def BytesToValue(data):
"""Converts a string of bytes into a type and value
Args:
A bytes value (which on Python 2 is an alias for str)
Return:
A tuple:
Type of data
Data, either a single element or a list of elements. Each element
is one of:
TYPE_STRING: str/bytes value from the property
TYPE_INT: a byte-swapped integer stored as a 4-byte str/bytes
TYPE_BYTE: a byte stored as a single-byte str/bytes
"""
data = bytes(data)
size = len(data)
strings = data.split(b'\0')
is_string = True
count = len(strings) - 1
if count > 0 and not len(strings[-1]):
for string in strings[:-1]:
if not string:
is_string = False
break
for ch in string:
# Handle Python 2 treating bytes as str
if type(ch) == str:
ch = ord(ch)
if ch < 32 or ch > 127:
is_string = False
break
else:
is_string = False
if is_string:
if count == 1:
if sys.version_info[0] >= 3: # pragma: no cover
return TYPE_STRING, strings[0].decode()
else:
return TYPE_STRING, strings[0]
else:
if sys.version_info[0] >= 3: # pragma: no cover
return TYPE_STRING, [s.decode() for s in strings[:-1]]
else:
return TYPE_STRING, strings[:-1]
if size % 4:
if size == 1:
return TYPE_BYTE, tools.ToChar(data[0])
else:
return TYPE_BYTE, [tools.ToChar(ch) for ch in list(data)]
val = []
for i in range(0, size, 4):
val.append(data[i:i + 4])
if size == 4:
return TYPE_INT, val[0]
else:
return TYPE_INT, val
def _GetPropertyValue(dtb, node, prop_name):
"""Low-level function to get the property value based on its offset
This looks directly in the device tree at the property's offset to find
its value. It is useful as a check that the property is in the correct
place.
Args:
node: Node to look in
prop_name: Property name to find
Returns:
Tuple:
Prop object found
Value of property as a string (found using property offset)
"""
prop = node.props[prop_name]
# Add 12, which is sizeof(struct fdt_property), to get to start of data
offset = prop.GetOffset() + 12
data = dtb.GetContents()[offset:offset + len(prop.value)]
return prop, [tools.ToChar(x) for x in data]