Split a quoted string by delimiter using python

splitquoted.py

from __future__ import unicode_literals
from __future__ import print_function

def SplitQuoted(inStr, delim=','):

	if '"' in delim or '\\' in delim:
		raise ValueError("Delimiter not supported")

	l = len(inStr)

	#Find escaped characters (so they can be ignored)
	c = 0
	escapedPos = set()
	while c < l:
		p = inStr.find("\\", c)
		if p != -1:
			escapedPos.add(p+1)
			c = p+2
		else:
			c = l

	#Identify quoted sections
	c = 0
	inquoted = False
	startPos = None
	quotedRanges = []
	while c < l:
		p = inStr.find('"', c)
		if p != -1:
			if p not in escapedPos:
				inquoted = not inquoted
				
				if inquoted:
					startPos = p
				else:
					quotedRanges.append((startPos, p))
			c = p+1
		else:
			c = l
	if inquoted: #Quote not closed
		quotedRanges.append((startPos, l))

	#Find delimiter markers
	c = 0
	rc = 0
	out = []
	prevP = 0
	while c < l:
		p = inStr.find(delim, c)

		inquoted = False		
		if len(quotedRanges) > 0:
			while p > quotedRanges[rc][1] and rc < len(quotedRanges)-1:
				rc += 1
			inquoted = p > quotedRanges[rc][0] and p < quotedRanges[rc][1]
		escaped = p in escapedPos

		if not inquoted and not escaped and p!=-1:
			out.append(inStr[prevP:p])
			prevP = p+len(delim)

		if p != -1:
			c = p+len(delim)
		else:
			c = l
	out.append(inStr[prevP:l])
	
	return out

if __name__=="__main__":

	t = 'a = foo, b = bar, c = "foo, bar", d = false, e = "false", f = "foo\\", bar", "xxx'
	r = SplitQuoted(t)
	chk = r == ['a = foo', ' b = bar', ' c = "foo, bar"', ' d = false', ' e = "false"', ' f = "foo\\", bar"', ' "xxx']
	print (chk)

	t = 'a = foo, b = bar, c = "foo, bar", d = false, e = "false", f = "foo\\", bar"'
	r = SplitQuoted(t)
	chk = r == ['a = foo', ' b = bar', ' c = "foo, bar"', ' d = false', ' e = "false"', ' f = "foo\\", bar"']
	print (chk)

	t = ''
	r = SplitQuoted(t)
	chk = r == ['']
	print (chk)

	t = ','
	r = SplitQuoted(t)
	chk = r == ['', '']
	print (chk)

	t = '",",""'
	r = SplitQuoted(t)
	chk = r == ['","', '""']
	print (chk)

	t = 'a=foo; b=bar; c="foo; bar"; d=false; e="false"; f="foo\\"; bar"'
	r = SplitQuoted(t, ';')
	chk = r == ['a=foo', ' b=bar', ' c="foo; bar"', ' d=false', ' e="false"', ' f="foo\\"; bar"']
	print (chk)

	t = "\\,"
	r = SplitQuoted(t)
	chk = r == ["\\,"]
	print (chk)

	t = ',"'
	r = SplitQuoted(t)
	chk = r == ['', '"']
	print (chk)

	t = '",'
	r = SplitQuoted(t)
	chk = r == ['",']
	print (chk)

	t = 'a'
	r = SplitQuoted(t)
	chk = r == ['a']
	print (chk)

	t = 'gr<>rg'
	r = SplitQuoted(t, '<>')
	chk = r == ['gr', 'rg']
	print (chk)

	t = 'gr<>rg"<>"foo<>ed>ple<fwr'
	r = SplitQuoted(t, '<>')
	chk = r == ['gr', 'rg"<>"foo', 'ed>ple<fwr']
	print (chk)