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alee-forth/dictionary.cpp

177 lines
3.9 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>
#include <cstring>
void Dictionary::initialize()
{
write(Base, 10);
write(Here, Begin);
write(Latest, Begin);
write(Compiling, 0);
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write(Source, Input + sizeof(Cell));
}
Addr Dictionary::allot(Cell amount) noexcept
{
Addr old = here();
here(old + amount);
return old;
}
void Dictionary::add(Cell value) noexcept
{
write(allot(sizeof(Cell)), value);
}
Addr Dictionary::aligned(Addr addr) const noexcept
{
auto unaligned = addr & (sizeof(Cell) - sizeof(uint8_t));
if (unaligned)
addr += sizeof(Cell) - unaligned;
return addr;
}
Addr Dictionary::alignhere() noexcept
{
here(aligned(here()));
return here();
}
void Dictionary::addDefinition(Word word) noexcept
{
add(word.size());
for (auto w = word.start; w != word.end; ++w)
writebyte(allot(1), readbyte(w));
alignhere();
}
Addr Dictionary::find(Word word) noexcept
{
Addr lt = latest(), oldlt;
do {
oldlt = lt;
const auto l = static_cast<Addr>(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) noexcept
{
const auto len = read(addr) & 0x1F;
return aligned(addr + sizeof(Cell) + len);
}
Word Dictionary::input() noexcept
{
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auto src = read(Dictionary::Source);
auto end = read(Dictionary::SourceLen);
auto idx = read(Dictionary::Input);
Addr wordstart = src + idx;
Addr wordend = wordstart;
while (idx < end) {
auto ch = readbyte(wordend);
if (ch == '\0')
break;
if (isspace(ch)) {
if (wordstart != wordend) {
writebyte(Dictionary::Input, idx + 1);
return {wordstart, wordend};
}
++wordstart;
}
++wordend;
++idx;
}
if (wordstart != wordend) {
writebyte(Dictionary::Input, idx + 1);
return {wordstart, wordend};
}
return {};
}
bool Dictionary::equal(Word word, const char *str, unsigned len) const noexcept
{
if (word.size() != len)
return false;
for (auto w = word.start; w != word.end; ++w) {
auto wc = readbyte(w);
if (wc != *str) {
if (isalpha(wc) && isalpha(*str) && (wc | 32) == (*str | 32)) {
++str;
continue;
}
return false;
}
++str;
}
return true;
}
bool Dictionary::equal(Word word, Word other) const noexcept
{
if (word.size() != other.size())
return false;
auto w = word.start, o = other.start;
while (w != word.end) {
auto wc = readbyte(w), oc = readbyte(o);
if (wc != oc) {
if (isalpha(wc) && isalpha(oc) && (wc | 32) == (oc | 32)) {
++w, ++o;
continue;
}
return false;
}
++w, ++o;
}
return true;
}