Request for comment: add support for compressor/decompressor-specific init/destroy

[palemieux]

WIP

Problem

The current C API does not allow compressors and decompressors to allocate/destroy internal resources that can be reused across calls on a given image, beyond very specific memory buffers (through calls to internal_encode_alloc_buffer()).

Solution

Add a per-pipeline and user-configurable initialization and teardown functions:

• decompress_init_fn
• decompress_destroy_fn
• compress_init_fn
• compress_destroy_fn

These functions are initialized to default in exr_decoding_choose_default_routines().

These functions are called in exr_decoding_initialize(), exr_decoding_destroy(), exr_encoding_initialize() and exr_encoding_destroy().

[kthurston]

@palemieux - sorry, am traveling so only looking at this in the web UI which is not my fave - I think I'd prefer this is done a bit differently, I will have a look and submit an alternative if so when I get home - could be I am just misreading your WIP.

[cary-ilm]

@palemieux and @kdt3rd, is this addressed by #2440?

[palemieux]

@cary-ilm Yes #2440 supersedes this.