mem_tools 0.9.0

Collection of tools to manipulate memory.
Documentation 
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/// Define a private namespace for all its items.
mod private
{
  // use crate::own::*;

  ///
  /// Are two pointers points on the same data.
  ///
  /// Does not require arguments to have the same type.
  #[ allow( unsafe_code ) ]
  pub fn same_data< T1 : ?Sized, T2 : ?Sized >( src1 : &T1, src2 : &T2 ) -> bool
  {
    extern "C" { fn memcmp( s1 : *const u8, s2 : *const u8, n : usize ) -> i32; }

    let mem1 = core::ptr::from_ref::<T1>(src1).cast::<u8>();
    let mem2 = core::ptr::from_ref::<T2>(src2).cast::<u8>();

    if !same_size( src1, src2 )
    {
      return false;
    }

    // Safety:
    // The `unsafe` block is required because we're calling a foreign function (`memcmp`)
    // and manually managing memory addresses.
    // `mem1` and `mem2` are obtained from valid references `src1` and `src2` using `core::ptr::from_ref`
    // and then cast to `*const u8`. This ensures they are valid, non-null, and properly aligned
    // pointers to the start of the data.
    // The size `n` is obtained from `core::mem::size_of_val(src1)`, which is the correct
    // size of the data pointed to by `src1`.
    // The `same_size` check (which compares `core::mem::size_of_val(src1)` and `core::mem::size_of_val(src2)`)
    // ensures that both memory regions have the same length. This guarantees that `memcmp`
    // will not read out of bounds for `src2` when comparing `n` bytes, as both `mem1` and `mem2`
    // are guaranteed to point to at least `n` bytes of valid memory.
    unsafe { memcmp( mem1, mem2, core::mem::size_of_val( src1 ) ) == 0 }
  }

  /* zzz : qqq : implement mem::same_data, comparing data. discuss */

  ///
  /// Are two pointers are the same, not taking into accoint type.
  ///
  /// Unlike `std::ptr::eq()` does not require arguments to have the same type.
  pub fn same_ptr< T1 : ?Sized, T2 : ?Sized >( src1 : &T1, src2 : &T2 ) -> bool
  {
    let mem1 = core::ptr::from_ref::<T1>(src1).cast::<()>();
    let mem2 = core::ptr::from_ref::<T2>(src2).cast::<()>();
    mem1 == mem2
  }

  ///
  /// Are two pointers points on data of the same size.
  pub fn same_size< T1 : ?Sized, T2 : ?Sized >( src1 : &T1, src2 : &T2 ) -> bool
  {
    core::mem::size_of_val( src1 ) == core::mem::size_of_val( src2 )
  }

  ///
  /// Are two pointers points on the same region, ie same size and same pointer.
  ///
  /// Does not require arguments to have the same type.
  pub fn same_region< T1 : ?Sized, T2 : ?Sized >( src1 : &T1, src2 : &T2 ) -> bool
  {
    same_ptr( src1, src2 ) && same_size( src1, src2 )
  }

}

#[ doc( inline ) ]
#[ allow( unused_imports ) ]
pub use own::*;

/// Own namespace of the module.
#[ allow( unused_imports ) ]
pub mod own
{
  use super::*;
  #[ doc( inline ) ]
  pub use super::
  {
    orphan::*,
  };
}

/// Orphan namespace of the module.
#[ allow( unused_imports ) ]
pub mod orphan
{
  use super::*;
  #[ doc( inline ) ]
  pub use super::
  {
    exposed::*,
    private::same_data,
    private::same_ptr,
    private::same_size,
    private::same_region,
  };
}

/// Exposed namespace of the module.
#[ allow( unused_imports ) ]
pub mod exposed
{
  use super::*;
  // Expose itself.
  pub use super::super::mem;

  #[ doc( inline ) ]
  pub use prelude::*;
}

/// Prelude to use essentials: `use my_module::prelude::*`.
#[ allow( unused_imports ) ]
pub mod prelude
{
  use super::*;
}