source: proto/matchparens/pdfparenmatch.py @ 4373

Last change on this file since 4373 was 3064, checked in by cameron, 6 years ago

Simplify parenthesis matching; fix paren match with comments.

File size: 2.2 KB
Line 
1#
2# Recursive Parenthesis Matching
3#
4#
5# Robert D. Cameron
6# October 14, 2012
7#
8import sys
9import pablo
10
11class Basis_bits():     
12        bit_0 = 0
13        bit_1 = 0
14        bit_2 = 0
15        bit_3 = 0
16        bit_4 = 0
17        bit_5 = 0
18        bit_6 = 0
19        bit_7 = 0
20
21class Lex ():
22        LParen = 0
23        RParen = 0
24       
25class Matches() :
26        closed = 0
27        instring = 0
28        error = 0
29
30
31def Classify_bytes(basis_bits, lex): 
32        temp1 = (basis_bits.bit_0 | basis_bits.bit_1)
33        temp2 = (basis_bits.bit_2 &~ basis_bits.bit_3)
34        temp3 = (temp2 &~ temp1)
35        temp4 = (basis_bits.bit_4 &~ basis_bits.bit_5)
36        temp5 = (basis_bits.bit_6 | basis_bits.bit_7)
37        temp6 = (temp4 &~ temp5)
38        lex.LParen = (temp3 & temp6)
39        temp7 = (basis_bits.bit_7 &~ basis_bits.bit_6)
40        temp8 = (temp4 & temp7)
41        lex.RParen = (temp3 & temp8)
42       
43def Match_Parens(lex, matches):
44        parens = lex.LParen | lex.RParen
45        pscan = pablo.AdvanceThenScanTo(lex.LParen, parens)
46        matches.closed = pscan & lex.RParen
47        matches.instring = pablo.ExclusiveSpan(lex.LParen, pscan) 
48        matches.error = pablo.atEOF(pscan)
49        # Not matched, still pending.
50        pending_LParen = pscan & lex.LParen
51        RParen_unmatched = lex.RParen &~ matches.closed
52        inPlay = pending_LParen | RParen_unmatched
53        while pending_LParen:
54                pscan = pablo.AdvanceThenScanTo(pending_LParen, inPlay)
55                matches.instring |= pablo.SpanUpTo(pending_LParen, pscan)
56                matches.closed |= pscan & lex.RParen
57                matches.error |= pablo.atEOF(pscan)
58                pending_LParen = pscan & lex.LParen
59                RParen_unmatched = lex.RParen &~ matches.closed
60                inPlay = pending_LParen | RParen_unmatched
61        #
62        # Any closing paren that was not actually used to close
63        # an opener is in error.
64        matches.error |= lex.RParen &~ matches.closed
65
66
67basis_bits = Basis_bits()
68lex = Lex()
69matches = Matches()
70
71if __name__ == "__main__":
72        #print "Starting ..."
73        if len(sys.argv) > 1:
74                u8data = pablo.readfile(sys.argv[1]) 
75                pablo.EOF_mask = pablo.transpose_streams(u8data, basis_bits)
76                Classify_bytes(basis_bits, lex)
77                Match_Parens(lex, matches)
78                lgth = len(u8data)
79                print "data:" + " "*(16-5) + u8data
80                print "errors" + " "*(16-6) + pablo.bitstream2string(matches.error, lgth+1)
81                print "instring:" + " "*(16-9) + pablo.bitstream2string(matches.instring, lgth)
82               
83        else:
84                print("Usage: python parenmatch.py <file>")
85       
86
87
Note: See TracBrowser for help on using the repository browser.