PeerStreamer

/*

 *  Copyright (c) 2010 Luca Abeni

 *

 *  This is free software; see lgpl-2.1.txt

 */

#include <stdint.h>

#include <stdlib.h>

#include <string.h>

#include <stdio.h>

#undef NDEBUG

#include <assert.h>

#include "net_helper.h"

#include "topocache.h"

#include "int_coding.h"

struct cache_entry {

  struct nodeID *id;

  uint32_t timestamp;

};

struct peer_cache {

  struct cache_entry *entries;

  int cache_size;

  int current_size;

  int metadata_size;

  uint8_t *metadata;

  int max_timestamp;

};

static int cache_insert(struct peer_cache *c, struct cache_entry *e, const void *meta)

{

  int i, position;

  if (c->current_size == c->cache_size) {

    return -2;

  }

  position = 0;

  for (i = 0; i < c->current_size; i++) {

    assert(e->id);

    assert(c->entries[i].id);

    if (c->entries[i].timestamp <= e->timestamp) {

      position = i + 1;

    }

    if (nodeid_equal(e->id, c->entries[i].id)) {

      if (c->entries[i].timestamp > e->timestamp) {

        assert(i >= position);

        nodeid_free(c->entries[i].id);

        c->entries[i] = *e;

        memcpy(c->metadata + i * c->metadata_size, meta, c->metadata_size);

        if (position != i) {

          memmove(c->entries + position + 1, c->entries + position, sizeof(struct cache_entry) * (i - position));

          memmove(c->metadata + (position + 1) * c->metadata_size, c->metadata + position * c->metadata_size, (i -position) * c->metadata_size);

        }

        return position;

      }

      return -1;

    }

  }

  if (position != c->current_size) {

    memmove(c->entries + position + 1, c->entries + position, sizeof(struct cache_entry) * (c->current_size - position));

    memmove(c->metadata + (position + 1) * c->metadata_size, c->metadata + position * c->metadata_size, (c->current_size - position) * c->metadata_size);

  }

  c->current_size++;

  c->entries[position] = *e;

  memcpy(c->metadata + position * c->metadata_size, meta, c->metadata_size);

  return position;

}

int cache_add_cache(struct peer_cache *dst, const struct peer_cache *src)

{

  struct cache_entry *e_orig;

  int count, j;

  struct cache_entry e_dup;

cache_check(dst);

cache_check(src);

  count = 0;

  j=0;

  while(dst->current_size < dst->cache_size && src->current_size > count) {

    count++;

    e_orig = src->entries + j;

    e_dup.id = nodeid_dup(e_orig->id);

    e_dup.timestamp = e_orig->timestamp;

    if (cache_insert(dst, &e_dup, src->metadata + src->metadata_size * j) < 0) {

      nodeid_free(e_dup.id);

    }

    j++;

  }

cache_check(dst);

cache_check(src);

  return dst->current_size;

}

struct nodeID *nodeid(const struct peer_cache *c, int i)

{

  if (i < c->current_size) {

    return c->entries[i].id;

  }

  return NULL;

}

const void *get_metadata(const struct peer_cache *c, int *size)

{

  *size = c->metadata_size;

  return c->metadata;

}

int cache_metadata_update(struct peer_cache *c, const struct nodeID *p, const void *meta, int meta_size)

{

  int i;

  if (!meta_size || meta_size != c->metadata_size) {

    return -3;

  }

  for (i = 0; i < c->current_size; i++) {

    if (nodeid_equal(c->entries[i].id, p)) {

      memcpy(c->metadata + i * meta_size, meta, meta_size);

      return 1;

    }

  }

  return 0;

}

int cache_add_ranked(struct peer_cache *c, struct nodeID *neighbour, const void *meta, int meta_size, ranking_function f, const void *tmeta)

{

  int i, pos = 0;

  if (meta_size && meta_size != c->metadata_size) {

    return -3;

  }

  for (i = 0; i < c->current_size; i++) {

    if (nodeid_equal(c->entries[i].id, neighbour)) {

      if (f != NULL) {

        cache_del(c,neighbour);

        if (i == c->current_size) break;

      } else {

          cache_metadata_update(c,neighbour,meta,meta_size);

          return -1;

      }

    }

    if ((f != NULL) && f(tmeta, meta, c->metadata+(c->metadata_size * i)) == 2) {

      pos++;

    }

  }

  if (c->current_size == c->cache_size) {

    return -2;

  }

  if (c->metadata_size) {

    memmove(c->metadata + (pos + 1) * c->metadata_size, c->metadata + pos * c->metadata_size, (c->current_size - pos) * c->metadata_size);

    if (meta_size) {

      memcpy(c->metadata + pos * c->metadata_size, meta, meta_size);

    } else {

      memset(c->metadata + pos * c->metadata_size, 0, c->metadata_size);

    }

  }

  for (i = c->current_size; i > pos; i--) {

    c->entries[i] = c->entries[i - 1];

  }

  c->entries[pos].id = nodeid_dup(neighbour);

  c->entries[pos].timestamp = 1;

  c->current_size++;

  return c->current_size;

}

int cache_add(struct peer_cache *c, struct nodeID *neighbour, const void *meta, int meta_size)

{

  return cache_add_ranked(c, neighbour, meta, meta_size, NULL, NULL);

}

int cache_del(struct peer_cache *c, const struct nodeID *neighbour)

{

  int i;

  int found = 0;

  for (i = 0; i < c->current_size; i++) {

    if (nodeid_equal(c->entries[i].id, neighbour)) {

      nodeid_free(c->entries[i].id);

      c->current_size--;

      found = 1;

      if (c->metadata_size && (i < c->current_size)) {

        memmove(c->metadata + c->metadata_size * i,

                c->metadata + c->metadata_size * (i + 1),

                c->metadata_size * (c->current_size - i));

      }

    }

    if (found && (i < c->current_size)) {

      c->entries[i] = c->entries[i + 1];

    }

  }

  return c->current_size;

}

void cache_update(struct peer_cache *c)

{

  int i;

  for (i = 0; i < c->current_size; i++) {

    if (c->max_timestamp && (c->entries[i].timestamp == c->max_timestamp)) {

      int j = i;

      while(j < c->current_size && c->entries[j].id) {

        nodeid_free(c->entries[j].id);

        c->entries[j++].id = NULL;

      }

      c->current_size = i;        /* The cache is ordered by timestamp...

                                   all the other entries wiil be older than

                                   this one, so remove all of them

                                */

    } else {

      c->entries[i].timestamp++;

    }

  }

}

struct peer_cache *cache_init(int n, int metadata_size, int max_timestamp)

{

  struct peer_cache *res;

  res = malloc(sizeof(struct peer_cache));

  if (res == NULL) {

    return NULL;

  }

  res->max_timestamp = max_timestamp;

  res->cache_size = n;

  res->current_size = 0;

  res->entries = malloc(sizeof(struct cache_entry) * n);

  if (res->entries == NULL) {

    free(res);

    return NULL;

  }

  memset(res->entries, 0, sizeof(struct cache_entry) * n);

  if (metadata_size) {

    res->metadata = malloc(metadata_size * n);

  } else {

    res->metadata = NULL;

  }

  if (res->metadata) {

    res->metadata_size = metadata_size;

    memset(res->metadata, 0, metadata_size * n);

  } else {

    res->metadata_size = 0;

  }

  return res;

}

void cache_free(struct peer_cache *c)

{

  int i;

  for (i = 0; i < c->current_size; i++) {

    if(c->entries[i].id) {

      nodeid_free(c->entries[i].id);

    }

  }

  free(c->entries);

  free(c->metadata);

  free(c);

}

static int in_cache(const struct peer_cache *c, const struct cache_entry *elem)

{

  int i;

  for (i = 0; i < c->current_size; i++) {

    if (nodeid_equal(c->entries[i].id, elem->id)) {

      return i;

    }

  }

  return -1;

}

struct nodeID *rand_peer(const struct peer_cache *c, void **meta, int max)

{

  int j;

  if (c->current_size == 0) {

    return NULL;

  }

  if (!max || max >= c->current_size)

    max = c->current_size;

  else

    ++max;

  j = ((double)rand() / (double)RAND_MAX) * max;

  if (meta) {

    *meta = c->metadata + (j * c->metadata_size);

  }

  return c->entries[j].id;

}

struct nodeID *last_peer(const struct peer_cache *c)

{

  if (c->current_size == 0) {

    return NULL;

  }

  return c->entries[c->current_size - 1].id;

}

struct peer_cache *rand_cache(struct peer_cache *c, int n)

{

  struct peer_cache *res;

cache_check(c);

  if (c->current_size < n) {

    n = c->current_size;

  }

  res = cache_init(n, c->metadata_size, c->max_timestamp);

  while(res->current_size < n) {

    int j;

    j = ((double)rand() / (double)RAND_MAX) * c->current_size;

    cache_insert(res, c->entries + j, c->metadata + c->metadata_size * j);

    c->current_size--;

    memmove(c->entries + j, c->entries + j + 1, sizeof(struct cache_entry) * (c->current_size - j));

    memmove(c->metadata + c->metadata_size * j, c->metadata + c->metadata_size * (j + 1), c->metadata_size * (c->current_size - j));

    c->entries[c->current_size].id = NULL;

cache_check(c);

  }

  return res;

}

struct peer_cache *entries_undump(const uint8_t *buff, int size)

{

  struct peer_cache *res;

  int i = 0;

  const uint8_t *p = buff;

  uint8_t *meta;

  int cache_size, metadata_size;

  cache_size = int_rcpy(buff);

  metadata_size = int_rcpy(buff + 4);

  p = buff + 8;

  res = cache_init(cache_size, metadata_size, 0);

  meta = res->metadata;

  while (p - buff < size) {

    int len;

    res->entries[i].timestamp = int_rcpy(p);

    p += sizeof(uint32_t);

    res->entries[i++].id = nodeid_undump(p, &len);

    p += len;

    if (metadata_size) {

      memcpy(meta, p, metadata_size);

      p += metadata_size;

      meta += metadata_size;

    }

  }

  res->current_size = i;

  assert(p - buff == size);

  return res;

}

int cache_header_dump(uint8_t *b, const struct peer_cache *c, int include_me)

{

  int_cpy(b, c->cache_size + (include_me ? 1 : 0));

  int_cpy(b + 4, c->metadata_size);

  return 8;

}

int entry_dump(uint8_t *b, const struct peer_cache *c, int i, size_t max_write_size)

{

  int res;

  int size = 0;

  if (i && (i >= c->cache_size - 1)) {

    return 0;

  }

  int_cpy(b, c->entries[i].timestamp);

  size = +4;

  res = nodeid_dump(b + size, c->entries[i].id, max_write_size - size);

  if (res < 0 ) {

    return -1;

  }

  size += res;

  if (c->metadata_size) {

    if (c->metadata_size > max_write_size - size) {

      return -1;

    }

    memcpy(b + size, c->metadata + c->metadata_size * i, c->metadata_size);

    size += c->metadata_size;

  }

  return size;

}

struct peer_cache *cache_rank (const struct peer_cache *c, ranking_function rank, const struct nodeID *target, const void *target_meta)

{

  struct peer_cache *res;

  int i,j,pos;

  res = cache_init(c->cache_size, c->metadata_size, c->max_timestamp);

  if (res == NULL) {

    return res;

  }

  for (i = 0; i < c->current_size; i++) {

    if (!target || !nodeid_equal(c->entries[i].id,target)) {

      pos = 0;

      for (j=0; j<res->current_size;j++) {

        if (((rank != NULL) && rank(target_meta, c->metadata+(c->metadata_size * i), res->metadata+(res->metadata_size * j)) == 2) ||

            ((rank == NULL) && res->entries[j].timestamp < c->entries[i].timestamp)) {

          pos++;

        }

      }

      if (c->metadata_size) {

        memmove(res->metadata + (pos + 1) * res->metadata_size, res->metadata + pos * res->metadata_size, (res->current_size - pos) * res->metadata_size);

        memcpy(res->metadata + pos * res->metadata_size, c->metadata+(c->metadata_size * i), res->metadata_size);

      }

      for (j = res->current_size; j > pos; j--) {

        res->entries[j] = res->entries[j - 1];

      }

      res->entries[pos].id = nodeid_dup(c->entries[i].id);

      res->entries[pos].timestamp = c->entries[i].timestamp;

      res->current_size++;

    }

  }

  return res;

}

struct peer_cache *cache_union(const struct peer_cache *c1, const struct peer_cache *c2, int *size)

{

  int n, pos;

  struct peer_cache *new_cache;

  uint8_t *meta;

  if (c1->metadata_size != c2->metadata_size) {

    return NULL;

  }

  new_cache = cache_init(c1->current_size + c2->current_size, c1->metadata_size, c1->max_timestamp);

  if (new_cache == NULL) {

    return NULL;

  }

  meta = new_cache->metadata;

  for (n = 0; n < c1->current_size; n++) {

    if (new_cache->metadata_size) {

      memcpy(meta, c1->metadata + n * c1->metadata_size, c1->metadata_size);

      meta += new_cache->metadata_size;

    }

    new_cache->entries[new_cache->current_size++] = c1->entries[n];

    c1->entries[n].id = NULL;

  }

  for (n = 0; n < c2->current_size; n++) {

    pos = in_cache(new_cache, &c2->entries[n]);

    if (pos >= 0 && new_cache->entries[pos].timestamp > c2->entries[n].timestamp) {

      cache_metadata_update(new_cache, c2->entries[n].id, c2->metadata + n * c2->metadata_size, c2->metadata_size);

      new_cache->entries[pos].timestamp = c2->entries[n].timestamp;

    }

    if (pos < 0) {

      if (new_cache->metadata_size) {

        memcpy(meta, c2->metadata + n * c2->metadata_size, c2->metadata_size);

        meta += new_cache->metadata_size;

      }

      new_cache->entries[new_cache->current_size++] = c2->entries[n];

      c2->entries[n].id = NULL;

    }

  }

  *size = new_cache->current_size;

  return new_cache;

}

int cache_resize (struct peer_cache *c, int size)

{

  int dif = size - c->cache_size;

  if (!dif) {

    return c->current_size;

  }

  c->entries = realloc(c->entries, sizeof(struct cache_entry) * size);

  if (dif > 0) {

    memset(c->entries + c->cache_size, 0, sizeof(struct cache_entry) * dif);

  } else if (c->current_size > size) {

    c->current_size = size;

  }

  if (c->metadata_size) {

    c->metadata = realloc(c->metadata, c->metadata_size * size);

    if (dif > 0) {

      memset(c->metadata + c->metadata_size * c->cache_size, 0, c->metadata_size * dif);

    }

  }

  c->cache_size = size;

  return c->current_size;

}

struct peer_cache *merge_caches(const struct peer_cache *c1, const struct peer_cache *c2, int newsize, int *source)

{

  int n1, n2;

  struct peer_cache *new_cache;

  uint8_t *meta;

  new_cache = cache_init(newsize, c1->metadata_size, c1->max_timestamp);

  if (new_cache == NULL) {

    return NULL;

  }

  meta = new_cache->metadata;

  *source = 0;

  for (n1 = 0, n2 = 0; new_cache->current_size < new_cache->cache_size;) {

    if ((n1 == c1->current_size) && (n2 == c2->current_size)) {

      return new_cache;

    }

    if (n1 == c1->current_size) {

      if (in_cache(new_cache, &c2->entries[n2]) < 0) {

        if (new_cache->metadata_size) {

          memcpy(meta, c2->metadata + n2 * c2->metadata_size, c2->metadata_size);

          meta += new_cache->metadata_size;

        }

        new_cache->entries[new_cache->current_size++] = c2->entries[n2];

        c2->entries[n2].id = NULL;

        *source |= 0x02;

      }

      n2++;

    } else if (n2 == c2->current_size) {

      if (in_cache(new_cache, &c1->entries[n1]) < 0) {

        if (new_cache->metadata_size) {

          memcpy(meta, c1->metadata + n1 * c1->metadata_size, c1->metadata_size);

          meta += new_cache->metadata_size;

        }

        new_cache->entries[new_cache->current_size++] = c1->entries[n1];

        c1->entries[n1].id = NULL;

        *source |= 0x01;

      }

      n1++;

    } else {

      if (c2->entries[n2].timestamp > c1->entries[n1].timestamp) {

        if (in_cache(new_cache, &c1->entries[n1]) < 0) {

          if (new_cache->metadata_size) {

            memcpy(meta, c1->metadata + n1 * c1->metadata_size, c1->metadata_size);

            meta += new_cache->metadata_size;

          }

          new_cache->entries[new_cache->current_size++] = c1->entries[n1];

          c1->entries[n1].id = NULL;

          *source |= 0x01;

        }

        n1++;

      } else {

        if (in_cache(new_cache, &c2->entries[n2]) < 0) {

          if (new_cache->metadata_size) {

            memcpy(meta, c2->metadata + n2 * c2->metadata_size, c2->metadata_size);

            meta += new_cache->metadata_size;

          }

          new_cache->entries[new_cache->current_size++] = c2->entries[n2];

          c2->entries[n2].id = NULL;

          *source |= 0x02;

        }

        n2++;

      }

    }

  }

  return new_cache;

}

void cache_check(const struct peer_cache *c)

{

  int i, j;

  for (i = 0; i < c->current_size; i++) {

    for (j = i + 1; j < c->current_size; j++) {

      assert(!nodeid_equal(c->entries[i].id, c->entries[j].id));

    }

  }

}