minisat/Main.C

/**************************************************************************************************
MiniSat -- Copyright (c) 2003-2005, Niklas Een, Niklas Sorensson

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
associated documentation files (the "Software"), to deal in the Software without restriction,
including without limitation the rights to use, copy, modify, merge, publish, distribute,
sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or
substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT
NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT
OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
**************************************************************************************************/

#include "Solver.h"
#include <ctime>
#include <unistd.h>
#include <signal.h>
#include <zlib.h>

//=================================================================================================
// Helpers:


// Reads an input stream to end-of-file and returns the result as a 'char*' terminated by '\0'
// (dynamic allocation in case 'in' is standard input).
//
char* readFile(gzFile in)
{
    char*   data = xmalloc<char>(65536);
    int     cap  = 65536;
    int     size = 0;

    while (!gzeof(in)){
        if (size == cap){
            cap *= 2;
            data = xrealloc(data, cap); }
        size += gzread(in, &data[size], 65536);
    }
    data = xrealloc(data, size+1);
    data[size] = '\0';

    return data;
}


//=================================================================================================
// DIMACS Parser:


static void skipWhitespace(char*& in) {
    while ((*in >= 9 && *in <= 13) || *in == 32)
        in++; }

static void skipLine(char*& in) {
    for (;;){
        if (*in == 0) return;
        if (*in == '\n') { in++; return; }
        in++; } }

static int parseInt(char*& in) {
    int     val = 0;
    bool    neg = false;
    skipWhitespace(in);
    if      (*in == '-') neg = true, in++;
    else if (*in == '+') in++;
    if (*in < '0' || *in > '9') fprintf(stderr, "PARSE ERROR! Unexpected char: %c\n", *in), exit(1);
    while (*in >= '0' && *in <= '9')
        val = val*10 + (*in - '0'),
        in++;
    return neg ? -val : val; }

static void readClause(char*& in, Solver& S, vec<Lit>& lits) {
    int     parsed_lit, var;
    lits.clear();
    for (;;){
        parsed_lit = parseInt(in);
        if (parsed_lit == 0) break;
        var = abs(parsed_lit)-1;
        while (var >= S.nVars()) S.newVar();
        lits.push( (parsed_lit > 0) ? Lit(var) : ~Lit(var) );
    }
}

static bool parse_DIMACS_main(char* in, Solver& S) {
    vec<Lit>    lits;
    for (;;){
        skipWhitespace(in);
        if (*in == 0)
            break;
        else if (*in == 'c' || *in == 'p')
            skipLine(in);
        else{
            readClause(in, S, lits);
            S.addClause(lits);
            if (!S.okay())
                return false;
        }
    }
    S.simplifyDB();
    return S.okay();
}


// Inserts problem into solver. Returns FALSE upon immediate conflict.
//
bool parse_DIMACS(gzFile in, Solver& S) {
    char* text = readFile(in);
    bool ret = parse_DIMACS_main(text, S);
    free(text);
    return ret; }


//=================================================================================================


void printStats(SolverStats& stats, double cpu_time)
{
    printf("restarts              : %"I64_fmt"\n", stats.starts);
    printf("conflicts             : %-12"I64_fmt"   (%.0f /sec)\n", stats.conflicts   , stats.conflicts   /cpu_time);
    printf("decisions             : %-12"I64_fmt"   (%.0f /sec)\n", stats.decisions   , stats.decisions   /cpu_time);
    printf("propagations          : %-12"I64_fmt"   (%.0f /sec)\n", stats.propagations, stats.propagations/cpu_time);
    printf("inspects              : %-12"I64_fmt"   (%.0f /sec)\n", stats.inspects    , stats.inspects    /cpu_time);
    printf("CPU time              : %g s\n", cpu_time);
}

Solver* solver;
static void SIGINT_handler(int signum) {
    printf("\n"); printf("*** INTERRUPTED ***\n");
    printStats(solver->stats, cpuTime());
    printf("\n"); printf("*** INTERRUPTED ***\n");
    exit(0); }


//=================================================================================================


int main(int argc, char** argv)
{
    Solver      S;
    bool        st;

    gzFile in = argc == 1 ? gzdopen(0, "rb") : gzopen(argv[1], "rb");
    if (in == NULL)
        fprintf(stderr, "ERROR! Could not open file: %s\n", argc == 1 ? "<stdin>" : argv[1]),
        exit(1);
    st = parse_DIMACS(in, S);
    gzclose(in);

    if (!st)
        printf("Trivial problem\nUNSATISFIABLE\n"),
        exit(20);

    S.verbosity = 1;
    solver = &S;
    signal(SIGINT,SIGINT_handler);
    st = S.solve();
    printStats(S.stats, cpuTime());
    printf("\n");
    printf(st ? "SATISFIABLE\n" : "UNSATISFIABLE\n");

    return 0;
}