result<u32> {
+        let a = self.read_u16()? as u32;
+        let b = self.read_u16()? as u32;
+        Ok(a << 16 | b)
+    }
+    fn read_i8(&mut self) -> Result<i8> {
+        Ok(self.get()? as i8)
+    }
+
+    fn read_i16(&mut self) -> Result<i16> {
+        let a = self.read_u8()? as i16;
+        let b = self.read_u8()? as i16;
+        Ok((a << 8 | b) as i16)
+    }
+
+    fn read_i32(&mut self) -> Result<i32> {
+        let a = self.read_u16()? as i32;
+        let b = self.read_u16()? as i32;
+        Ok(a << 16 | b)
+    }
+
+    fn read_block(&mut self) -> Result<Block> {
+        let origin = self.read_u32()?;
+        let len = self.read_u32()? as usize;
+        Ok(Block::new(origin, self.slice(len)))
+    }
+
+    fn read_op(&mut self) -> Result<Operation> {
+        Ok(num_to_op(self.read_u8()?))
+    }
+}
\ No newline at end of file
diff --git a/src/ijvm/block.rs b/src/ijvm/block.rs
new file mode 100644
index 0000000..1d6a88f
--- /dev/null
+++ b/src/ijvm/block.rs
@@ -0,0 +1,71 @@
+use ijvm::Result;
+use ijvm::binread::BinReadable;
+
+#[derive(Debug)]
+pub struct Block {
+    origin: u32,
+
+    length: usize,
+    pointer: usize,
+    source: Vec<u8>
+}
+
+impl Block {
+    pub fn new(origin: u32, source: &[u8]) -> Block {
+        Block {
+            origin: origin,
+            length: source.len(),
+            pointer: 0,
+            source: source.to_owned()
+        }
+    }
+
+    pub fn jump(&mut self, offset: i32) -> Result<()> {
+        if offset < 0 {
+            if (-offset as usize) > self.pointer {
+                return Err("Jump before block")
+            }
+            self.pointer -= -offset as usize;
+        } else {
+            if self.pointer + (offset as usize) >= self.length {
+                return Err("Jump outside of block")
+            }
+            self.pointer += offset as usize;
+        }
+        Ok(())
+    }
+
+    pub fn seek(&mut self, location: usize) -> Result<()> {
+        if location >= self.length {
+            println!("hoho {}", location);
+            return Err("Seek outside of block")
+        }
+        self.pointer = location;
+        Ok(())
+    }
+}
+
+impl BinReadable for Block {
+    fn get(&mut self) -> Result<u8> {
+        if self.pointer >= self.length {
+            return Err("EOF reached")
+        }
+        let byte = self.source[self.pointer];
+        self.pointer += 1;
+        return Ok(byte)
+    }
+
+    fn len(&self) -> usize {
+        return self.source.len()
+    }
+
+    fn cur(&self) -> usize {
+        return self.pointer;
+    }
+
+    fn slice(&mut self, len: usize) -> &[u8] {
+        let slice = &self.source[self.pointer..self.pointer+len];
+        self.pointer += len;
+        slice
+    }
+}
diff --git a/src/ijvm/frame.rs b/src/ijvm/frame.rs
new file mode 100644
index 0000000..30a3e0f
--- /dev/null
+++ b/src/ijvm/frame.rs
@@ -0,0 +1,33 @@
+use ijvm::Result;
+use ijvm::stack::Stack;
+
+#[derive(Debug)]
+pub struct Frame {
+    pub stack: Stack,
+    locals: Vec<i32>,
+}
+
+impl Frame {
+    pub fn new(num_locals: usize) -> Frame {
+//        println!("Initializing frame of len {}", num_locals);
+        return Frame {
+            stack: Stack::new(),
+            locals: vec![0; num_locals+1],
+        }
+    }
+
+    pub fn get(&self, offset: usize) -> Result<i32> {
+        if offset >= self.locals.len() {
+            return Err("Local variable out of range");
+        }
+        return Ok(self.locals[offset])
+    }
+
+    pub fn set(&mut self, offset: usize, val: i32) -> Result<()> {
+        if offset >= self.locals.len() {
+            return Err("Local variable out of range");
+        }
+        self.locals[offset] = val;
+        return Ok(());
+    }
+}
\ No newline at end of file
diff --git a/src/ijvm/ijvmreader.rs b/src/ijvm/ijvmreader.rs
new file mode 100644
index 0000000..e227282
--- /dev/null
+++ b/src/ijvm/ijvmreader.rs
@@ -0,0 +1,48 @@
+use std::io::Read;
+use std::fs::File;
+use ijvm::Result;
+use ijvm::binread::BinReadable;
+
+pub struct IJVMReader {
+    pointer: usize,
+    source: Vec<u8>
+}
+
+impl IJVMReader {
+    pub fn new(path: &str) -> Result<IJVMReader> {
+        let file = match File::open(path) {
+            Ok(file) => file,
+            Err(_) => return Err("Could not open file"),
+        };
+        let abc: Vec<u8> = file.bytes().map(|e| e.unwrap()).collect();
+        Ok(IJVMReader {
+            pointer: 0,
+            source: abc
+        })
+    }
+}
+
+impl BinReadable for IJVMReader {
+    fn get(&mut self) -> Result<u8> {
+        if self.pointer >= self.source.len() {
+            return Err("EOF reached")
+        }
+        let byte = self.source[self.pointer];
+        self.pointer += 1;
+        return Ok(byte)
+    }
+
+    fn len(&self) -> usize {
+        return self.source.len()
+    }
+
+    fn cur(&self) -> usize {
+        return self.pointer;
+    }
+
+    fn slice(&mut self, len: usize) -> &[u8] {
+        let slice = &self.source[self.pointer..self.pointer+len];
+        self.pointer += len;
+        slice
+    }
+}
diff --git a/src/ijvm/machine.rs b/src/ijvm/machine.rs
new file mode 100644
index 0000000..050fcd4
--- /dev/null
+++ b/src/ijvm/machine.rs
@@ -0,0 +1,96 @@
+use ijvm::block::Block;
+
+use ijvm::ops::Operation;
+use ijvm::ijvmreader::IJVMReader;
+use ijvm::binread::BinReadable;
+use ijvm::binread::BinRead;
+use ijvm::frame::Frame;
+use ijvm::stack::Stack;
+use ijvm::pool::Pool;
+use ijvm::Result;
+
+const MAGIC_HEADER:u32 = 0x1deadfad;
+const ANTI_BS_SIZE:usize = 0xFFFF;
+
+pub struct Machine {
+    pub wide: bool,
+    pub pool: Pool,
+    pub block: Block,
+    pub frame: Vec<Frame>
+}
+
+impl Machine {
+    pub fn new(pool: Pool, block: Block) -> Machine{
+        Machine {
+            wide: false,
+            pool: pool,
+            block: block,
+            frame: vec![Frame::new(ANTI_BS_SIZE)],
+        }
+    }
+
+    pub fn new_from_file(file: &str) -> Result<Machine> {
+        let mut reader = IJVMReader::new(file).unwrap();
+        let magic = reader.read_u32()?;
+        if magic != MAGIC_HEADER {
+            return Err("Invalid magic header");
+        }
+        let constants = match reader.read_block() {
+            Ok(a) => a,
+            Err(_) => return Err("Failed to read constants block")
+        };
+        let text = match reader.read_block() {
+            Ok(block) => block,
+            Err(_) => return Err("Failed to read text block")
+        };
+
+        let pool = Pool::new(constants)?;
+
+        return Ok(Machine::new(pool, text));
+    }
+
+    pub fn step(&mut self) -> Result<()> {
+        match self.block.read_op() {
+            Ok(Operation::Op(a, func)) => {
+//                println!("{}", a);
+//                println!("Stack: {:?}", self.cur_frame().stack.data);
+                let x = func(self);
+//                println!("Stack: {:?}", self.cur_frame().stack.data);
+                x
+            },
+            Ok(Operation::Invalid(a)) => {
+                println!("OP: {}", a);
+                Err("Invalid op")
+            },
+            Err(str) => Err(str)
+        }
+    }
+
+    pub fn has_step(&self) -> bool {
+        return self.block.has_i8();
+    }
+
+    pub fn get_program_counter(&self) -> usize {
+        return self.block.cur()
+    }
+
+    pub fn cur_frame(&mut self) -> &mut Frame {
+        return self.frame.last_mut().unwrap();
+    }
+
+    pub fn cur_stack(&mut self) -> &mut Stack {
+        return &mut self.cur_frame().stack;
+    }
+
+//    pub fn get_stack_pointer(&self) -> usize {
+//        return self.frame.last().unwrap().stack.len();
+//    }
+
+    pub fn read_index(&mut self) -> Result<usize> {
+        if self.wide {
+            self.wide = false;
+            return Ok(self.block.read_u16()? as usize)
+        }
+        Ok(self.block.read_u8()? as usize)
+    }
+}
\ No newline at end of file
diff --git a/src/ijvm/mod.rs b/src/ijvm/mod.rs
new file mode 100644
index 0000000..8a8fb8b
--- /dev/null
+++ b/src/ijvm/mod.rs
@@ -0,0 +1,10 @@
+pub mod ijvmreader;
+pub mod binread;
+pub mod block;
+pub mod ops;
+pub mod machine;
+pub mod stack;
+pub mod pool;
+pub mod frame;
+
+type Result<T> = ::std::result::Result<T, &'static str>;
diff --git a/src/ijvm/ops.rs b/src/ijvm/ops.rs
new file mode 100644
index 0000000..2252b82
--- /dev/null
+++ b/src/ijvm/ops.rs
@@ -0,0 +1,245 @@
+use ijvm::binread::BinRead;
+use ijvm::machine::Machine;
+use ijvm::frame::Frame;
+use ijvm::Result;
+use std::io::Write;
+use std::io::Read;
+
+pub type OpFunc = fn(&mut Machine) -> Result<()>;
+
+pub enum Operation {
+    Op(&'static str, OpFunc),
+    Invalid(u8)
+}
+
+const JUMP_OFFSET: i32 = 3;
+
+pub fn num_to_op(op: u8) -> Operation {
+    match op {
+        0x00 => Operation::Op("NOP", nop),
+        0x10 => Operation::Op("BIPUSH", bipush),
+        0x13 => Operation::Op("LDC_W", ldc_w),
+        0x15 => Operation::Op("ILOAD", iload),
+        0x36 => Operation::Op("ISTORE", istore),
+        0x57 => Operation::Op("POP", pop),
+        0x59 => Operation::Op("DUP", dup),
+        0x5F => Operation::Op("SWAP", swap),
+        0x60 => Operation::Op("IADD", iadd),
+        0x64 => Operation::Op("ISUB", isub),
+        0x7E => Operation::Op("IAND", iand),
+        0xB0 => Operation::Op("IOR", ior),
+        0x84 => Operation::Op("IINC", iinc),
+        0x99 => Operation::Op("IFEQ", ifeq),
+        0x9b => Operation::Op("IFLT", iflt),
+        0x9F => Operation::Op("IF_ICMPEQ", if_icmpeq),
+        0xA7 => Operation::Op("GOTO", goto),
+        0xAC => Operation::Op("IRETURN", ireturn),
+        0xB6 => Operation::Op("INVOKEVIRTUAL", invokevirtual),
+        0xC4 => Operation::Op("WIDE", wide),
+        0xFC => Operation::Op("IN", _in),
+        0xFD => Operation::Op("OUT", out),
+        0xFF => Operation::Op("HALT", halt),
+
+        0xF0 => Operation::Op("SLP", slp),
+        x => Operation::Invalid(x)
+    }
+}
+
+fn nop(_: &mut Machine) -> Result<()> {
+    Ok(())
+}
+
+fn bipush(machine: &mut Machine) -> Result<()> {
+    let val = match machine.block.read_i8() {
+        Ok(a) => a,
+        Err(_) => return Err("Expected argument"),
+    } as i32;
+    machine.cur_stack().push(val);
+    Ok(())
+}
+
+fn dup(machine: &mut Machine) -> Result<()> {
+    let val = machine.cur_stack().top()?;
+    machine.cur_stack().push(val);
+    Ok(())
+}
+
+fn out(machine: &mut Machine) -> Result<()> {
+    let val = machine.cur_stack().pop()?;
+    print!("{}", val as u8 as char);
+    ::std::io::stdout().flush().unwrap();
+    Ok(())
+}
+
+fn pop(machine: &mut Machine) -> Result<()> {
+    machine.cur_stack().pop()?;
+    Ok(())
+}
+
+fn iadd(machine: &mut Machine) -> Result<()> {
+    let a = machine.cur_stack().pop()?;
+    let b = machine.cur_stack().pop()?;
+    machine.cur_stack().push(a + b);
+    Ok(())
+}
+
+fn isub(machine: &mut Machine) -> Result<()> {
+    let a = machine.cur_stack().pop()?;
+    let b = machine.cur_stack().pop()?;
+    machine.cur_stack().push(b - a);
+    Ok(())
+}
+
+fn _in(machine: &mut Machine) -> Result<()> {
+   let char: Option<u8> =
+       ::std::io::stdin()
+       .bytes()
+       .next()
+       .and_then(|r| r.ok());
+    let val = match char {
+        None => 0 as i32,
+        Some(i) => i as i32
+    };
+    machine.cur_stack().push(val);
+    Ok(())
+}
+
+fn goto(machine: &mut Machine) -> Result<()> {
+    let offset = machine.block.read_i16()? as i32 - JUMP_OFFSET;
+    machine.block.jump(offset)
+}
+
+fn halt(_: &mut Machine) -> Result<()> {
+    Err("Halt")
+}
+
+fn ifeq(machine: &mut Machine) -> Result<()> {
+    let offset = machine.block.read_i16()? as i32 - JUMP_OFFSET;
+    if machine.cur_stack().pop()? == 0 {
+        return machine.block.jump(offset)
+    }
+    Ok(())
+}
+
+fn iflt(machine: &mut Machine) -> Result<()> {
+    let offset = machine.block.read_i16()? as i32 - JUMP_OFFSET;
+    if machine.cur_stack().pop()? < 0 {
+        return machine.block.jump(offset)
+    }
+    Ok(())
+}
+
+fn if_icmpeq(machine: &mut Machine) -> Result<()> {
+    let offset = machine.block.read_i16()? as i32 - JUMP_OFFSET;
+    if machine.cur_stack().pop()? == machine.cur_stack().pop()? {
+        return machine.block.jump(offset)
+    }
+    Ok(())
+}
+
+fn iand(machine: &mut Machine) -> Result<()> {
+    let a = machine.cur_stack().pop()?;
+    let b = machine.cur_stack().pop()?;
+    machine.cur_stack().push(a & b);
+    Ok(())
+}
+
+fn ior(machine: &mut Machine) -> Result<()> {
+    let a = machine.cur_stack().pop()?;
+    let b = machine.cur_stack().pop()?;
+    machine.cur_stack().push(a | b);
+    Ok(())
+}
+
+fn ldc_w(machine: &mut Machine) -> Result<()> {
+    let offset = machine.block.read_i16()? as usize;
+    let val = machine.pool.get(offset)?;
+    machine.cur_stack().push(val);
+    Ok(())
+}
+
+fn swap(machine: &mut Machine) -> Result<()> {
+    let a = machine.cur_stack().pop()?;
+    let b = machine.cur_stack().pop()?;
+    machine.cur_stack().push(a);
+    machine.cur_stack().push(b);
+    Ok(())
+}
+
+fn wide(machine: &mut Machine) -> Result<()> {
+    machine.wide = true;
+    Ok(())
+}
+
+fn iload(machine: &mut Machine) -> Result<()> {
+    let a = machine.read_index()?;
+    let val = machine.cur_frame().get(a)?;
+    machine.cur_stack().push(val);
+    Ok(())
+}
+
+fn istore(machine: &mut Machine) -> Result<()> {
+    let a = machine.read_index()?;
+    let val = machine.cur_stack().pop()?;
+    machine.cur_frame().set(a, val)
+}
+
+fn iinc(machine: &mut Machine) -> Result<()> {
+    let a = machine.read_index()?;
+    let b = machine.block.read_i8()?;
+    let val = machine.cur_frame().get(a)?;
+    machine.cur_frame().set(a, val + b as i32)
+}
+
+fn invokevirtual(machine: &mut Machine) -> Result<()> {
+    let method_index = machine.block.read_u16()?;
+    let invoke_addr = machine.pool.get(method_index as usize)?;
+    let return_addr = machine.get_program_counter();
+//    println!("METHOD {}", method_index);
+    machine.block.seek(invoke_addr as usize)?;
+    let arg_count = machine.block.read_u16()?;
+    let var_count = machine.block.read_u16()?;
+    let mut newframe = Frame::new((arg_count + var_count) as usize);
+
+    // Lifetime for cur_stack
+    {
+        let mut cur_stack = machine.cur_stack();
+        for i in 1..arg_count {
+            newframe.set((arg_count - i) as usize, cur_stack.pop()?)?;
+        }
+
+        cur_stack.pop()?; // Nuke the OBJREF
+    }
+
+//    println!("retaddr set {}" ,return_addr);
+    newframe.set(0, return_addr as i32)?;
+
+    machine.frame.push(newframe);
+    Ok(())
+
+}
+
+fn ireturn(machine: &mut Machine) -> Result<()> {
+    let mut prev_frame: Frame = match machine.frame.pop() {
+        Some(a) => a,
+        None => return Err("Got no frame... somehow...")
+    };
+//    println!("stack: {:?}", prev_frame.stack);
+    let result = prev_frame.stack.pop()?;
+    let return_addr = prev_frame.get(0)?;
+//    println!("result: {}\nretaddr: {}", result, return_addr);
+    machine.cur_stack().push(result);
+    machine.block.seek(return_addr as usize)
+}
+
+fn slp(machine: &mut Machine) -> Result<()> {
+    use std::time;
+    use std::thread;
+    let val = match machine.block.read_u8() {
+        Ok(a) => a,
+        Err(_) => return Err("Expected argument"),
+    } as u64;
+    let slpdur = time::Duration::from_millis(val*100);
+    thread::sleep(slpdur);
+    Ok(())
+}
\ No newline at end of file
diff --git a/src/ijvm/pool.rs b/src/ijvm/pool.rs
new file mode 100644
index 0000000..97c0ade
--- /dev/null
+++ b/src/ijvm/pool.rs
@@ -0,0 +1,28 @@
+use ijvm::Result;
+use ijvm::block::Block;
+use ijvm::binread::{BinRead, BinReadable};
+
+#[derive(Debug)]
+pub struct Pool {
+    pub data: Vec<i32>
+}
+
+impl Pool {
+    pub fn new(mut block: Block) -> Result<Pool> {
+        let cap = block.len() / 4;
+        let mut vec = Vec::with_capacity(cap);
+        while block.has_i32() {
+            vec.push(block.read_i32()?);
+        }
+        Ok(Pool {
+            data: vec
+        })
+    }
+
+    pub fn get(&self, index: usize) -> Result<i32> {
+        if index >= self.data.len() {
+            return Err("No such constant")
+        }
+        Ok(self.data[index])
+    }
+}
diff --git a/src/ijvm/stack.rs b/src/ijvm/stack.rs
new file mode 100644
index 0000000..349c53b
--- /dev/null
+++ b/src/ijvm/stack.rs
@@ -0,0 +1,40 @@
+use ijvm::Result;
+
+#[derive(Debug)]
+pub struct Stack {
+    pub data: Vec<i32>
+}
+
+impl Stack {
+    pub fn new() -> Stack {
+        Stack {
+            data: Vec::new()
+        }
+    }
+
+//    pub fn len(&self) -> usize {
+//        return self.data.len();
+//    }
+
+    pub fn top(&self) -> Result<i32> {
+        Ok(match  self.data.last() {
+            Some(a) => *a,
+            None => return Err("Stack empty"),
+        })
+    }
+
+    pub fn pop(&mut self) -> Result<i32> {
+        Ok(match self.data.pop() {
+            Some(a) => a,
+            None => return Err("Stack empty"),
+        })
+    }
+
+    pub fn push(&mut self, val: i32) {
+        self.data.push(val);
+    }
+
+    pub fn len(&self) -> usize {
+        self.data.len()
+    }
+}
\ No newline at end of file
diff --git a/src/main.rs b/src/main.rs
new file mode 100644
index 0000000..5f1d798
--- /dev/null
+++ b/src/main.rs
@@ -0,0 +1,31 @@
+mod ijvm;
+
+
+use ijvm::machine::Machine;
+use std::env;
+
+
+fn main() {
+    let args: Vec<String> = env::args().collect();
+
+    if args.len() < 2 {
+        println!("Usage: {} ijvmfile", args[0]);
+        return;
+    }
+
+    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;
+            }
+        }
+    }
+}
\ No newline at end of file