298 lines
7.5 KiB
C
298 lines
7.5 KiB
C
/* aoc-c.c: Advent of Code 2019, day 5 parts 1 & 2
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*
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* Copyright (C) 2021 Bruno Raoult ("br")
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* Licensed under the GNU General Public License v3.0 or later.
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* Some rights reserved. See COPYING.
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*
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* You should have received a copy of the GNU General Public License along with this
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* program. If not, see <https://www.gnu.org/licenses/gpl-3.0-standalone.html>.
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*
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* SPDX-License-Identifier: GPL-3.0-or-later <https://spdx.org/licenses/GPL-3.0-or-later.html>
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <string.h>
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#include "br.h"
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#include "bits.h"
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#include "debug.h"
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static struct {
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int cur;
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int length;
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int val[10];
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} input, output;
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typedef enum {
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ADD = 1,
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MUL = 2,
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INP = 3,
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OUT = 4,
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JMP_T = 5,
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JMP_F = 6,
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SET_LT = 7,
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SET_EQ = 8,
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HLT = 99
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} opcode_t;
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/**
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* ops - array of op-codes mnemoand number of parameters
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* @len: number of parameters
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* @mnemo: op mnemo
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*/
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static struct {
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opcode_t op;
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u8 len;
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u8 next;
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char *mnemo;
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} ops[] = {
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[ADD] = { ADD, 3, 4, __stringify(ADD) },
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[MUL] = { MUL, 3, 4, __stringify(MUL) },
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[INP] = { INP, 1, 2, __stringify(INP) },
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[OUT] = { OUT, 1, 2, __stringify(OUT) },
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[JMP_T] = { JMP_T, 2, 0, __stringify(JMP_T) },
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[JMP_F] = { JMP_F, 2, 0, __stringify(JMP_F) },
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[SET_LT] = { SET_LT, 3, 4, __stringify({SET_LT) },
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[SET_EQ] = { SET_EQ, 3, 4, __stringify(SET_EQ) },
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[HLT] = { HLT, 0, 1, __stringify(HLT) }
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};
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union mem {
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struct {
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u8 op: 8;
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u8 nargs;
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u8 flags: 8;
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};
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uint instr;
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int param;
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int *ind;
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};
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#define MAXOPS 1024
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struct program {
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int length; /* total program length */
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int cur; /* current position */
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union mem mem[MAXOPS]; /* should really be dynamic */
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};
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static int _flag_pow10[] = {1, 100, 1000, 10000};
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#define OP(p, n) ((p->mem[n].instr) % 100)
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#define MODE(p, n, i) (((p->mem[n].instr) / _flag_pow10[i]) % 10)
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static int print_opcode(struct program *p, int pos)
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{
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int op = OP(p, pos);
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if (ops[op].op) {
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int nargs = ops[op].len;
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log(3, "%03d [%2d][%6s]\t", pos, op, ops[op].mnemo);
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for (int i = 1; i <= nargs; ++i) {
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int direct = p->mem[pos + i].param;
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if (i > 1)
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log(3, ", ");
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if (i < 3 && !MODE(p, pos, i)) {
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log(3, "*[%d]=", direct);
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int val = p->mem[direct].param;
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log(3, "%d", val);
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} else {
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log(3, "%d", direct);
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}
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}
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log(3, "\n");
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return nargs;
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} else {
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log(3, "%03d \t", pos);
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log(3, "%d\n", p->mem[pos].param);
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return 0;
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}
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}
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static void print_program_codes(struct program *p)
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{
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log(3, "program codes: length=%d\n", p->length);
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for (int i = 0; i < p->length; ++i)
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log(3, "%d ", p->mem[i].param);
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log(3, "\n");
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}
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static void print_program(struct program *p)
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{
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print_program_codes(p);
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log(3, "program: length=%d\n", p->length);
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for (int i = 0; i < p->length; ++i) {
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i += print_opcode(p, i);
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}
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}
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#define INDIRECT(p, n) (p->mem[n].param)
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/**
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*/
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static int peek(struct program *p, int pos, int arg)
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{
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int flag = MODE(p, pos, arg);
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int ret = p->mem[pos + arg].param;
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if (!flag)
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ret = p->mem[ret].param;
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return ret;
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}
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static int poke(struct program *p, int pos, int arg, int val)
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{
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int addr = p->mem[pos + arg].param;
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p->mem[addr].param = val;
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return val;
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}
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static int run(struct program *p)
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{
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while (1) {
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int op = OP(p, p->cur);
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int n1, n2;
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if (!(ops[op].op)) {
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fprintf(stderr, "PANIC: illegal instruction %d at %d.\n", op, p->cur);
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return -1;
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}
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log(3, "OP=%s\n", ops[op].mnemo? ops[op].mnemo: "UNKNOWN");
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switch (op) {
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case ADD:
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n1 = peek(p, p->cur, 1);
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n2 = peek(p, p->cur, 2);
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poke(p, p->cur, 3, n1 + n2);
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break;
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case MUL:
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n1 = peek(p, p->cur, 1);
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n2 = peek(p, p->cur, 2);
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poke(p, p->cur, 3, n1 * n2);
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break;
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case INP:
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poke(p, p->cur, 1, input.val[input.cur++]);
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break;
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case OUT:
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output.val[output.length++] = peek(p, p->cur, 1);
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break;
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case JMP_T:
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n1 = peek(p, p->cur, 1);
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n2 = peek(p, p->cur, 2);
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if (n1)
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p->cur = n2;
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else
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p->cur += ops[op].len + 1;
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break;
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case JMP_F:
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n1 = peek(p, p->cur, 1);
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n2 = peek(p, p->cur, 2);
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if (!n1)
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p->cur = n2;
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else
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p->cur += ops[op].len + 1;
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break;
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case SET_LT:
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n1 = peek(p, p->cur, 1);
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n2 = peek(p, p->cur, 2);
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poke(p, p->cur, 3, n1 < n2 ? 1: 0);
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break;
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case SET_EQ:
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n1 = peek(p, p->cur, 1);
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n2 = peek(p, p->cur, 2);
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poke(p, p->cur, 3, n1 == n2 ? 1: 0);
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break;
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case HLT:
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return p->mem[0].param;
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default:
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fprintf(stderr, "unknown error\n");
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exit (1);
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}
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p->cur += ops[op].next;
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}
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return -1;
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}
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static struct program *parse()
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{
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size_t alloc = 0;
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ssize_t buflen;
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char *buf = NULL, *token;
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int input;
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struct program *prog = NULL;
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if ((buflen = getline(&buf, &alloc, stdin)) <= 0) {
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fprintf(stderr, "error reading file.\n");
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goto end;
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}
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if (!(prog = calloc(1, sizeof(struct program)))) {
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fprintf(stderr, "cannot allocate program.\n");
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goto freebuf;
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}
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for (token = strtok(buf, ","); token; token = strtok(NULL, ",")) {
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if (prog->length >= MAXOPS - 1) {
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fprintf(stderr, "overflow !\n");
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free(prog);
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prog = NULL;
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goto freebuf;
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}
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input=atoi(token);
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prog->mem[prog->length++].param = input;
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}
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freebuf:
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free(buf);
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end:
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return prog;
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}
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static int part1(struct program *p)
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{
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if (!input.length)
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input.val[input.length++] = 1;
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run(p);
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return output.val[output.length - 1];
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}
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static int part2(struct program *p)
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{
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if (!input.length)
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input.val[input.length++] = 5;
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run(p);
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return output.val[output.length - 1];
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}
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static int usage(char *prg)
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{
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fprintf(stderr, "Usage: %s [-d debug_level] [-p part] [-i input]\n", prg);
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return 1;
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}
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int main(int ac, char **av)
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{
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int opt, part = 1;
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struct program *p;
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while ((opt = getopt(ac, av, "d:p:i:")) != -1) {
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switch (opt) {
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case 'd':
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debug_level_set(atoi(optarg));
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break;
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case 'i':
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input.val[input.length++] = atoi(optarg);
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break;
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case 'p': /* 1 or 2 */
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part = atoi(optarg);
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if (part < 1 || part > 2)
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return usage(*av);
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break;
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default:
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return usage(*av);
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}
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}
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if (optind < ac)
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return usage(*av);
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p = parse();
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print_program(p);
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printf("%s : res=%d\n", *av, part == 1? part1(p): part2(p));
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exit (0);
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}
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