/*
 * ================================
 * eli960@qq.com
 * http://linuxmail.cn
 * 2016年01月15日
 * ================================
 */

#include "zcc/zcc_cdb.h"
#include "zcc/zcc_intpack.h"

zcc_namespace_begin;

cdb_walker::cdb_walker()
{
 reset();
}

cdb_walker::cdb_walker(cdb_reader &reader)
{
 reset();
 set_reader(reader);
}

cdb_walker::~cdb_walker()
{
 close();
}

void cdb_walker::set_reader(cdb_reader &reader)
{
 reader_ = &reader;
 klen_ = -1;
}

void cdb_walker::close()
{
 if (!reader_)
 {
 return;
 }
 reset();
 reader_ = 0;
}

void cdb_walker::reset()
{
 klen_ = -1;
 hash_vector_data_ = 0;
 hash_vector_size_ = 0;
 hash_vector_i_ = 0;
 ndata_ = 0;
 ncount_ = 0;
 ni_ = 0;
}

static int get_next_ok(char *data_begin, char *data, int sn, int key_length, int val_length, void **key, int *klen, void **val, int *vlen)
{
 data += (key_length + ((val_length == 536870912) ? 4 : val_length)) * sn;

 if (key)
 {
 *key = data;
 }
 if (klen)
 {
 *klen = key_length;
 }

 if (val_length == 536870912)
 {
 int offset = int_unpack(data + key_length);
 if (offset == 0)
 {
 if (val)
 {
 *val = var_blank_buffer;
 }
 if (vlen)
 {
 *vlen = 0;
 }
 }
 else
 {
 data = data_begin + offset;
 int ch, size = 0, shift = 0;
 while (1)
 {
 ch = *data++;
 size |= ((ch & 0177) << shift);
 if (ch & 0200)
 {
 break;
 }
 shift += 7;
 }
 if (val)
 {
 *val = data;
 }
 if (vlen)
 {
 *vlen = size;
 }
 }
 }
 else
 {
 if (val)
 {
 *val = data + key_length;
 }
 if (vlen)
 {
 *vlen = val_length;
 }
 }
 return 1;
}

int cdb_walker::walk(void **key, int *klen, void **val, int *vlen)
{
 if (klen_ == -2)
 {
 return 0;
 }
 cdb_reader *cdb = reader_;
 if (!cdb)
 {
 return false;
 }
 char *data_begin = (char *)(void *)(cdb->data_);

 if (klen_ == -1)
 {
 klen_ = 0;
 hash_vector_i_ = -1;
 ni_ = -1;
 }
 for (; klen_ <= cdb->max_key_length_; klen_++)
 {
 int offset = int_unpack(data_begin + 24 + 4 * klen_);
 if (offset == 0)
 {
 continue;
 }
 if (hash_vector_i_ == -1)
 {
 hash_vector_data_ = data_begin + offset + 4;
 hash_vector_size_ = int_unpack(hash_vector_data_ - 4);
 hash_vector_i_ = 0;
 ni_ = -1;
 }
 for (; hash_vector_i_ < hash_vector_size_; hash_vector_i_++)
 {
 int offset = int_unpack(hash_vector_data_ + 4 * hash_vector_i_);
 if (offset == 0)
 {
 continue;
 }
 if (ni_ == -1)
 {
 ndata_ = data_begin + offset + 4;
 ncount_ = int_unpack(data_begin + offset);
 ni_ = 0;
 }
 for (; ni_ < ncount_;)
 {
 if (get_next_ok(data_begin, ndata_, ni_, klen_, cdb->val_length_, key, klen, val, vlen) < 1)
 {
 return -1;
 }
 ni_++;
 return 1;
 }
 ni_ = -1;
 }
 hash_vector_i_ = -1;
 }

 if (klen_ > cdb->max_key_length_)
 {
 klen_ = -2;
 return 0;
 }
 return 0;
}

zcc_namespace_end;