It is possible for this routine to expand some inputs, and in fact
it does for certan strings in the proposed Korean translation of
CircuitPython (#1858). I did not determine what the maximum
expansion is -- it's probably modest, like len()/7+2 bytes or
something -- so I tried to just make enc[] an adequate
over-allocation, and then ensured that all the strings in the
proposed ko.po now worked. The worst actual expansion seems to be a
string that goes from 65 UTF-8-encoded bytes to 68 compressed bytes
(+4.6%). Only a few out of all strings are reported as
non-compressed.
The original formulation was because I saw the need to avoid a transition
from playing to stopped exactly when a resume was taking place. However,
@tannewt was concerned about this pause causing trouble, because it could
be relatively lengthy (several ms even in a typical case).
After reflection, I've convinced myself that updating the registers
in this order in resume avoids a window where a "stopped" event can
be missed as long as the shortcut is updated first.
Testing re-performed: pause/resume testing of looped RawSample and
WaveFile audio sources.
It lets us re-use the same buffer for playing multiple files.
This also allows us to control the size of the buffer. Half of the
buffer will be used for the fist, and half for the second internal
buffer.
Testing performed: installed freshly built .uf2 on a Particle Xenon.
Checked that circuitpython still starts.
Checked that the size of all .uf2 files for nrf builds are plausible.
Aside from memory savings, the performance of Python code (pystone)
increased by about +14%.
However, this adds about 12-16 seconds to each nrf build.
Timings & Sizes (build system: i5-3320M, -j5 parallelism on 4 threads):
Before:
$ make -j5 BOARD=particle_xenon
765004 bytes free in flash out of 1048576 bytes ( 1024.0 kb ).
232076 bytes free in ram for stack out of 245760 bytes ( 240.0 kb ).
68.54user 11.83system 0:34.34elapsed 234%CPU
pystones before: 570
After:
$ make -j5 BOARD=particle_xenon
804284 bytes free in flash out of 1048576 bytes ( 1024.0 kb ).
232072 bytes free in ram for stack out of 245760 bytes ( 240.0 kb ).
71.06user 11.77system 0:46.91elapsed 176%CPU
pystones after: 650
Timings on travis:
Before:
Build feather_nrf52840_express for pl took 55.79s and succeeded
Build feather_nrf52840_express for zh_Latn_pinyin took 3.18s and succeeded
After:
Build feather_nrf52840_express for pl took 62.72s and succeeded
Build feather_nrf52840_express for zh_Latn_pinyin took 19.10s
Closes: #1396
Snekboard does not expose any pins for SPI to the user, so delete
the SPI object reference as that won't work.
Signed-off-by: Keith Packard <keithp@keithp.com>
Snekboard has been assigned the following PIDs:
PID 0x004D # bootloader
PID 0x804D # arduino
PID 0x804E # circuitpython
Signed-off-by: Keith Packard <keithp@keithp.com>
