QGIS » QGIS Application

'''

Created on Dec 11, 2015

@author: dewey dunnington <[email protected]>

'''

from PyQt4.QtCore import QTextStream, QString

#subclass QTextSream

class MacAwareQTextStream(QTextStream):

    def __init__(self, qstring):

        QTextStream.__init__(self, qstring)

        self.newline = None

    def readLineWithNewline(self, newline, bufferlen=128, prefix=QString("")):

        start = self.pos()

        buf = self.read(bufferlen)

        if buf.contains(newline):

            pos = buf.indexOf(newline)

            line = buf.left(pos)

            if not self.seek(start+pos+newline.length()):

                self.seek(line.length())

            return line.prepend(prefix)

        elif buf.length() < bufferlen:

            #is last line

            return buf.prepend(prefix)

        else:

            #try bigger buffer

            return self.readLineWithNewline(newline, bufferlen*2, buf.prepend(prefix))

    def findNewline(self, bufferlen):

        buf = self.read(bufferlen)

        if buf.contains("\r\n"):

            return QString("\r\n")

        elif buf.contains("\n"):

            return QString("\n")

        elif buf.contains("\r"):

            buf2 = self.read(1)

            if buf2 == "\n":

                return QString("\r\n")

            else:

                return QString("\r")

        elif self.atEnd(): #no new line in file

            return QString("\n")

        else:

            return self.findNewline(bufferlen*2)

    def readLine(self):

        bufferlen = 1024

        if self.newline is None:

            #need to determine newline chars

            self.newline = self.findNewline(bufferlen)

            self.seek(0)

        return self.readLineWithNewline(self.newline, bufferlen)

#generate test strings

maclines = QString("line1\rline2\rline3")

windowslines = QString("line1\r\nline2\r\nline3")

unixlines = QString("line1\nline2\nline3")

#test read line with newline

print "Windows lines"

qts = MacAwareQTextStream(windowslines)

while not qts.atEnd():

    print qts.readLineWithNewline(QString("\r\n"))

print "end"

qts.seek(0)

while not qts.atEnd():

    print qts.readLine()

print "end\n"

print "mac lines"

qts = MacAwareQTextStream(maclines)

while not qts.atEnd():

    print qts.readLineWithNewline(QString("\r"))

print "end"

qts.seek(0)

while not qts.atEnd():

    print qts.readLine()

print "end\n"

print "unix lines"

qts = MacAwareQTextStream(unixlines)

while not qts.atEnd():

    print qts.readLineWithNewline(QString("\n"))

print "end"

qts.seek(0)

while not qts.atEnd():

    print qts.readLine()

print "end\n"