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alee-forth/dictionary.cpp

78 lines
1.7 KiB
C++

/**
* Alee Forth: A portable and concise Forth implementation in modern C++.
* Copyright (C) 2023 Clyne Sullivan <clyne@bitgloo.com>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
#include "dictionary.hpp"
Addr Dictionary::allot(Cell amount)
{
Addr old = here;
here += amount;
return old;
}
void Dictionary::add(Cell value)
{
write(here++, value);
}
void Dictionary::addDefinition(std::string_view str)
{
add(str.size());
for (char c : str)
add(c);
}
bool Dictionary::issame(Addr addr, std::string_view str, std::size_t n)
{
if (str.size() != n)
return false;
for (char c : str) {
if (read(addr++) != c)
return false;
}
return true;
}
Addr Dictionary::find(std::string_view str)
{
if (latest == 0)
return 0;
auto lt = latest;
do {
const auto l = read(lt);
const auto len = l & 0x1F;
if (issame(lt + 1, str, len))
return lt;
else
lt -= l >> 6;
} while (lt);
return 0;
}
Addr Dictionary::getexec(Addr addr)
{
const auto len = read(addr) & 0x1F;
return addr + 1 + len;
}