Question

我正在尝试为boost :: unordered_map添加一台漂亮的打印机，方法是在现有的boost pretty打印机列表中添加一台新的打印机： https://sourceware.org/gdb/wiki/STLSupport https://github.com/ruediger/Boost-Pretty-Printer

然而，当我尝试打印地图时，会多次打印很多值并且会出现一些不需要的字符。我不确定应该对我现有的代码进行哪些修改，使其仅打印一次，不包含任何不需要的字符。这是我在myMap.cpp中更新myMap的循环：

 for (int i=0; i<=10; i++)
 {
 string s = to_string(i);
 myMap[s] = i;
 }

当我在gdb中打印myMap作为

时

(gdb)p myMap

我得到如下结果：

$1 = boost::unordered::detail = {"1" = 1, "0" = 0, "2" = 2, "1" = 1, "0" = 0, "3" = 3, 
"2" = 2, "1" = 1, "0" = 0, "4" = 4, "3" = 3, "2" = 2, "1" = 1, "0" = 0, "5" = 5, "4" = 4, 
"3" = 3, "2" = 2, "1" = 1, "0" = 0, "6" = 6, "5" = 5, "4" = 4, "3" = 3, "2" = 2, "1" = 1, 
 "0" = 0, "7" = 7, "10" = 10, "6" = 6, "5" = 5, "4" = 4, "3" = 3, "2" = 2, "1" = 1, 
"0" = 0, "8" = 8, "7" = 7, "10" = 10, "6" = 6, "5" = 5, "4" = 4, "3" = 3, "2" = 2, 
"1" = 1, "0" = 0, "9" = 9, "8" = 8, "7" = 7, "10" = 10, "6" = 6, "5" = 5, "4" = 4, 
"3" = 3, "2" = 2, "1" = 1, "0" = 0, 
" \204`", '\000' <repeats 13 times>, "\321\n\002", '\000' <repeats 181 times>... = 0, 
"9" = 9, "8" = 8, "7" = 7, "10" = 10, "6" = 6, "5" = 5, "4" = 4, "3" = 3, "2" = 2, 
"1" = 1, "0" = 0}

我的漂亮打印机的python代码如下所示：

@_register_printer
class BoostUnorderedMap:
"Pretty Printer for boost::unordered_map"
printer_name = 'boost::unordered_map'
version = '1.40'
type_name_re = '^boost::unordered::unordered_map<.*>$'

class _iterator:
def __init__(self,fields):
   type_1 = fields.val.type.template_argument(0)
   type_2 = fields.val.type.template_argument(1)

   self.buckets = fields.val['table_']['buckets_']
   self.bucket_count = fields.val['table_']['bucket_count_']
   self.bucket_size = fields.val['table_']['size_']
   self.current_bucket = 0
   self.value = 0
   self.iteration = 0
   self.temp_node = 0
   self.bucket_to_start = 0
   pair = "std::pair<%s const, %s>" % (type_1, type_2)
   self.pair_pointer = gdb.lookup_type(pair).pointer()
   self.base_pointer = gdb.lookup_type("boost::unordered::detail::value_base< %s >" % pair).pointer()
   self.node_pointer = gdb.lookup_type("boost::unordered::detail::ptr_node<std::pair<std::basic_string<char, std::char_traits<char>, std::allocator<char> > const, int> >").pointer()
   self.node = self.buckets[self.current_bucket]['next_']



def __iter__(self):
    return self

def next(self): 
    while not self.node:
            self.current_bucket = self.current_bucket + 1
            if self.current_bucket >= self.bucket_count:
                raise StopIteration
            self.node = self.buckets[self.current_bucket]['next_']

    iterator = self.node.cast(self.node_pointer).cast(self.base_pointer).cast(self.pair_pointer).dereference()   
        self.node = self.node['next_']

        return ('%s' % iterator['first'], iterator['second'])

def __init__(self, val):
self.val = val

def children(self):
return self._iterator(self)

def to_string(self):
return "boost::unordered::detail"

任何帮助都将不胜感激。

Answer 1

如果不了解有关Boost内部的更多信息，很难确切地知道出了什么问题。如果是我，我可能会破解“下一步”方法来添加一些调试打印以查看出错的地方。

无论如何，有一件事在你的Python代码中脱颖而出。现在你要返回像这样的子元素：

    return ('%s' % iterator['first'], iterator['second'])

但是，使用此API的常用方法是将地图的键和值作为单独的子项返回，然后使用返回“map”的display_hint方法。参见

https://sourceware.org/gdb/onlinedocs/gdb/Pretty-Printing-API.html

您可以在下一个方法中使用“yield”轻松完成此操作。

Boost unordered_map漂亮的打印机多次打印值以及不需要的值

1 个答案: