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alee-forth/dictionary.cpp

141 lines
3.2 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"
#include <cctype>
Addr Dictionary::allot(Cell amount)
{
Addr old = here;
here += amount;
return old;
}
void Dictionary::add(Cell value)
{
write(allot(sizeof(Cell)), value);
}
Addr Dictionary::aligned(Addr addr) const noexcept
{
if (addr & (sizeof(Cell) - sizeof(uint8_t)))
addr = (addr + sizeof(Cell)) & ~(sizeof(Cell) - sizeof(uint8_t));
return addr;
}
Addr Dictionary::alignhere()
{
here = aligned(here);
return here;
}
void Dictionary::addDefinition(Word word)
{
add(word.size());
for (unsigned i = 0; i < word.size(); ++i)
writebyte(allot(1), readbyte(word.start + i));
alignhere();
}
Addr Dictionary::find(Word word)
{
Addr lt = latest(), oldlt;
do {
oldlt = lt;
const Cell l = read(lt);
const Addr len = l & 0x1F;
const Word lw {
static_cast<Addr>(lt + sizeof(Cell)),
static_cast<Addr>(lt + sizeof(Cell) + len)
};
if (equal(word, lw))
return lt;
else
lt -= l >> 6;
} while (lt != oldlt);
return 0;
}
Addr Dictionary::getexec(Addr addr)
{
const auto len = read(addr) & 0x1F;
return aligned(addr + sizeof(Cell) + len);
}
Word Dictionary::input()
{
const auto len = read(Dictionary::Input);
if (len == 0)
return {};
Addr wordstart = Dictionary::Input + sizeof(Cell) + Dictionary::InputCells
- len;
Addr wordend = wordstart;
auto cnt = len;
while (cnt) {
auto b = readbyte(wordend);
if (isspace(b) || b == '\0') {
if (wordstart != wordend) {
Word word {wordstart, wordend};
writebyte(Dictionary::Input, cnt - 1);
return word;
} else {
++wordstart;
}
}
++wordend;
--cnt;
}
return {};
}
bool Dictionary::equal(Word word, std::string_view sv) const
{
if (sv.size() != word.end - word.start)
return false;
for (unsigned i = 0; i < sv.size(); ++i) {
if (sv[i] != readbyte(word.start + i))
return false;
}
return true;
}
bool Dictionary::equal(Word word, Word other) const
{
if (word.size() != other.size())
return false;
for (unsigned i = 0; i < word.size(); ++i) {
if (readbyte(word.start + i) != readbyte(other.start + i))
return false;
}
return true;
}