Navigation app: reduce memory usage #362
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- Renaming and reformatting according to coding conventions - declare iconMap as constexpr and use char* instead of std::string This reduces the flash usage from 424644B to 419344B (-5300B)!
jonvmey
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May 26, 2021
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This PR slightly changes how
iconMapis declared to reduce significantly the FLASH and RAM memory consumed by this app.Before this change,
iconMapwas declare as a non-const member variable of Navigation. It means that this array was stored in FLASH. When Navigation was instantiated, the content of the flash was copied into RAM.Also,
iconMapwas declared asstd::array<std::pair<std::string, const char*>, 89>. Each item of the array was 28B long (24B for the string, 4B for the ptr to char). Usingconst char*instead ofstd::stringfrees 20B per element in the array.Now, the array is declared as
static constexpr std::array<std::pair<const char*, const char*>, 86>: 8B per element and it only lives in.rodatawhich is in FLASH. No need to copy it into RAM.In the end, 5300B of flash were freed, and probably that much in the heap (RAM):
424644 960 47676 473280 738c0 pinetime-app-1.0.0.out419344 960 47676 467980 7240c pinetime-app-1.0.0.out