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// Note: Optimizes only when you call optimize or optimizeBlock persistable sclass BlockOptimizedIntMatrix extends AbstractMatrix<Int> { // Each block is square with side length being a power of two // (i.e. blockSize = 1 << blockShift) int blockShift, blockSize; int bw, bh; // number of block cols/block rows int[][] fullBlocks; // if entry != null, it's a detailed block int[] simpleBlocks; // if fullBlocks entry is null, find block value here *(int *w, int *h, int *blockShift) { blockSize = 1 << blockShift; bw = rshift_ceil(w, blockShift); bh = rshift_ceil(h, blockShift); simpleBlocks = new int[bw*bh]; fullBlocks = new int[bw*bh][]; } public Int get(int x, int y) { int bx = x >> blockShift, by = y >> blockShift; int iBlock = by*bw+bx; int[] block = fullBlocks[iBlock]; if (block != null) ret block[x & (blockSize-1) | ((y & (blockSize-1)) << blockShift)]; ret simpleBlocks[iBlock]; } public void set(int x, int y, Int a) { int bx = x >> blockShift, by = y >> blockShift; int iBlock = by*bw+bx; int[] block = fullBlocks[iBlock]; if (block == null) { int val = simpleBlocks[iBlock]; if (val == a) ret; // no change // convert to full block block = new int[1 << (blockShift*2)]; fullBlocks[iBlock] = block; fillArray(block, val); simpleBlocks[iBlock] = 0; // set irrelevant array entry to 0 for beauty reasons } block[x & (blockSize-1) | ((y & (blockSize-1)) << blockShift)] = a; } void optimizeBlock(int iBlock) { int[] block = fullBlocks[iBlock]; if (block == null) ret; // already optimized int val = block[0]; for (int i = 1; i < block.length; i++) if (block[i] != val) ret; // Can't optimize // Can optimize! simpleBlocks[iBlock] = val; fullBlocks[iBlock] = null; } // optimize all blocks void optimize { int n = simpleBlocks.length; for i to n: optimizeBlock(i); } }
Began life as a copy of #1033112
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Snippet ID: | #1035234 |
Snippet name: | BlockOptimizedIntMatrix - Matrix<Int> stored in blocks of a fixed size (very compact if an entire block is one value, gracefully degrades otherwise) |
Eternal ID of this version: | #1035234/14 |
Text MD5: | 4c1fdbf19bffd3977b4ad546058b8db5 |
Transpilation MD5: | 61c0caaecbcc7c194e9be38ed5e41a6f |
Author: | stefan |
Category: | javax |
Type: | JavaX fragment (include) |
Public (visible to everyone): | Yes |
Archived (hidden from active list): | No |
Created/modified: | 2022-04-20 20:55:40 |
Source code size: | 2109 bytes / 69 lines |
Pitched / IR pitched: | No / No |
Views / Downloads: | 185 / 277 |
Version history: | 13 change(s) |
Referenced in: | [show references] |