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/*!
* \file language_base.h
*
* \brief Language Base class for Polymorphism.
*/
#ifndef LANGUAGE_BASE_H
#define LANGUAGE_BASE_H
#include <vector>
#include <unordered_map>
#include <string>
#include "misc_log_ex.h"
/*!
* \namespace Language
* \brief Mnemonic language related namespace.
*/
namespace Language
{
/*!
* \brief Returns a string made of (at most) the first count characters in s.
* Assumes well formedness. No check is made for this.
* \param s The string from which to return the first count characters.
* \param count How many characters to return.
* \return A string consisting of the first count characters in s.
*/
inline std::string utf8prefix(const std::string &s, size_t count)
{
std::string prefix = "";
const char *ptr = s.c_str();
while (count-- && *ptr)
{
prefix += *ptr++;
while (((*ptr) & 0xc0) == 0x80)
prefix += *ptr++;
}
return prefix;
}
/*!
* \class Base
* \brief A base language class which all languages have to inherit from for
* Polymorphism.
*/
class Base
{
protected:
enum {
ALLOW_SHORT_WORDS = 1<<0,
ALLOW_DUPLICATE_PREFIXES = 1<<1,
};
const std::vector<std::string> word_list; /*!< A pointer to the array of words */
std::unordered_map<std::string, uint32_t> word_map; /*!< hash table to find word's index */
std::unordered_map<std::string, uint32_t> trimmed_word_map; /*!< hash table to find word's trimmed index */
std::string language_name; /*!< Name of language */
uint32_t unique_prefix_length; /*!< Number of unique starting characters to trim the wordlist to when matching */
/*!
* \brief Populates the word maps after the list is ready.
*/
void populate_maps(uint32_t flags = 0)
{
int ii;
std::vector<std::string>::const_iterator it;
if (word_list.size () != 1626)
throw std::runtime_error("Wrong word list length for " + language_name);
for (it = word_list.begin(), ii = 0; it != word_list.end(); it++, ii++)
{
word_map[*it] = ii;
if ((*it).size() < unique_prefix_length)
{
if (flags & ALLOW_SHORT_WORDS)
MWARNING(language_name << " word '" << *it << "' is shorter than its prefix length, " << unique_prefix_length);
else
throw std::runtime_error("Too short word in " + language_name + " word list: " + *it);
}
std::string trimmed;
if (it->length() > unique_prefix_length)
{
trimmed = utf8prefix(*it, unique_prefix_length);
}
else
{
trimmed = *it;
}
if (trimmed_word_map.find(trimmed) != trimmed_word_map.end())
{
if (flags & ALLOW_DUPLICATE_PREFIXES)
MWARNING("Duplicate prefix in " << language_name << " word list: " << trimmed);
else
throw std::runtime_error("Duplicate prefix in " + language_name + " word list: " + trimmed);
}
trimmed_word_map[trimmed] = ii;
}
}
public:
Base(const char *language_name, const std::vector<std::string> &words, uint32_t prefix_length):
word_list(words),
unique_prefix_length(prefix_length),
language_name(language_name)
{
}
virtual ~Base()
{
}
/*!
* \brief Returns a pointer to the word list.
* \return A pointer to the word list.
*/
const std::vector<std::string>& get_word_list() const
{
return word_list;
}
/*!
* \brief Returns a pointer to the word map.
* \return A pointer to the word map.
*/
const std::unordered_map<std::string, uint32_t>& get_word_map() const
{
return word_map;
}
/*!
* \brief Returns a pointer to the trimmed word map.
* \return A pointer to the trimmed word map.
*/
const std::unordered_map<std::string, uint32_t>& get_trimmed_word_map() const
{
return trimmed_word_map;
}
/*!
* \brief Returns the name of the language.
* \return Name of the language.
*/
const std::string &get_language_name() const
{
return language_name;
}
/*!
* \brief Returns the number of unique starting characters to be used for matching.
* \return Number of unique starting characters.
*/
uint32_t get_unique_prefix_length() const
{
return unique_prefix_length;
}
};
}
#endif
