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#!/usr/bin/python
#
# Copyright (C) 2016 Google, Inc
# Written by Simon Glass <sjg@chromium.org>
#
# SPDX-License-Identifier: GPL-2.0+
#
import struct
# A list of types we support
(TYPE_BYTE, TYPE_INT, TYPE_STRING, TYPE_BOOL) = range(4)
def BytesToValue(bytes):
"""Converts a string of bytes into a type and value
Args:
A string containing bytes
Return:
A tuple:
Type of data
Data, either a single element or a list of elements. Each element
is one of:
TYPE_STRING: string value from the property
TYPE_INT: a byte-swapped integer stored as a 4-byte string
TYPE_BYTE: a byte stored as a single-byte string
"""
size = len(bytes)
strings = bytes.split('\0')
is_string = True
count = len(strings) - 1
if count > 0 and not strings[-1]:
for string in strings[:-1]:
if not string:
is_string = False
break
for ch in string:
if ch < ' ' or ch > '~':
is_string = False
break
else:
is_string = False
if is_string:
if count == 1:
return TYPE_STRING, strings[0]
else:
return TYPE_STRING, strings[:-1]
if size % 4:
if size == 1:
return TYPE_BYTE, bytes[0]
else:
return TYPE_BYTE, list(bytes)
val = []
for i in range(0, size, 4):
val.append(bytes[i:i + 4])
if size == 4:
return TYPE_INT, val[0]
else:
return TYPE_INT, val
def GetEmpty(type):
"""Get an empty / zero value of the given type
Returns:
A single value of the given type
"""
if type == TYPE_BYTE:
return chr(0)
elif type == TYPE_INT:
return struct.pack('<I', 0);
elif type == TYPE_STRING:
return ''
else:
return True
def fdt32_to_cpu(val):
"""Convert a device tree cell to an integer
Args:
Value to convert (4-character string representing the cell value)
Return:
A native-endian integer value
"""
return struct.unpack(">I", val)[0]