checkpoint

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>

src/sat/dimacs.cpp

@@ -0,0 +1,132 @@
+/*++
+Copyright (c) 2011 Microsoft Corporation
+
+Module Name:
+
+    dimacs.cpp
+
+Abstract:
+
+    Dimacs CNF parser
+
+Author:
+
+    Leonardo de Moura (leonardo) 2011-07-26.
+
+Revision History:
+
+--*/
+#include"dimacs.h"
+#undef max
+#undef min
+#include"sat_solver.h"
+
+class stream_buffer {
+    std::istream & m_stream;
+    int            m_val;
+public:
+    
+    stream_buffer(std::istream & s):
+        m_stream(s) {
+        m_val = m_stream.get();
+    }
+
+    int  operator *() const { 
+        return m_val;
+    }
+
+    void operator ++() { 
+        m_val = m_stream.get();
+    }
+};
+
+template<typename Buffer>
+void skip_whitespace(Buffer & in) {
+    while ((*in >= 9 && *in <= 13) || *in == 32) {
+        ++in; 
+    }
+}
+
+template<typename Buffer>
+void skip_line(Buffer & in) {
+    while(true) {
+        if (*in == EOF) {
+            return;
+        }
+        if (*in == '\n') { 
+            ++in; 
+            return; 
+        }
+        ++in; 
+    } 
+}
+
+template<typename Buffer>
+int parse_int(Buffer & in) {
+    int     val = 0;
+    bool    neg = false;
+    skip_whitespace(in);
+
+    if (*in == '-') {
+        neg = true;
+        ++in;
+    }
+    else if (*in == '+') {
+        ++in;
+    }
+
+    if (*in < '0' || *in > '9') {
+        std::cerr << "(error, \"unexpected char: " << *in << "\")\n";
+        exit(3);
+        exit(ERR_PARSER);
+    }
+
+    while (*in >= '0' && *in <= '9') {
+        val = val*10 + (*in - '0');
+        ++in;
+    }
+
+    return neg ? -val : val; 
+}
+
+template<typename Buffer>
+void read_clause(Buffer & in, sat::solver & solver, sat::literal_vector & lits) {
+    int     parsed_lit;
+    int     var;
+    
+    lits.reset();
+
+    while (true) { 
+        parsed_lit = parse_int(in);
+        if (parsed_lit == 0)
+            break;
+        var = abs(parsed_lit);
+        SASSERT(var > 0);
+        while (static_cast<unsigned>(var) >= solver.num_vars())
+            solver.mk_var();
+        lits.push_back(sat::literal(var, parsed_lit < 0));
+    }
+}
+
+template<typename Buffer>
+void parse_dimacs_core(Buffer & in, sat::solver & solver) {
+    sat::literal_vector lits;
+    while (true) {
+        skip_whitespace(in);
+        if (*in == EOF) {
+            break;
+        }
+        else if (*in == 'c' || *in == 'p') {
+            skip_line(in);
+        }
+        else {
+            read_clause(in, solver, lits);
+            solver.mk_clause(lits.size(), lits.c_ptr());
+        }
+    }
+}
+
+void parse_dimacs(std::istream & in, sat::solver & solver) {
+    stream_buffer _in(in);
+    parse_dimacs_core(_in, solver);
+}

src/sat/dimacs.h

@@ -0,0 +1,27 @@
+/*++
+Copyright (c) 2011 Microsoft Corporation
+
+Module Name:
+
+    dimacs.h
+
+Abstract:
+
+    Dimacs CNF parser
+
+Author:
+
+    Leonardo de Moura (leonardo) 2011-07-26.
+
+Revision History:
+
+--*/
+#ifndef _DIMACS_H_
+#define _DIMACS_H_
+
+#include"sat_types.h"
+
+void parse_dimacs(std::istream & s, sat::solver & solver);
+
+#endif /* _DIMACS_PARSER_H_ */
+