def split_sum_s_expr(expr, solv, extra_defs, typ):
"""divides up a linear expression 'a - b - 1 + a'
into ({'a':2, 'b': -1}, -1) i.e. 'a' times 2 etc and constant
value of -1."""
def rec(expr):
return split_sum_s_expr(expr, solv, extra_defs, typ)
if expr[0] == 'bvadd':
var = {}
const = 0
for x in expr[1:]:
(var2, const2) = rec(x)
for (v, count) in var2.iteritems():
var.setdefault(v, 0)
var[v] += count
const += const2
return (var, const)
elif expr[0] == 'bvsub':
(_, lhs, rhs) = expr
(lvar, lconst) = rec(lhs)
(rvar, rconst) = rec(rhs)
const = lconst - rconst
var = dict([(v, lvar.get(v, 0) - rvar.get(v, 0))
for v in set.union(set(lvar), set(rvar))])
return (var, const)
elif expr in solv.defs:
return rec(solv.defs[expr])
elif expr in extra_defs:
return rec(extra_defs[expr])
elif expr[:2] in ['#x', '#b']:
val = solver.smt_to_val(expr)
assert val.kind == 'Num'
return ({}, val.val)
else:
return ({expr: 1}, 0)
def split_sum_s_expr (expr, solv, extra_defs):
"""divides up a linear expression 'a - b - 1 + a'
into ({'a':2, 'b': -1}, -1)"""
if expr[0] == 'bvadd':
var = {}
const = 0
for x in expr[1:]:
(var2, const2) = split_sum_s_expr (x, solv, extra_defs)
for (v, count) in var2.iteritems ():
var.setdefault (v, 0)
var[v] += count
const += const2
return (var, const)
elif expr[0] == 'bvsub':
(_, lhs, rhs) = expr
(lvar, lconst) = split_sum_s_expr (lhs, solv, extra_defs)
(rvar, rconst) = split_sum_s_expr (rhs, solv, extra_defs)
const = lconst - rconst
var = dict ([(v, lvar.get (v, 0) - rvar.get (v, 0))
for v in set.union (set (lvar), set (rvar))])
return (var, const)
elif expr in solv.defs:
return split_sum_s_expr (solv.defs[expr], solv, extra_defs)
elif expr in extra_defs:
return split_sum_s_expr (extra_defs[expr], solv, extra_defs)
elif expr[:2] in ['#x', '#b']:
val = solver.smt_to_val (expr)
assert val.kind == 'Num'
return ({}, val.val)
else:
return ({expr: 1}, 0)
def eval_model (m, s, toplevel = None):
if s in m:
return m[s]
if toplevel == None:
toplevel = s
if type (s) == str:
try:
result = solver.smt_to_val (s)
except Exception, e:
trace ('Error with eval_model')
trace (toplevel)
raise e
return result
def str_to_num(smt_str):
v = solver.smt_to_val(smt_str)
return expr_num(v)
