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/**
* 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 "alee.hpp"
LIBALEE_SECTION
void Dictionary::initialize()
{
write(Base, 10);
write(Here, Begin);
write(Latest, Begin);
write(Compiling, 0);
write(Source, Input + sizeof(Cell));
}
LIBALEE_SECTION
Addr Dictionary::allot(Cell amount) noexcept
{
Addr old = here();
decltype(capacity()) neww = old + amount;
if (neww < capacity()) {
write(Here, static_cast<Addr>(neww));
} else {
// TODO how to handle allot failure? Error code?
}
return old;
}
LIBALEE_SECTION
void Dictionary::add(Cell value) noexcept
{
write(allot(sizeof(Cell)), value);
}
LIBALEE_SECTION
Addr Dictionary::aligned(Addr addr)
{
return (addr + (sizeof(Cell) - 1)) & ~(sizeof(Cell) - 1);
}
LIBALEE_SECTION
Addr Dictionary::alignhere() noexcept
{
here(aligned(here()));
return here();
}
LIBALEE_SECTION
void Dictionary::addDefinition(Word word) noexcept
{
Cell wsize = word.size();
add(wsize);
if (alignhere() - latest() >= MaxDistance)
add(0);
auto addr = allot(wsize);
auto it = word.begin(this);
const auto end = word.end(this);
while (it != end)
writebyte(addr++, *it++);
alignhere();
}
LIBALEE_SECTION
Addr Dictionary::find(Word word) noexcept
{
Addr lt = latest();
for (;;) {
const Addr l = read(lt);
const Addr len = l & 0x1F;
Word lw;
if ((l >> DistancePos) < MaxDistance) {
lw = Word::fromLength(lt + sizeof(Cell), len);
if (equal(word, lw))
return lt;
else if (lt == Begin)
break;
else
lt -= l >> DistancePos;
} else {
lw = Word::fromLength(lt + 2 * sizeof(Cell), len);
if (equal(word, lw))
return lt;
else if (lt == Begin)
break;
else
lt -= static_cast<Addr>(read(lt + sizeof(Cell)));
}
}
return 0;
}
LIBALEE_SECTION
Addr Dictionary::getexec(Addr addr) noexcept
{
const Addr l = read(addr);
const Addr len = l & 0x1Fu;
addr += sizeof(Cell);
if ((l >> DistancePos) == MaxDistance)
addr += sizeof(Cell);
addr += len;
return aligned(addr);
}
LIBALEE_SECTION
bool Dictionary::hasInput() const noexcept
{
const Addr src = read(Dictionary::Source);
const Addr end = read(Dictionary::SourceLen);
auto idx = static_cast<uint8_t>(read(Dictionary::Input));
while (idx < end) {
auto ch = readbyte(src + idx);
if (ch == '\0') {
break;
} else if (!isspace(ch)) {
return true;
}
++idx;
}
return false;
}
LIBALEE_SECTION
Word Dictionary::input() noexcept
{
const Addr src = read(Dictionary::Source);
const Addr end = read(Dictionary::SourceLen);
auto idx = static_cast<uint8_t>(read(Dictionary::Input));
Addr wstart = src + idx;
Addr wend = wstart;
while (idx < end) {
auto ch = readbyte(wend);
if (isspace(ch)) {
if (wend - wstart > 0)
break;
++wstart;
} else if (ch == '\0') {
break;
}
++wend;
++idx;
}
writebyte(Dictionary::Input, ++idx);
return Word(wstart, wend);
}
LIBALEE_SECTION
bool Dictionary::equal(Word word, const char *str, unsigned len) const noexcept
{
return word.size() == len && equal(word.begin(this), word.end(this), str);
}
LIBALEE_SECTION
bool Dictionary::equal(Word word, Word other) const noexcept
{
return word.size() == other.size() && equal(word.begin(this), word.end(this), other.begin(this));
}
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