1# Audio HAL
2
3Directory structure of the audio HAL related code.
4
5Run `common/all-versions/copyHAL.sh` to create a new version of the audio HAL
6based on an existing one.
7
8## Directory Structure
9
10* `2.0` — version 2.0 of the core HIDL API. Note that `.hal` files
11  can not be moved into the `core` directory because that would change
12  its namespace and include path.
13   - `config` — the XSD schema for the Audio Policy Manager
14     configuration file.
15* `4.0` — version 4.0 of the core HIDL API.
16* ...
17* `common` — common types for audio core and effect HIDL API.
18   - `2.0` — version 2.0 of the common types HIDL API.
19   - `4.0` — version 4.0.
20   - ...
21   - `7.0` — version 7.0.
22      - `example` — example implementation of the core and effect
23        V7.0 API. It represents a "fake" audio HAL that doesn't
24        actually communicate with hardware.
25   - `all-versions` — code common to all version of both core and effect API.
26      - `default` — shared code of the default implementation.
27         - `service` — vendor HAL service for hosting the default
28           implementation.
29      - `test` — utilities used by tests.
30      - `util` — utilities used by both implementation and tests.
31* `core` — VTS tests and the default implementation of the core API
32  (not HIDL API, it's in `audio/N.M`).
33   - `7.0` — code specific to version V7.0 of the core HIDL API
34   - `all-versions` — the code is common between all versions,
35     version-specific parts are enclosed into conditional directives
36     of preprocessor or reside in dedicated files.
37       - `default` — code that wraps the legacy API (from
38         `hardware/libhardware`).
39         - `util` — utilities for the default implementation.
40       - `vts` VTS tests for the core HIDL API.
41* `effect` — same for the effect HIDL API.
42   - `2.0`
43      - `config` — the XSD schema for the Audio Effects configuration file.
44   - `4.0`
45   - ...
46   - `all-versions`
47       - `default` — code that wraps the legacy API (from
48         `hardware/libhardware`).
49         - `util` — utilities for the default implementation.
50       - `vts` VTS tests for the effect HIDL API.
51* `policy` — Configurable Audio Policy schemes.
52   - `1.0` — note that versions of CAP are not linked to the versions
53     of audio HAL.
54      - `vts` — VTS tests for validating actual configuration files.
55      - `xml` — XSD schemas for CAP configuration files.
56