private static void hbMakeCodeLengths()

in src/main/java/org/apache/commons/compress/compressors/bzip2/BZip2CompressorOutputStream.java [229:368]
108 lines of code
23 McCabe index (conditional complexity)

    private static void hbMakeCodeLengths(final byte[] len, final int[] freq, final Data dat, final int alphaSize, final int maxLen) {
        /*
         * Nodes and heap entries run from 1. Entry 0 for both the heap and nodes is a sentinel.
         */
        final int[] heap = dat.heap;
        final int[] weight = dat.weight;
        final int[] parent = dat.parent;

        for (int i = alphaSize; --i >= 0;) {
            weight[i + 1] = (freq[i] == 0 ? 1 : freq[i]) << 8;
        }

        for (boolean tooLong = true; tooLong;) {
            tooLong = false;

            int nNodes = alphaSize;
            int nHeap = 0;
            heap[0] = 0;
            weight[0] = 0;
            parent[0] = -2;

            for (int i = 1; i <= alphaSize; i++) {
                parent[i] = -1;
                nHeap++;
                heap[nHeap] = i;

                int zz = nHeap;
                final int tmp = heap[zz];
                while (weight[tmp] < weight[heap[zz >> 1]]) {
                    heap[zz] = heap[zz >> 1];
                    zz >>= 1;
                }
                heap[zz] = tmp;
            }

            while (nHeap > 1) {
                final int n1 = heap[1];
                heap[1] = heap[nHeap];
                nHeap--;

                int yy = 0;
                int zz = 1;
                int tmp = heap[1];

                while (true) {
                    yy = zz << 1;

                    if (yy > nHeap) {
                        break;
                    }

                    if (yy < nHeap && weight[heap[yy + 1]] < weight[heap[yy]]) {
                        yy++;
                    }

                    if (weight[tmp] < weight[heap[yy]]) {
                        break;
                    }

                    heap[zz] = heap[yy];
                    zz = yy;
                }

                heap[zz] = tmp;

                final int n2 = heap[1];
                heap[1] = heap[nHeap];
                nHeap--;

                yy = 0;
                zz = 1;
                tmp = heap[1];

                while (true) {
                    yy = zz << 1;

                    if (yy > nHeap) {
                        break;
                    }

                    if (yy < nHeap && weight[heap[yy + 1]] < weight[heap[yy]]) {
                        yy++;
                    }

                    if (weight[tmp] < weight[heap[yy]]) {
                        break;
                    }

                    heap[zz] = heap[yy];
                    zz = yy;
                }

                heap[zz] = tmp;
                nNodes++;
                parent[n1] = parent[n2] = nNodes;

                final int weight_n1 = weight[n1];
                final int weight_n2 = weight[n2];
                weight[nNodes] = (weight_n1 & 0xffffff00) + (weight_n2 & 0xffffff00) | 1 + Math.max(weight_n1 & 0x000000ff, weight_n2 & 0x000000ff);

                parent[nNodes] = -1;
                nHeap++;
                heap[nHeap] = nNodes;

                tmp = 0;
                zz = nHeap;
                tmp = heap[zz];
                final int weight_tmp = weight[tmp];
                while (weight_tmp < weight[heap[zz >> 1]]) {
                    heap[zz] = heap[zz >> 1];
                    zz >>= 1;
                }
                heap[zz] = tmp;

            }

            for (int i = 1; i <= alphaSize; i++) {
                int j = 0;
                int k = i;

                for (int parent_k; (parent_k = parent[k]) >= 0;) {
                    k = parent_k;
                    j++;
                }

                len[i - 1] = (byte) j;
                if (j > maxLen) {
                    tooLong = true;
                }
            }

            if (tooLong) {
                for (int i = 1; i < alphaSize; i++) {
                    int j = weight[i] >> 8;
                    j = 1 + (j >> 1);
                    weight[i] = j << 8;
                }
            }
        }
    }