util.py

#
# This file is part of the micropython-esp32-ulp project,
# https://github.com/micropython/micropython-esp32-ulp
#
# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
# SPDX-License-Identifier: MIT

DEBUG=False

importgc
importos

NORMAL, WHITESPACE=0, 1


defgarbage_collect(msg, verbose=DEBUG):
free_before=gc.mem_free()
gc.collect()
free_after=gc.mem_free()
ifverbose:
print("%s: %d --gc--> %d bytes free"% (msg, free_before, free_after))


defsplit_tokens(line):
buf=""
tokens= []
state=NORMAL
forcinline:
ifcin"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_":
ifstate!=NORMAL:
iflen(buf) >0:
tokens.append(buf)
buf=""
state=NORMAL
buf+=c
elifcin" \t":
ifstate!=WHITESPACE:
iflen(buf) >0:
tokens.append(buf)
buf=""
state=WHITESPACE
buf+=c
else:
iflen(buf) >0:
tokens.append(buf)
buf=""
tokens.append(c)

iflen(buf) >0:
tokens.append(buf)

returntokens


defvalidate_expression(param):
fortokeninsplit_tokens(param):
state=0
forcintoken:
ifcnotin' \t+-*/%()<>&|~xX0123456789abcdefABCDEF':
returnFalse

# the following allows hex digits a-f after 0x but not otherwise
ifstate==0:
ifcin'abcdefABCDEF':
returnFalse
ifc=='0':
state=1
continue

ifstate==1:
state=2ifcin'xX'else0
continue

ifstate==2:
ifcnotin'0123456789abcdefABCDEF':
state=0
returnTrue


deffile_exists(filename):
try:
os.stat(filename)
returnTrue
exceptOSError:
pass
returnFalse