teems/Enclave/OblivAlgs/WaksmanNetwork.hpp

#ifndef __WAKSMANNETWORK_HPP__
#define __WAKSMANNETWORK_HPP__

#include <unordered_map>
#include <vector>
#include "oasm_lib.h"
#include <sgx_tcrypto.h>
#include "utils.hpp"
#include "RecursiveShuffle.hpp"
#include "aes.hpp"

// #define PROFILE_MTAPPLYPERM

typedef __uint128_t randkey_t;
#define FPERM_OSWAP_STYLE OSWAP_8_16X // OSwap_Style for forward perm (consistent w/ randkey_t)

// A struct to hold a multi-thread evaluation plan for a
// WaksmanNetwork of a given size and number of threads

// If you have a WaksmanNetwork with N>2 items, and you want to apply
// it using nthreads>1 threads, this WaksmanNetwork will itself use
// the first (N-1)/2 input switches and N/2 output switches (in
// addition to those used by its subnetworks); it will recurse into
// the left subnetwork containing (N+1)/2 items and (nthreads+1)/2
// threads, and into the right subnetwork containing N/2 items and
// nthreads/2 threads.  If N=2, then there is just a single output
// switch and no subnetworks.  If N<2, there are no switches and no
// subnetworks.  If nthreads=1, we compute the total number of inputs
// and output switches used by this WaksmanNetwork and its
// subnetworks, but just store the total in this WNEvalPlan with no
// WNEvalPlans for the subnetworks.

struct WNEvalPlan {
  // The number of items for the represented WaksmanNetwork
  uint32_t N;
  // The number of threads to use to evaluate it
  uint32_t nthreads;
  // The total number of input and output switches used by this
  // WaksmanNetwork and its subnetworks
  size_t subtree_num_inswitches, subtree_num_outswitches;
  // If N>2 and nthreads>1, these are the evaluation plans for the
  // subnetworks.  This vector will contain 0 (if N<=2 or nthreads=1)
  // or 2 (otherwise) items.
  std::vector<WNEvalPlan> subplans;

  WNEvalPlan(uint32_t N, uint32_t nthreads) : N(N), nthreads(nthreads) {
      if (N<2) {
          subtree_num_inswitches = 0;
          subtree_num_outswitches = 0;
      } else if (N == 2) {
          subtree_num_inswitches = 0;
          subtree_num_outswitches = 1;
      } else if (nthreads <= 1) {
          subtree_num_inswitches = 0;
          subtree_num_outswitches = 0;
          count_switches(N);
      } else {
        const uint32_t Nleft = (N+1)/2;
        const uint32_t Nright = N/2;
        const uint32_t numInSwitches = (N-1)/2;
        const uint32_t numOutSwitches = N/2;
        const uint32_t nthr_left = (nthreads+1)/2;
        const uint32_t nthr_right = nthreads/2;
        subplans.emplace_back(Nleft, nthr_left);
        subplans.emplace_back(Nright, nthr_right);
        subtree_num_inswitches = numInSwitches +
            subplans[0].subtree_num_inswitches +
            subplans[1].subtree_num_inswitches;
        subtree_num_outswitches = numOutSwitches +
            subplans[0].subtree_num_outswitches +
            subplans[1].subtree_num_outswitches;
      }
  }

  // Count the number of input and output switches used by a
  // WaksmanNetwork with N items.  Add those values to
  // subtree_num_inswitches and subtree_num_outswitches.
  void count_switches(uint32_t N) {
    if (N<2) {
      return;
    }
    if (N == 2) {
      subtree_num_outswitches += 1;
      return;
    }
    const uint32_t Nleft = (N+1)/2;
    const uint32_t Nright = N/2;
    const uint32_t numInSwitches = (N-1)/2;
    const uint32_t numOutSwitches = N/2;

    subtree_num_inswitches += numInSwitches;
    subtree_num_outswitches += numOutSwitches;
    count_switches(Nleft);
    count_switches(Nright);
  }

  void dump(int indent = 0) {
      printf("%*sN = %lu, nthreads = %lu, inswitches = %lu, outswitches = %lu\n",
          indent, "", N, nthreads, subtree_num_inswitches,
          subtree_num_outswitches);
      if (subplans.size() > 0) {
          subplans[0].dump(indent+2);
          subplans[1].dump(indent+2);
      }
  }
};

/*
  WaksmanNetwork Class: Contains a Waksman permutation network and can apply it to an input array.
    setPermutation(uint32_t *permutation, unsigned char *forward_perm, [optional preallocated
      memory regions]): Takes permutation as an array of N index values (i.e. values in [N]) and
      optional pointers to allocated memory. It sets the Waksman network switches to that
      permutation.
    applyPermutation(unsigned char *buf, size_t block_size): Takes buffer of N items of block_size
      bytes each and applies stored permutation in-place (i.e. modifying input buffer).
    applyInversePermutation(unsigned char *buf, size_t block_size): Takes buffer of N items of
      block_size bytes each and applies inverse of stored permutation in-place.
*/

class WaksmanNetwork {
  uint32_t Ntotal; // number of items to permute
  std::vector<uint32_t> inSwitchVec; // input layer of (numbered) switches
  std::vector<uint8_t> outSwitchVec; // output layer of switches

  // A struct to keep track of the current subnet number, and input and
  // output switches, for each subnet as we traverse the network.
  struct WNTraversal {
    uint64_t subnetNumber;
    uint32_t *inSwitches;
    uint8_t *outSwitches;

    WNTraversal(WaksmanNetwork &wn) : subnetNumber(0),
        inSwitches(wn.inSwitchVec.data()),
        outSwitches(wn.outSwitchVec.data()) {}
  };

  struct appInvPermArgs {
      WaksmanNetwork &wn;
      unsigned char *buf;
      size_t block_size;
      const WNEvalPlan &plan;
      WNTraversal &traversal;

      appInvPermArgs(WaksmanNetwork &wn, unsigned char *buf,
          size_t block_size, const WNEvalPlan &plan, WNTraversal &traversal)
          : wn(wn), buf(buf), block_size(block_size), plan(plan),
          traversal(traversal) {}
  };

  template <OSwap_Style oswap_style>
  static void *applyInversePermutation_launch(void *voidarg)
  {
      appInvPermArgs *arg = (appInvPermArgs *)voidarg;
      arg->wn.applyInversePermutation<oswap_style>(arg->buf, arg->block_size,
          arg->plan, arg->traversal);
      return NULL;
  }

  // A struct to hold pre-allocated memory (and AES keys) so that we
  // only allocate memory once, before the recursive setPermutation is
  // called.
  struct WNMem {
    unsigned char *forward_perm;
    uint32_t *unselected_cnt;
    std::unordered_map<randkey_t, std::pair<uint32_t, uint32_t>> *reverse_perm;
    AESkey forward_key, reverse_key;

    WNMem(WaksmanNetwork &wn) {
        // Round Ntotal up to an even number
        uint32_t Neven = wn.Ntotal + (wn.Ntotal&1);
        forward_perm = new unsigned char[Neven * (sizeof(randkey_t) + 8)];
        unselected_cnt = new uint32_t[wn.Ntotal];
        reverse_perm = new std::unordered_map<randkey_t, std::pair<uint32_t, uint32_t>>;
        __m128i forward_rawkey, reverse_rawkey;
        getRandomBytes((unsigned char *) &forward_rawkey, sizeof(forward_rawkey));
        getRandomBytes((unsigned char *) &reverse_rawkey, sizeof(reverse_rawkey));
        AES_128_Key_Expansion(forward_key, forward_rawkey);
        AES_128_Key_Expansion(reverse_key, reverse_rawkey);
    }

    ~WNMem() {
        delete[] forward_perm;
        delete[] unselected_cnt;
        delete reverse_perm;
    }
  };

  void setPermutation(uint32_t *permutation, uint32_t N,
    uint32_t depth, WNTraversal &traversal, const WNMem &mem);

  template <OSwap_Style oswap_style>
  void applyPermutation(unsigned char *buf, uint32_t N,
    size_t block_size, WNTraversal &traversal);

  template <OSwap_Style oswap_style>
  void applyInversePermutation(unsigned char *buf, uint32_t N,
    size_t block_size, WNTraversal &traversal);

  template <OSwap_Style oswap_style>
  void applyInversePermutation(unsigned char *buf, size_t block_size,
    const WNEvalPlan &plan, WNTraversal &traversal);

public:

  // Set up the WaksmanNetwork for N items.  N need not be a power of 2.
  // N <= 2^31
  WaksmanNetwork(uint32_t N);

  void setPermutation(uint32_t *permutation);

  template <OSwap_Style oswap_style>
  void applyPermutation(unsigned char *buf, size_t block_size);

  template <OSwap_Style oswap_style>
  void applyInversePermutation(unsigned char *buf, size_t block_size);

  template <OSwap_Style oswap_style>
  void applyInversePermutation(unsigned char *buf, size_t block_size,
    const WNEvalPlan &plan);

};

// Define this to show the intermediate states of applyPermutation
// #define SHOW_APPLYPERM

// Apply permutation encoded by control bits to data elements in buffer. Permutes in place.
template <OSwap_Style oswap_style>
void WaksmanNetwork::applyPermutation(unsigned char *buf, size_t block_size) {
    FOAV_SAFE_CNTXT(AP, Ntotal)
    if (Ntotal > 1) {
        WNTraversal traversal(*this);
        applyPermutation<oswap_style>(buf, Ntotal, block_size, traversal);
    }
}

// Apply permutation encoded by control bits to data elements in buffer. Permutes in place.
template <OSwap_Style oswap_style>
void WaksmanNetwork::applyPermutation(unsigned char *buf, uint32_t N,
    size_t block_size, WNTraversal &traversal) {

  FOAV_SAFE_CNTXT(AP, Ntotal)
  FOAV_SAFE_CNTXT(AP, N)
  if (N < 2) return;

  const uint32_t Nleft = (N+1)/2;
  const uint32_t Nright = N/2;
  const uint32_t numInSwitches = (N-1)/2;
  const uint32_t numOutSwitches = N/2;
  const uint32_t *inSwitch = traversal.inSwitches;
  const uint8_t *outSwitch = traversal.outSwitches;

  traversal.subnetNumber += 1;
  traversal.inSwitches += numInSwitches;
  traversal.outSwitches += numOutSwitches;

#ifdef SHOW_APPLYPERM
  printf("s");
  for(uint32_t i=0;i<N;++i) {
    printf(" %2d", *(uint32_t*)(buf+block_size*i));
  }
  printf("\n");
#endif

  if (N == 2) {
#ifdef SHOW_APPLYPERM
    printf("o");
    for(uint32_t i=0;i<numOutSwitches;++i) {
      printf(" %s", outSwitch[i] ? " X" : "||");
    }
    printf("\n");
#endif
    oswap_buffer<oswap_style>(buf, buf + block_size, (uint32_t) block_size, outSwitch[0]);
#ifdef SHOW_APPLYPERM
    printf("e");
    for(uint32_t i=0;i<N;++i) {
      printf(" %2d", *(uint32_t*)(buf+block_size*i));
    }
    printf("\n");
#endif
  } else {
#ifdef SHOW_APPLYPERM
    printf("i");
    for(uint32_t i=0;i<numInSwitches;++i) {
      printf(" %s", (inSwitch[i]&1) ? " X" : "||");
    }
    printf("\n");
#endif
    // Apply input switches to permutation
    const uint32_t *curInSwitchVal = inSwitch;
    for (uint32_t i=0; i<numInSwitches; i++) {
      oswap_buffer<oswap_style>(buf + block_size*(i), buf + block_size*(Nleft+i), block_size,
        (*curInSwitchVal)&1);
      curInSwitchVal += 1;
    }
#ifdef SHOW_APPLYPERM
    printf(" ");
    for(uint32_t i=0;i<N;++i) {
      printf(" %2d", *(uint32_t*)(buf+block_size*i));
    }
    printf("\n");
#endif

    // Apply subnetwork switches
    applyPermutation<oswap_style>(buf, Nleft, block_size, traversal);
    applyPermutation<oswap_style>(buf + block_size*Nleft, Nright,
        block_size, traversal);

#ifdef SHOW_APPLYPERM
    printf("r");
    for(uint32_t i=0;i<N;++i) {
      printf(" %2d", *(uint32_t*)(buf+block_size*i));
    }
    printf("\n");
    printf("o");
    for(uint32_t i=0;i<numOutSwitches;++i) {
      printf(" %s", outSwitch[i] ? " X" : "||");
    }
    printf("\n");
#endif
    // Apply output switches to permutation
    for (uint32_t i=0; i<numOutSwitches; i++) {
      oswap_buffer<oswap_style>(buf + block_size*i, buf + block_size*(Nleft+i), block_size,
        *outSwitch);
      ++outSwitch;
    }
#ifdef SHOW_APPLYPERM
    printf("e");
    for(uint32_t i=0;i<N;++i) {
      printf(" %2d", *(uint32_t*)(buf+block_size*i));
    }
    printf("\n");
#endif
  }
}

// Apply permutation encoded by control bits to data elements in buffer
// using a multithread evaluation plan. Permutes in place.
template <OSwap_Style oswap_style>
void WaksmanNetwork::applyInversePermutation(unsigned char *buf,
        size_t block_size, const WNEvalPlan &plan) {
    FOAV_SAFE_CNTXT(AP, Ntotal)
    if (Ntotal > 1) {
        WNTraversal traversal(*this);
        applyInversePermutation<oswap_style>(buf, block_size, plan, traversal);
    }
}

template <typename CBT>
struct ApplySwitchesArgs {
    unsigned char *buf;
    size_t block_size;
    const CBT* switches;
    uint32_t swStart, swEnd;
    uint32_t stride;
};

// Apply a consecutive sequence of input or output switches, using
// arguments passed as an ApplySwitchesArgs*.  CBT is the
// control bit type (uint32_t for input switches or uint8_t for output
// switches).
template <OSwap_Style oswap_style, typename CBT>
static void* applySwitchesRange(void *voidargs)
{
    const ApplySwitchesArgs<CBT>* args =
        (const ApplySwitchesArgs<CBT> *)voidargs;
    unsigned char *buf = args->buf;
    const size_t block_size = args->block_size;
    const uint32_t swStart = args->swStart;
    const CBT* switches = args->switches + swStart;
    const uint32_t swEnd = args->swEnd;
    const uint32_t stride = args->stride;

    FOAV_SAFE_CNTXT(applySwitchesRange, swEnd)
    for (uint32_t i=swStart; i<swEnd; ++i) {
        FOAV_SAFE2_CNTXT(applySwitchesRange, i, swEnd)
        oswap_buffer<oswap_style>(buf + block_size*(i),
            buf + block_size*(stride+i), block_size,
            (*switches)&1);
        ++switches;
    }

    return NULL;
}

// Apply a consecutive sequence of input or output switches using
// up to nthreads threads.  CBT is the control bit type (uint32_t for
// input switches or uint8_t for output switches), but it will be
// deduced automatically from the type of the switches argument.
template <OSwap_Style oswap_style, typename CBT>
static void applySwitches(unsigned char *buf, size_t block_size,
    const CBT* switches, uint32_t numSwitches, uint32_t stride,
    uint32_t nthreads)
{
    uint32_t threads_to_use = nthreads;
    ApplySwitchesArgs<CBT> asargs[threads_to_use];
    uint32_t inc = numSwitches / threads_to_use;
    uint32_t extra = numSwitches % threads_to_use;
    uint32_t last = 0;

    for (uint32_t t=0; t<threads_to_use; ++t) {
        uint32_t next = last + inc + (t < extra);
        asargs[t] = { buf, block_size, switches, last, next, stride };
        last = next;
        if (t > 0) {
            threadpool_dispatch(g_thread_id+t,
                applySwitchesRange<oswap_style,CBT>, &asargs[t]);
        }
    }
    // Do the first block ourselves
    applySwitchesRange<oswap_style,CBT>(&asargs[0]);
    for (size_t t=1; t<threads_to_use; ++t) {
        threadpool_join(g_thread_id+t, NULL);
    }
}

// Apply inverse of permutation encoded by control bits to data elements
// in buffer using a multithread evaluation plan. Permutes in place.
template <OSwap_Style oswap_style>
void WaksmanNetwork::applyInversePermutation(unsigned char *buf,
    size_t block_size, const WNEvalPlan &plan, WNTraversal &traversal) {

  const uint32_t N = plan.N;
  const uint32_t nthreads = plan.nthreads;

  if (N < 2) return;
  if (nthreads <= 1) {
#ifdef PROFILE_MTAPPLYPERM
unsigned long start = printf_with_rtclock("Thread %u starting single-threaded applyInversePermutation(N=%lu)\n", g_thread_id, N);
#endif
    applyInversePermutation<oswap_style>(buf, N, block_size, traversal);
#ifdef PROFILE_MTAPPLYPERM
printf_with_rtclock_diff(start, "Thread %u ending single-threaded applyInversePermutation(N=%lu)\n", g_thread_id, N);
#endif
    return;
  }

#ifdef PROFILE_MTAPPLYPERM
unsigned long start = printf_with_rtclock("Thread %u starting applyInversePermutation(N=%lu, nthreads=%lu)\n", g_thread_id, N, nthreads);
#endif

  const uint32_t Nleft = (N+1)/2;
  const uint32_t Nright = N/2;
  const uint32_t numInSwitches = (N-1)/2;
  const uint32_t numOutSwitches = N/2;
  const uint32_t *inSwitch = traversal.inSwitches;
  const uint8_t *outSwitch = traversal.outSwitches;
  const uint32_t nthr_left = (nthreads+1)/2;
  const uint32_t nthr_right = nthreads/2;

  WNTraversal lefttraversal = traversal;
  lefttraversal.inSwitches += numInSwitches;
  lefttraversal.outSwitches += numOutSwitches;
  traversal.inSwitches +=
    plan.subplans[0].subtree_num_inswitches + numInSwitches;
  traversal.outSwitches +=
    plan.subplans[0].subtree_num_outswitches + numOutSwitches;

#ifdef SHOW_APPLYPERM
  printf("s");
  for(uint32_t i=0;i<N;++i) {
    printf(" %2d", *(uint32_t*)(buf+block_size*i));
  }
  printf("\n");
#endif

  FOAV_SAFE_CNTXT(AIP, N)
  if (N == 2) {
#ifdef SHOW_APPLYPERM
    printf("o");
    for(uint32_t i=0;i<numOutSwitches;++i) {
      printf(" %s", outSwitch[i] ? " X" : "||");
    }
    printf("\n");
#endif
    oswap_buffer<oswap_style>(buf, buf + block_size, (uint32_t) block_size,
        outSwitch[0]);
#ifdef SHOW_APPLYPERM
    printf("e");
    for(uint32_t i=0;i<N;++i) {
      printf(" %2d", *(uint32_t*)(buf+block_size*i));
    }
    printf("\n");
#endif
  } else {
    // Apply output switches to permutation
#ifdef SHOW_APPLYPERM
    printf("o");
    for(uint32_t i=0;i<numOutSwitches;++i) {
      printf(" %s", outSwitch[i] ? " X" : "||");
    }
    printf("\n");
#endif
#ifdef PROFILE_MTAPPLYPERM
unsigned long outswstart = printf_with_rtclock("Thread %u starting output switches (N=%lu, nthreads=%lu)\n", g_thread_id, N, nthreads);
#endif
    applySwitches<oswap_style>(buf, block_size, outSwitch, numOutSwitches,
        Nleft, nthreads);
#ifdef PROFILE_MTAPPLYPERM
printf_with_rtclock_diff(outswstart, "Thread %u ending output switches (N=%lu, nthreads=%lu)\n", g_thread_id, N, nthreads);
#endif
#ifdef SHOW_APPLYPERM
    printf(" ");
    for(uint32_t i=0;i<N;++i) {
      printf(" %2d", *(uint32_t*)(buf+block_size*i));
    }
    printf("\n");
#endif

    // Apply subnetwork switches
    threadid_t rightthreadid = g_thread_id + nthr_left;
    appInvPermArgs rightargs(*this, buf + block_size*Nleft,
        block_size, plan.subplans[1], traversal);
    threadpool_dispatch(rightthreadid,
        applyInversePermutation_launch<oswap_style>, &rightargs);
    applyInversePermutation<oswap_style>(buf, block_size,
        plan.subplans[0], lefttraversal);
    threadpool_join(rightthreadid, NULL);

    // Apply input switches to permutation
#ifdef SHOW_APPLYPERM
    printf("r");
    for(uint32_t i=0;i<N;++i) {
      printf(" %2d", *(uint32_t*)(buf+block_size*i));
    }
    printf("\n");
    printf("i");
    for(uint32_t i=0;i<numInSwitches;++i) {
      printf(" %s", (inSwitch[i]&1) ? " X" : "||");
    }
    printf("\n");
#endif
#ifdef PROFILE_MTAPPLYPERM
unsigned long inswstart = printf_with_rtclock("Thread %u starting input switches (N=%lu, nthreads=%lu)\n", g_thread_id, N, nthreads);
#endif
    applySwitches<oswap_style>(buf, block_size, inSwitch, numInSwitches,
        Nleft, nthreads);
#ifdef PROFILE_MTAPPLYPERM
printf_with_rtclock_diff(inswstart, "Thread %u ending input switches (N=%lu, nthreads=%lu)\n", g_thread_id, N, nthreads);
#endif
#ifdef SHOW_APPLYPERM
    printf("e");
    for(uint32_t i=0;i<N;++i) {
      printf(" %2d", *(uint32_t*)(buf+block_size*i));
    }
    printf("\n");
#endif
  }

#ifdef PROFILE_MTAPPLYPERM
printf_with_rtclock_diff(start, "Thread %u ending applyInversePermutation(N=%lu, nthreads=%lu)\n", g_thread_id, N, nthreads);
#endif

}


// Apply inverse of permutation in control bits to data elements in buffer. Permutes in place.
template <OSwap_Style oswap_style>
void WaksmanNetwork::applyInversePermutation(unsigned char *buf, size_t block_size) {
    FOAV_SAFE_CNTXT(AIP, Ntotal)
    if (Ntotal > 1) {
        WNTraversal traversal(*this);
        applyInversePermutation<oswap_style>(buf, Ntotal, block_size,
            traversal);
    }
}

// Apply inverse of permutation in control bits to data elements in buffer. Permutes in place.
template <OSwap_Style oswap_style>
void WaksmanNetwork::applyInversePermutation(unsigned char *buf,
    uint32_t N, size_t block_size, WNTraversal &traversal) {
  FOAV_SAFE_CNTXT(AIP, N)
  if (N < 2) return;

  const uint32_t Nleft = (N+1)/2;
  const uint32_t Nright = N/2;
  const uint32_t numInSwitches = (N-1)/2;
  const uint32_t numOutSwitches = N/2;
  const uint32_t *inSwitch = traversal.inSwitches;
  const uint8_t *outSwitch = traversal.outSwitches;

  traversal.subnetNumber += 1;
  traversal.inSwitches += numInSwitches;
  traversal.outSwitches += numOutSwitches;

#ifdef SHOW_APPLYPERM
  printf("s");
  for(uint32_t i=0;i<N;++i) {
    printf(" %2d", *(uint32_t*)(buf+block_size*i));
  }
  printf("\n");
#endif

  FOAV_SAFE_CNTXT(AIP, N)
  if (N == 2) {
#ifdef SHOW_APPLYPERM
    printf("o");
    for(uint32_t i=0;i<numOutSwitches;++i) {
      printf(" %s", outSwitch[i] ? " X" : "||");
    }
    printf("\n");
#endif
    oswap_buffer<oswap_style>(buf, buf + block_size, (uint32_t) block_size,
        outSwitch[0]);
#ifdef SHOW_APPLYPERM
    printf("e");
    for(uint32_t i=0;i<N;++i) {
      printf(" %2d", *(uint32_t*)(buf+block_size*i));
    }
    printf("\n");
#endif
  } else {
    // Apply output switches to permutation
#ifdef SHOW_APPLYPERM
    printf("o");
    for(uint32_t i=0;i<numOutSwitches;++i) {
      printf(" %s", outSwitch[i] ? " X" : "||");
    }
    printf("\n");
#endif
    FOAV_SAFE_CNTXT(AIP, numOutSwitches)
    for (uint32_t i=0; i<numOutSwitches; i++) {
    FOAV_SAFE2_CNTXT(AIP, i, numOutSwitches)
      oswap_buffer<oswap_style>(buf + block_size*i, buf + block_size*(Nleft+i), block_size,
        *outSwitch);
      ++outSwitch;
    }
#ifdef SHOW_APPLYPERM
    printf(" ");
    for(uint32_t i=0;i<N;++i) {
      printf(" %2d", *(uint32_t*)(buf+block_size*i));
    }
    printf("\n");
#endif

    // Apply subnetwork switches
    applyInversePermutation<oswap_style>(buf, Nleft,
        block_size, traversal);
    applyInversePermutation<oswap_style>(buf + block_size*Nleft, Nright,
        block_size, traversal);

    // Apply input switches to permutation
#ifdef SHOW_APPLYPERM
    printf("r");
    for(uint32_t i=0;i<N;++i) {
      printf(" %2d", *(uint32_t*)(buf+block_size*i));
    }
    printf("\n");
    printf("i");
    for(uint32_t i=0;i<numInSwitches;++i) {
      printf(" %s", (inSwitch[i]&1) ? " X" : "||");
    }
    printf("\n");
#endif
    const uint32_t *curInSwitchVal = inSwitch;
    FOAV_SAFE_CNTXT(AIP, numInSwitches)
    for (uint32_t i=0; i<numInSwitches; i++) {
    FOAV_SAFE2_CNTXT(AIP, i, numInSwitches)
      oswap_buffer<oswap_style>(buf + block_size*(i), buf + block_size*(Nleft+i), block_size,
        (*curInSwitchVal&1));
      curInSwitchVal += 1;
    }
#ifdef SHOW_APPLYPERM
    printf("e");
    for(uint32_t i=0;i<N;++i) {
      printf(" %2d", *(uint32_t*)(buf+block_size*i));
    }
    printf("\n");
#endif
  }
}


#if 0
void OblivWaksmanShuffle(unsigned char *buffer, uint32_t N, size_t block_size, enc_ret *ret);

void DecryptAndOblivWaksmanShuffle(unsigned char *encrypted_buffer, uint32_t N,
  size_t encrypted_block_size, unsigned char *result_buffer, enc_ret *ret);

void DecryptAndOWSS(unsigned char *encrypted_buffer, uint32_t N,
  size_t encrypted_block_size, unsigned char *result_buffer, enc_ret *ret);

void DecryptAndMTSS(unsigned char *encrypted_buffer, uint32_t N,
  size_t encrypted_block_size, size_t nthreads,
  unsigned char *result_buffer, enc_ret *ret);
#endif

#endif