Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Add compress function to return object with reduced memory usage #123

Open
wants to merge 3 commits into
base: master
Choose a base branch
from
Open

Add compress function to return object with reduced memory usage #123

wants to merge 3 commits into from

Commits on Jan 17, 2022

  1. Add compress function to return object with reduced memory usage 

    Objects are modified in place, arrays are replaced with an array that
only has exactly the amount of capacity needed.

This is useful in cases where the polygons will be used for a long time.
By default, arrays are reserved with extra capacity that won't be used.
(The empty array starts with a capacity of 16 elements by now,
which is inefficient for decoded points of length 2)
slice() allocates a new array, seemingly with shrunken capacity
according to process.memoryUsage.

This has an optional option to deduplicate identical points,
which may be useful for collections of polygons sharing points as well
as for calling compress multiple times with different objects.
It's only safe for read-only uses, so it is disabled by default.

For example, in node-geo-tz issue 131, I saw this change to memory usage
and decoding time on Linux. This is useful for long-running processes
that repeatedly use the objects.

1. No Override:                               1.280 GB (1.8 seconds)
2. Defaults for cache(no numericArrayCache):  0.708 GB (3.4 seconds)
3. Adding the second Map (numericArrayCache): 0.435 GB (6.7 seconds)

Closes mapbox#122
    @TysonAndre
    TysonAndre committed Jan 17, 2022
    Configuration menu
    Copy the full SHA
    8f6f509 View commit details
    Browse the repository at this point in the history

  2. Handle INF/NAN

    @TysonAndre
    TysonAndre committed Jan 17, 2022
    Configuration menu
    Copy the full SHA
    3fe4c68 View commit details
    Browse the repository at this point in the history

  3. Handle negative 0

    @TysonAndre
    TysonAndre committed Jan 17, 2022
    Configuration menu
    Copy the full SHA
    c13f9c8 View commit details
    Browse the repository at this point in the history