drm_fourcc/
lib.rs

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1#![allow(non_camel_case_types)]
2#![warn(clippy::cargo)]
3#![cfg_attr(not(feature = "std"), no_std)]
4
5//! [`DrmFourcc`] is an enum representing every pixel format supported by DRM
6//! (as of kernel version 5.10.0).
7//!
8//! A [fourcc][fourcc_wiki] is four bytes of ascii representing some data format. This enum contains
9//! every fourcc representing a pixel format supported by [DRM][drm_wiki], the Linux Direct
10//! Rendering Manager. The names of pixel formats generally provide clues as to
11//! how they work, for more information you may find
12//! [this guide][drm_format_guide] helpful.
13//!
14//! To get the bytes of the fourcc representing the format, cast to `u32`.
15//!
16//! ```
17//! # use drm_fourcc::DrmFourcc;
18//! assert_eq!(DrmFourcc::Xrgb8888 as u32, 875713112);
19//! ```
20//!
21//! To get the string form of the fourcc, use [`ToString::to_string`].
22//!
23//! ```
24//! # use drm_fourcc::DrmFourcc;
25//! assert_eq!(DrmFourcc::Xrgb8888.to_string(), "XR24");
26//! ```
27//!
28//!
29//! We also provide a type for representing a fourcc/modifier pair
30//!
31//! ```
32//! # use drm_fourcc::{DrmFormat, DrmFourcc, DrmModifier};
33//! let format = DrmFormat {
34//!     code: DrmFourcc::Xrgb8888,
35//!     modifier: DrmModifier::Linear,
36//! };
37//! ```
38//!
39//! The enums are autogenerated from the [canonical list][canonical] in the Linux source code.
40//!
41//! ## Features
42//! - `serde` - Derive Serialize/Deserialize where it makes sense
43//! - `build_bindings` - Re-generate autogenerated code. Useful if you need varients added in a
44//!     more recent kernel version.
45//!
46//! [fourcc_wiki]: https://en.wikipedia.org/wiki/FourCC
47//! [drm_wiki]: https://en.wikipedia.org/wiki/Direct_Rendering_Managerz
48//! [canonical]: https://github.com/torvalds/linux/blame/master/include/uapi/drm/drm_fourcc.h
49//! [drm_format_guide]: https://afrantzis.com/pixel-format-guide/drm.html
50use core::convert::TryFrom;
51use core::fmt;
52use core::fmt::{Debug, Display, Formatter};
53use core::hash::{Hash, Hasher};
54
55#[cfg(feature = "std")]
56use std::string::{String, ToString};
57
58#[cfg(feature = "std")]
59use std::error::Error;
60
61pub use as_enum::{DrmFourcc, DrmModifier, DrmVendor};
62
63mod as_enum;
64mod consts;
65
66#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
67#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
68pub struct DrmFormat {
69    pub code: DrmFourcc,
70    pub modifier: DrmModifier,
71}
72
73impl DrmFourcc {
74    /// Get the string representation of the format's fourcc.
75    #[cfg(feature = "std")]
76    #[deprecated(since = "2.2.0", note = "Use `ToString::to_string` instead")]
77    pub fn string_form(&self) -> String {
78        self.display_form().to_string()
79    }
80
81    // Internal helper to clarify it always has Display.
82    fn display_form(&self) -> impl Display + Debug {
83        fourcc_display_form(*self as u32).expect("Must be valid fourcc")
84    }
85}
86
87impl Debug for DrmFourcc {
88    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
89        f.debug_tuple("DrmFourcc")
90            .field(&self.display_form())
91            .finish()
92    }
93}
94
95impl Display for DrmFourcc {
96    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
97        Display::fmt(&self.display_form(), f)
98    }
99}
100
101impl TryFrom<u32> for DrmFourcc {
102    type Error = UnrecognizedFourcc;
103
104    /// Convert from an u32
105    ///
106    #[cfg_attr(feature = "std", doc = "```")]
107    #[cfg_attr(not(feature = "std"), doc = "```ignore")]
108    /// # use drm_fourcc::DrmFourcc;
109    /// # use std::convert::TryFrom;
110    /// assert_eq!(DrmFourcc::try_from(875710274).unwrap(), DrmFourcc::Bgr888);
111    ///
112    /// assert!(DrmFourcc::try_from(0).is_err());
113    ///
114    /// // If the u32 is in the valid format to be a fourcc, you can see its string form
115    /// assert_eq!(DrmFourcc::try_from(828601953).unwrap_err().string_form(), Some("avc1".to_string()));
116    /// ```
117    fn try_from(value: u32) -> Result<Self, Self::Error> {
118        Self::from_u32(value).ok_or(UnrecognizedFourcc(value))
119    }
120}
121
122/// Wraps some u32 that isn't a DRM fourcc we recognize
123///
124#[cfg_attr(feature = "std", doc = "```")]
125#[cfg_attr(not(feature = "std"), doc = "```ignore")]
126/// # use drm_fourcc::{DrmFourcc, UnrecognizedFourcc};
127/// # use std::convert::TryFrom;
128/// // Get the u32
129/// assert_eq!(UnrecognizedFourcc(42).0, 42);
130///
131/// // Get the string form
132/// assert_eq!(UnrecognizedFourcc(828601953).string_form(), Some("avc1".to_string()));
133/// assert_eq!(UnrecognizedFourcc(0).string_form(), None);
134/// ```
135#[derive(Copy, Clone, Eq, PartialEq)]
136#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
137pub struct UnrecognizedFourcc(pub u32);
138
139impl UnrecognizedFourcc {
140    /// If the u32 is in a valid format to be a fourcc, get its string form.
141    ///
142    /// Note that this requires the `std` feature to be enabled. The [`display`] method is an
143    /// alternative that does not require this dependency.
144    #[cfg(feature = "std")]
145    pub fn string_form(&self) -> Option<String> {
146        fourcc_string_form(self.0)
147    }
148
149    /// If the u32 is in a valid format to be a fourcc, get an opaque type to display it.
150    ///
151    /// This can be treated as a slightly generalized form of [`string_form`] that is also
152    /// available when the crate does not depend on the standard or `alloc` crate.
153    ///
154    /// ```
155    /// # use drm_fourcc::UnrecognizedFourcc;
156    /// assert!(UnrecognizedFourcc(828601953).display().is_some());
157    /// assert!(UnrecognizedFourcc(0).display().is_none());
158    /// ```
159    pub fn display(&self) -> Option<impl Display> {
160        fourcc_display_form(self.0)
161    }
162}
163
164impl Debug for UnrecognizedFourcc {
165    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
166        let mut debug = &mut f.debug_tuple("UnrecognizedFourcc");
167
168        if let Some(string_form) = fourcc_display_form(self.0) {
169            debug = debug.field(&string_form);
170        }
171
172        debug.field(&self.0).finish()
173    }
174}
175
176impl Display for UnrecognizedFourcc {
177    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
178        Debug::fmt(&self, f)
179    }
180}
181
182#[cfg(feature = "std")]
183impl Error for UnrecognizedFourcc {}
184
185#[cfg(feature = "std")]
186fn fourcc_string_form(fourcc: u32) -> Option<String> {
187    fourcc_display_form(fourcc).map(|val| val.to_string())
188}
189
190fn fourcc_display_form(fourcc: u32) -> Option<impl Display + Debug> {
191    let raw_bytes = fourcc.to_le_bytes();
192    let mut chars = ::core::str::from_utf8(&raw_bytes).ok()?.chars();
193
194    let first = chars.next().unwrap();
195    let second = chars.next().unwrap();
196
197    // first two bytes must be characters
198    for char in [first, second].iter().copied() {
199        if !char.is_ascii_alphanumeric() {
200            return None;
201        }
202    }
203
204    let mut bytes = raw_bytes;
205    // Bytes in tail are allowed to be NUL
206    for byte in &mut bytes[4 - chars.as_str().len()..] {
207        if *byte == b'\0' {
208            *byte = b' ';
209        }
210    }
211
212    /// A pre-formatted string representing a valid FourCC format.
213    ///
214    /// This differs from the byte representation only in that NUL-characters beyond the leading
215    /// two have been replaced by spaces.
216    struct FormatFourccRaw {
217        bytes: [u8; 4],
218    }
219
220    impl Display for FormatFourccRaw {
221        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
222            let chars = ::core::str::from_utf8(&self.bytes[..]).expect("validated previously");
223            f.write_str(chars)
224        }
225    }
226
227    impl Debug for FormatFourccRaw {
228        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
229            Display::fmt(self, f)
230        }
231    }
232
233    Some(FormatFourccRaw { bytes })
234}
235
236impl TryFrom<u8> for DrmVendor {
237    type Error = UnrecognizedVendor;
238
239    /// Convert from an u8
240    ///
241    /// ```
242    /// # use drm_fourcc::DrmVendor;
243    /// # use std::convert::TryFrom;
244    /// assert_eq!(DrmVendor::try_from(2).unwrap(), DrmVendor::Amd);
245    ///
246    /// assert!(DrmVendor::try_from(0).is_err());
247    /// ```
248    fn try_from(value: u8) -> Result<Self, Self::Error> {
249        Self::from_u8(value).ok_or(UnrecognizedVendor(value))
250    }
251}
252
253/// Wraps some u8 that isn't a DRM vendor we recognize
254///
255/// ```
256/// # use drm_fourcc::{DrmVendor, UnrecognizedVendor};
257/// # use std::convert::TryFrom;
258/// // Get the u8
259/// assert_eq!(UnrecognizedVendor(42).0, 42);
260/// ```
261#[derive(Debug, Copy, Clone, Eq, PartialEq)]
262#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
263pub struct UnrecognizedVendor(pub u8);
264
265impl Display for UnrecognizedVendor {
266    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
267        Debug::fmt(&self, f)
268    }
269}
270
271#[cfg(feature = "std")]
272impl Error for UnrecognizedVendor {}
273
274impl From<u64> for DrmModifier {
275    /// Convert from an u64
276    ///
277    /// ```
278    /// # use drm_fourcc::DrmModifier;
279    /// assert_eq!(DrmModifier::from(0), DrmModifier::Linear);
280    /// ```
281    fn from(value: u64) -> Self {
282        Self::from_u64(value)
283    }
284}
285
286/// Wraps some u64 that isn't a DRM modifier we recognize
287///
288/// ```
289/// # use drm_fourcc::{DrmModifier, UnrecognizedModifier};
290/// # use std::convert::TryFrom;
291/// // Get the u64
292/// assert_eq!(UnrecognizedModifier(42).0, 42);
293/// ```
294#[derive(Debug, Copy, Clone, Eq, PartialEq)]
295#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
296pub struct UnrecognizedModifier(pub u64);
297
298impl Display for UnrecognizedModifier {
299    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
300        Debug::fmt(&self, f)
301    }
302}
303
304#[cfg(feature = "std")]
305impl Error for UnrecognizedModifier {}
306
307impl UnrecognizedModifier {
308    /// Get the vendor of the unrecognized modifier, if any
309    ///
310    /// ```
311    /// # use drm_fourcc::{DrmModifier, DrmVendor, UnrecognizedModifier, UnrecognizedVendor};
312    /// assert_eq!(UnrecognizedModifier(216172782113783827).vendor(), Ok(Some(DrmVendor::Nvidia)));
313    /// assert_eq!(UnrecognizedModifier(2).vendor(), Ok(None));
314    /// assert_eq!(UnrecognizedModifier(8646911284551352320).vendor(), Err(UnrecognizedVendor(120)));
315    /// ```
316    pub fn vendor(&self) -> Result<Option<DrmVendor>, UnrecognizedVendor> {
317        let vendor = (self.0 >> 56) as u8;
318        if vendor == 0 {
319            Ok(None)
320        } else {
321            DrmVendor::try_from(vendor).map(Some)
322        }
323    }
324}
325
326impl From<DrmModifier> for u64 {
327    /// Convert to an u64
328    ///
329    /// ```
330    /// # use drm_fourcc::DrmModifier;
331    /// assert_eq!(0u64, DrmModifier::Linear.into());
332    /// ```
333    fn from(val: DrmModifier) -> u64 {
334        val.into_u64()
335    }
336}
337
338impl PartialEq for DrmModifier {
339    fn eq(&self, other: &Self) -> bool {
340        self.into_u64() == other.into_u64()
341    }
342}
343impl Eq for DrmModifier {}
344
345impl PartialEq<u64> for DrmModifier {
346    fn eq(&self, other: &u64) -> bool {
347        &self.into_u64() == other
348    }
349}
350
351impl Hash for DrmModifier {
352    fn hash<H: Hasher>(&self, state: &mut H) {
353        self.into_u64().hash(state);
354    }
355}
356
357impl DrmModifier {
358    /// Get the vendor of the modifier, if any
359    ///
360    /// ```
361    /// # use drm_fourcc::{DrmModifier, DrmVendor, UnrecognizedVendor};
362    /// assert_eq!(DrmModifier::I915_x_tiled.vendor(), Ok(Some(DrmVendor::Intel)));
363    /// assert_eq!(DrmModifier::Linear.vendor(), Ok(None));
364    /// assert_eq!(DrmModifier::Unrecognized(8646911284551352320).vendor(), Err(UnrecognizedVendor(120)));
365    /// ```
366    pub fn vendor(&self) -> Result<Option<DrmVendor>, UnrecognizedVendor> {
367        let vendor = (self.into_u64() >> 56) as u8;
368        if vendor == 0 {
369            Ok(None)
370        } else {
371            DrmVendor::try_from(vendor).map(Some)
372        }
373    }
374}
375
376// Bindgen will always insert `use` statements for these types even though we seriously never use
377// them in normal compilation. Instead, we only use fixed-size types that translate to pure Rust
378// types.
379#[allow(dead_code)]
380pub(crate) mod _fake_ctypes {
381    pub struct c_uchar;
382    pub struct c_uint;
383    pub struct c_ulong;
384}
385
386#[cfg(test)]
387pub mod tests {
388    use super::*;
389
390    #[test]
391    fn a_specific_var_has_correct_value() {
392        assert_eq!(consts::DRM_FOURCC_AYUV, 1448433985);
393    }
394
395    #[test]
396    fn enum_member_casts_to_const() {
397        assert_eq!(
398            DrmFourcc::Xrgb8888 as u32,
399            consts::DRM_FOURCC_XRGB8888 as u32
400        );
401    }
402
403    #[test]
404    #[cfg(feature = "std")]
405    fn enum_member_has_correct_string_format() {
406        assert_eq!(DrmFourcc::Xrgb8888.to_string(), "XR24");
407    }
408
409    #[test]
410    #[cfg(feature = "std")]
411    fn fourcc_string_form_handles_valid() {
412        assert_eq!(fourcc_string_form(875713112).unwrap(), "XR24");
413        assert_eq!(fourcc_string_form(828601953).unwrap(), "avc1");
414        assert_eq!(fourcc_string_form(0x316376).unwrap(), "vc1 ");
415    }
416
417    #[test]
418    #[cfg(feature = "std")]
419    fn unrecognized_handles_valid_fourcc() {
420        assert_eq!(
421            UnrecognizedFourcc(828601953).to_string(),
422            "UnrecognizedFourcc(avc1, 828601953)"
423        );
424    }
425
426    #[test]
427    #[cfg(feature = "std")]
428    fn unrecognized_handles_invalid_fourcc() {
429        assert_eq!(UnrecognizedFourcc(0).to_string(), "UnrecognizedFourcc(0)");
430    }
431
432    #[test]
433    fn can_clone_result() {
434        let a = DrmFourcc::try_from(0);
435        let b = a;
436        assert_eq!(a, b);
437    }
438}
drm_fourcc/lib.rs

drm_fourcc/
lib.rs
