--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/py/utils.py	Mon Nov 19 22:46:34 2012 +0800
@@ -0,0 +1,125 @@
+import os
+import sys
+#import ctypes
+import time
+import select
+import logging
+
+L = logging.info
+W = logging.warning
+E = logging.error
+
+DEFAULT_TRIES = 3
+READLINE_SELECT_TIMEOUT = 1
+
+clock_gettime = None
+no_clock_gettime = True
+def monotonic_time():
+    global clock_gettime
+    global no_clock_gettime
+    if no_clock_gettime:
+        return time.time()
+
+    class timespec(ctypes.Structure):
+        _fields_ = [
+            ('tv_sec', ctypes.c_long),
+            ('tv_nsec', ctypes.c_long)
+        ]
+    if not clock_gettime:
+        try:
+            librt = ctypes.CDLL('librt.so.0', use_errno=True)
+            clock_gettime = librt.clock_gettime
+            clock_gettime.argtypes = [ctypes.c_int, ctypes.POINTER(timespec)]
+        except:
+            W("No clock_gettime(), using fake fallback.")
+            no_clock_gettime = True
+            return time.time()
+        
+    t = timespec()
+    CLOCK_MONOTONIC = 1 # see <linux/time.h>
+
+    if clock_gettime(CLOCK_MONOTONIC, ctypes.pointer(t)) != 0:
+        errno_ = ctypes.get_errno()
+        raise OSError(errno_, os.strerror(errno_))
+    return t.tv_sec + t.tv_nsec * 1e-9
+
+# decorator, tries a number of times, returns None on failure, sleeps between
+# Must be used as "@retry()" if arguments are defaulted
+def retry(retries=DEFAULT_TRIES, try_time = 1):
+    def inner(func):
+        def new_f(*args, **kwargs):
+            for i in range(retries):
+                d = func(*args, **kwargs)
+                if d is not None:
+                    return d
+                time.sleep(try_time)
+            return None
+
+        new_f.func_name = func.func_name
+        return new_f
+    return inner
+
+def readline(sock):
+    timeout = READLINE_SELECT_TIMEOUT
+    buf = ''
+    while True:
+        (rlist, wlist, xlist) = select.select([sock], [], [], timeout)
+        if sock not in rlist:
+            # hit timeout
+            return None
+
+        c = sock.recv(1)
+        if c == '':
+            # lightblue timeout
+            return None
+        if c == '\r':
+            continue
+
+        buf += c
+        if c == '\n':
+            return buf
+
+# from http://blog.stalkr.net/2011/04/pctf-2011-32-thats-no-bluetooth.html
+def crc16(buff, crc = 0, poly = 0x8408):
+    l = len(buff)
+    i = 0
+    while i < l:
+        ch = ord(buff[i])
+        uc = 0
+        while uc < 8:
+            if (crc & 1) ^ (ch & 1):
+                crc = (crc >> 1) ^ poly
+            else:
+                crc >>= 1
+            ch >>= 1
+            uc += 1
+        i += 1
+    return crc
+
+def cheap_daemon():
+    L("Daemonising.")
+    sys.stdout.flush()
+    sys.stderr.flush()
+    out = file('/dev/null', 'a+')
+    os.dup2(out.fileno(), sys.stdout.fileno())
+    os.dup2(out.fileno(), sys.stderr.fileno())
+
+    try:
+        pid = os.fork()
+        if pid > 0:
+            sys.exit(0)
+    except OSError, e:
+        E("Bad fork()")
+        sys.exit(1)
+
+    os.setsid()
+
+    try:
+        pid = os.fork()
+        if pid > 0:
+            sys.exit(0)
+    except OSError, e:
+        E("Bad fork()")
+        sys.exit(1)
+
+