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Maps internals in Go
Idea Map is passed as a value, but it consists of a pointer to hmap which has all the details on map implementation. So, if you change/add to map, it will be reflected everywhere. And that’s why you cannot assign to an uninitialized map (no memory allocated, no hash seed generated yet). runtime/map.go
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type hmap struct { count int // # live cells == size of map. Must be first (used by len() builtin) B uint8 // log_2 of # of buckets (can hold up to loadFactor * 2^B items) hash0 uint32 // hash seed buckets unsafe.Pointer // array of 2^B Buckets. may be nil if count==0. oldbuckets unsafe.Pointer // previous bucket array of half the size, non-nil only when growing nevacuate uintptr // progress counter for evacuation (buckets less than this have been evacuated) } |
Buckets …