Grow ArrayCollection geometrically when inserting at an index - #106
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rotundtapir wants to merge 1 commit into
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rotundtapir wants to merge 1 commit into
rotundtapir wants to merge 1 commit into
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add(index, item) went through slideRight(), which reserved exactly the missing slot, so every insertion reallocated and copied the whole array. Building a type block entry by entry, as merging tables does, was quadratic because of it. Also fix ensureCapacity(int) allocating too little when some capacity is already free: it subtracted the free slots from the request and then added the result to the size instead of to the current length, which could leave fewer free slots than asked for.
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I can't merge because i blocked |
rotundtapir
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Done, the commit is rewritten without the co-author line, same code. Thanks for taking a look! |
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add(index, item)goes throughslideRight(), which reserves exactly the missing slot, so inserting n items one at a time copies the array n times. Building a type block entry by entry, asTableBlock.merge()does, is quadratic because of it. With this change alone,ApkBundle.mergeModules()on the split bundle of the Google app (com.google.android.googlequicksearchbox 17.61.20, 87 MB resources.arsc) spends 16 s merging instead of 39 s.It also fixes
ensureCapacity(int)allocating too little when some capacity is already free. It subtracted the free slots from the request and then added the result to the size instead of the current length, so it could leave fewer free slots than asked for.ArrayCollectionTestcovers both.Independent of #104. It's the first of three split-merge changes; the other two (merging bundle tables without copying the base table, and less memory per table entry) will follow separately.