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

use std::ptr;

use super::Flags;
use ffi::*;
use libc::c_int;
use util::format;
use {frame, Error};

#[derive(Eq, PartialEq, Copy, Clone, Debug)]
pub struct Definition {
    pub format: format::Pixel,
    pub width: u32,
    pub height: u32,
}

pub struct Context {
    ptr: *mut SwsContext,

    input: Definition,
    output: Definition,
}

unsafe impl Send for Context {}

impl Context {
    #[inline(always)]
    pub unsafe fn as_ptr(&self) -> *const SwsContext {
        self.ptr as *const _
    }

    #[inline(always)]
    pub unsafe fn as_mut_ptr(&mut self) -> *mut SwsContext {
        self.ptr
    }
}

impl Context {
    pub fn get(
        src_format: format::Pixel,
        src_w: u32,
        src_h: u32,
        dst_format: format::Pixel,
        dst_w: u32,
        dst_h: u32,
        flags: Flags,
    ) -> Result<Self, Error> {
        unsafe {
            let ptr = sws_getContext(
                src_w as c_int,
                src_h as c_int,
                src_format.into(),
                dst_w as c_int,
                dst_h as c_int,
                dst_format.into(),
                flags.bits(),
                ptr::null_mut(),
                ptr::null_mut(),
                ptr::null_mut(),
            );

            if !ptr.is_null() {
                Ok(Context {
                    ptr,

                    input: Definition {
                        format: src_format,
                        width: src_w,
                        height: src_h,
                    },

                    output: Definition {
                        format: dst_format,
                        width: dst_w,
                        height: dst_h,
                    },
                })
            } else {
                Err(Error::InvalidData)
            }
        }
    }

    pub fn cached(
        &mut self,
        src_format: format::Pixel,
        src_w: u32,
        src_h: u32,
        dst_format: format::Pixel,
        dst_w: u32,
        dst_h: u32,
        flags: Flags,
    ) {
        self.input = Definition {
            format: src_format,
            width: src_w,
            height: src_h,
        };

        self.output = Definition {
            format: dst_format,
            width: dst_w,
            height: dst_h,
        };

        unsafe {
            self.ptr = sws_getCachedContext(
                self.as_mut_ptr(),
                src_w as c_int,
                src_h as c_int,
                src_format.into(),
                dst_w as c_int,
                dst_h as c_int,
                dst_format.into(),
                flags.bits(),
                ptr::null_mut(),
                ptr::null_mut(),
                ptr::null(),
            );
        }
    }

    #[inline]
    pub fn input(&self) -> &Definition {
        &self.input
    }

    #[inline]
    pub fn output(&self) -> &Definition {
        &self.output
    }

    pub fn run(&mut self, input: &frame::Video, output: &mut frame::Video) -> Result<(), Error> {
        if input.format() != self.input.format
            || input.width() != self.input.width
            || input.height() != self.input.height
        {
            return Err(Error::InputChanged);
        }

        unsafe {
            if output.is_empty() {
                output.alloc(self.output.format, self.output.width, self.output.height);
            }
        }

        if output.format() != self.output.format
            || output.width() != self.output.width
            || output.height() != self.output.height
        {
            return Err(Error::OutputChanged);
        }

        unsafe {
            sws_scale(
                self.as_mut_ptr(),
                (*input.as_ptr()).data.as_ptr() as *const *const _,
                (*input.as_ptr()).linesize.as_ptr() as *const _,
                0,
                self.input.height as c_int,
                (*output.as_mut_ptr()).data.as_ptr() as *const *mut _,
                (*output.as_mut_ptr()).linesize.as_ptr() as *mut _,
            );
        }

        Ok(())
    }
}

impl Drop for Context {
    fn drop(&mut self) {
        unsafe {
            sws_freeContext(self.as_mut_ptr());
        }
    }
}