# grep.py - logic for history walk and grep

#

# Copyright 2005-2007 Matt Mackall <mpm@selenic.com>

#

# This software may be used and distributed according to the terms of the

# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

import difflib

def matchlines(body, regexp):

    begin = 0

    linenum = 0

    while begin < len(body):

        match = regexp.search(body, begin)

        if not match:

            break

        mstart, mend = match.span()

        linenum += body.count(b'\n', begin, mstart) + 1

        lstart = body.rfind(b'\n', begin, mstart) + 1 or begin

        begin = body.find(b'\n', mend) + 1 or len(body) + 1

        lend = begin - 1

        yield linenum, mstart - lstart, mend - lstart, body[lstart:lend]

class linestate(object):

    def __init__(self, line, linenum, colstart, colend):

        self.line = line

        self.linenum = linenum

        self.colstart = colstart

        self.colend = colend

    def __hash__(self):

        return hash(self.line)

    def __eq__(self, other):

        return self.line == other.line

    def findpos(self, regexp):

        """Iterate all (start, end) indices of matches"""

        yield self.colstart, self.colend

        p = self.colend

        while p < len(self.line):

            m = regexp.search(self.line, p)

            if not m:

                break

            if m.end() == p:

                p += 1

            else:

                yield m.span()

                p = m.end()

def difflinestates(a, b):

    sm = difflib.SequenceMatcher(None, a, b)

    for tag, alo, ahi, blo, bhi in sm.get_opcodes():

        if tag == 'insert':

            for i in pycompat.xrange(blo, bhi):

                yield (b'+', b[i])

        elif tag == 'delete':

            for i in pycompat.xrange(alo, ahi):

                yield (b'-', a[i])

        elif tag == 'replace':

            for i in pycompat.xrange(alo, ahi):

                yield (b'-', a[i])

            for i in pycompat.xrange(blo, bhi):

                yield (b'+', b[i])