src/Backend/inc_solver.c

   1 /*      Copyright (c) 2015 Regents of the University of California
   2  *
   3  *      Author: Brian Demsky <bdemsky@uci.edu>
   4  *
   5  *      This program is free software; you can redistribute it and/or
   6  *      modify it under the terms of the GNU General Public License
   7  *      version 2 as published by the Free Software Foundation.
   8  */
   9
  10 #include "inc_solver.h"
  11 #define SATSOLVER "sat_solver"
  12 #include <fcntl.h>
  13 #include "common.h"
  14 #include <string.h>
  15
  16 IncrementalSolver *allocIncrementalSolver() {
  17         IncrementalSolver *This = (IncrementalSolver *)ourmalloc(sizeof(IncrementalSolver));
  18         This->buffer = ((int *)ourmalloc(sizeof(int) * IS_BUFFERSIZE));
  19         This->solution = NULL;
  20         This->solutionsize = 0;
  21         This->offset = 0;
  22         createSolver(This);
  23         return This;
  24 }
  25
  26 void deleteIncrementalSolver(IncrementalSolver *This) {
  27         killSolver(This);
  28         ourfree(This->buffer);
  29         if (This->solution != NULL)
  30                 ourfree(This->solution);
  31         ourfree(This);
  32 }
  33
  34 void resetSolver(IncrementalSolver *This) {
  35         killSolver(This);
  36         This->offset = 0;
  37         createSolver(This);
  38 }
  39
  40 void addClauseLiteral(IncrementalSolver *This, int literal) {
  41         This->buffer[This->offset++] = literal;
  42         if (This->offset == IS_BUFFERSIZE) {
  43                 flushBufferSolver(This);
  44         }
  45 }
  46
  47 void addArrayClauseLiteral(IncrementalSolver *This, uint numliterals, int *literals) {
  48         uint index = 0;
  49         while (true) {
  50                 uint bufferspace = IS_BUFFERSIZE - This->offset;
  51                 uint numtowrite = numliterals - index;
  52                 if (bufferspace > numtowrite) {
  53                         memcpy(&This->buffer[This->offset], &literals[index], numtowrite * sizeof(int));
  54                         This->offset += numtowrite;
  55                         This->buffer[This->offset++] = 0;       //have one extra spot always
  56                         if (This->offset == IS_BUFFERSIZE) {//Check if full
  57                                 flushBufferSolver(This);
  58                         }
  59                         return;
  60                 } else {
  61                         memcpy(&This->buffer[This->offset], &literals[index], bufferspace * sizeof(int));
  62                         This->offset += bufferspace;
  63                         index += bufferspace;
  64                         flushBufferSolver(This);
  65                 }
  66         }
  67 }
  68
  69 void finishedClauses(IncrementalSolver *This) {
  70         addClauseLiteral(This, 0);
  71 }
  72
  73 void freeze(IncrementalSolver *This, int variable) {
  74         addClauseLiteral(This, IS_FREEZE);
  75         addClauseLiteral(This, variable);
  76 }
  77
  78 int solve(IncrementalSolver *This) {
  79         //add an empty clause
  80         startSolve(This);
  81         return getSolution(This);
  82 }
  83
  84 void startSolve(IncrementalSolver *This) {
  85         addClauseLiteral(This, IS_RUNSOLVER);
  86         flushBufferSolver(This);
  87 }
  88
  89 int getSolution(IncrementalSolver *This) {
  90         int result = readIntSolver(This);
  91         if (result == IS_SAT) {
  92                 int numVars = readIntSolver(This);
  93                 if (numVars > This->solutionsize) {
  94                         if (This->solution != NULL)
  95                                 ourfree(This->solution);
  96                         This->solution = (int *) ourmalloc((numVars + 1) * sizeof(int));
  97                         This->solution[0] = 0;
  98                 }
  99                 readSolver(This, &This->solution[1], numVars * sizeof(int));
 100                 This->solutionsize = numVars;
 101         }
 102         return result;
 103 }
 104
 105 int readIntSolver(IncrementalSolver *This) {
 106         int value;
 107         readSolver(This, &value, 4);
 108         return value;
 109 }
 110
 111 void readSolver(IncrementalSolver *This, void *tmp, ssize_t size) {
 112         char *result = (char *) tmp;
 113         ssize_t bytestoread = size;
 114         ssize_t bytesread = 0;
 115         do {
 116                 ssize_t n = read(This->from_solver_fd, &((char *)result)[bytesread], bytestoread);
 117                 if (n == -1) {
 118                         model_print("Read failure\n");
 119                         exit(-1);
 120                 }
 121                 bytestoread -= n;
 122                 bytesread += n;
 123         } while (bytestoread != 0);
 124 }
 125
 126 bool getValueSolver(IncrementalSolver *This, int variable) {
 127         return This->solution[variable];
 128 }
 129
 130 void createSolver(IncrementalSolver *This) {
 131         int to_pipe[2];
 132         int from_pipe[2];
 133         if (pipe(to_pipe) || pipe(from_pipe)) {
 134                 model_print("Error creating pipe.\n");
 135                 exit(-1);
 136         }
 137         if ((This->solver_pid = fork()) == -1) {
 138                 model_print("Error forking.\n");
 139                 exit(-1);
 140         }
 141         if (This->solver_pid == 0) {
 142                 //Solver process
 143                 close(to_pipe[1]);
 144                 close(from_pipe[0]);
 145                 int fd = open("log_file", O_WRONLY | O_CREAT | O_TRUNC, S_IRWXU);
 146
 147                 if ((dup2(to_pipe[0], 0) == -1) ||
 148                                 (dup2(from_pipe[1], IS_OUT_FD) == -1) ||
 149                                 (dup2(fd, 1) == -1)) {
 150                         model_print("Error duplicating pipes\n");
 151                 }
 152                 //    setsid();
 153                 execlp(SATSOLVER, SATSOLVER, NULL);
 154                 model_print("execlp Failed\n");
 155                 close(fd);
 156         } else {
 157                 //Our process
 158                 This->to_solver_fd = to_pipe[1];
 159                 This->from_solver_fd = from_pipe[0];
 160                 close(to_pipe[0]);
 161                 close(from_pipe[1]);
 162         }
 163 }
 164
 165 void killSolver(IncrementalSolver *This) {
 166         close(This->to_solver_fd);
 167         close(This->from_solver_fd);
 168         //Stop the solver
 169         if (This->solver_pid > 0) {
 170                 int status;
 171                 kill(This->solver_pid, SIGKILL);
 172                 waitpid(This->solver_pid, &status, 0);
 173         }
 174 }
 175
 176 //DEBUGGING CODE STARTS
 177 bool first = true;
 178 //DEBUGGING CODE ENDS
 179
 180 void flushBufferSolver(IncrementalSolver *This) {
 181         ssize_t bytestowrite = sizeof(int) * This->offset;
 182         ssize_t byteswritten = 0;
 183         //DEBUGGING CODE STARTS
 184         for (uint i = 0; i < This->offset; i++) {
 185                 if (first)
 186                         printf("(");
 187                 if (This->buffer[i] == 0) {
 188                         printf(")\n");
 189                         first = true;
 190                 } else {
 191                         if (!first)
 192                                 printf(" + ");
 193                         first = false;
 194                         printf("%d", This->buffer[i]);
 195                 }
 196         }
 197         //DEBUGGING CODE ENDS
 198         do {
 199                 ssize_t n = write(This->to_solver_fd, &((char *)This->buffer)[byteswritten], bytestowrite);
 200                 if (n == -1) {
 201                         perror("Write failure\n");
 202                         model_print("to_solver_fd=%d\n",This->to_solver_fd);
 203                         exit(-1);
 204                 }
 205                 bytestowrite -= n;
 206                 byteswritten += n;
 207         } while (bytestowrite != 0);
 208         This->offset = 0;
 209 }