X-Git-Url: https://git.nihav.org/?a=blobdiff_plain;f=nihav-core%2Fsrc%2Fio%2Fbyteio.rs;h=7da5e2232a902d5307813b0ae2a1a237fcb76d2b;hb=b36f412c24813b14cb2b1f8fd151863e2a49c1e2;hp=ba3d95c08a3044a4dc9264f38c4de37a03cb6796;hpb=b2939bd867eda60d083199153fb9103fc54426bb;p=nihav.git

diff --git a/nihav-core/src/io/byteio.rs b/nihav-core/src/io/byteio.rs
index ba3d95c..7da5e22 100644
--- a/nihav-core/src/io/byteio.rs
+++ b/nihav-core/src/io/byteio.rs
@@ -200,6 +200,7 @@ write_int_func!(write_u64le, u64, 8, to_le);
 /// # Ok(())
 /// # }
 /// ````
+#[allow(clippy::identity_op)]
 pub fn write_u24be(dst: &mut [u8], val: u32) -> ByteIOResult<()> {
     if dst.len() < 3 { return Err(ByteIOError::WriteError); }
     dst[0] = (val >> 16) as u8;
@@ -208,6 +209,7 @@ pub fn write_u24be(dst: &mut [u8], val: u32) -> ByteIOResult<()> {
     Ok(())
 }
 /// Writes 24-bit little-endian integer to the provided buffer.
+#[allow(clippy::identity_op)]
 pub fn write_u24le(dst: &mut [u8], val: u32) -> ByteIOResult<()> {
     if dst.len() < 3 { return Err(ByteIOError::WriteError); }
     dst[0] = (val >>  0) as u8;
@@ -267,6 +269,20 @@ impl<'a> ByteReader<'a> {
         self.io.peek_byte()
     }
 
+    /// Reads four-byte array from the stream.
+    pub fn read_tag(&mut self)  -> ByteIOResult<[u8; 4]> {
+        let mut buf = [0u8; 4];
+        self.io.read_buf(&mut buf)?;
+        Ok(buf)
+    }
+
+    /// Reads four-byte array from the stream without advancing read position.
+    pub fn peek_tag(&mut self)  -> ByteIOResult<[u8; 4]> {
+        let mut buf = [0u8; 4];
+        self.io.peek_buf(&mut buf)?;
+        Ok(buf)
+    }
+
     /// Reads 16-bit big-endian integer from the stream.
     pub fn read_u16be(&mut self) -> ByteIOResult<u16> {
         read_int!(self, u16, 2, to_be)
@@ -638,6 +654,16 @@ pub struct FileWriter {
     file:     File,
 }
 
+/// Bytestream writer to memory.
+///
+/// Unlike [`MemoryWriter`] which writes to an array of fixed size, `GrowableMemoryWriter` grows output size when output size exceeds capacity.
+///
+/// [`MemoryWriter`]: ./struct.MemoryWriter.html
+pub struct GrowableMemoryWriter<'a> {
+    buf:    &'a mut Vec<u8>,
+    pos:    usize,
+}
+
 impl<'a> ByteWriter<'a> {
     /// Constructs a new instance of `ByteWriter`.
     pub fn new(io: &'a mut ByteIO) -> Self { ByteWriter { io } }
@@ -783,9 +809,85 @@ impl<'a> ByteIO for MemoryWriter<'a> {
 
     fn write_buf(&mut self, buf: &[u8]) -> ByteIOResult<()> {
         if self.pos + buf.len() > self.buf.len() { return Err(ByteIOError::WriteError); }
-        for i in 0..buf.len() {
-            self.buf[self.pos + i] = buf[i];
+        self.buf[self.pos..][..buf.len()].copy_from_slice(buf);
+        self.pos += buf.len();
+        Ok(())
+    }
+
+    fn tell(&mut self) -> u64 {
+        self.pos as u64
+    }
+
+    fn seek(&mut self, pos: SeekFrom) -> ByteIOResult<u64> {
+        let cur_pos  = self.pos       as i64;
+        let cur_size = self.buf.len() as i64;
+        match pos {
+            SeekFrom::Start(x)   => self.real_seek(x as i64),
+            SeekFrom::Current(x) => self.real_seek(cur_pos + x),
+            SeekFrom::End(x)     => self.real_seek(cur_size + x),
+        }
+    }
+
+    fn is_eof(&self) -> bool {
+        self.pos >= self.buf.len()
+    }
+
+    fn is_seekable(&mut self) -> bool {
+        true
+    }
+
+    fn size(&mut self) -> i64 {
+        self.buf.len() as i64
+    }
+}
+
+impl<'a> GrowableMemoryWriter<'a> {
+
+    /// Constructs a new instance of `GrowableMemoryWriter`.
+    pub fn new_write(buf: &'a mut Vec<u8>) -> Self {
+        GrowableMemoryWriter { buf, pos: 0 }
+    }
+
+    fn real_seek(&mut self, pos: i64) -> ByteIOResult<u64> {
+        if pos < 0 || (pos as usize) > self.buf.len() {
+            return Err(ByteIOError::WrongRange)
+        }
+        self.pos = pos as usize;
+        Ok(pos as u64)
+    }
+}
+
+impl<'a> ByteIO for GrowableMemoryWriter<'a> {
+    #[allow(unused_variables)]
+    fn read_byte(&mut self) -> ByteIOResult<u8> {
+        Err(ByteIOError::NotImplemented)
+    }
+
+    #[allow(unused_variables)]
+    fn peek_byte(&mut self) -> ByteIOResult<u8> {
+        Err(ByteIOError::NotImplemented)
+    }
+
+    #[allow(unused_variables)]
+    fn read_buf(&mut self, buf: &mut [u8]) -> ByteIOResult<usize> {
+        Err(ByteIOError::NotImplemented)
+    }
+
+    #[allow(unused_variables)]
+    fn read_buf_some(&mut self, buf: &mut [u8]) -> ByteIOResult<usize> {
+        Err(ByteIOError::NotImplemented)
+    }
+
+    #[allow(unused_variables)]
+    fn peek_buf(&mut self, buf: &mut [u8]) -> ByteIOResult<usize> {
+        Err(ByteIOError::NotImplemented)
+    }
+
+    fn write_buf(&mut self, buf: &[u8]) -> ByteIOResult<()> {
+        if self.pos + buf.len() > self.buf.len() {
+            self.buf.resize(self.pos + buf.len(), 0);
         }
+        self.buf[self.pos..][..buf.len()].copy_from_slice(buf);
         self.pos += buf.len();
         Ok(())
     }