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use crate::*;
pub fn read_at_offset<T, V, R>(offset: &V, src: &mut R, ctx: &mut SpCtx) -> Result<T, SpError>
where
V: Copy + Into<u64>,
T: SpRead + SpOptHints,
R: Read + ?Sized,
{
let offset: usize = (*offset).into() as usize;
if offset < ctx.cursor {
return Err(SpError::InvalidBytes);
}
#[cfg(feature = "verbose")]
crate::debug!(
"[0x{:X}] : Skipping 0x{:X} bytes to offset 0x{:X}",
ctx.cursor,
offset - ctx.cursor,
offset
);
let mut dst = [0u8; MAX_ALLOC_SIZE];
while ctx.cursor != offset {
let bytes_to_read = std::cmp::min(MAX_ALLOC_SIZE, offset - ctx.cursor);
validate_reader_exact(&mut dst[..bytes_to_read], src)?;
ctx.cursor += bytes_to_read;
}
T::inner_from_reader(src, ctx)
}
pub fn readall_at_offset<T, V, R>(
offset: &V,
total: &V,
src: &mut R,
ctx: &mut SpCtx,
) -> Result<T, SpError>
where
V: Copy + Into<u64>,
T: SpRead + SpOptHints,
R: Read + ?Sized,
{
let offset: usize = (*offset).into() as usize;
let total: usize = (*total).into() as usize;
if offset < ctx.cursor || offset > total {
return Err(SpError::InvalidBytes);
}
#[cfg(feature = "verbose")]
crate::debug!(
"[0x{:X}] : Skipping 0x{:X} bytes to offset 0x{:X}",
ctx.cursor,
offset - ctx.cursor,
offset
);
let mut dst = [0u8; MAX_ALLOC_SIZE];
while ctx.cursor != offset {
let bytes_to_read = std::cmp::min(MAX_ALLOC_SIZE, offset - ctx.cursor);
validate_reader_exact(&mut dst[..bytes_to_read], src)?;
ctx.cursor += bytes_to_read;
}
ctx.count = Some((total - ctx.cursor) / std::mem::size_of::<T>());
T::inner_from_reader(src, ctx)
}
pub fn write_at_offset<T, V, W>(
this: &T,
offset: &V,
ctx: &mut SpCtx,
dst: &mut W,
) -> Result<usize, SpError>
where
V: Copy + Into<u64>,
T: SpWrite,
W: Write + ?Sized,
{
let offset: usize = (*offset).into() as usize;
if offset < ctx.cursor {
return Err(SpError::InvalidBytes);
}
#[cfg(feature = "verbose")]
crate::debug!(
"[0x{:X}] : Writing 0x{:X} bytes to reach offset 0x{:X}",
ctx.cursor,
offset - ctx.cursor,
offset
);
let mut bytes_written = 0;
let src = [0u8; MAX_ALLOC_SIZE];
let mut tmp_ctx = SpCtx::default();
tmp_ctx.count = Some(0);
while ctx.cursor + bytes_written != offset {
let bytes_to_write = std::cmp::min(MAX_ALLOC_SIZE, offset - ctx.cursor);
bytes_written += (&src[..bytes_to_write]).inner_to_writer(&mut tmp_ctx, dst)?;
}
ctx.cursor += bytes_written;
Ok(bytes_written + this.inner_to_writer(ctx, dst)?)
}
pub fn writeall_at_offset<T, V, W>(
this: &T,
offset: &V,
ctx: &mut SpCtx,
dst: &mut W,
) -> Result<usize, SpError>
where
V: Copy + Into<u64>,
T: SpWrite,
W: Write + ?Sized,
{
ctx.count = Some(usize::MAX);
write_at_offset(this, offset, ctx, dst)
}
#[inline(always)]
pub fn validate_reader<R: Read + ?Sized>(
static_size: usize,
dst: &mut Vec<u8>,
src: &mut R,
) -> Result<(), SpError> {
let mut bytes_read = 0;
while bytes_read < static_size {
let cur_len = dst.len();
let cur_chunk_len = std::cmp::min(MAX_ALLOC_SIZE, static_size - bytes_read);
dst.reserve(cur_chunk_len);
unsafe {
dst.set_len(cur_len + cur_chunk_len);
}
let dst_slice = &mut dst.as_mut_slice()[cur_len..];
if let Err(e) = validate_reader_exact(dst_slice, src) {
unsafe {
dst.set_len(cur_len);
}
return Err(e);
}
bytes_read += cur_chunk_len;
}
Ok(())
}
#[inline(always)]
pub fn validate_reader_exact<R: Read + ?Sized>(dst: &mut [u8], src: &mut R) -> Result<(), SpError> {
#[cfg(feature = "verbose")]
crate::debug!("Read({})", dst.len());
if src.read_exact(dst).is_err() {
return Err(SpError::NotEnoughSpace);
}
Ok(())
}
#[inline(always)]
pub fn validate_cursor<T: AsRef<[u8]>>(
static_size: usize,
src: &mut Cursor<T>,
) -> Result<*mut u8, crate::SpError> {
let idx = src.position();
let bytes = src.get_ref().as_ref();
#[cfg(feature = "verbose")]
{
let len_left = if (bytes.len() as u64) < idx {
0
} else {
(bytes.len() as u64) - idx
};
debug!("Check src.len({}) < {}", len_left, static_size);
}
if idx + static_size as u64 > bytes.len() as u64 {
return Err(SpError::NotEnoughSpace);
}
let checked_bytes = unsafe { bytes.as_ptr().add(idx as usize) as _ };
src.set_position(idx + static_size as u64);
Ok(checked_bytes)
}