1 files changed, 260 insertions, 0 deletions
diff --git a/vendor/object/src/write/util.rs b/vendor/object/src/write/util.rs
new file mode 100644
index 0000000..f7ee2f4
--- /dev/null
+++ b/vendor/object/src/write/util.rs
@@ -0,0 +1,260 @@
+use alloc::vec::Vec;
+#[cfg(feature = "std")]
+use std::{io, mem};
+
+use crate::pod::{bytes_of, bytes_of_slice, Pod};
+
+/// Trait for writable buffer.
+#[allow(clippy::len_without_is_empty)]
+pub trait WritableBuffer {
+    /// Returns position/offset for data to be written at.
+    ///
+    /// Should only be used in debug assertions
+    fn len(&self) -> usize;
+
+    /// Reserves specified number of bytes in the buffer.
+    ///
+    /// This will be called exactly once before writing anything to the buffer,
+    /// and the given size is the exact total number of bytes that will be written.
+    fn reserve(&mut self, size: usize) -> Result<(), ()>;
+
+    /// Writes zero bytes at the end of the buffer until the buffer
+    /// has the specified length.
+    fn resize(&mut self, new_len: usize);
+
+    /// Writes the specified slice of bytes at the end of the buffer.
+    fn write_bytes(&mut self, val: &[u8]);
+
+    /// Writes the specified `Pod` type at the end of the buffer.
+    fn write_pod<T: Pod>(&mut self, val: &T)
+    where
+        Self: Sized,
+    {
+        self.write_bytes(bytes_of(val))
+    }
+
+    /// Writes the specified `Pod` slice at the end of the buffer.
+    fn write_pod_slice<T: Pod>(&mut self, val: &[T])
+    where
+        Self: Sized,
+    {
+        self.write_bytes(bytes_of_slice(val))
+    }
+}
+
+impl<'a> dyn WritableBuffer + 'a {
+    /// Writes the specified `Pod` type at the end of the buffer.
+    pub fn write<T: Pod>(&mut self, val: &T) {
+        self.write_bytes(bytes_of(val))
+    }
+
+    /// Writes the specified `Pod` slice at the end of the buffer.
+    pub fn write_slice<T: Pod>(&mut self, val: &[T]) {
+        self.write_bytes(bytes_of_slice(val))
+    }
+}
+
+impl WritableBuffer for Vec<u8> {
+    #[inline]
+    fn len(&self) -> usize {
+        self.len()
+    }
+
+    #[inline]
+    fn reserve(&mut self, size: usize) -> Result<(), ()> {
+        debug_assert!(self.is_empty());
+        self.reserve(size);
+        Ok(())
+    }
+
+    #[inline]
+    fn resize(&mut self, new_len: usize) {
+        debug_assert!(new_len >= self.len());
+        self.resize(new_len, 0);
+    }
+
+    #[inline]
+    fn write_bytes(&mut self, val: &[u8]) {
+        debug_assert!(self.len() + val.len() <= self.capacity());
+        self.extend_from_slice(val)
+    }
+}
+
+/// A [`WritableBuffer`] that streams data to a [`Write`](std::io::Write) implementation.
+///
+/// [`Self::result`] must be called to determine if an I/O error occurred during writing.
+///
+/// It is advisable to use a buffered writer like [`BufWriter`](std::io::BufWriter)
+/// instead of an unbuffered writer like [`File`](std::fs::File).
+#[cfg(feature = "std")]
+#[derive(Debug)]
+pub struct StreamingBuffer<W> {
+    writer: W,
+    len: usize,
+    result: Result<(), io::Error>,
+}
+
+#[cfg(feature = "std")]
+impl<W> StreamingBuffer<W> {
+    /// Create a new `StreamingBuffer` backed by the given writer.
+    pub fn new(writer: W) -> Self {
+        StreamingBuffer {
+            writer,
+            len: 0,
+            result: Ok(()),
+        }
+    }
+
+    /// Unwraps this [`StreamingBuffer`] giving back the original writer.
+    pub fn into_inner(self) -> W {
+        self.writer
+    }
+
+    /// Returns any error that occurred during writing.
+    pub fn result(&mut self) -> Result<(), io::Error> {
+        mem::replace(&mut self.result, Ok(()))
+    }
+}
+
+#[cfg(feature = "std")]
+impl<W: io::Write> WritableBuffer for StreamingBuffer<W> {
+    #[inline]
+    fn len(&self) -> usize {
+        self.len
+    }
+
+    #[inline]
+    fn reserve(&mut self, _size: usize) -> Result<(), ()> {
+        Ok(())
+    }
+
+    #[inline]
+    fn resize(&mut self, new_len: usize) {
+        debug_assert!(self.len <= new_len);
+        while self.len < new_len {
+            let write_amt = (new_len - self.len - 1) % 1024 + 1;
+            self.write_bytes(&[0; 1024][..write_amt]);
+        }
+    }
+
+    #[inline]
+    fn write_bytes(&mut self, val: &[u8]) {
+        if self.result.is_ok() {
+            self.result = self.writer.write_all(val);
+        }
+        self.len += val.len();
+    }
+}
+
+/// A trait for mutable byte slices.
+///
+/// It provides convenience methods for `Pod` types.
+pub(crate) trait BytesMut {
+    fn write_at<T: Pod>(self, offset: usize, val: &T) -> Result<(), ()>;
+}
+
+impl<'a> BytesMut for &'a mut [u8] {
+    #[inline]
+    fn write_at<T: Pod>(self, offset: usize, val: &T) -> Result<(), ()> {
+        let src = bytes_of(val);
+        let dest = self.get_mut(offset..).ok_or(())?;
+        let dest = dest.get_mut(..src.len()).ok_or(())?;
+        dest.copy_from_slice(src);
+        Ok(())
+    }
+}
+
+/// Write an unsigned number using the LEB128 encoding to a buffer.
+///
+/// Returns the number of bytes written.
+pub(crate) fn write_uleb128(buf: &mut Vec<u8>, mut val: u64) -> usize {
+    let mut len = 0;
+    loop {
+        let mut byte = (val & 0x7f) as u8;
+        val >>= 7;
+        let done = val == 0;
+        if !done {
+            byte |= 0x80;
+        }
+
+        buf.push(byte);
+        len += 1;
+
+        if done {
+            return len;
+        }
+    }
+}
+
+/// Write a signed number using the LEB128 encoding to a buffer.
+///
+/// Returns the number of bytes written.
+#[allow(dead_code)]
+pub(crate) fn write_sleb128(buf: &mut Vec<u8>, mut val: i64) -> usize {
+    let mut len = 0;
+    loop {
+        let mut byte = val as u8;
+        // Keep the sign bit for testing
+        val >>= 6;
+        let done = val == 0 || val == -1;
+        if done {
+            byte &= !0x80;
+        } else {
+            // Remove the sign bit
+            val >>= 1;
+            byte |= 0x80;
+        }
+
+        buf.push(byte);
+        len += 1;
+
+        if done {
+            return len;
+        }
+    }
+}
+
+pub(crate) fn align(offset: usize, size: usize) -> usize {
+    (offset + (size - 1)) & !(size - 1)
+}
+
+#[allow(dead_code)]
+pub(crate) fn align_u32(offset: u32, size: u32) -> u32 {
+    (offset + (size - 1)) & !(size - 1)
+}
+
+#[allow(dead_code)]
+pub(crate) fn align_u64(offset: u64, size: u64) -> u64 {
+    (offset + (size - 1)) & !(size - 1)
+}
+
+pub(crate) fn write_align(buffer: &mut dyn WritableBuffer, size: usize) {
+    let new_len = align(buffer.len(), size);
+    buffer.resize(new_len);
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn bytes_mut() {
+        let data = vec![0x01, 0x23, 0x45, 0x67];
+
+        let mut bytes = data.clone();
+        bytes.extend_from_slice(bytes_of(&u16::to_be(0x89ab)));
+        assert_eq!(bytes, [0x01, 0x23, 0x45, 0x67, 0x89, 0xab]);
+
+        let mut bytes = data.clone();
+        assert_eq!(bytes.write_at(0, &u16::to_be(0x89ab)), Ok(()));
+        assert_eq!(bytes, [0x89, 0xab, 0x45, 0x67]);
+
+        let mut bytes = data.clone();
+        assert_eq!(bytes.write_at(2, &u16::to_be(0x89ab)), Ok(()));
+        assert_eq!(bytes, [0x01, 0x23, 0x89, 0xab]);
+
+        assert_eq!(bytes.write_at(3, &u16::to_be(0x89ab)), Err(()));
+        assert_eq!(bytes.write_at(4, &u16::to_be(0x89ab)), Err(()));
+        assert_eq!(vec![].write_at(0, &u32::to_be(0x89ab)), Err(()));
+    }
+}