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

pub struct LennaImageBuffer {
    pub data: Vec<u8>,
}

// source: https://michael-f-bryan.github.io/rust-ffi-guide/send_basic.html
#[no_mangle]
pub unsafe extern "C" fn lenna_plugin_image_destroy(img: *mut LennaImageBuffer) {
    if !img.is_null() {
        drop(Box::from_raw(img));
    }
}

#[no_mangle]
pub unsafe extern "C" fn lenna_plugin_image_length(img: *const LennaImageBuffer) -> libc::size_t {
    if img.is_null() {
        return 0;
    }

    (&*img).data.len() as libc::size_t
}

#[no_mangle]
pub unsafe extern "C" fn lenna_plugin_image(
    img: *const LennaImageBuffer,
    buffer: *mut libc::c_char,
    length: libc::size_t,
) -> libc::c_int {
    if img.is_null() || buffer.is_null() {
        return -1;
    }

    let img = &*img;
    let buffer: &mut [u8] = std::slice::from_raw_parts_mut(buffer as *mut u8, length as usize);

    if buffer.len() < img.data.len() {
        return -1;
    }

    std::ptr::copy_nonoverlapping(img.data.as_ptr(), buffer.as_mut_ptr(), img.data.len());

    img.data.len() as libc::c_int
}

/// The macro used to generate ffi c api.
#[macro_export]
macro_rules! export_c_plugin {
    ($processor:ident) => {
        #[doc(hidden)]
        #[no_mangle]
        pub extern "C" fn lenna_plugin_id() -> *const std::os::raw::c_char {
            let processor = $processor::default();
            std::ffi::CString::new(processor.id()).unwrap().into_raw()
        }

        #[doc(hidden)]
        #[no_mangle]
        pub extern "C" fn lenna_plugin_name() -> *const std::os::raw::c_char {
            let processor = $processor::default();
            std::ffi::CString::new(processor.name()).unwrap().into_raw()
        }

        #[doc(hidden)]
        #[no_mangle]
        pub extern "C" fn lenna_plugin_title() -> *const std::os::raw::c_char {
            let processor = $processor::default();
            std::ffi::CString::new(processor.title())
                .unwrap()
                .into_raw()
        }

        #[doc(hidden)]
        #[no_mangle]
        pub extern "C" fn lenna_plugin_version() -> *const std::os::raw::c_char {
            let processor = $processor::default();
            std::ffi::CString::new(processor.version())
                .unwrap()
                .into_raw()
        }

        #[doc(hidden)]
        #[no_mangle]
        pub extern "C" fn lenna_plugin_author() -> *const std::os::raw::c_char {
            let processor = $processor::default();
            std::ffi::CString::new(processor.author())
                .unwrap()
                .into_raw()
        }

        #[doc(hidden)]
        #[no_mangle]
        pub extern "C" fn lenna_plugin_description() -> *const std::os::raw::c_char {
            let processor = $processor::default();
            std::ffi::CString::new(processor.description())
                .unwrap()
                .into_raw()
        }

        #[doc(hidden)]
        #[no_mangle]
        pub unsafe extern "C" fn lenna_plugin_process(
            data: *mut libc::c_char,
            length: libc::size_t,
        ) -> *mut $crate::plugins::c::LennaImageBuffer {
            let mut processor = $processor::default();
            let config: $crate::core::config::ProcessorConfig =
                $crate::core::config::ProcessorConfig {
                    id: processor.id(),
                    config: processor.default_config(),
                };
            let buffer: &mut [u8] =
                std::slice::from_raw_parts_mut(data as *mut u8, length as usize);
            let img = $crate::io::read::read_from_data(buffer.to_vec()).unwrap();

            let mut lenna_img = Box::new(img);

            processor.process(config, &mut lenna_img).unwrap();

            let out_data =
                $crate::io::write::write_to_data(&lenna_img, image::ImageOutputFormat::Png)
                    .unwrap();

            let buffer: $crate::plugins::c::LennaImageBuffer =
                $crate::plugins::c::LennaImageBuffer { data: out_data };

            Box::into_raw(Box::new(buffer))
        }

        #[doc(hidden)]
        #[no_mangle]
        pub unsafe extern "C" fn lenna_plugin_process_base64(
            b64img: *const std::os::raw::c_char,
        ) -> *const std::os::raw::c_char {
            let mut processor = $processor::default();
            let config: $crate::core::config::ProcessorConfig =
                $crate::core::config::ProcessorConfig {
                    id: processor.id(),
                    config: processor.default_config(),
                };

            let data = std::ffi::CStr::from_ptr(b64img).to_str().unwrap();
            let buffer: Vec<u8> = base64::decode(data).unwrap();
            let img = $crate::io::read::read_from_data(buffer).unwrap();

            let mut lenna_img = Box::new(img);

            processor.process(config, &mut lenna_img).unwrap();

            let out_data =
                $crate::io::write::write_to_data(&lenna_img, image::ImageOutputFormat::Png)
                    .unwrap();

            let b64img = base64::encode(out_data);

            std::ffi::CString::new(b64img).unwrap().into_raw()
        }
    };
}

#[cfg(test)]
mod tests {

    #[test]
    fn module() {
        use crate::core::processor::Processor;
        use crate::core::resize::Resize;
        #[allow(non_camel_case_types)]
        type resize = Resize;
        export_c_plugin!(resize);
    }
}