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use std::io::{self,Write,BufWriter,Seek,SeekFrom};
use std::fs::File;
use std::path::Path;
use std::marker::PhantomData;
use byteorder::{WriteBytesExt, LittleEndian};
use crate::serialize::{AutoSerialize, Serialize, TypeWrite};
use crate::header::{self, DType, VersionProps, HeaderSizeType, HeaderEncoding};
use crate::read::Order;
// Long enough to accomodate a large integer followed by ",), }".
// Used when no shape is provided.
const FILLER_FOR_UNKNOWN_SIZE: &'static [u8] = &[b'*'; 19];
struct DataFromBuilder<T: ?Sized> {
order: Order,
dtype: DType,
shape: Option<Vec<u64>>,
_marker: PhantomData<fn(&T)>, // contravariant
}
pub use write_options::{WriteOptions, WriterBuilder};
pub mod write_options {
//! Types and traits related to the implementation of [`WriteOptions`].
//!
//! There are numerous types and traits involved in the implementation of [`WriteOptions`].
//! Most of them are not that important; their purpose is to implement a form of typestate.
//! E.g. you are forbidden from calling [`WriterBuilder::begin_nd`] until you have called
//! [`WriterBuilder::shape`], [`WriterBuilder::dtype`], and [`WriterBuilder::writer`].
//!
//! The most important things from this module ([`WriteOptions`] and [`WriterBuilder`]) are exported
//! from the root of the crate, so you typically do not need to look in here.
use super::*;
/// Represents an almost-empty configuration for an [`NpyWriter`].
///
/// Construction of an [`NpyWriter`] always begins here, with a call to [`WriteOptions::new`].
/// Then the methods of the [`WriterBuilder`] trait must be used to supply options.
/// See that trait for more details.
#[derive(Debug)]
pub struct WriteOptions<T: ?Sized> {
order: Order,
_marker: PhantomData<fn(&T)>, // contravariant
}
impl<T: ?Sized> WriteOptions<T> {
/// Construct an almost empty Writer configuration.
pub fn new() -> Self { WriteOptions {
order: Order::C,
_marker: PhantomData,
}}
}
impl<T: ?Sized> Default for WriteOptions<T> {
fn default() -> Self { Self::new() }
}
impl<T: ?Sized> Clone for WriteOptions<T> {
fn clone(&self) -> Self { WriteOptions { order: self.order.clone(), _marker: self._marker }}
}
/// Trait that provides methods on [`WriteOptions`].
///
/// To obtain an initial instance of this trait, call [`WriteOptions::new`].
///
/// The majority of methods return a type that also implements [`WriterBuilder`]; they are meant
/// to be chained together to construct a full config.
pub trait WriterBuilder<T: Serialize + ?Sized>: Sized {
/// Calls [`Self::dtype`] with the default dtype for the type to be serialized.
///
/// **Calling this method or [`Self::dtype`] is required.**
fn default_dtype(self) -> WithDType<Self> where T: AutoSerialize { self.dtype(T::default_dtype()) }
/// Use the specified dtype.
///
/// **Calling `dtype` (or [`Self::default_dtype`]) is required.**
fn dtype(self, dtype: DType) -> WithDType<Self> { WithDType { inner: self, dtype } }
/// Set the shape for an n-d array.
///
/// This is required for any array of dimension `!= 1`.
fn shape(self, shape: &[u64]) -> WithShape<Self> { WithShape { inner: self, shape: shape.to_vec() } }
/// Set the ouput [`Write`] object.
///
/// **Calling this method is required.** In some cases (e.g. the builder obtained from an [`NpzWriter`][crate::npz::NpzWriter]),
/// it will already have been called for you.
fn writer<W>(self, writer: W) -> WithWriter<W, Self>
where
Self: MissingWriter,
{ WithWriter { inner: self, writer } }
/// Set the data order for arrays with more than one dimension.
///
/// If this is not called, `Order::C` is assumed.
fn order(self, order: Order) -> Self;
// getters for properties not encoded in typestate
#[doc(hidden)] fn __get_order(&self) -> Order;
/// Begin writing an array of the previously supplied [`shape`][Self::shape].
fn begin_nd(self) -> io::Result<NpyWriter<T, <Self as HasWriter>::Writer>>
where
Self: HasDType + HasWriter + HasShape,
<Self as HasWriter>::Writer: Write,
{
NpyWriter::_begin(DataFromBuilder {
dtype: self.__get_dtype(),
order: self.__get_order(),
shape: Some(self.__get_shape()),
_marker: PhantomData,
}, MaybeSeek::Isnt(self.__into_writer()))
}
/// Begin writing a 1d array, of length to be inferred from the number of elements written.
///
/// Notice that, in contrast to [`Self::begin_nd`], this method requires [`Seek`]. If you have
/// a `Vec<u8>`, you can wrap it in an [`io::Cursor`] to satisfy this requirement.
///
/// **Note:** At present, any [`shape`][Self::shape] you *did* happen to provide will be ignored and not
/// validated against the number of elements written. This may change in the future.
fn begin_1d(self) -> io::Result<NpyWriter<T, <Self as HasWriter>::Writer>>
where
Self: HasDType + HasWriter,
<Self as HasWriter>::Writer: Write + Seek,
{
NpyWriter::_begin(DataFromBuilder {
dtype: self.__get_dtype(),
order: self.__get_order(),
shape: None,
_marker: PhantomData,
}, MaybeSeek::new_seek(self.__into_writer()))
}
}
/// Return type of [`WriterBuilder::writer`]. It represents a config with a known output stream.
#[derive(Debug, Clone)]
pub struct WithWriter<W, Builder> {
pub(super) writer: W,
pub(super) inner: Builder,
}
/// Return type of [`WriterBuilder::dtype`]. It represents a config with a known dtype.
#[derive(Debug, Clone)]
pub struct WithDType<Builder> {
pub(super) dtype: DType,
pub(super) inner: Builder,
}
/// Return type of [`WriterBuilder::shape`]. It represents a config with a known array shape.
#[derive(Debug, Clone)]
pub struct WithShape<Builder> {
pub(super) shape: Vec<u64>,
pub(super) inner: Builder,
}
/// Indicates that a Writer options type includes a DType.
///
/// If you are receiving the following compiler error:
///
/// > ```text
/// > the trait bound `npyz::WriteOptions<_>: npyz::write_options::HasDType` is not satisfied
/// > ```
///
/// Then it is most likely because you are missing a call to [`WriterBuilder::dtype`]
/// or [`WriterBuilder::default_dtype`].
pub trait HasDType {
#[doc(hidden)] fn __get_dtype(&self) -> DType;
}
/// Indicates that a Writer options type includes a shape.
///
/// If you are receiving the following compiler error:
///
/// > ```text
/// > the trait bound `npyz::WriteOptions<i64>: npyz::write_options::HasShape` is not satisfied
/// > ```
///
/// Then it is most likely because you are missing a call to [`WriterBuilder::shape`].
pub trait HasShape {
#[doc(hidden)] fn __get_shape(&self) -> Vec<u64>;
}
/// Indicates that a Writer options type includes an output stream.
///
/// If you are receiving the following compiler error:
///
/// > ```text
/// > the trait bound `npyz::WriteOptions<i64>: npyz::write_options::HasWriter` is not satisfied
/// > ```
///
/// Then it is most likely because you are missing a call to [`WriterBuilder::writer`].
pub trait HasWriter {
/// The type of the output stream.
type Writer;
#[doc(hidden)]
fn __into_writer(self) -> Self::Writer;
}
// NOTE: This mainly exists to prevent the accidental usage of `.writer()` when working with NPZ files.
// (somebody could absent-mindedly copy a piece of Builder code that writes to `Cursor<Vec<u8>>`,
// and this wouldn't generate an "unused" warning due to the `&mut cursor`)
//
/// Indicates that a Writer options type does not yet have an output stream.
///
/// If you are receiving the following compiler error:
///
/// > ```text
/// > the trait bound `npyz::write_options::HasWriter<...>: npyz::write_options::MissingWriter` is not satisfied
/// > ```
///
/// Then it is most likely because you are calling [`WriterBuilder::writer`] on a builder
/// that already has a writer. For instance, [`NpzWriter::array`][crate::npz::NpzWriter::array] comes with a writer,
/// so you do not need to add one.
pub trait MissingWriter {}
impl<T: Serialize + ?Sized> WriterBuilder<T> for WriteOptions<T> {
fn order(mut self, order: Order) -> Self { self.order = order; self }
fn __get_order(&self) -> Order { self.order }
}
impl<W, T: Serialize + ?Sized, B: WriterBuilder<T>> WriterBuilder<T> for WithWriter<W, B> {
fn order(mut self, order: Order) -> Self { self.inner = self.inner.order(order); self }
fn __get_order(&self) -> Order { self.inner.__get_order() }
}
impl<T: Serialize + ?Sized, B: WriterBuilder<T>> WriterBuilder<T> for WithDType<B> {
fn order(mut self, order: Order) -> Self { self.inner = self.inner.order(order); self }
fn __get_order(&self) -> Order { self.inner.__get_order() }
}
impl<T: Serialize + ?Sized, B: WriterBuilder<T>> WriterBuilder<T> for WithShape<B> {
fn order(mut self, order: Order) -> Self { self.inner = self.inner.order(order); self }
fn __get_order(&self) -> Order { self.inner.__get_order() }
}
// Now the silly part where we have to write O(n^2) trait impls
// Base cases
impl<B> HasDType for WithDType<B> {
fn __get_dtype(&self) -> DType { self.dtype.clone() }
}
impl<B> HasShape for WithShape<B> {
fn __get_shape(&self) -> Vec<u64> { self.shape.to_vec() }
}
impl<W, B> HasWriter for WithWriter<W, B> {
type Writer = W;
fn __into_writer(self) -> Self::Writer { self.writer }
}
impl<T: ?Sized> MissingWriter for WriteOptions<T> {}
// Recursive cases
macro_rules! forward_typestate_impls {
( $(
( $inner:tt $impl_generics:tt $Self:tt ): ( $($Trait:ident)* )
)* ) => {
$($( forward_typestate_impls!(@single $inner $impl_generics $Self [$Trait]); )*)*
};
(@single [$inner:ident] [$($impl_generics:tt)*] [$Self:ty] [HasDType]) => {
impl<$($impl_generics)*> HasDType for $Self where $inner: HasDType {
fn __get_dtype(&self) -> DType { self.inner.__get_dtype() }
}
};
(@single [$inner:ident] [$($impl_generics:tt)*] [$Self:ty] [HasShape]) => {
impl<$($impl_generics)*> HasShape for $Self where $inner: HasShape {
fn __get_shape(&self) -> Vec<u64> { self.inner.__get_shape() }
}
};
(@single [$inner:ident] [$($impl_generics:tt)*] [$Self:ty] [HasWriter]) => {
impl<$($impl_generics)*> HasWriter for $Self where $inner: HasWriter {
type Writer = $inner::Writer;
fn __into_writer(self) -> Self::Writer { self.inner.__into_writer() }
}
};
(@single [$inner:ident] [$($impl_generics:tt)*] [$Self:ty] [MissingWriter]) => {
impl<$($impl_generics)*> MissingWriter for $Self where $inner: MissingWriter { }
};
}
forward_typestate_impls!{
([B] [B] [WithShape<B>]): (/*HasShape*/ HasDType HasWriter MissingWriter)
([B] [B] [WithDType<B>]): (HasShape /*HasDType*/ HasWriter MissingWriter)
([B] [W, B] [WithWriter<W, B>]): (HasShape HasDType /*HasWriter MissingWriter*/)
}
}
/// Interface for writing an NPY file to a data stream.
///
/// To construct an instance of this, you must go through the [`WriterBuilder`] trait:
///
/// <!-- example so nobody has an excuse for not seeing the link to WriterBuilder -->
/// ```rust
/// use npyz::WriterBuilder;
///
/// fn main() -> std::io::Result<()> {
/// // Any io::Write is supported. For this example we'll
/// // use Vec<u8> to serialize in-memory.
/// let mut out_buf = vec![];
/// let mut writer = {
/// npyz::WriteOptions::new()
/// .default_dtype()
/// .shape(&[2, 3])
/// .writer(&mut out_buf)
/// .begin_nd()?
/// };
///
/// writer.push(&100)?;
/// writer.push(&101)?;
/// writer.push(&102)?;
/// // can write elements from iterators too
/// writer.extend(vec![200, 201, 202])?;
/// writer.finish()?;
///
/// eprintln!("{:02x?}", out_buf);
/// Ok(())
/// }
/// ```
pub struct NpyWriter<Row: Serialize + ?Sized, W: Write> {
start_pos: Option<u64>,
shape_info: ShapeInfo,
num_items: u64,
fw: MaybeSeek<W>,
writer: <Row as Serialize>::TypeWriter,
version_props: VersionProps,
}
enum ShapeInfo {
// No shape was written; we'll return to write a 1D shape on `finish()`.
Automatic { offset_in_header_text: u64 },
// The complete shape has already been written.
// Raise an error on `finish()` if the wrong number of elements is given.
Known { expected_num_items: u64 },
}
/// [`NpyWriter`] that writes an entire file.
#[deprecated(since = "0.5.0", note = "Doesn't carry its weight. Use to_file_1d instead, or replicate the original behavior with Builder::new().default_dtype().begin_1d(std::io::BufWriter::new(std::fs::File::create(path)?))")]
pub type OutFile<Row> = NpyWriter<Row, BufWriter<File>>;
#[allow(deprecated)]
impl<Row: AutoSerialize> OutFile<Row> {
/// Create a file, using the default format for the given type.
#[deprecated(since = "0.5.0", note = "Doesn't carry its weight. Use to_file_1d instead, or replicate the original behavior with Builder::new().default_dtype().begin_1d(std::io::BufWriter::new(std::fs::File::create(path)?))")]
pub fn open<P: AsRef<Path>>(path: P) -> io::Result<Self> {
WriteOptions::new()
.default_dtype()
.writer(BufWriter::new(File::create(path)?))
.begin_1d()
}
}
#[allow(deprecated)]
impl<Row: Serialize> OutFile<Row> {
/// Finish writing the file and close it. Alias for [`NpyWriter::finish`].
///
/// If omitted, the file will be closed on drop automatically, ignoring any errors
/// encountered during the process.
#[deprecated(since = "0.5.0", note = "use .finish() instead")]
pub fn close(self) -> io::Result<()> {
self.finish()
}
}
impl<Row: Serialize + ?Sized , W: Write> NpyWriter<Row, W> {
fn _begin(builder: DataFromBuilder<Row>, mut fw: MaybeSeek<W>) -> io::Result<Self> {
let DataFromBuilder { dtype, order, shape, _marker } = builder;
let start_pos = match fw {
MaybeSeek::Is(ref mut fw) => Some(fw.seek(SeekFrom::Current(0))?),
MaybeSeek::Isnt(_) => None,
};
if let DType::Array(..) = dtype {
panic!("the outermost dtype cannot be an array (got: {:?})", dtype);
}
let (dict_text, shape_info) = create_dict(&dtype, order, shape.as_deref());
let (header_text, version, version_props) = determine_required_version_and_pad_header(dict_text);
fw.write_all(&[0x93u8])?;
fw.write_all(b"NUMPY")?;
fw.write_all(&[version.0, version.1])?;
assert_eq!((header_text.len() + version_props.bytes_before_text()) % 16, 0);
match version_props.header_size_type {
HeaderSizeType::U16 => {
assert!(header_text.len() <= u16::MAX as usize);
fw.write_u16::<LittleEndian>(header_text.len() as u16)?;
},
HeaderSizeType::U32 => {
assert!(header_text.len() <= u32::MAX as usize);
fw.write_u32::<LittleEndian>(header_text.len() as u32)?;
},
}
fw.write_all(&header_text)?;
let writer = match Row::writer(&dtype) {
Ok(writer) => writer,
Err(e) => return Err(io::Error::new(io::ErrorKind::InvalidData, e.to_string())),
};
Ok(NpyWriter {
start_pos,
shape_info,
num_items: 0,
fw,
writer,
version_props,
})
}
/// Append a single row to the file
pub fn push(&mut self, row: &Row) -> io::Result<()> {
self.num_items += 1;
self.writer.write_one(&mut self.fw, row)
}
/// Write an iterator to the file
pub fn extend(&mut self, rows: impl IntoIterator<Item=Row>) -> io::Result<()> where Row: Sized {
rows.into_iter().try_for_each(|row| self.push(&row))
}
fn finish_(&mut self) -> io::Result<()> {
match self.shape_info {
ShapeInfo::Known { expected_num_items } => {
if expected_num_items != self.num_items {
return Err(io::Error::new(io::ErrorKind::InvalidData, {
format!("shape has {} item(s), but {} item(s) were written!", expected_num_items, self.num_items)
}));
}
},
ShapeInfo::Automatic { offset_in_header_text } => {
// Write the size to the header
let shape_pos = self.start_pos.unwrap() + self.version_props.bytes_before_text() as u64 + offset_in_header_text;
let end_pos = self.fw.seek(SeekFrom::Current(0))?;
self.fw.seek(SeekFrom::Start(shape_pos))?;
let length = format!("{}", self.num_items);
self.fw.write_all(length.as_bytes())?;
self.fw.write_all(&b",), }"[..])?;
self.fw.write_all(&::std::iter::repeat(b' ').take(FILLER_FOR_UNKNOWN_SIZE.len() - length.len()).collect::<Vec<_>>())?;
self.fw.seek(SeekFrom::Start(end_pos))?;
},
}
self.fw.flush()?;
Ok(())
}
/// Finish writing the file.
///
/// If no shape was provided, this will update the header to reflect the number of
/// elements written. If a shape was provided and the number of inserted elements is
/// incorrect, an error is returned.
///
/// This is automatically called on drop, but in that case, errors are ignored.
pub fn finish(mut self) -> io::Result<()> {
self.finish_()
}
}
fn create_dict(dtype: &DType, order: Order, shape: Option<&[u64]>) -> (Vec<u8>, ShapeInfo) {
let mut header: Vec<u8> = vec![];
header.extend(&b"{'descr': "[..]);
header.extend(dtype.descr().as_bytes());
header.extend(&b", 'fortran_order': "[..]);
match order {
Order::C => header.extend(&b"False"[..]),
Order::Fortran => header.extend(&b"True"[..]),
}
header.extend(&b", 'shape': ("[..]);
let shape_info = match shape {
Some(shape) => {
for x in shape {
write!(header, "{}, ", x).unwrap();
}
header.extend(&b"), }"[..]);
ShapeInfo::Known { expected_num_items: shape.iter().product() }
},
None => {
let shape_offset = header.len() as u64;
header.extend(FILLER_FOR_UNKNOWN_SIZE);
header.extend(&b",), }"[..]);
ShapeInfo::Automatic { offset_in_header_text: shape_offset }
},
};
(header, shape_info)
}
impl<Row: Serialize + ?Sized, W: Write> Drop for NpyWriter<Row, W> {
fn drop(&mut self) {
let _ = self.finish_(); // Ignore the errors
}
}
/// This does two things:
///
/// - Get the minimum version required to write a file, based on its header text.
/// - Pad the end of the header text so that the data begins aligned to 16 bytes.
///
/// Why must it do these together? It turns out there's a tricky corner-case interaction for
/// header lengths close to but *just under* 65536, where the padding can push the length over
/// the 65536 threshold, causing version 2 to be used and therefore use 2 additional bytes.
/// Those additional bytes in turn could throw off the padding.
fn determine_required_version_and_pad_header(mut header_utf8: Vec<u8>) -> (Vec<u8>, (u8, u8), VersionProps) {
use HeaderSizeType::*;
use HeaderEncoding::*;
// I'm almost 100% certain that, when regarding the initial length of dict_utf8,
// there is a precise value at which the optimal version suddenly switches from 1 to 2.
// I think it is either 65524, 65525, or 65526; just not sure which. (the newline makes it weird)
//
// Unfortunately testing this edge case is not easy, so to be safe we'll give ourselves more wiggle
// room than could possibly ever be affected by padding and/or pre-header bytes. - ExpHP
const SAFE_U16_CUTOFF: usize = 0xffff_fc00; // = 0x1_0000_0000 - 0x400 (which doesn't compile on WASM)
let required_props = VersionProps {
header_size_type: if header_utf8.len() >= SAFE_U16_CUTOFF { U32 } else { U16 },
encoding: if header_utf8.iter().any(|b| !b.is_ascii()) { Utf8 } else { Ascii },
};
let version = header::get_minimal_version(required_props);
// Actual props may differ from required props. (e.g. if it has unicode, then it needs
// to use version 3 which will cause the size to be upgraded to U32 even if not needed)
let actual_props = header::get_version_props(version).expect("generated internally so must be valid");
// Now pad using the final choice of version.
//
// From the numpy documentation:
//
// It is terminated by a newline (\n) and padded with spaces (\x20) to make the total of
// len(magic string) + 2 + len(length) + HEADER_LEN be evenly divisible by 64 for alignment purposes.
const ALIGN_TO: usize = 64;
let bytes_before_text = actual_props.bytes_before_text();
header_utf8.extend(&::std::iter::repeat(b' ').take(ALIGN_TO - 1 - ((header_utf8.len() + bytes_before_text) % ALIGN_TO)).collect::<Vec<_>>());
header_utf8.push(b'\n');
assert_eq!((header_utf8.len() + bytes_before_text) % ALIGN_TO, 0);
(header_utf8, version, actual_props)
}
#[deprecated(since = "0.5.0", note = "renamed to to_file_1d")]
/// Serialize an iterator over a struct to a NPY file.
///
/// This only saves a 1D array. To save an ND array, **you must use the [`WriterBuilder`] API.**
pub fn to_file<S, T, P>(filename: P, data: T) -> std::io::Result<()>
where
P: AsRef<Path>,
S: AutoSerialize,
T: IntoIterator<Item=S>,
{
to_file_1d(filename, data)
}
/// Serialize an iterator over a struct to a NPY file.
///
/// This only saves a 1D array. To save an ND array, **you must use the [`WriterBuilder`] API.**
pub fn to_file_1d<S, T, P>(filename: P, data: T) -> std::io::Result<()>
where
P: AsRef<Path>,
S: AutoSerialize,
T: IntoIterator<Item=S>,
{
#![allow(deprecated)]
let mut of = OutFile::open(filename)?;
for row in data {
of.push(&row)?;
}
of.close()
}
// module encapsulating the unsafety of MaybeSeek
use maybe_seek::MaybeSeek;
mod maybe_seek {
use super::*;
// A writer that implements Seek even if W doesn't (by potentially panicking).
//
// The peculiar design of this is explained in greater detail here:
// https://github.com/ExpHP/npyz/issues/42#issuecomment-873263846
pub(crate) enum MaybeSeek<W> {
// a trait object is needed to smuggle in access to Seek methods without every method needing a Seek bound
Is(Box<dyn WriteSeek<W>>),
Isnt(W),
}
// Note: W = Self. It is used to allow W to stand in for the "lifetime" of W
// when casting W to a trait object.
pub(crate) trait WriteSeek<W>: Write + Seek + sealed::Sealed<W> {}
mod sealed {
use super::*;
pub(crate) trait Sealed<W> {}
impl<W: Write + Seek> Sealed<W> for W {}
}
impl<W: Write + Seek> WriteSeek<W> for W {}
impl<W: Write> Write for MaybeSeek<W> {
fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
match self {
MaybeSeek::Is(w) => (*w).write(buf),
MaybeSeek::Isnt(w) => w.write(buf),
}
}
fn flush(&mut self) -> io::Result<()> {
match self {
MaybeSeek::Is(w) => (*w).flush(),
MaybeSeek::Isnt(w) => w.flush(),
}
}
}
impl<W> Seek for MaybeSeek<W> {
fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
match self {
MaybeSeek::Is(w) => (*w).seek(pos),
MaybeSeek::Isnt(_) => unreachable!("(BUG!) .seek() called on MaybeSeek::Isnt!"),
}
}
}
impl<W: WriteSeek<W>> MaybeSeek<W> {
pub fn new_seek(w: W) -> Self {
let inner = unsafe {
// The Self type is W, so all lifetime information contained in the unnamed
// lifetime here is also contained in W.
//
// Because `dyn WriteSeek<W> + '_` is invariant in W, the compiler will
// conservatively assume that it carries all borrows held by W; just as if
// we *hadn't* erased the lifetime.
//
// See discussion here:
// https://users.rust-lang.org/t/a-trait-object-with-an-implied-lifetime/29340
std::mem::transmute::<
Box<dyn WriteSeek<W> + '_>,
Box<dyn WriteSeek<W> + 'static>,
>(Box::new(w))
};
MaybeSeek::Is(inner)
}
}
}
/// Quick API for writing a 1D array to a vector of bytes.
#[cfg(test)]
pub(crate) fn to_bytes_1d<T: AutoSerialize>(data: &[T]) -> io::Result<Vec<u8>> {
let mut cursor = io::Cursor::new(vec![]);
to_writer_1d(&mut cursor, data)?;
Ok(cursor.into_inner())
}
/// Quick API for writing a 1D array to an io::Write.
#[cfg(test)]
pub(crate) fn to_writer_1d<W: io::Write + io::Seek, T: AutoSerialize>(writer: W, data: &[T]) -> io::Result<()> {
// we might change this later and/or remove the Seek bound from the current function, but for now this will do
to_writer_1d_with_seeking(writer, data)
}
/// Quick API for writing an n-d array to an io::Write.
#[cfg(test)]
pub(crate) fn to_writer_nd<W: io::Write, T: AutoSerialize>(writer: W, data: &[T], shape: &[u64]) -> io::Result<()> {
let mut writer = WriteOptions::new().default_dtype().writer(writer).shape(shape).begin_nd()?;
writer.extend(data)?;
writer.finish()
}
/// Quick API for writing a 1D array to an io::Write in a manner which makes use of io::Seek.
///
/// (tests will use this instead of 'to_writer_1d' if their purpose is to test the correctness of seek behavior,
/// so that changing 'to_writer_1d' to be Seek-less won't affect these tests)
#[cfg(test)]
pub(crate) fn to_writer_1d_with_seeking<W: io::Write + io::Seek, T: AutoSerialize>(writer: W, data: &[T]) -> io::Result<()> {
let mut writer = WriteOptions::new().default_dtype().writer(writer).begin_1d()?;
writer.extend(data)?;
writer.finish()
}
#[cfg(test)]
mod tests {
use super::*;
use std::io::{self, Cursor};
use crate::NpyFile;
fn bytestring_contains(haystack: &[u8], needle: &[u8]) -> bool {
if needle.is_empty() {
return true;
}
haystack.windows(needle.len()).any(move |w| w == needle)
}
#[test]
fn write_1d_simple() -> io::Result<()> {
let raw_buffer = to_bytes_1d(&[1.0, 3.0, 5.0])?;
let reader = NpyFile::new(&raw_buffer[..])?;
assert_eq!(reader.into_vec::<f64>()?, vec![1.0, 3.0, 5.0]);
Ok(())
}
#[test]
fn write_1d_in_the_middle() -> io::Result<()> {
let mut cursor = Cursor::new(vec![]);
let prefix = b"lorem ipsum dolor sit amet.";
let suffix = b"and they lived happily ever after.";
// write to the cursor both before and after writing the file
cursor.write_all(prefix)?;
to_writer_1d_with_seeking(&mut cursor, &[1.0, 3.0, 5.0])?;
cursor.write_all(suffix)?;
// check that the seeking did not interfere with our extra writes
let raw_buffer = cursor.into_inner();
assert!(raw_buffer.starts_with(prefix));
assert!(raw_buffer.ends_with(suffix));
// check the bytes written by `OutFile`
let written_bytes = &raw_buffer[prefix.len()..raw_buffer.len() - suffix.len()];
let reader = NpyFile::new(&written_bytes[..])?;
assert_eq!(reader.into_vec::<f64>()?, vec![1.0, 3.0, 5.0]);
Ok(())
}
#[test]
fn implicit_finish() -> io::Result<()> {
let mut cursor = Cursor::new(vec![]);
let mut writer = WriteOptions::new().default_dtype().writer(&mut cursor).begin_1d()?;
writer.extend(vec![1.0, 3.0, 5.0, 7.0])?;
// don't call finish
drop(writer);
// check that the shape was written
let raw_buffer = cursor.into_inner();
println!("{:?}", raw_buffer);
assert!(bytestring_contains(&raw_buffer, b"'shape': (4,"));
Ok(())
}
#[test]
fn write_nd_simple() -> io::Result<()> {
let mut buffer = vec![];
to_writer_nd(&mut buffer, &[00, 01, 02, 10, 11, 12], &[2, 3])?;
let reader = NpyFile::new(&buffer[..])?;
assert_eq!(reader.shape(), &[2, 3][..]);
assert_eq!(reader.into_vec::<i32>()?, vec![00, 01, 02, 10, 11, 12]);
Ok(())
}
#[test]
fn write_nd_wrong_len() -> io::Result<()> {
let try_writing = |elems: &[i32]| -> io::Result<()> {
let mut buf = vec![];
let mut writer = WriteOptions::new().default_dtype().writer(&mut buf).shape(&[2, 3]).begin_nd()?;
for &x in elems {
writer.push(&x)?;
}
writer.finish()?;
Ok(())
};
assert!(try_writing(&[00, 01, 02, 10, 11]).is_err());
assert!(try_writing(&[00, 01, 02, 10, 11, 12]).is_ok());
assert!(try_writing(&[00, 01, 02, 10, 11, 12, 20]).is_err());
Ok(())
}
}