使用布尔运算符在 Z3 中定义约束 [英] Defining constraints in Z3 using Boolean operators

问题描述

比方说，我想将字符串的每个字符限制为字符集:[a-zA-Z0-9_] 使用 Z3 约束，我可以使用布尔运算符来指定吗?

举个例子:

input = [BitVec("input%s" % i, 8) for i in range(10)]对于范围内的我(10):s.add(input[i] >= 0x30 and input[i] <= 0x39)s.add(input[i] >= 0x41 and input[i] <= 0x5A)s.add(input[i] >= 0x61 and input[i] <= 0x7A)

这是正确的吗?还有其他有效的方法来定义约束吗?

通常在 Python 中，我可以执行以下操作:

导入字符串charset = string.uppercase + string.lowercase + string.digits + "_"对于我在字符集中:...

可以做类似的事情来定义 Z3 中的约束吗?

谢谢.

解决方案

解决这个问题的最好方法是简单地使用 z3 的正则表达式匹配工具:

from z3 import *导入字符串lower = Union([Re(c) for c in string.lowercase])upper = Union([Re(c) for c in string.uppercase])digs = Union([Re(c) for c in string.digits])uscore = Re('_')charset = Union(lower, upper, digs, uscore)lang = Plus(字符集)s = 求解器()test = String("测试")s.add(长度(测试) == 10)s.add(InRe(test, lang))打印 s.check()打印 s.model()

打印:

sat[测试=9L25ZPC1B8"]

或者您可以使用它来测试特定字符串是否属于您定义的正则表达式:

<预><代码>>>>打印(简化(InRe(hEllO_123"，lang)))真的>>>打印(简化(InRe(%$"，lang)))错误的

Let's say, I want to restrict each character of the string to the charset: [a-zA-Z0-9_] using Z3 constraints, can I use a boolean operator to specify that?

As an example:

input = [BitVec("input%s" % i, 8) for i in range(10)]

for i in range(10):
  s.add(input[i] >= 0x30 and input[i] <= 0x39)
  s.add(input[i] >= 0x41 and input[i] <= 0x5A)
  s.add(input[i] >= 0x61 and input[i] <= 0x7A)

Is this correct? Any other efficient way to define constraints?

Usually in Python, I could do something like:

import string

charset = string.uppercase + string.lowercase + string.digits + "_"

for i in charset:
    ...

Can something similar be done to define constraints in Z3?

Thanks.

解决方案

The best way to go about this would be to simply use z3's regular-expression matching facilities:

from z3 import *
import string

lower  = Union([Re(c) for c in string.lowercase])
upper  = Union([Re(c) for c in string.uppercase])
digs   = Union([Re(c) for c in string.digits])
uscore = Re('_')

charset = Union(lower, upper, digs, uscore)
lang    = Plus(charset)


s = Solver()
test = String("test")
s.add(Length(test) == 10)
s.add(InRe(test, lang))

print s.check()
print s.model()

This prints:

sat
[test = "9L25ZPC1B8"]

Or you can use it to test whether particular strings belong to the regular-expression you've defined:

>>> print (simplify(InRe("hEllO_123", lang)))
True
>>> print (simplify(InRe("%$", lang)))
False

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