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// Copyright (c) 2023, Marvin Borner <dev@marvinborner.de>
// SPDX-License-Identifier: MIT
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <build.h>
#include <log.h>
static void write_bit(char val, FILE *file, char *byte, int *bit)
{
if (*bit > 7) { // flush byte
fwrite(byte, 1, 1, file);
*byte = 0;
*bit = 0;
}
if (val)
*byte |= 1UL << (7 - *bit);
(*bit)++;
}
static void rec_write_bblc(struct tree *tree, FILE *file, char *byte, int *bit)
{
switch (tree->type) {
case ABS:
write_bit(0, file, byte, bit);
write_bit(0, file, byte, bit);
rec_write_bblc(tree->u.abs.term, file, byte, bit);
break;
case APP:
write_bit(0, file, byte, bit);
write_bit(1, file, byte, bit);
write_bit(0, file, byte, bit);
rec_write_bblc(tree->u.app.lhs, file, byte, bit);
rec_write_bblc(tree->u.app.rhs, file, byte, bit);
break;
case VAR:
for (int i = 0; i <= tree->u.var.index; i++)
write_bit(1, file, byte, bit);
write_bit(0, file, byte, bit);
break;
case REF:
write_bit(0, file, byte, bit);
write_bit(1, file, byte, bit);
write_bit(1, file, byte, bit);
// TODO: The bit-order of encoded shorts is kinda arbitrary
short ref = tree->u.ref.index;
for (int i = 0; i < 16; i++)
write_bit((ref >> i) & 1, file, byte, bit);
break;
default:
fatal("invalid type %d\n", tree->type);
}
}
// writes bit-encoded blc into file
static void write_bblc(struct tree *tree, FILE *file)
{
char byte = 0;
int bit = 0;
rec_write_bblc(tree, file, &byte, &bit);
if (bit) // flush final
fwrite(&byte, 1, 1, file);
}
void write_bloc(struct list *table, const char *path)
{
short length = table->val;
debug("writing bloc with %ld elements to %s\n", length, path);
FILE *file = fopen(path, "wb");
fwrite(BLOC_IDENTIFIER, BLOC_IDENTIFIER_LENGTH, 1, file);
fwrite(&length, 2, 1, file);
struct list *iterator = table;
while (iterator) {
write_bblc(iterator->data, file);
iterator = iterator->next;
}
fclose(file);
}
static void fprint_bloc_blc(struct term *term, struct bloc_parsed *bloc,
FILE *file)
{
switch (term->type) {
case ABS:
fprintf(file, "00");
fprint_bloc_blc(term->u.abs.term, bloc, file);
break;
case APP:
fprintf(file, "01");
fprint_bloc_blc(term->u.app.lhs, bloc, file);
fprint_bloc_blc(term->u.app.rhs, bloc, file);
break;
case VAR:
for (int i = 0; i <= term->u.var.index; i++)
fprintf(file, "1");
fprintf(file, "0");
break;
case REF:
if (term->u.ref.index + 1 >= bloc->length)
fatal("invalid ref index %ld\n", term->u.ref.index);
fprint_bloc_blc(
bloc->entries[bloc->length - term->u.ref.index - 2],
bloc, file);
break;
default:
fatal("invalid type %d\n", term->type);
}
}
void write_blc(struct bloc_parsed *bloc, const char *path)
{
FILE *file = fopen(path, "wb");
fprint_bloc_blc(bloc->entries[bloc->length - 1], bloc, file);
fprintf(file, "\n");
fclose(file);
}
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