Package saferio provides I/O functions that avoid allocating large amounts of memory unnecessarily. This is intended for packages that read data from an [io.Reader] where the size is part of the input data but the input may be corrupt, or may be provided by an untrustworthy attacker.
Static methods
staticinlinereadData(_r:Reader, _n:GoUInt64):{_1:Error, _0:Slice<GoUInt8>}
ReadData reads n bytes from the input stream, but avoids allocating all n bytes if n is large. This avoids crashing the program by allocating all n bytes in cases where n is incorrect.
The error is io.EOF only if no bytes were read. If an io.EOF happens after reading some but not all the bytes, ReadData returns io.ErrUnexpectedEOF.
staticinlinereadDataAt(_r:ReaderAt, _n:GoUInt64, _off:GoInt64):{_1:Error, _0:Slice<GoUInt8>}
ReadDataAt reads n bytes from the input stream at off, but avoids allocating all n bytes if n is large. This avoids crashing the program by allocating all n bytes in cases where n is incorrect.
staticinlinesliceCap(_v:AnyInterface, _c:GoUInt64):GoInt
SliceCap returns the capacity to use when allocating a slice. After the slice is allocated with the capacity, it should be built using append. This will avoid allocating too much memory if the capacity is large and incorrect.
A negative result means that the value is always too big.
The element type is described by passing a pointer to a value of that type. This would ideally use generics, but this code is built with the bootstrap compiler which need not support generics. We use a pointer so that we can handle slices of interface type.