MTF generator bzip2

#include <cassert>
#include <cstring>
#include <iostream>
using namespace std;

#define BZ_RUNA 0
#define BZ_RUNB 1

void generateMTFValues(char* block) {
    char yy[256];
    int i, j;
    int zPend;
    int wr;
    int EOB;

    // CONSTRUCTION
    int nblock = strlen(block);
    cout << "char count " << nblock << endl;

    unsigned int* ptr = (unsigned int*) malloc(sizeof(unsigned int) * nblock);
    for (int i = 0; i < nblock; i++) {
        ptr[i] = i + 1;
    }

    // mtfv is the mtf output, which the decoder reads on the other side
    unsigned int *mtfv = (unsigned int*) malloc(sizeof(unsigned int) * (nblock + 1));

    bool inUse[256] = {0};
    char* ch = block;
    while (*ch) {
        inUse[*ch] = true;
        ch++;
    }
    int unseqToSeq[256] = {0};
    int mtfFreq[258] = {0};
    // CONSTRUCTION END

    int nInUse = 0;
    for (int i = 0; i < 256; i++)
        if (inUse[i]) {
            unseqToSeq[i] = nInUse;
            nInUse++;
        }
    EOB = nInUse + 1;

    for (i = 0; i <= EOB; i++) mtfFreq[i] = 0;

    wr = 0;

    // this is the *running* frequency of the zero index in mtf
    zPend = 0;
    for (i = 0; i < nInUse; i++) yy[i] = (char) i;

    for (i = 0; i < nblock; i++) {
        char ll_i;
        // j is an index into the original block
        j = ptr[i] - 1;
        if (j < 0) j += nblock;
        // get the mtf index of the j-th byte from the block
        ll_i = unseqToSeq[block[j]];

        if (yy[0] == ll_i) {
            zPend++;
        } else {
            if (zPend > 0) {
                // give the binary output of zPend
                zPend--;
                while (true) {
                    if (zPend & 1) {
                        mtfv[wr] = BZ_RUNB;
                        wr++;
                        mtfFreq[BZ_RUNB]++;
                    } else {
                        mtfv[wr] = BZ_RUNA;
                        wr++;
                        mtfFreq[BZ_RUNA]++;
                    }
                    if (zPend < 2) break;
                    zPend = (zPend - 2) / 2;
                };
                zPend = 0;
            }
            {
                register char rtmp;
                register char *ryy_j;
                register char rll_i;

                // shift all values to the right in yy
                // and pick the rightmost value to the front
                rtmp = yy[1];
                yy[1] = yy[0];
                ryy_j = &(yy[1]);
                rll_i = ll_i;
                while (rll_i != rtmp) {
                    register char rtmp2;
                    ryy_j++;
                    rtmp2 = rtmp;
                    rtmp = *ryy_j;
                    *ryy_j = rtmp2;
                };
                yy[0] = rtmp;
                // ryy_j is the pointer index of rtmp in the live yy array
                j = ryy_j - &(yy[0]);
                // so j is the index
                // and j + 1 is the 1-offset position
                mtfv[wr] = j + 1;
                wr++;
                mtfFreq[j + 1]++;
            }

        }
    }

    if (zPend > 0) {
        zPend--;
        while (true) {
            if (zPend & 1) {
                mtfv[wr] = BZ_RUNB;
                wr++;
                mtfFreq[BZ_RUNB]++;
            } else {
                mtfv[wr] = BZ_RUNA;
                wr++;
                mtfFreq[BZ_RUNA]++;
            }
            if (zPend < 2) break;
            zPend = (zPend - 2) / 2;
        };
        zPend = 0;
    }

    mtfv[wr] = EOB;
    wr++;
    mtfFreq[EOB]++;

    // OUTPUT start
    cout << "MTF Selectors" << endl;
    for (int i = 0; i < wr; i++) {
        cout << mtfv[i] << ", ";
    }
    cout << endl;

    cout << "Frequency" << endl;
    for (int i = 0; i <= EOB; i++) {
        cout << mtfFreq[i] << ", ";
    }
    cout << endl;
    // OUTPUT end
}

int main(int argc, char* argv[]) {
    // pass string as second argument

    assert(argc == 2);

    generateMTFValues(argv[1]);
}