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    // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
    // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
    // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
    // option. This file may not be copied, modified, or distributed
    // except according to those terms.

    // TODO - Optimize the XORs
    // TODO - Maybe use macros to specialize BlockEngine for encryption or decryption?
    // TODO - I think padding could be done better. Maybe macros for BlockEngine would help this too.

    use std::cmp;
    use std::iter::repeat;

    use buffer::{ReadBuffer, WriteBuffer, OwnedReadBuffer, OwnedWriteBuffer, BufferResult,
        RefReadBuffer, RefWriteBuffer};
    use buffer::BufferResult::{BufferUnderflow, BufferOverflow};
    use cryptoutil::{self, symm_enc_or_dec};
    use symmetriccipher::{BlockEncryptor, BlockEncryptorX8, Encryptor, BlockDecryptor, Decryptor,
        SynchronousStreamCipher, SymmetricCipherError};
    use symmetriccipher::SymmetricCipherError::{InvalidPadding, InvalidLength};

    /// The BlockProcessor trait is used to implement modes that require processing complete blocks of
    /// data. The methods of this trait are called by the BlockEngine which is in charge of properly
    /// buffering input data.
    trait BlockProcessor {
        /// Process a block of data. The in_hist and out_hist parameters represent the input and output
        /// when the last block was processed. These values are necessary for certain modes.
        fn process_block(&mut self, in_hist: &[u8], out_hist: &[u8], input: &[u8], output: &mut [u8]);
    }

    /// A PaddingProcessor handles adding or removing padding
    pub trait PaddingProcessor {
        /// Add padding to the last block of input data
        /// If the mode can't handle a non-full block, it signals that error by simply leaving the block
        /// as it is which will be detected as an InvalidLength error.
        fn pad_input<W: WriteBuffer>(&mut self, input_buffer: &mut W);

        /// Remove padding from the last block of output data
        /// If false is returned, the processing fails
        fn strip_output<R: ReadBuffer>(&mut self, output_buffer: &mut R) -> bool;
    }

    /// The BlockEngine is implemented as a state machine with the following states. See comments in the
    /// BlockEngine code for more information on the states.
    #[derive(Clone, Copy)]
    enum BlockEngineState {
        FastMode,
        NeedInput,
        NeedOutput,
        LastInput,
        LastInput2,
        Finished,
        Error(SymmetricCipherError)
    }

    /// BlockEngine buffers input and output data and handles sending complete block of data to the
    /// Processor object. Additionally, BlockEngine handles logic necessary to add or remove padding by
    /// calling the appropriate methods on the Processor object.
    struct BlockEngine<P, X> {
        /// The block sized expected by the Processor
        block_size: usize,

        /// in_hist and out_hist keep track of data that was input to and output from the last
        /// invocation of the process_block() method of the Processor. Depending on the mode, these may
        /// be empty vectors if history is not needed.
        in_hist: Vec<u8>,
        out_hist: Vec<u8>,

        /// If some input data is supplied, but not a complete blocks worth, it is stored in this buffer
        /// until enough arrives that it can be passed to the process_block() method of the Processor.
        in_scratch: OwnedWriteBuffer,

        /// If input data is processed but there isn't enough space in the output buffer to store it,
        /// it is written into out_write_scratch. OwnedWriteBuffer's may be converted into
        /// OwnedReaderBuffers without re-allocating, so, after being written, out_write_scratch is
        /// turned into out_read_scratch. After that, if is written to the output as more output becomes
        /// available. The main point is - only out_write_scratch or out_read_scratch contains a value
        /// at any given time; never both.
        out_write_scratch: Option<OwnedWriteBuffer>,
        out_read_scratch: Option<OwnedReadBuffer>,

        /// The processor that implements the particular block mode.
        processor: P,

        /// The padding processor
        padding: X,

        /// The current state of the operation.
        state: BlockEngineState
    }

    fn update_history(in_hist: &mut [u8], out_hist: &mut [u8], last_in: &[u8], last_out: &[u8]) {
        let in_hist_len = in_hist.len();
        if in_hist_len > 0 {
            cryptoutil::copy_memory(
                &last_in[last_in.len() - in_hist_len..],
                in_hist);
        }
        let out_hist_len = out_hist.len();
        if out_hist_len > 0 {
            cryptoutil::copy_memory(
                &last_out[last_out.len() - out_hist_len..],
                out_hist);
        }
    }

    impl <P: BlockProcessor, X: PaddingProcessor> BlockEngine<P, X> {
        /// Create a new BlockProcessor instance with the given processor and block_size. No history
        /// will be saved.
        fn new(processor: P, padding: X, block_size: usize) -> BlockEngine<P, X> {
            BlockEngine {
                block_size: block_size,
                in_hist: Vec::new(),
                out_hist: Vec::new(),
                in_scratch: OwnedWriteBuffer::new(repeat(0).take(block_size).collect()),
                out_write_scratch: Some(OwnedWriteBuffer::new(repeat(0).take(block_size).collect())),
                out_read_scratch: None,
                processor: processor,
                padding: padding,
                state: BlockEngineState::FastMode
            }
        }

        /// Create a new BlockProcessor instance with the given processor, block_size, and initial input
        /// and output history.
        fn new_with_history(
                processor: P,
                padding: X,
                block_size: usize,
                in_hist: Vec<u8>,
                out_hist: Vec<u8>) -> BlockEngine<P, X> {
            BlockEngine {
                in_hist: in_hist,
                out_hist: out_hist,
                ..BlockEngine::new(processor, padding, block_size)
            }
        }

        /// This implements the FastMode state. Ideally, the encryption or decryption operation should
        /// do the bulk of its work in FastMode. Significantly, FastMode avoids doing copies as much as
        /// possible. The FastMode state does not handle the final block of data.
        fn fast_mode<R: ReadBuffer, W: WriteBuffer>(
                &mut self,
                input: &mut R,
                output: &mut W) -> BlockEngineState {
            fn has_next<R: ReadBuffer, W: WriteBuffer>(
                    input: &mut R,
                    output: &mut W,
                    block_size: usize) -> bool {
                // Not the greater than - very important since this method must never process the last
                // block.
                let enough_input = input.remaining() > block_size;
                let enough_output = output.remaining() >= block_size;
                enough_input && enough_output
            };
            fn split_at<'a>(vec: &'a [u8], at: usize) -> (&'a [u8], &'a [u8]) {
                (&vec[..at], &vec[at..])
            }

            // First block processing. We have to retrieve the history information from self.in_hist and
            // self.out_hist.
            if !has_next(input, output, self.block_size) {
                if input.is_empty() {
                    return BlockEngineState::FastMode;
                } else {
                    return BlockEngineState::NeedInput;
                }
            } else {
                let next_in = input.take_next(self.block_size);
                let next_out = output.take_next(self.block_size);
                self.processor.process_block(
                    &self.in_hist[..],
                    &self.out_hist[..],
                    next_in,
                    next_out);
            }

            // Process all remaing blocks. We can pull the history out of the buffers without having to
            // do any copies
            let next_in_size = self.in_hist.len() + self.block_size;
            let next_out_size = self.out_hist.len() + self.block_size;
            while has_next(input, output, self.block_size) {
                input.rewind(self.in_hist.len());
                let (in_hist, next_in) = split_at(input.take_next(next_in_size), self.in_hist.len());
                output.rewind(self.out_hist.len());
                let (out_hist, next_out) = output.take_next(next_out_size).split_at_mut(
                    self.out_hist.len());
                self.processor.process_block(
                    in_hist,
                    out_hist,
                    next_in,
                    next_out);
            }

            // Save the history and then transition to the next state
            {
                input.rewind(self.in_hist.len());
                let last_in = input.take_next(self.in_hist.len());
                output.rewind(self.out_hist.len());
                let last_out = output.take_next(self.out_hist.len());
                update_history(
                    &mut self.in_hist,
                    &mut self.out_hist,
                    last_in,
                    last_out);
            }
            if input.is_empty() {
                BlockEngineState::FastMode
            } else {
                BlockEngineState::NeedInput
            }
        }

        /// This method implements the BlockEngine state machine.
        fn process<R: ReadBuffer, W: WriteBuffer>(
                &mut self,
                input: &mut R,
                output: &mut W,
                eof: bool) -> Result<BufferResult, SymmetricCipherError> {
            // Process a block of data from in_scratch and write the result to out_write_scratch.
            // Finally, convert out_write_scratch into out_read_scratch.
            fn process_scratch<P: BlockProcessor, X: PaddingProcessor>(me: &mut BlockEngine<P, X>) {
                let mut rin = me.in_scratch.take_read_buffer();
                let mut wout = me.out_write_scratch.take().unwrap();

                {
                    let next_in = rin.take_remaining();
                    let next_out = wout.take_remaining();
                    me.processor.process_block(
                        &me.in_hist[..],
                        &me.out_hist[..],
                        next_in,
                        next_out);
                    update_history(
                        &mut me.in_hist,
                        &mut me.out_hist,
                        next_in,
                        next_out);
                }

                let rb = wout.into_read_buffer();
                me.out_read_scratch = Some(rb);
            };

            loop {
                match self.state {
                    // FastMode tries to process as much data as possible while minimizing copies.
                    // FastMode doesn't make use of the scratch buffers and only updates the history
                    // just before exiting.
                    BlockEngineState::FastMode => {
                        self.state = self.fast_mode(input, output);
                        match self.state {
                            BlockEngineState::FastMode => {
                                // If FastMode completes but stays in the FastMode state, it means that
                                // we've run out of input data.
                                return Ok(BufferUnderflow);
                            }
                            _ => {}
                        }
                    }

                    // The NeedInput mode is entered when there isn't enough data to run in FastMode
                    // anymore. Input data is buffered in in_scratch until there is a full block or eof
                    // occurs. IF eof doesn't occur, the data is processed and then we go to the
                    // NeedOutput state. Otherwise, we go to the LastInput state. This state always
                    // writes all available data into in_scratch before transitioning to the next state.
                    BlockEngineState::NeedInput => {
                        input.push_to(&mut self.in_scratch);
                        if !input.is_empty() {
                            // !is_empty() guarantees two things - in_scratch is full and its not the
                            // last block. This state must never process the last block.
                            process_scratch(self);
                            self.state = BlockEngineState::NeedOutput;
                        } else {
                            if eof {
                                self.state = BlockEngineState::LastInput;
                            } else {
                                return Ok(BufferUnderflow);
                            }
                        }
                    }

                    // The NeedOutput state just writes buffered processed data to the output stream
                    // until all of it has been written.
                    BlockEngineState::NeedOutput => {
                        let mut rout = self.out_read_scratch.take().unwrap();
                        rout.push_to(output);
                        if rout.is_empty() {
                            self.out_write_scratch = Some(rout.into_write_buffer());
                            self.state = BlockEngineState::FastMode;
                        } else {
                            self.out_read_scratch = Some(rout);
                            return Ok(BufferOverflow);
                        }
                    }

                    // None of the other states are allowed to process the last block of data since
                    // last block handling is a little tricky due to modes have special needs regarding
                    // padding. When the last block of data is detected, this state is transitioned to
                    // for handling.
                    BlockEngineState::LastInput => {
                        // We we arrive in this state, we know that all input data that is going to be
                        // supplied has been suplied and that that data has been written to in_scratch
                        // by the NeedInput state. Furthermore, we know that one of three things must be
                        // true about in_scratch:
                        // 1) It is empty. This only occurs if the input is zero length. We can do last
                        //    block processing by executing the pad_input() method of the processor
                        //    which may either pad out to a full block or leave it empty, process the
                        //    data if it was padded out to a full block, and then pass it to
                        //    strip_output().
                        // 2) It is partially filled. This will occur if the input data was not a
                        //    multiple of the block size. Processing proceeds identically to case #1.
                        // 3) It is full. This case occurs when the input data was a multiple of the
                        //    block size. This case is a little trickier, since, depending on the mode,
                        //    we might actually have 2 blocks worth of data to process - the last user
                        //    supplied block (currently in in_scratch) and then another block that could
                        //    be added as padding. Processing proceeds by first processing the data in
                        //    in_scratch and writing it to out_scratch. Then, the now-empty in_scratch
                        //    buffer is passed to pad_input() which may leave it empty or write a block
                        //    of padding to it. If no padding is added, processing proceeds as in cases
                        //    #1 and #2. However, if padding is added, now have data in in_scratch and
                        //    also in out_scratch meaning that we can't immediately process the padding
                        //    data since we have nowhere to put it. So, we transition to the LastInput2
                        //    state which will first write out the last non-padding block, then process
                        //    the padding block (in in_scratch) and write it to the now-empty
                        //    out_scratch.
                        if !self.in_scratch.is_full() {
                            self.padding.pad_input(&mut self.in_scratch);
                            if self.in_scratch.is_full() {
                                process_scratch(self);
                                if self.padding.strip_output(self.out_read_scratch.as_mut().unwrap()) {
                                    self.state = BlockEngineState::Finished;
                                } else {
                                    self.state = BlockEngineState::Error(InvalidPadding);
                                }
                            } else if self.in_scratch.is_empty() {
                                self.state = BlockEngineState::Finished;
                            } else {
                                self.state = BlockEngineState::Error(InvalidLength);
                            }
                        } else {
                            process_scratch(self);
                            self.padding.pad_input(&mut self.in_scratch);
                            if self.in_scratch.is_full() {
                                self.state = BlockEngineState::LastInput2;
                            } else if self.in_scratch.is_empty() {
                                if self.padding.strip_output(self.out_read_scratch.as_mut().unwrap()) {
                                    self.state = BlockEngineState::Finished;
                                } else {
                                    self.state = BlockEngineState::Error(InvalidPadding);
                                }
                            } else {
                                self.state = BlockEngineState::Error(InvalidLength);
                            }
                        }
                    }

                    // See the comments on LastInput for more details. This state handles final blocks
                    // of data in the case that the input was a multiple of the block size and the mode
                    // decided to add a full extra block of padding.
                    BlockEngineState::LastInput2 => {
                        let mut rout = self.out_read_scratch.take().unwrap();
                        rout.push_to(output);
                        if rout.is_empty() {
                            self.out_write_scratch = Some(rout.into_write_buffer());
                            process_scratch(self);
                            if self.padding.strip_output(self.out_read_scratch.as_mut().unwrap()) {
                                self.state = BlockEngineState::Finished;
                            } else {
                                self.state = BlockEngineState::Error(InvalidPadding);
                            }
                        } else {
                            self.out_read_scratch = Some(rout);
                            return Ok(BufferOverflow);
                        }
                    }

                    // The Finished mode just writes the data in out_scratch to the output until there
                    // is no more data left.
                    BlockEngineState::Finished => {
                        match self.out_read_scratch {
                            Some(ref mut rout) => {
                                rout.push_to(output);
                                if rout.is_empty() {
                                    return Ok(BufferUnderflow);
                                } else {
                                    return Ok(BufferOverflow);
                                }
                            }
                            None => { return Ok(BufferUnderflow); }
                        }
                    }

                    // The Error state is used to store error information.
                    BlockEngineState::Error(err) => {
                        return Err(err);
                    }
                }
            }
        }
        fn reset(&mut self) {
            self.state = BlockEngineState::FastMode;
            self.in_scratch.reset();
            if self.out_read_scratch.is_some() {
                let ors = self.out_read_scratch.take().unwrap();
                let ows = ors.into_write_buffer();
                self.out_write_scratch = Some(ows);
            } else {
                self.out_write_scratch.as_mut().unwrap().reset();
            }
        }
        fn reset_with_history(&mut self, in_hist: &[u8], out_hist: &[u8]) {
            self.reset();
            cryptoutil::copy_memory(in_hist, &mut self.in_hist);
            cryptoutil::copy_memory(out_hist, &mut self.out_hist);
        }
    }

    /// No padding mode for ECB and CBC encryption
    #[derive(Clone, Copy)]
    pub struct NoPadding;

    impl PaddingProcessor for NoPadding {
        fn pad_input<W: WriteBuffer>(&mut self, _: &mut W) { }
        fn strip_output<R: ReadBuffer>(&mut self, _: &mut R) -> bool { true }
    }

    /// PKCS padding mode for ECB and CBC encryption
    #[derive(Clone, Copy)]
    pub struct PkcsPadding;

    // This class implements both encryption padding, where padding is added, and decryption padding,
    // where padding is stripped. Since BlockEngine doesn't know if its an Encryption or Decryption
    // operation, it will call both methods if given a chance. So, this class can't be passed directly
    // to BlockEngine. Instead, it must be wrapped with EncPadding or DecPadding which will ensure that
    // only the propper methods are called. The client of the library, however, doesn't have to
    // distinguish encryption padding handling from decryption padding handline, which is the whole
    // point.
    impl PaddingProcessor for PkcsPadding {
        fn pad_input<W: WriteBuffer>(&mut self, input_buffer: &mut W) {
            let rem = input_buffer.remaining();
            assert!(rem != 0 && rem <= 255);
            for v in input_buffer.take_remaining().iter_mut() {
                *v = rem as u8;
            }
        }
        fn strip_output<R: ReadBuffer>(&mut self, output_buffer: &mut R) -> bool {
            let last_byte: u8;
            {
                let data = output_buffer.peek_remaining();
                last_byte = *data.last().unwrap();
                for &x in data.iter().rev().take(last_byte as usize) {
                    if x != last_byte {
                        return false;
                    }
                }
            }
            output_buffer.truncate(last_byte as usize);
            true
        }
    }

    /// Wraps a PaddingProcessor so that only pad_input() will actually be called.
    pub struct EncPadding<X> {
        padding: X
    }

    impl <X: PaddingProcessor> EncPadding<X> {
        fn wrap(p: X) -> EncPadding<X> { EncPadding { padding: p } }
    }

    impl <X: PaddingProcessor> PaddingProcessor for EncPadding<X> {
        fn pad_input<W: WriteBuffer>(&mut self, a: &mut W) { self.padding.pad_input(a); }
        fn strip_output<R: ReadBuffer>(&mut self, _: &mut R) -> bool { true }
    }

    /// Wraps a PaddingProcessor so that only strip_output() will actually be called.
    pub struct DecPadding<X> {
        padding: X
    }

    impl <X: PaddingProcessor> DecPadding<X> {
        fn wrap(p: X) -> DecPadding<X> { DecPadding { padding: p } }
    }

    impl <X: PaddingProcessor> PaddingProcessor for DecPadding<X> {
        fn pad_input<W: WriteBuffer>(&mut self, _: &mut W) { }
        fn strip_output<R: ReadBuffer>(&mut self, a: &mut R) -> bool { self.padding.strip_output(a) }
    }

    struct EcbEncryptorProcessor<T> {
        algo: T
    }

    impl <T: BlockEncryptor> BlockProcessor for EcbEncryptorProcessor<T> {
        fn process_block(&mut self, _: &[u8], _: &[u8], input: &[u8], output: &mut [u8]) {
            self.algo.encrypt_block(input, output);
        }
    }

    /// ECB Encryption mode
    pub struct EcbEncryptor<T, X> {
        block_engine: BlockEngine<EcbEncryptorProcessor<T>, X>
    }

    impl <T: BlockEncryptor, X: PaddingProcessor> EcbEncryptor<T, X> {
        /// Create a new ECB encryption mode object
        pub fn new(algo: T, padding: X) -> EcbEncryptor<T, EncPadding<X>> {
            let block_size = algo.block_size();
            let processor = EcbEncryptorProcessor {
                algo: algo
            };
            EcbEncryptor {
                block_engine: BlockEngine::new(processor, EncPadding::wrap(padding), block_size)
            }
        }
        pub fn reset(&mut self) {
            self.block_engine.reset();
        }
    }

    impl <T: BlockEncryptor, X: PaddingProcessor> Encryptor for EcbEncryptor<T, X> {
        fn encrypt(&mut self, input: &mut RefReadBuffer, output: &mut RefWriteBuffer, eof: bool)
                -> Result<BufferResult, SymmetricCipherError> {
            self.block_engine.process(input, output, eof)
        }
    }

    struct EcbDecryptorProcessor<T> {
        algo: T
    }

    impl <T: BlockDecryptor> BlockProcessor for EcbDecryptorProcessor<T> {
        fn process_block(&mut self, _: &[u8], _: &[u8], input: &[u8], output: &mut [u8]) {
            self.algo.decrypt_block(input, output);
        }
    }

    /// ECB Decryption mode
    pub struct EcbDecryptor<T, X> {
        block_engine: BlockEngine<EcbDecryptorProcessor<T>, X>
    }

    impl <T: BlockDecryptor, X: PaddingProcessor> EcbDecryptor<T, X> {
        /// Create a new ECB decryption mode object
        pub fn new(algo: T, padding: X) -> EcbDecryptor<T, DecPadding<X>> {
            let block_size = algo.block_size();
            let processor = EcbDecryptorProcessor {
                algo: algo
            };
            EcbDecryptor {
                block_engine: BlockEngine::new(processor, DecPadding::wrap(padding), block_size)
            }
        }
        pub fn reset(&mut self) {
            self.block_engine.reset();
        }
    }

    impl <T: BlockDecryptor, X: PaddingProcessor> Decryptor for EcbDecryptor<T, X> {
        fn decrypt(&mut self, input: &mut RefReadBuffer, output: &mut RefWriteBuffer, eof: bool)
                -> Result<BufferResult, SymmetricCipherError> {
            self.block_engine.process(input, output, eof)
        }
    }

    struct CbcEncryptorProcessor<T> {
        algo: T,
        temp: Vec<u8>
    }

    impl <T: BlockEncryptor> BlockProcessor for CbcEncryptorProcessor<T> {
        fn process_block(&mut self, _: &[u8], out_hist: &[u8], input: &[u8], output: &mut [u8]) {
            for ((&x, &y), o) in input.iter().zip(out_hist.iter()).zip(self.temp.iter_mut()) {
                *o = x ^ y;
            }
            self.algo.encrypt_block(&self.temp[..], output);
        }
    }

    /// CBC encryption mode
    pub struct CbcEncryptor<T, X> {
        block_engine: BlockEngine<CbcEncryptorProcessor<T>, X>
    }

    impl <T: BlockEncryptor, X: PaddingProcessor> CbcEncryptor<T, X> {
        /// Create a new CBC encryption mode object
        pub fn new(algo: T, padding: X, iv: Vec<u8>) -> CbcEncryptor<T, EncPadding<X>> {
            let block_size = algo.block_size();
            let processor = CbcEncryptorProcessor {
                algo: algo,
                temp: repeat(0).take(block_size).collect()
            };
            CbcEncryptor {
                block_engine: BlockEngine::new_with_history(
                    processor,
                    EncPadding::wrap(padding),
                    block_size,
                    Vec::new(),
                    iv)
            }
        }
        pub fn reset(&mut self, iv: &[u8]) {
            self.block_engine.reset_with_history(&[], iv);
        }
    }

    impl <T: BlockEncryptor, X: PaddingProcessor> Encryptor for CbcEncryptor<T, X> {
        fn encrypt(&mut self, input: &mut RefReadBuffer, output: &mut RefWriteBuffer, eof: bool)
                -> Result<BufferResult, SymmetricCipherError> {
            self.block_engine.process(input, output, eof)
        }
    }

    struct CbcDecryptorProcessor<T> {
        algo: T,
        temp: Vec<u8>
    }

    impl <T: BlockDecryptor> BlockProcessor for CbcDecryptorProcessor<T> {
        fn process_block(&mut self, in_hist: &[u8], _: &[u8], input: &[u8], output: &mut [u8]) {
            self.algo.decrypt_block(input, &mut self.temp);
            for ((&x, &y), o) in self.temp.iter().zip(in_hist.iter()).zip(output.iter_mut()) {
                *o = x ^ y;
            }
        }
    }

    /// CBC decryption mode
    pub struct CbcDecryptor<T, X> {
        block_engine: BlockEngine<CbcDecryptorProcessor<T>, X>
    }

    impl <T: BlockDecryptor, X: PaddingProcessor> CbcDecryptor<T, X> {
        /// Create a new CBC decryption mode object
        pub fn new(algo: T, padding: X, iv: Vec<u8>) -> CbcDecryptor<T, DecPadding<X>> {
            let block_size = algo.block_size();
            let processor = CbcDecryptorProcessor {
                algo: algo,
                temp: repeat(0).take(block_size).collect()
            };
            CbcDecryptor {
                block_engine: BlockEngine::new_with_history(
                    processor,
                    DecPadding::wrap(padding),
                    block_size,
                    iv,
                    Vec::new())
            }
        }
        pub fn reset(&mut self, iv: &[u8]) {
            self.block_engine.reset_with_history(iv, &[]);
        }
    }

    impl <T: BlockDecryptor, X: PaddingProcessor> Decryptor for CbcDecryptor<T, X> {
        fn decrypt(&mut self, input: &mut RefReadBuffer, output: &mut RefWriteBuffer, eof: bool)
                -> Result<BufferResult, SymmetricCipherError> {
            self.block_engine.process(input, output, eof)
        }
    }

    fn add_ctr(ctr: &mut [u8], mut ammount: u8) {
        for i in ctr.iter_mut().rev() {
            let prev = *i;
            *i = i.wrapping_add(ammount);
            if *i >= prev {
                break;
            }
            ammount = 1;
        }
    }

    /// CTR Mode
    pub struct CtrMode<A> {
        algo: A,
        ctr: Vec<u8>,
        bytes: OwnedReadBuffer
    }

    impl <A: BlockEncryptor> CtrMode<A> {
        /// Create a new CTR object
        pub fn new(algo: A, ctr: Vec<u8>) -> CtrMode<A> {
            let block_size = algo.block_size();
            CtrMode {
                algo: algo,
                ctr: ctr,
                bytes: OwnedReadBuffer::new_with_len(repeat(0).take(block_size).collect(), 0)
            }
        }
        pub fn reset(&mut self, ctr: &[u8]) {
            cryptoutil::copy_memory(ctr, &mut self.ctr);
            self.bytes.reset();
        }
        fn process(&mut self, input: &[u8], output: &mut [u8]) {
            assert!(input.len() == output.len());
            let len = input.len();
            let mut i = 0;
            while i < len {
                if self.bytes.is_empty() {
                    let mut wb = self.bytes.borrow_write_buffer();
                    self.algo.encrypt_block(&self.ctr[..], wb.take_remaining());
                    add_ctr(&mut self.ctr, 1);
                }
                let count = cmp::min(self.bytes.remaining(), len - i);
                let bytes_it = self.bytes.take_next(count).iter();
                let in_it = input[i..].iter();
                let out_it = output[i..].iter_mut();
                for ((&x, &y), o) in bytes_it.zip(in_it).zip(out_it) {
                    *o = x ^ y;
                }
                i += count;
            }
        }
    }

    impl <A: BlockEncryptor> SynchronousStreamCipher for CtrMode<A> {
        fn process(&mut self, input: &[u8], output: &mut [u8]) {
            self.process(input, output);
        }
    }

    impl <A: BlockEncryptor> Encryptor for CtrMode<A> {
        fn encrypt(&mut self, input: &mut RefReadBuffer, output: &mut RefWriteBuffer, _: bool)
                -> Result<BufferResult, SymmetricCipherError> {
            symm_enc_or_dec(self, input, output)
        }
    }

    impl <A: BlockEncryptor> Decryptor for CtrMode<A> {
        fn decrypt(&mut self, input: &mut RefReadBuffer, output: &mut RefWriteBuffer, _: bool)
                -> Result<BufferResult, SymmetricCipherError> {
            symm_enc_or_dec(self, input, output)
        }
    }

    /// CTR Mode that operates on 8 blocks at a time
    pub struct CtrModeX8<A> {
        algo: A,
        ctr_x8: Vec<u8>,
        bytes: OwnedReadBuffer
    }

    fn construct_ctr_x8(in_ctr: &[u8], out_ctr_x8: &mut [u8]) {
        for (i, ctr_i) in out_ctr_x8.chunks_mut(in_ctr.len()).enumerate() {
            cryptoutil::copy_memory(in_ctr, ctr_i);
            add_ctr(ctr_i, i as u8);
        }
    }

    impl <A: BlockEncryptorX8> CtrModeX8<A> {
        /// Create a new CTR object that operates on 8 blocks at a time
        pub fn new(algo: A, ctr: &[u8]) -> CtrModeX8<A> {
            let block_size = algo.block_size();
            let mut ctr_x8: Vec<u8> = repeat(0).take(block_size * 8).collect();
            construct_ctr_x8(ctr, &mut ctr_x8);
            CtrModeX8 {
                algo: algo,
                ctr_x8: ctr_x8,
                bytes: OwnedReadBuffer::new_with_len(repeat(0).take(block_size * 8).collect(), 0)
            }
        }
        pub fn reset(&mut self, ctr: &[u8]) {
            construct_ctr_x8(ctr, &mut self.ctr_x8);
            self.bytes.reset();
        }
        fn process(&mut self, input: &[u8], output: &mut [u8]) {
            // TODO - Can some of this be combined with regular CtrMode?
            assert!(input.len() == output.len());
            let len = input.len();
            let mut i = 0;
            while i < len {
                if self.bytes.is_empty() {
                    let mut wb = self.bytes.borrow_write_buffer();
                    self.algo.encrypt_block_x8(&self.ctr_x8[..], wb.take_remaining());
                    for ctr_i in &mut self.ctr_x8.chunks_mut(self.algo.block_size()) {
                        add_ctr(ctr_i, 8);
                    }
                }
                let count = cmp::min(self.bytes.remaining(), len - i);
                let bytes_it = self.bytes.take_next(count).iter();
                let in_it = input[i..].iter();
                let out_it = &mut output[i..];
                for ((&x, &y), o) in bytes_it.zip(in_it).zip(out_it.iter_mut()) {
                    *o = x ^ y;
                }
                i += count;
            }
        }
    }

    impl <A: BlockEncryptorX8> SynchronousStreamCipher for CtrModeX8<A> {
        fn process(&mut self, input: &[u8], output: &mut [u8]) {
            self.process(input, output);
        }
    }

    impl <A: BlockEncryptorX8> Encryptor for CtrModeX8<A> {
        fn encrypt(&mut self, input: &mut RefReadBuffer, output: &mut RefWriteBuffer, _: bool)
                -> Result<BufferResult, SymmetricCipherError> {
            symm_enc_or_dec(self, input, output)
        }
    }

    impl <A: BlockEncryptorX8> Decryptor for CtrModeX8<A> {
        fn decrypt(&mut self, input: &mut RefReadBuffer, output: &mut RefWriteBuffer, _: bool)
                -> Result<BufferResult, SymmetricCipherError> {
            symm_enc_or_dec(self, input, output)
        }
    }

    #[cfg(test)]
    mod test {
        use std::iter::repeat;

        use aessafe;
        use blockmodes::{EcbEncryptor, EcbDecryptor, CbcEncryptor, CbcDecryptor, CtrMode, CtrModeX8,
            NoPadding, PkcsPadding};
        use buffer::{ReadBuffer, WriteBuffer, RefReadBuffer, RefWriteBuffer, BufferResult};
        use buffer::BufferResult::{BufferUnderflow, BufferOverflow};
        use symmetriccipher::{Encryptor, Decryptor};
        use symmetriccipher::SymmetricCipherError::{self, InvalidLength, InvalidPadding};

        use std::cmp;

        trait CipherTest {
            fn get_plain<'a>(&'a self) -> &'a [u8];
            fn get_cipher<'a>(&'a self) -> &'a [u8];
        }

        struct EcbTest {
            key: Vec<u8>,
            plain: Vec<u8>,
            cipher: Vec<u8>
        }

        impl CipherTest for EcbTest {
            fn get_plain<'a>(&'a self) -> &'a [u8] {
                &self.plain[..]
            }
            fn get_cipher<'a>(&'a self) -> &'a [u8] {
                &self.cipher[..]
            }
        }

        struct CbcTest {
            key: Vec<u8>,
            iv: Vec<u8>,
            plain: Vec<u8>,
            cipher: Vec<u8>
        }

        impl CipherTest for CbcTest {
            fn get_plain<'a>(&'a self) -> &'a [u8] {
                &self.plain[..]
            }
            fn get_cipher<'a>(&'a self) -> &'a [u8] {
                &self.cipher[..]
            }
        }

        struct CtrTest {
            key: Vec<u8>,
            ctr: Vec<u8>,
            plain: Vec<u8>,
            cipher: Vec<u8>
        }

        impl CipherTest for CtrTest {
            fn get_plain<'a>(&'a self) -> &'a [u8] {
                &self.plain[..]
            }
            fn get_cipher<'a>(&'a self) -> &'a [u8] {
                &self.cipher[..]
            }
        }

        fn aes_ecb_no_padding_tests() -> Vec<EcbTest> {
            vec![
                EcbTest {
                    key: repeat(0).take(16).collect(),
                    plain: repeat(0).take(32).collect(),
                    cipher: vec![
                        0x66, 0xe9, 0x4b, 0xd4, 0xef, 0x8a, 0x2c, 0x3b,
                        0x88, 0x4c, 0xfa, 0x59, 0xca, 0x34, 0x2b, 0x2e,
                        0x66, 0xe9, 0x4b, 0xd4, 0xef, 0x8a, 0x2c, 0x3b,
                        0x88, 0x4c, 0xfa, 0x59, 0xca, 0x34, 0x2b, 0x2e ]
                }
            ]
        }

        fn aes_ecb_pkcs_padding_tests() -> Vec<EcbTest> {
            vec![
                EcbTest {
                    key: repeat(0).take(16).collect(),
                    plain: repeat(0).take(32).collect(),
                    cipher: vec![
                        0x66, 0xe9, 0x4b, 0xd4, 0xef, 0x8a, 0x2c, 0x3b,
                        0x88, 0x4c, 0xfa, 0x59, 0xca, 0x34, 0x2b, 0x2e,
                        0x66, 0xe9, 0x4b, 0xd4, 0xef, 0x8a, 0x2c, 0x3b,
                        0x88, 0x4c, 0xfa, 0x59, 0xca, 0x34, 0x2b, 0x2e,
                        0x01, 0x43, 0xdb, 0x63, 0xee, 0x66, 0xb0, 0xcd,
                        0xff, 0x9f, 0x69, 0x91, 0x76, 0x80, 0x15, 0x1e ]
                },
                EcbTest {
                    key: repeat(0).take(16).collect(),
                    plain: repeat(0).take(33).collect(),
                    cipher: vec![
                        0x66, 0xe9, 0x4b, 0xd4, 0xef, 0x8a, 0x2c, 0x3b,
                        0x88, 0x4c, 0xfa, 0x59, 0xca, 0x34, 0x2b, 0x2e,
                        0x66, 0xe9, 0x4b, 0xd4, 0xef, 0x8a, 0x2c, 0x3b,
                        0x88, 0x4c, 0xfa, 0x59, 0xca, 0x34, 0x2b, 0x2e,
                        0x7a, 0xdc, 0x99, 0xb2, 0x9e, 0x82, 0xb1, 0xb2,
                        0xb0, 0xa6, 0x5a, 0x38, 0xbc, 0x57, 0x8a, 0x01 ]
                }
            ]
        }

        fn aes_cbc_no_padding_tests() -> Vec<CbcTest> {
            vec![
                CbcTest {
                    key: repeat(1).take(16).collect(),
                    iv: repeat(3).take(16).collect(),
                    plain: repeat(2).take(32).collect(),
                    cipher: vec![
                        0x5e, 0x77, 0xe5, 0x9f, 0x8f, 0x85, 0x94, 0x34,
                        0x89, 0xa2, 0x41, 0x49, 0xc7, 0x5f, 0x4e, 0xc9,
                        0xe0, 0x9a, 0x77, 0x36, 0xfb, 0xc8, 0xb2, 0xdc,
                        0xb3, 0xfb, 0x9f, 0xc0, 0x31, 0x4c, 0xb0, 0xb1 ]
                }
            ]
        }

        fn aes_cbc_pkcs_padding_tests() -> Vec<CbcTest> {
            vec![
                CbcTest {
                    key: repeat(1).take(16).collect(),
                    iv: repeat(3).take(16).collect(),
                    plain: repeat(2).take(32).collect(),
                    cipher: vec![
                        0x5e, 0x77, 0xe5, 0x9f, 0x8f, 0x85, 0x94, 0x34,
                        0x89, 0xa2, 0x41, 0x49, 0xc7, 0x5f, 0x4e, 0xc9,
                        0xe0, 0x9a, 0x77, 0x36, 0xfb, 0xc8, 0xb2, 0xdc,
                        0xb3, 0xfb, 0x9f, 0xc0, 0x31, 0x4c, 0xb0, 0xb1,
                        0xa4, 0xc2, 0xe4, 0x62, 0xef, 0x7a, 0xe3, 0x7e,
                        0xef, 0x88, 0xf3, 0x27, 0xbd, 0x9c, 0xc8, 0x4d ]
                },
                CbcTest {
                    key: repeat(1).take(16).collect(),
                    iv: repeat(3).take(16).collect(),
                    plain: repeat(2).take(33).collect(),
                    cipher: vec![
                        0x5e, 0x77, 0xe5, 0x9f, 0x8f, 0x85, 0x94, 0x34,
                        0x89, 0xa2, 0x41, 0x49, 0xc7, 0x5f, 0x4e, 0xc9,
                        0xe0, 0x9a, 0x77, 0x36, 0xfb, 0xc8, 0xb2, 0xdc,
                        0xb3, 0xfb, 0x9f, 0xc0, 0x31, 0x4c, 0xb0, 0xb1,
                        0x6c, 0x47, 0xcd, 0xec, 0xae, 0xbb, 0x1a, 0x65,
                        0x04, 0xd2, 0x32, 0x23, 0xa6, 0x8d, 0x4a, 0x65 ]
                }
            ]
        }

        fn aes_ctr_tests() -> Vec<CtrTest> {
            vec![
                CtrTest {
                    key: repeat(1).take(16).collect(),
                    ctr: repeat(3).take(16).collect(),
                    plain: repeat(2).take(33).collect(),
                    cipher: vec![
                        0x64, 0x3e, 0x05, 0x19, 0x79, 0x78, 0xd7, 0x45,
                        0xa9, 0x10, 0x5f, 0xd8, 0x4c, 0xd7, 0xe6, 0xb1,
                        0x5f, 0x66, 0xc6, 0x17, 0x4b, 0x25, 0xea, 0x24,
                        0xe6, 0xf9, 0x19, 0x09, 0xb7, 0xdd, 0x84, 0xfb,
                        0x86 ]
                }
            ]
        }

        // Test the mode by encrypting all of the data at once
        fn run_full_test<T: CipherTest, E: Encryptor, D: Decryptor>(
                test: &T,
                enc: &mut E,
                dec: &mut D) {
            let mut cipher_out: Vec<u8> = repeat(0).take(test.get_cipher().len()).collect();
            {
                let mut buff_in = RefReadBuffer::new(test.get_plain());
                let mut buff_out = RefWriteBuffer::new(&mut cipher_out);
                match enc.encrypt(&mut buff_in, &mut buff_out, true) {
                    Ok(BufferUnderflow) => {}
                    Ok(BufferOverflow) => panic!("Encryption not completed"),
                    Err(_) => panic!("Error"),
                }
            }
            assert!(test.get_cipher() == &cipher_out[..]);

            let mut plain_out: Vec<u8> = repeat(0).take(test.get_plain().len()).collect();
            {
                let mut buff_in = RefReadBuffer::new(test.get_cipher());
                let mut buff_out = RefWriteBuffer::new(&mut plain_out);
                match dec.decrypt(&mut buff_in, &mut buff_out, true) {
                    Ok(BufferUnderflow) => {}
                    Ok(BufferOverflow) => panic!("Decryption not completed"),
                    Err(_) => panic!("Error"),
                }
            }
            assert!(test.get_plain() == &plain_out[..]);
        }

        /// Run and encryption or decryption operation, passing in variable sized input and output
        /// buffers.
        ///
        /// # Arguments
        /// * input - The complete input vector
        /// * output - The complete output vector
        /// * op - A closure that runs either an encryption or decryption operation
        /// * next_in_len - A closure that returns the length to use for the next input buffer; If the
        ///                 returned value is not in a valid range, it will be fixed up by this
        ///                 function.
        /// * next_out_len - A closure that returns the length to use for the next output buffer; If the
        ///                  returned value is not in a valid range, it will be fixed up by this
        ///                  function.
        /// * immediate_eof - Whether eof should be set immediately upon running out of input or if eof
        ///                   should be passed only after all input has been consumed.
        fn run_inc<OpFunc, NextInFunc, NextOutFunc>(
                input: &[u8],
                output: &mut [u8],
                mut op: OpFunc,
                mut next_in_len: NextInFunc,
                mut next_out_len: NextOutFunc,
                immediate_eof: bool)
                where
                    OpFunc: FnMut(&mut RefReadBuffer, &mut RefWriteBuffer, bool) ->
                        Result<BufferResult, SymmetricCipherError>,
                    NextInFunc: FnMut() -> usize,
                    NextOutFunc: FnMut() -> usize {
            use std::cell::Cell;

            let in_len = input.len();
            let out_len = output.len();

            let mut state: Result<BufferResult, SymmetricCipherError> = Ok(BufferUnderflow);
            let mut in_pos: usize = 0;
            let mut out_pos: usize = 0;
            let eof = Cell::new(false);

            let mut in_end = |in_pos: usize, primary: bool| {
                if eof.get() {
                    return in_len;
                }
                let x = next_in_len();
                if x >= in_len && immediate_eof {
                    eof.set(true);
                }
                cmp::min(in_len, in_pos + cmp::max(x, if primary { 1 } else { 0 }))
            };

            let mut out_end = |out_pos: usize| {
                let x = next_out_len();
                cmp::min(out_len, out_pos + cmp::max(x, 1))
            };

            loop {
                match state {
                    Ok(BufferUnderflow) => {
                        if in_pos == input.len() {
                            break;
                        }
                        let mut tmp_in = RefReadBuffer::new(&input[in_pos..in_end(in_pos, true)]);
                        let out_end = out_end(out_pos);
                        let mut tmp_out = RefWriteBuffer::new(&mut output[out_pos..out_end]);
                        state = op(&mut tmp_in, &mut tmp_out, eof.get());
                        match state {
                            Ok(BufferUnderflow) => assert!(tmp_in.is_empty()),
                            _ => {}
                        }
                        in_pos += tmp_in.position();
                        out_pos += tmp_out.position();
                    }
                    Ok(BufferOverflow) => {
                        let mut tmp_in = RefReadBuffer::new(&input[in_pos..in_end(in_pos, false)]);
                        let out_end = out_end(out_pos);
                        let mut tmp_out = RefWriteBuffer::new(&mut output[out_pos..out_end]);
                        state = op(&mut tmp_in, &mut tmp_out, eof.get());
                        match state {
                            Ok(BufferOverflow) => assert!(tmp_out.is_full()),
                            _ => {}
                        }
                        in_pos += tmp_in.position();
                        out_pos += tmp_out.position();
                    }
                    Err(InvalidPadding) => panic!("Invalid Padding"),
                    Err(InvalidLength) => panic!("Invalid Length")
                }
            }

            if !eof.get() {
                eof.set(true);
                let mut tmp_out = RefWriteBuffer::new(&mut output[out_pos..out_end(out_pos)]);
                state = op(&mut RefReadBuffer::new(&[]), &mut tmp_out, eof.get());
                out_pos += tmp_out.position();
            }

            loop {
                match state {
                    Ok(BufferUnderflow) => {
                        break;
                    }
                    Ok(BufferOverflow) => {
                        let out_end = out_end(out_pos);
                        let mut tmp_out = RefWriteBuffer::new(&mut output[out_pos..out_end]);
                        state = op(&mut RefReadBuffer::new(&[]), &mut tmp_out, eof.get());
                        assert!(tmp_out.is_full());
                        out_pos += tmp_out.position();
                    }
                    Err(InvalidPadding) => panic!("Invalid Padding"),
                    Err(InvalidLength) => panic!("Invalid Length")
                }
            }
        }

        fn run_inc1_test<T: CipherTest, E: Encryptor, D: Decryptor>(
                test: &T,
                enc: &mut E,
                dec: &mut D) {
            let mut cipher_out: Vec<u8> = repeat(0).take(test.get_cipher().len()).collect();
            run_inc(
                test.get_plain(),
                &mut cipher_out,
                |in_buff: &mut RefReadBuffer, out_buff: &mut RefWriteBuffer, eof: bool| {
                    enc.encrypt(in_buff, out_buff, eof)
                },
                || { 0 },
                || { 1 },
                false);
            assert!(test.get_cipher() == &cipher_out[..]);

            let mut plain_out: Vec<u8> = repeat(0).take(test.get_plain().len()).collect();
            run_inc(
                test.get_cipher(),
                &mut plain_out,
                |in_buff: &mut RefReadBuffer, out_buff: &mut RefWriteBuffer, eof: bool| {
                    dec.decrypt(in_buff, out_buff, eof)
                },
                || { 0 },
                || { 1 },
                false);
            assert!(test.get_plain() == &plain_out[..]);
        }

        fn run_rand_test<T, E, D, NewEncFunc, NewDecFunc>(
                test: &T,
                mut new_enc: NewEncFunc,
                mut new_dec: NewDecFunc)
                where
                    T: CipherTest,
                    E: Encryptor,
                    D: Decryptor,
                    NewEncFunc: FnMut() -> E,
                    NewDecFunc: FnMut() -> D{
            use rand;
            use rand::Rng;

            let tmp : &[_] = &[1, 2, 3, 4];
            let mut rng1: rand::StdRng = rand::SeedableRng::from_seed(tmp);
            let mut rng2: rand::StdRng = rand::SeedableRng::from_seed(tmp);
            let mut rng3: rand::StdRng = rand::SeedableRng::from_seed(tmp);
            let max_size = cmp::max(test.get_plain().len(), test.get_cipher().len());

            let mut r1 = || {
                rng1.gen_range(0, max_size)
            };
            let mut r2 = || {
                rng2.gen_range(0, max_size)
            };

            for _ in 0..1000 {
                let mut enc = new_enc();
                let mut dec = new_dec();

                let mut cipher_out: Vec<u8> = repeat(0).take(test.get_cipher().len()).collect();
                run_inc(
                    test.get_plain(),
                    &mut cipher_out,
                    |in_buff: &mut RefReadBuffer, out_buff: &mut RefWriteBuffer, eof: bool| {
                        enc.encrypt(in_buff, out_buff, eof)
                    },
                    || { r1() },
                    || { r2() },
                    rng3.gen());
                assert!(test.get_cipher() == &cipher_out[..]);

                let mut plain_out: Vec<u8> = repeat(0).take(test.get_plain().len()).collect();
                run_inc(
                    test.get_cipher(),
                    &mut plain_out,
                    |in_buff: &mut RefReadBuffer, out_buff: &mut RefWriteBuffer, eof: bool| {
                        dec.decrypt(in_buff, out_buff, eof)
                    },
                    || { r1() },
                    || { r2() },
                    rng3.gen());
                assert!(test.get_plain() == &plain_out[..]);
            }
        }

        fn run_test<T, E, D, NewEncFunc, NewDecFunc>(
                test: &T,
                mut new_enc: NewEncFunc,
                mut new_dec: NewDecFunc)
                where
                    T: CipherTest,
                    E: Encryptor,
                    D: Decryptor,
                    NewEncFunc: FnMut() -> E,
                    NewDecFunc: FnMut() -> D{
            run_full_test(test, &mut new_enc(), &mut new_dec());
            run_inc1_test(test, &mut new_enc(), &mut new_dec());
            run_rand_test(test, new_enc, new_dec);
        }

        #[test]
        fn aes_ecb_no_padding() {
            let tests = aes_ecb_no_padding_tests();
            for test in tests.iter() {
                run_test(
                    test,
                    || {
                        let aes_enc = aessafe::AesSafe128Encryptor::new(&test.key[..]);
                        EcbEncryptor::new(aes_enc, NoPadding)
                    },
                    || {
                        let aes_dec = aessafe::AesSafe128Decryptor::new(&test.key[..]);
                        EcbDecryptor::new(aes_dec, NoPadding)
                    });
            }
        }

        #[test]
        fn aes_ecb_pkcs_padding() {
            let tests = aes_ecb_pkcs_padding_tests();
            for test in tests.iter() {
                run_test(
                    test,
                    || {
                        let aes_enc = aessafe::AesSafe128Encryptor::new(&test.key[..]);
                        EcbEncryptor::new(aes_enc, PkcsPadding)
                    },
                    || {
                        let aes_dec = aessafe::AesSafe128Decryptor::new(&test.key[..]);
                        EcbDecryptor::new(aes_dec, PkcsPadding)
                    });
            }
        }

        #[test]
        fn aes_cbc_no_padding() {
            let tests = aes_cbc_no_padding_tests();
            for test in tests.iter() {
                run_test(
                    test,
                    || {
                        let aes_enc = aessafe::AesSafe128Encryptor::new(&test.key[..]);
                        CbcEncryptor::new(aes_enc, NoPadding, test.iv.clone())
                    },
                    || {
                        let aes_dec = aessafe::AesSafe128Decryptor::new(&test.key[..]);
                        CbcDecryptor::new(aes_dec, NoPadding, test.iv.clone())
                    });
            }
        }

        #[test]
        fn aes_cbc_pkcs_padding() {
            let tests = aes_cbc_pkcs_padding_tests();
            for test in tests.iter() {
                run_test(
                    test,
                    || {
                        let aes_enc = aessafe::AesSafe128Encryptor::new(&test.key[..]);
                        CbcEncryptor::new(aes_enc, PkcsPadding, test.iv.clone())
                    },
                    || {
                        let aes_dec = aessafe::AesSafe128Decryptor::new(&test.key[..]);
                        CbcDecryptor::new(aes_dec, PkcsPadding, test.iv.clone())
                    });
            }
        }

        #[test]
        fn aes_ctr() {
            let tests = aes_ctr_tests();
            for test in tests.iter() {
                run_test(
                    test,
                    || {
                        let aes_enc = aessafe::AesSafe128Encryptor::new(&test.key[..]);
                        CtrMode::new(aes_enc, test.ctr.clone())
                    },
                    || {
                        let aes_enc = aessafe::AesSafe128Encryptor::new(&test.key[..]);
                        CtrMode::new(aes_enc, test.ctr.clone())
                    });
            }
        }

        #[test]
        fn aes_ctr_x8() {
            let tests = aes_ctr_tests();
            for test in tests.iter() {
                run_test(
                    test,
                    || {
                        let aes_enc = aessafe::AesSafe128EncryptorX8::new(&test.key[..]);
                        CtrModeX8::new(aes_enc, &test.ctr[..])
                    },
                    || {
                        let aes_enc = aessafe::AesSafe128EncryptorX8::new(&test.key[..]);
                        CtrModeX8::new(aes_enc, &test.ctr[..])
                    });
            }
        }
    }

    #[cfg(all(test, feature = "with-bench"))]
    mod bench {
        use aessafe;
        use blockmodes::{EcbEncryptor, CbcEncryptor, CtrMode, CtrModeX8,
            NoPadding, PkcsPadding};
        use buffer::{ReadBuffer, WriteBuffer, RefReadBuffer, RefWriteBuffer};
        use buffer::BufferResult::{BufferUnderflow, BufferOverflow};
        use symmetriccipher::{Encryptor};

        use test::Bencher;

        #[bench]
        pub fn aes_ecb_no_padding_bench(bh: &mut Bencher) {
            let key = [1u8; 16];
            let plain = [3u8; 512];
            let mut cipher = [3u8; 528];

            let aes_enc = aessafe::AesSafe128Encryptor::new(&key);
            let mut enc = EcbEncryptor::new(aes_enc, NoPadding);

            bh.iter( || {
                enc.reset();

                let mut buff_in = RefReadBuffer::new(&plain);
                let mut buff_out = RefWriteBuffer::new(&mut cipher);

                match enc.encrypt(&mut buff_in, &mut buff_out, true) {
                    Ok(BufferUnderflow) => {}
                    Ok(BufferOverflow) => panic!("Encryption not completed"),
                    Err(_) => panic!("Error"),
                }
            });

            bh.bytes = (plain.len()) as u64;
        }

        #[bench]
        pub fn aes_cbc_pkcs_padding_bench(bh: &mut Bencher) {
            let key = [1u8; 16];
            let iv = [2u8; 16];
            let plain = [3u8; 512];
            let mut cipher = [3u8; 528];

            let aes_enc = aessafe::AesSafe128Encryptor::new(&key);
            let mut enc = CbcEncryptor::new(aes_enc, PkcsPadding, iv.to_vec());

            bh.iter( || {
                enc.reset(&iv);

                let mut buff_in = RefReadBuffer::new(&plain);
                let mut buff_out = RefWriteBuffer::new(&mut cipher);

                match enc.encrypt(&mut buff_in, &mut buff_out, true) {
                    Ok(BufferUnderflow) => {}
                    Ok(BufferOverflow) => panic!("Encryption not completed"),
                    Err(_) => panic!("Error"),
                }
            });

            bh.bytes = (plain.len()) as u64;
        }

        #[bench]
        pub fn aes_ctr_bench(bh: &mut Bencher) {
            let key = [1u8; 16];
            let ctr = [2u8; 16];
            let plain = [3u8; 512];
            let mut cipher = [3u8; 528];

            let aes_enc = aessafe::AesSafe128Encryptor::new(&key);
            let mut enc = CtrMode::new(aes_enc, ctr.to_vec());

            bh.iter( || {
                enc.reset(&ctr);

                let mut buff_in = RefReadBuffer::new(&plain);
                let mut buff_out = RefWriteBuffer::new(&mut cipher);

                match enc.encrypt(&mut buff_in, &mut buff_out, true) {
                    Ok(BufferUnderflow) => {}
                    Ok(BufferOverflow) => panic!("Encryption not completed"),
                    Err(_) => panic!("Error"),
                }
            });

            bh.bytes = (plain.len()) as u64;
        }

        #[bench]
        pub fn aes_ctr_x8_bench(bh: &mut Bencher) {
            let key = [1u8; 16];
            let ctr = [2u8; 16];
            let plain = [3u8; 512];
            let mut cipher = [3u8; 528];

            let aes_enc = aessafe::AesSafe128EncryptorX8::new(&key);
            let mut enc = CtrModeX8::new(aes_enc, &ctr);

            bh.iter( || {
                enc.reset(&ctr);

                let mut buff_in = RefReadBuffer::new(&plain);
                let mut buff_out = RefWriteBuffer::new(&mut cipher);

                match enc.encrypt(&mut buff_in, &mut buff_out, true) {
                    Ok(BufferUnderflow) => {}
                    Ok(BufferOverflow) => panic!("Encryption not completed"),
                    Err(_) => panic!("Error"),
                }
            });

            bh.bytes = (plain.len()) as u64;
        }
    }

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