exif 0.0.1

Rust wrapper for libexif
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use std::ffi::CStr;

use exif_sys::*;

use bits::*;
use internal::*;

/// EXIF tag.
pub struct Tag {
    inner: ExifTag,
}

impl FromLibExif<ExifTag> for Tag {
    fn from_libexif(tag: ExifTag) -> Tag {
        Tag { inner: tag }
    }
}

impl Tag {
    /// The name of the EXIF tag when found in the given IFD.
    pub fn name(&self, ifd: IFD) -> &'static str {
        let ptr = unsafe { exif_tag_get_name_in_ifd(self.inner, ifd.to_libexif()) };

        assert!(!ptr.is_null());

        let cstr = unsafe { CStr::from_ptr(ptr) };
        cstr.to_str().expect("invalid UTF-8")
    }

    /// The title of the EXIF tag when found in the given IFD.
    pub fn title(&self, ifd: IFD) -> &'static str {
        let ptr = unsafe { exif_tag_get_title_in_ifd(self.inner, ifd.to_libexif()) };

        assert!(!ptr.is_null());

        let cstr = unsafe { CStr::from_ptr(ptr) };
        cstr.to_str().expect("invalid UTF-8")
    }

    /// A verbose description of the EXIF tag when found in the given IFD.
    pub fn description(&self, ifd: IFD) -> &'static str {
        let ptr = unsafe { exif_tag_get_description_in_ifd(self.inner, ifd.to_libexif()) };

        assert!(!ptr.is_null());

        let cstr = unsafe { CStr::from_ptr(ptr) };
        cstr.to_str().expect("invalid UTF-8")
    }

    /// The EXIF tag's support level with the given IFD and encoding.
    ///
    /// This method returns the tag's support level according to the EXIF specification.
    pub fn support_level(&self, ifd: IFD, encoding: DataEncoding) -> SupportLevel {
        let support_level = unsafe {
            exif_tag_get_support_level_in_ifd(self.inner,
                                              ifd.to_libexif(),
                                              encoding.to_libexif())
        };

        SupportLevel::from_libexif(support_level)
    }
}