BorrowedCursor in core::io - Rust (original) (raw)
Struct BorrowedCursor
pub struct BorrowedCursor<'a> { /* private fields */ }🔬This is a nightly-only experimental API. (core_io_borrowed_buf #117693)
Expand description
A writeable view of the unfilled portion of a BorrowedBuf.
Data can be written directly to the cursor by using append or indirectly by getting a slice of part or all of the cursor and writing into the slice. In the indirect case, the caller must call advance after writing to inform the cursor how many bytes have been written.
Once data is written to the cursor, it becomes part of the filled portion of the underlyingBorrowedBuf and can no longer be accessed or re-written by the cursor. I.e., the cursor tracks the unfilled part of the underlying BorrowedBuf.
The lifetime 'a is a bound on the lifetime of the underlying buffer (which means it is a bound on the data in that buffer by transitivity).
🔬This is a nightly-only experimental API. (core_io_borrowed_buf #117693)
Reborrows this cursor by cloning it with a smaller lifetime.
Since a cursor maintains unique access to its underlying buffer, the borrowed cursor is not accessible while the new cursor exists.
🔬This is a nightly-only experimental API. (core_io_borrowed_buf #117693)
Returns the available space in the cursor.
🔬This is a nightly-only experimental API. (core_io_borrowed_buf #117693)
Returns the number of bytes written to the BorrowedBuf this cursor was created from.
In particular, the count returned is shared by all reborrows of the cursor.
🔬This is a nightly-only experimental API. (core_io_borrowed_buf #117693)
Returns a mutable reference to the whole cursor.
§Safety
The caller must not uninitialize any previously initialized bytes.
🔬This is a nightly-only experimental API. (core_io_borrowed_buf #117693)
Advances the cursor by asserting that n bytes have been filled.
After advancing, the n bytes are no longer accessible via the cursor and can only be accessed via the underlying buffer. I.e., the buffer’s filled portion grows by n elements and its unfilled portion (and the capacity of this cursor) shrinks by n elements.
§Safety
The caller must ensure that the first n bytes of the cursor have been initialized. nmust not exceed the remaining capacity of this cursor.
🔬This is a nightly-only experimental API. (core_io_borrowed_buf #117693)
Appends data to the cursor, advancing position within its buffer.
§Panics
Panics if self.capacity() is less than buf.len().
🔬This is a nightly-only experimental API. (core_io_borrowed_buf #117693)
Runs the given closure with a BorrowedBuf containing the unfilled part of the cursor.
This enables inspecting what was written to the cursor.
§Panics
Panics if the BorrowedBuf given to the closure is replaced by another one.
Creates a new BorrowedBuf from a cursor.
Use BorrowedCursor::with_unfilled_buf instead for a safer alternative.
Converts to this type from the input type.