CRF/darts.h

//
//  Darts -- Double-ARray Trie System
//
//  $Id: darts.h 1577 2007-01-30 17:01:10Z taku $;
//
//  Copyright(C) 2001-2007 Taku Kudo <taku@chasen.org>
//
#ifndef DARTS_H_
#define DARTS_H_

#define DARTS_VERSION "0.31"
#include <vector>
#include <cstring>
#include <cstdio>

#ifdef HAVE_ZLIB_H
namespace zlib {
#include <zlib.h>
}
#define SH(p)((unsigned short)(unsigned char)((p)[0]) | ((unsigned short)(unsigned char)((p)[1]) << 8))
#define LG(p)((unsigned long)(SH(p)) |((unsigned long)(SH((p)+2)) << 16))
#endif

namespace CRFPP {
namespace Darts {

template <class T> inline T _max(T x, T y) { return(x > y) ? x : y; }
template <class T> inline T* _resize(T* ptr, size_t n, size_t l, T v) {
  T *tmp = new T[l];
  for (size_t i = 0; i < n; ++i) tmp[i] = ptr[i];
  for (size_t i = n; i < l; ++i) tmp[i] = v;
  delete [] ptr;
  return tmp;
}

template <class T>
class Length {
 public: size_t operator()(const T *key) const
  { size_t i; for (i = 0; key[i] != (T)0; ++i) {} return i; }
};

template <> class Length<char> {
 public: size_t operator()(const char *key) const
  { return std::strlen(key); }
};

template  <class node_type_,  class node_u_type_,
           class array_type_, class array_u_type_,
           class length_func_ = Length<node_type_> >
class DoubleArrayImpl {
 private:

  struct node_t {
    array_u_type_ code;
    size_t     depth;
    size_t     left;
    size_t     right;
  };

  struct unit_t {
    array_type_   base;
    array_u_type_ check;
  };

  unit_t        *array_;
  unsigned char *used_;
  size_t        size_;
  size_t        alloc_size_;
  node_type_    **key_;
  size_t        key_size_;
  size_t        *length_;
  array_type_   *value_;
  size_t        progress_;
  size_t        next_check_pos_;
  bool          no_delete_;
  int           error_;
  int (*progress_func_)(size_t, size_t);

  size_t resize(const size_t new_size) {
    unit_t tmp;
    tmp.base = 0;
    tmp.check = 0;
    array_ = _resize(array_, alloc_size_, new_size, tmp);
    used_  = _resize(used_, alloc_size_, new_size,
                     static_cast<unsigned char>(0));
    alloc_size_ = new_size;
    return new_size;
  }

  size_t fetch(const node_t &parent, std::vector <node_t> &siblings) {
    if (error_ < 0) return 0;

    array_u_type_ prev = 0;

    for (size_t i = parent.left; i < parent.right; ++i) {
      if ((length_ ? length_[i] : length_func_()(key_[i])) < parent.depth)
        continue;

      const node_u_type_ *tmp = reinterpret_cast<node_u_type_ *>(key_[i]);

      array_u_type_ cur = 0;
      if ((length_ ? length_[i] : length_func_()(key_[i])) != parent.depth)
        cur = (array_u_type_)tmp[parent.depth] + 1;

      if (prev > cur) {
        error_ = -3;
        return 0;
      }

      if (cur != prev || siblings.empty()) {
        node_t tmp_node;
        tmp_node.depth = parent.depth + 1;
        tmp_node.code  = cur;
        tmp_node.left  = i;
        if (!siblings.empty()) siblings[siblings.size()-1].right = i;

        siblings.push_back(tmp_node);
      }

      prev = cur;
    }

    if (!siblings.empty())
      siblings[siblings.size()-1].right = parent.right;

    return siblings.size();
  }

  size_t insert(const std::vector <node_t> &siblings) {
    if (error_ < 0) return 0;

    size_t begin = 0;
    size_t pos   = _max((size_t)siblings[0].code + 1, next_check_pos_) - 1;
    size_t nonzero_num = 0;
    int    first = 0;

    if (alloc_size_ <= pos) resize(pos + 1);

    while (true) {
   next:
      ++pos;

      if (alloc_size_ <= pos) resize(pos + 1);

      if (array_[pos].check) {
        ++nonzero_num;
        continue;
      } else if (!first) {
        next_check_pos_ = pos;
        first = 1;
      }

      begin = pos - siblings[0].code;
      if (alloc_size_ <= (begin + siblings[siblings.size()-1].code))
        resize(static_cast<size_t>(alloc_size_ *
                                   _max(1.05, 1.0 * key_size_ / progress_)));

      if (used_[begin]) continue;

      for (size_t i = 1; i < siblings.size(); ++i)
        if (array_[begin + siblings[i].code].check != 0) goto next;

      break;
    }

    // -- Simple heuristics --
    // if the percentage of non-empty contents in check between the index
    // 'next_check_pos' and 'check' is greater than some constant
    // value(e.g. 0.9),
    // new 'next_check_pos' index is written by 'check'.
    if (1.0 * nonzero_num/(pos - next_check_pos_ + 1) >= 0.95)
      next_check_pos_ = pos;

    used_[begin] = 1;
    size_ = _max(size_,
                 begin +
                 static_cast<size_t>(siblings[siblings.size() - 1].code + 1));

    for (size_t i = 0; i < siblings.size(); ++i)
      array_[begin + siblings[i].code].check = begin;

    for (size_t i = 0; i < siblings.size(); ++i) {
      std::vector <node_t> new_siblings;

      if (!fetch(siblings[i], new_siblings)) {
        array_[begin + siblings[i].code].base =
            value_ ?
            static_cast<array_type_>(-value_[siblings[i].left]-1) :
            static_cast<array_type_>(-siblings[i].left-1);

        if (value_ && (array_type_)(-value_[siblings[i].left]-1) >= 0) {
          error_ = -2;
          return 0;
        }

        ++progress_;
        if (progress_func_)(*progress_func_)(progress_, key_size_);

      } else {
        size_t h = insert(new_siblings);
        array_[begin + siblings[i].code].base = h;
      }
    }

    return begin;
  }

 public:

  typedef array_type_  value_type;
  typedef node_type_   key_type;
  typedef array_type_  result_type;  // for compatibility

  struct result_pair_type {
    value_type value;
    size_t     length;
  };

  explicit DoubleArrayImpl(): array_(0), used_(0),
                              size_(0), alloc_size_(0),
                              no_delete_(0), error_(0) {}
  ~DoubleArrayImpl() { clear(); }

  void set_result(value_type& x, value_type r, size_t) {
    x = r;
  }

  void set_result(result_pair_type& x, value_type r, size_t l) {
    x.value = r;
    x.length = l;
  }

  void set_array(void *ptr, size_t size = 0) {
    clear();
    array_ = reinterpret_cast<unit_t *>(ptr);
    no_delete_ = true;
    size_ = size;
  }

  const void *array() const {
    return const_cast<const void *>(reinterpret_cast<void *>(array_));
  }

  void clear() {
    if (!no_delete_)
      delete [] array_;
    delete [] used_;
    array_ = 0;
    used_ = 0;
    alloc_size_ = 0;
    size_ = 0;
    no_delete_ = false;
  }

  size_t unit_size()  const { return sizeof(unit_t); }
  size_t size()       const { return size_; }
  size_t total_size() const { return size_ * sizeof(unit_t); }

  size_t nonzero_size() const {
    size_t result = 0;
    for (size_t i = 0; i < size_; ++i)
      if (array_[i].check) ++result;
    return result;
  }

  int build(size_t     key_size,
            key_type   **key,
            size_t     *length = 0,
            value_type *value = 0,
            int (*progress_func)(size_t, size_t) = 0) {
    if (!key_size || !key) return 0;

    progress_func_ = progress_func;
    key_           = key;
    length_        = length;
    key_size_      = key_size;
    value_         = value;
    progress_      = 0;

    resize(8192);

    array_[0].base = 1;
    next_check_pos_ = 0;

    node_t root_node;
    root_node.left  = 0;
    root_node.right = key_size;
    root_node.depth = 0;

    std::vector <node_t> siblings;
    fetch(root_node, siblings);
    insert(siblings);

    size_ += (1 << 8 * sizeof(key_type)) + 1;
    if (size_ >= alloc_size_) resize(size_);

    delete [] used_;
    used_ = 0;

    return error_;
  }

  int open(const char *file,
           const char *mode = "rb",
           size_t offset = 0,
           size_t size = 0) {
    std::FILE *fp = std::fopen(file, mode);
    if (!fp) return -1;
    if (std::fseek(fp, offset, SEEK_SET) != 0) return -1;

    if (!size) {
      if (std::fseek(fp, 0L,     SEEK_END) != 0) return -1;
      size = std::ftell(fp);
      if (std::fseek(fp, offset, SEEK_SET) != 0) return -1;
    }

    clear();

    size_ = size;
    size_ /= sizeof(unit_t);
    array_ = new unit_t[size_];
    if (size_ != std::fread(reinterpret_cast<unit_t *>(array_),
                            sizeof(unit_t), size_, fp)) return -1;
    std::fclose(fp);

    return 0;
  }

  int save(const char *file,
           const char *mode = "wb",
           size_t offset = 0) {
    if (!size_) return -1;
    std::FILE *fp = std::fopen(file, mode);
    if (!fp) return -1;
    if (size_ != std::fwrite(reinterpret_cast<unit_t *>(array_),
                             sizeof(unit_t), size_, fp))
      return -1;
    std::fclose(fp);
    return 0;
  }

#ifdef HAVE_ZLIB_H
  int gzopen(const char *file,
             const char *mode = "rb",
             size_t offset = 0,
             size_t size = 0) {
    std::FILE *fp  = std::fopen(file, mode);
    if (!fp) return -1;
    clear();

    size_ = size;
    if (!size_) {
      if (-1L != static_cast<long>(std::fseek(fp, -8, SEEK_END))) {
        char buf[8];
        if (std::fread(static_cast<char*>(buf),
                       1, 8, fp) != sizeof(buf)) {
          std::fclose(fp);
          return -1;
        }
        size_ = LG(buf+4);
        size_ /= sizeof(unit_t);
      }
    }
    std::fclose(fp);

    if (!size_) return -1;

    zlib::gzFile gzfp = zlib::gzopen(file, mode);
    if (!gzfp) return -1;
    array_ = new unit_t[size_];
    if (zlib::gzseek(gzfp, offset, SEEK_SET) != 0) return -1;
    zlib::gzread(gzfp, reinterpret_cast<unit_t *>(array_),
                 sizeof(unit_t) * size_);
    zlib::gzclose(gzfp);
    return 0;
  }

  int gzsave(const char *file, const char *mode = "wb",
             size_t offset = 0) {
    zlib::gzFile gzfp = zlib::gzopen(file, mode);
    if (!gzfp) return -1;
    zlib::gzwrite(gzfp, reinterpret_cast<unit_t *>(array_),
                  sizeof(unit_t) * size_);
    zlib::gzclose(gzfp);
    return 0;
  }
#endif

  template <class T>
  inline void exactMatchSearch(const key_type *key,
                               T & result,
                               size_t len = 0,
                               size_t node_pos = 0) {
    result = exactMatchSearch<T> (key, len, node_pos);
    return;
  }

  template <class T>
  inline T exactMatchSearch(const key_type *key,
                            size_t len = 0,
                            size_t node_pos = 0) {
    if (!len) len = length_func_()(key);

    T result;
    set_result(result, -1, 0);

    register array_type_  b = array_[node_pos].base;
    register array_u_type_ p;

    for (register size_t i = 0; i < len; ++i) {
      p = b +(node_u_type_)(key[i]) + 1;
      if (static_cast<array_u_type_>(b) == array_[p].check)
        b = array_[p].base;
      else
        return result;
    }

    p = b;
    array_type_ n = array_[p].base;
    if (static_cast<array_u_type_>(b) == array_[p].check && n < 0)
      set_result(result, -n-1, len);

    return result;
  }

  template <class T>
  size_t commonPrefixSearch(const key_type *key,
                            T* result,
                            size_t result_len,
                            size_t len = 0,
                            size_t node_pos = 0) {
    if (!len) len = length_func_()(key);

    register array_type_  b   = array_[node_pos].base;
    register size_t     num = 0;
    register array_type_  n;
    register array_u_type_ p;

    for (register size_t i = 0; i < len; ++i) {
      p = b;  // + 0;
      n = array_[p].base;
      if ((array_u_type_) b == array_[p].check && n < 0) {
        // result[num] = -n-1;
        if (num < result_len) set_result(result[num], -n-1, i);
        ++num;
      }

      p = b +(node_u_type_)(key[i]) + 1;
      if ((array_u_type_) b == array_[p].check)
        b = array_[p].base;
      else
        return num;
    }

    p = b;
    n = array_[p].base;

    if ((array_u_type_)b == array_[p].check && n < 0) {
      if (num < result_len) set_result(result[num], -n-1, len);
      ++num;
    }

    return num;
  }

  value_type traverse(const key_type *key,
                      size_t &node_pos,
                      size_t &key_pos,
                      size_t len = 0) {
    if (!len) len = length_func_()(key);

    register array_type_  b = array_[node_pos].base;
    register array_u_type_ p;

    for (; key_pos < len; ++key_pos) {
      p = b +(node_u_type_)(key[key_pos]) + 1;
      if (static_cast<array_u_type_>(b) == array_[p].check) {
        node_pos = p;
        b = array_[p].base;
      } else {
        return -2;  // no node
      }
    }

    p = b;
    array_type_ n = array_[p].base;
    if (static_cast<array_u_type_>(b) == array_[p].check && n < 0)
      return -n-1;

    return -1;  // found, but no value
  }
};

#if 4 == 2
typedef Darts::DoubleArrayImpl<char, unsigned char, short,
                               unsigned short> DoubleArray;
#define DARTS_ARRAY_SIZE_IS_DEFINED 1
#endif

#if 4 == 4 && !defined(DARTS_ARRAY_SIZE_IS_DEFINED)
typedef Darts::DoubleArrayImpl<char, unsigned char, int,
                               unsigned int> DoubleArray;
#define DARTS_ARRAY_SIZE_IS_DEFINED 1
#endif

#if 4 == 4 && !defined(DARTS_ARRAY_SIZE_IS_DEFINED)
typedef Darts::DoubleArrayImpl<char, unsigned char, long,
                               unsigned long> DoubleArray;
#define DARTS_ARRAY_SIZE_IS_DEFINED 1
#endif

#if 4 == 8 && !defined(DARTS_ARRAY_SIZE_IS_DEFINED)
typedef Darts::DoubleArrayImpl<char, unsigned char, long long,
                               unsigned long long> DoubleArray;
#endif
}
}
#endif