1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176

// Copyright 2015 The Gfx-rs Developers.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#![deny(missing_docs, missing_copy_implementations)]

//! Memory mapping

use std::marker::PhantomData;
use std::ops::{Deref, DerefMut};
use super::{Resources, Factory};

/// Unsafe operations for a buffer mapping
pub trait Raw {
    /// Set the element at `index` to `val`. Not bounds-checked.
    unsafe fn set<T>(&self, index: usize, val: T);
    /// Returns a slice of the specified length.
    unsafe fn to_slice<T>(&self, len: usize) -> &[T];
    /// Returns a mutable slice of the specified length.
    unsafe fn to_mut_slice<T>(&self, len: usize) -> &mut [T];
}

/// A handle to a readable map, which can be sliced.
pub struct Readable<'a, T: Copy, R: 'a + Resources, F: 'a + Factory<R>> where
    F::Mapper: 'a
{
    raw: F::Mapper,
    len: usize,
    factory: &'a mut F,
    phantom_t: PhantomData<T>
}

impl<'a, T: Copy, R: Resources, F: Factory<R>> Deref for Readable<'a, T, R, F> where
    F::Mapper: 'a,
{
    type Target = [T];

    fn deref(&self) -> &[T] {
        unsafe { self.raw.to_slice(self.len) }
    }
}

impl<'a, T: Copy, R: Resources, F: Factory<R>> Drop for Readable<'a, T, R, F> where
    F::Mapper: 'a,
{
    fn drop(&mut self) {
        self.factory.unmap_buffer_raw(self.raw.clone())
    }
}

/// A handle to a writable map, which only allows setting elements.
pub struct Writable<'a, T: Copy, R: 'a + Resources, F: 'a + Factory<R>> where
    F::Mapper: 'a
{
    raw: F::Mapper,
    len: usize,
    factory: &'a mut F,
    phantom_t: PhantomData<T>
}

impl<'a, T: Copy, R: Resources, F: Factory<R>> Writable<'a, T, R, F> where
    F::Mapper: 'a
{
    /// Set a value in the buffer
    pub fn set(&mut self, idx: usize, val: T) {
        if idx >= self.len {
            panic!("Tried to write out of bounds to a WritableMapping!")
        }
        unsafe { self.raw.set(idx, val); }
    }
}

impl<'a, T: Copy, R: Resources, F: Factory<R>> Drop for Writable<'a, T, R, F> where
    F::Mapper: 'a,
{
    fn drop(&mut self) {
        self.factory.unmap_buffer_raw(self.raw.clone())
    }
}

/// A handle to a complete readable/writable map, which can be sliced both ways.
pub struct RW<'a, T: Copy, R: 'a + Resources, F: 'a + Factory<R>> where
    F::Mapper: 'a
{
    raw: F::Mapper,
    len: usize,
    factory: &'a mut F,
    phantom_t: PhantomData<T>
}

impl<'a, T: Copy, R: Resources, F: Factory<R>> Deref for RW<'a, T, R, F> where
    F::Mapper: 'a
{
    type Target = [T];

    fn deref(&self) -> &[T] {
        unsafe { self.raw.to_slice(self.len) }
    }
}

impl<'a, T: Copy, R: Resources, F: Factory<R>> DerefMut for RW<'a, T, R, F> where
    F::Mapper: 'a
{
    fn deref_mut(&mut self) -> &mut [T] {
        unsafe { self.raw.to_mut_slice(self.len) }
    }
}

impl<'a, T: Copy, R: Resources, F: Factory<R>> Drop for RW<'a, T, R, F> where
    F::Mapper: 'a
{
    fn drop(&mut self) {
        self.factory.unmap_buffer_raw(self.raw.clone())
    }
}

/// A service trait with methods for mapping already implemented.
/// To be used by device back ends.
#[allow(missing_docs)]
pub trait Builder<'a, R: Resources> {
    type RawMapping: Raw;

    fn map_readable<T: Copy>(&'a mut self, Self::RawMapping, usize)
                    -> Readable<T, R, Self>;
    fn map_writable<T: Copy>(&'a mut self, Self::RawMapping, usize)
                    -> Writable<T, R, Self>;
    fn map_read_write<T: Copy>(&'a mut self, Self::RawMapping, usize)
                      -> RW<T, R, Self>;
}


impl<'a, R: Resources, F: Factory<R>> Builder<'a, R> for F where
    F::Mapper: 'a
{
    type RawMapping = F::Mapper;

    fn map_readable<T: Copy>(&'a mut self, map: F::Mapper,
                    length: usize) -> Readable<T, R, Self> {
        Readable {
            raw: map,
            len: length,
            factory: self,
            phantom_t: PhantomData,
        }
    }

    fn map_writable<T: Copy>(&'a mut self, map: F::Mapper,
                    length: usize) -> Writable<T, R, Self> {
        Writable {
            raw: map,
            len: length,
            factory: self,
            phantom_t: PhantomData,
        }
    }

    fn map_read_write<T: Copy>(&'a mut self, map: F::Mapper,
                      length: usize) -> RW<T, R, Self> {
        RW {
            raw: map,
            len: length,
            factory: self,
            phantom_t: PhantomData,
        }
    }
}