reorganizing the code

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

src/math/polynomial/sexpr2upolynomial.cpp

@@ -0,0 +1,112 @@
+/*++
+Copyright (c) 2011 Microsoft Corporation
+
+Module Name:
+
+    sexpr2upolynomial.cpp
+
+Abstract:
+
+    sexpr to upolynomial converter
+    
+Author:
+
+    Leonardo (leonardo) 2011-12-28
+
+Notes:
+
+--*/
+#include"sexpr2upolynomial.h"
+#include"sexpr.h"
+
+sexpr2upolynomial_exception::sexpr2upolynomial_exception(char const * msg, sexpr const * s):
+    cmd_exception(msg, s->get_line(), s->get_pos()) {
+}
+
+#define MAX_POLYNOMIAL_DEPTH 1 << 16
+
+// Simple recursive parser
+void sexpr2upolynomial(upolynomial::manager & m, sexpr const * s, upolynomial::numeral_vector & p, unsigned depth) {
+    if (depth > MAX_POLYNOMIAL_DEPTH)
+        throw sexpr2upolynomial_exception("invalid univariate polynomial, too complex", s);
+    if (s->is_composite()) {
+        unsigned num = s->get_num_children();
+        if (num == 0)
+            throw sexpr2upolynomial_exception("invalid univariate polynomial, symbol expected", s);
+        sexpr * h = s->get_child(0);
+        if (!h->is_symbol())
+            throw sexpr2upolynomial_exception("invalid univariate polynomial, symbol expected", s);
+        symbol op = h->get_symbol();
+        if (op == "+") {
+            if (num <= 1)
+                throw sexpr2upolynomial_exception("invalid univariate polynomial, '+' operator expects at least one argument", s);
+            sexpr2upolynomial(m, s->get_child(1), p, depth+1);
+            upolynomial::scoped_numeral_vector arg(m);
+            for (unsigned i = 2; i < num; i++) {
+                m.reset(arg);
+                sexpr2upolynomial(m, s->get_child(i), arg, depth+1);
+                m.add(arg.size(), arg.c_ptr(), p.size(), p.c_ptr(), p);
+            }
+        }
+        else if (op == "-") {
+            if (num <= 1)
+                throw sexpr2upolynomial_exception("invalid univariate polynomial, '-' operator expects at least one argument", s);
+            sexpr2upolynomial(m, s->get_child(1), p, depth+1);
+            if (num == 2) {
+                m.neg(p);
+                return;
+            }
+            upolynomial::scoped_numeral_vector arg(m);
+            for (unsigned i = 2; i < num; i++) {
+                m.reset(arg);
+                sexpr2upolynomial(m, s->get_child(i), arg, depth+1);
+                m.sub(p.size(), p.c_ptr(), arg.size(), arg.c_ptr(), p);
+            }
+        }
+        else if (op == "*") {
+            if (num <= 1)
+                throw sexpr2upolynomial_exception("invalid univariate polynomial, '*' operator expects at least one argument", s);
+            sexpr2upolynomial(m, s->get_child(1), p, depth+1);
+            upolynomial::scoped_numeral_vector arg(m);
+            for (unsigned i = 2; i < num; i++) {
+                m.reset(arg);
+                sexpr2upolynomial(m, s->get_child(i), arg, depth+1);
+                m.mul(arg.size(), arg.c_ptr(), p.size(), p.c_ptr(), p);
+            }
+        }
+        else if (op == "^") {
+            if (num != 3)
+                throw sexpr2upolynomial_exception("invalid univariate polynomial, '^' operator expects two arguments", s);
+            sexpr2upolynomial(m, s->get_child(1), p, depth+1);
+            sexpr * arg2 = s->get_child(2);
+            if (!arg2->is_numeral() || !arg2->get_numeral().is_unsigned())
+                throw sexpr2upolynomial_exception("invalid univariate polynomial, exponent must be an unsigned integer", arg2);
+            unsigned k = arg2->get_numeral().get_unsigned();
+            m.pw(p.size(), p.c_ptr(), k, p);
+        }
+        else {
+            throw sexpr2upolynomial_exception("invalid univariate polynomial, '+', '-', '^' or '*' expected", s);
+        }
+    }
+    else if (s->is_numeral()) {
+        // make constant polynomial
+        rational a = s->get_numeral();
+        if (!a.is_int())
+            throw sexpr2upolynomial_exception("invalid univariate polynomial, integer coefficient expected", s);
+        m.set(1, &a, p);
+    }
+    else if (s->is_symbol()) {
+        if (s->get_symbol() != "x") 
+            throw sexpr2upolynomial_exception("invalid univariate polynomial, variable 'x' expected", s);
+        // make identity
+        rational as[2] = { rational(0), rational(1) };
+        m.set(2, as, p);
+    }
+    else {
+        throw sexpr2upolynomial_exception("invalid univariate polynomial, unexpected ", s);
+    }
+} 
+
+void sexpr2upolynomial(upolynomial::manager & m, sexpr const * s, upolynomial::numeral_vector & p) {
+    sexpr2upolynomial(m, s, p, 0);
+}