| Dan Talayco | f75360a | 2010-02-05 22:22:54 -0800 | [diff] [blame] | 1 | """This module converts C types to Python struct pattern string. |
| 2 | |
| 3 | Date June 2009 |
| 4 | Created by ykk |
| 5 | """ |
| 6 | import cheader |
| 7 | import struct |
| 8 | |
| 9 | class cstruct2py: |
| 10 | """Class converts C struct to Python struct pattern string |
| 11 | |
| 12 | Date October 2009 |
| 13 | Created by ykk |
| 14 | """ |
| 15 | def __init__(self): |
| 16 | """Initialize |
| 17 | """ |
| 18 | ##Mapping |
| 19 | self.structmap = {} |
| 20 | self.structmap["char"] = "c" |
| 21 | self.structmap["signed char"] = "b" |
| 22 | self.structmap["uint8_t"]=\ |
| 23 | self.structmap["unsigned char"] = "B" |
| 24 | self.structmap["short"] = "h" |
| 25 | self.structmap["uint16_t"] =\ |
| 26 | self.structmap["unsigned short"] = "H" |
| 27 | self.structmap["int"] = "i" |
| 28 | self.structmap["unsigned int"] = "I" |
| 29 | self.structmap["long"] = "l" |
| 30 | self.structmap["uint32_t"] =\ |
| 31 | self.structmap["unsigned long"] = "L" |
| 32 | self.structmap["long long"] = "q" |
| 33 | self.structmap["uint64_t"] =\ |
| 34 | self.structmap["unsigned long long"] = "Q" |
| 35 | self.structmap["float"] = "f" |
| 36 | self.structmap["double"] = "d" |
| 37 | |
| 38 | def get_pattern(self,ctype): |
| 39 | """Get pattern string for ctype. |
| 40 | Return None if ctype is not expanded. |
| 41 | """ |
| 42 | if (ctype.expanded): |
| 43 | if (isinstance(ctype, cheader.cprimitive)): |
| 44 | return self.structmap[ctype.typename] |
| 45 | elif (isinstance(ctype, cheader.cstruct)): |
| 46 | string="" |
| 47 | for member in ctype.members: |
| 48 | string += self.get_pattern(member) |
| 49 | return string |
| 50 | elif (isinstance(ctype, cheader.carray)): |
| 51 | if (ctype.size == 0): |
| 52 | return "" |
| 53 | else: |
| 54 | string = self.get_pattern(ctype.object) |
| 55 | return string * ctype.size |
| 56 | return None |
| 57 | |
| 58 | def get_size(self, ctype, prefix="!"): |
| 59 | """Return size of struct or pattern specified |
| 60 | """ |
| 61 | if (isinstance(ctype, str)): |
| 62 | return struct.calcsize(ctype) |
| 63 | elif (isinstance(ctype, cheader.ctype)): |
| 64 | return struct.calcsize(prefix + self.get_pattern(ctype)) |
| 65 | else: |
| 66 | return 0 |
| 67 | |
| 68 | class structpacker: |
| 69 | """Pack/unpack packets with ctype. |
| 70 | |
| 71 | Date October 2009 |
| 72 | Created by ykk |
| 73 | """ |
| 74 | def __init__(self, prefix=""): |
| 75 | """Initialize with prefix to struct |
| 76 | """ |
| 77 | ##Reference to prefix |
| 78 | self.prefix = prefix |
| 79 | |
| 80 | def pack(self, ctype, *arg): |
| 81 | """Pack packet accordingly ctype or pattern provided. |
| 82 | Return struct packed. |
| 83 | """ |
| 84 | if (isinstance(ctype, str)): |
| 85 | return struct.pack(self.prefix+ctype, *arg) |
| 86 | elif (isinstance(ctype, cheader.ctype)): |
| 87 | return struct.pack(self.prefix+cstruct2py.get_pattern(ctype), |
| 88 | *arg) |
| 89 | else: |
| 90 | return None |
| 91 | |
| 92 | def unpack_from_front(self, ctype, binaryString, returnDictionary=True): |
| 93 | """Unpack packet using front of packet, |
| 94 | accordingly ctype or pattern provided. |
| 95 | |
| 96 | Return (dictionary of values indexed by arg name, |
| 97 | remaining binary string) if ctype is cheader.ctype |
| 98 | and returnDictionary is True, |
| 99 | else return (array of data unpacked, remaining binary string). |
| 100 | """ |
| 101 | pattern = "" |
| 102 | if (isinstance(ctype, str)): |
| 103 | pattern = ctype |
| 104 | elif (isinstance(ctype, cheader.ctype)): |
| 105 | pattern = cstruct2py.get_pattern(ctype) |
| 106 | else: |
| 107 | return None |
| 108 | dsize = struct.calcsize(pattern) |
| 109 | |
| 110 | if (dsize > len(binaryString)): |
| 111 | return None |
| 112 | |
| 113 | return (structpacker.peek_from_front(self, pattern, binaryString, returnDictionary), |
| 114 | binaryString[dsize:]) |
| 115 | |
| 116 | def peek_from_front(self, ctype, binaryString, returnDictionary=True): |
| 117 | """Unpack packet using front of packet, |
| 118 | accordingly ctype or pattern provided. |
| 119 | |
| 120 | Return dictionary of values indexed by arg name, |
| 121 | if ctype is cheader.ctype and returnDictionary is True, |
| 122 | else return array of data unpacked. |
| 123 | """ |
| 124 | pattern = self.prefix |
| 125 | if (isinstance(ctype, str)): |
| 126 | pattern += ctype |
| 127 | elif (isinstance(ctype, cheader.ctype)): |
| 128 | pattern += cstruct2py.get_pattern(ctype) |
| 129 | else: |
| 130 | return None |
| 131 | dsize = struct.calcsize(pattern) |
| 132 | if (dsize > len(binaryString)): |
| 133 | return None |
| 134 | data = struct.unpack(pattern, binaryString[0:dsize]) |
| 135 | |
| 136 | #Return values |
| 137 | if (isinstance(ctype, str) or |
| 138 | (not returnDictionary)): |
| 139 | return data |
| 140 | else: |
| 141 | return self.data2dic(data, ctype) |
| 142 | |
| 143 | def data2dic(self,ctype,data): |
| 144 | """Convert data to dictionary |
| 145 | """ |
| 146 | valDic = {} |
| 147 | names = ctype.get_names() |
| 148 | for name in names: |
| 149 | valDic[name] = [] |
| 150 | for d in data: |
| 151 | name = names.pop(0) |
| 152 | valDic[name].append(d) |
| 153 | return valDic |
| 154 | |