i have been thinking of several ways to integrate the string escape code in
logprintf. the more i think about it, the more i like the idea of including
in wget a stripped-down version of vsnprintf to be used inside logprintf.
this function would also understand a special escape code (%e? %es?) that
would actually trigger the escaping of the given string before the
interpolation (but only if we print to a tty).
to test which kind of conversions are used by wget inside logprintf calls,
yesterday i came up with this python 2.3 script (i know, it is not very
pythonic but this is not the point since it works pretty well):
#!/usr/bin/env python
import sys
import sets
debug = False
used_fmt_codes = sets.Set([])
def debug_print (str):
if debug:
print str
def debug_format (str):
pretty_print (str)
examine_format (str)
def is_escaped (str, index):
tmp = index - 1
count = 0
while (str[tmp] == '\\'):
tmp -= 1
count += 1
if count % 2:
return True
return False
def retrieve_format_string (str):
i = str.find ('"')
j = str.find ('"', i + 1)
while (is_escaped(str, j)):
j = str.find ('"', j + 1)
return str[i:j+1]
def retrieve_format_code (str, index):
chars = "c%msbpxXdiuofg"
i = index + 1
while (str[i] not in chars):
i += 1
return str[index:i+1]
def examine_format (str):
fmtstr = retrieve_format_string (str)
i = fmtstr.find ('%')
debug_print("format code(s):")
while (i >= 0):
fmt = retrieve_format_code (fmtstr, i)
#print fmt
used_fmt_codes.add(fmt)
i = fmtstr.find ('%', i + len(fmt))
def pretty_print (str):
print " ".join(str.split())
def process_logprintf (file, func):
keep_scanning = False
for line in file:
if not keep_scanning:
i = line.find("logprintf")
if i >= 0:
debug_print("found logprintf")
debug_print(line[:-1])
j = line.find ('(', i + len("logprintf"))
if j < 0:
debug_print("checking next line for open brace")
keep_scanning = True
continue
count = 1
debug_print("found open brace, count = %d" % count)
for c in range (j+1, len(line)-1):
if line[c] == '(':
count += 1
debug_print("found open brace, count = %d" % count)
elif line[c] == ')':
count -= 1
debug_print("found closing brace, count = %d" % count)
if count == 0:
str = line[i:c+1]
func(str)
break
if count != 0:
debug_print("keep scanning on next line, count = %d" %
count)
str = line[i:-1]
keep_scanning = True
else:
debug_print("scanning going on")
debug_print(line[:-1])
for c in range (0, len(line)-1):
if line[c] == '(':
count += 1
debug_print("found opening brace, count = %d" % count)
elif line[c] == ')':
count -= 1
debug_print("found closing brace, count = %d" % count)
if count == 0:
str += line[:c+1]
keep_scanning = False
func(str)
break
if count != 0:
debug_print("keep scanning on next line, count = %d" % count)
str += line[:-1]
debug_print(line[:-1])
if __name__ == "__main__":
for i in range (1, len(sys.argv)):
print "opening file %s" % sys.argv[i]
file = open(sys.argv[i])
process_logprintf(file, examine_format)
print used_fmt_codes
# vim: et ts=4 sw=4
the result is:
Set(['%5ld', '%%', '%d', '%ld', '%2d', '%.2f', '%3d', '%c', '%s', '%*s'])
so, all the conversions we need are:
- integer with long and field size
- % charachter escape
- charachter
- string
- float with decimal field size
given this consideration, what i was planning to do is to borrow some code
from the vsnprintf implementation in dietlibc and adapt it for our needs.
what do you think about it?
--
Aequam memento rebus in arduis servare mentem...
Mauro Tortonesi
University of Ferrara - Dept. of Eng. http://www.ing.unife.it
Institute of Human & Machine Cognition http://www.ihmc.us
Deep Space 6 - IPv6 for Linux http://www.deepspace6.net
Ferrara Linux User Group http://www.ferrara.linux.it
