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alee-forth/dictionary.cpp

89 lines
2.0 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(allot(sizeof(Cell)), value);
}
Addr Dictionary::alignhere()
{
if (here & (sizeof(Cell) - sizeof(uint8_t)))
here = (here + sizeof(Cell)) & ~(sizeof(Cell) - sizeof(uint8_t));
return here;
}
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;
addr += sizeof(Cell);
}
return true;
}
Addr Dictionary::find(std::string_view str)
{
if (latest == 0)
return 0;
Addr lt = latest, oldlt;
do {
oldlt = lt;
const auto l = read(lt);
const auto len = l & 0x1F;
if (issame(lt + sizeof(Cell), str, len))
return lt;
else
lt -= l >> 6;
} while (lt != oldlt);
return 0;
}
Addr Dictionary::getexec(Addr addr)
{
const auto len = read(addr) & 0x1F;
return addr + (1 + len) * sizeof(Cell);
}