add a 'Ragel' based DNS TXT parser & hook it up. With this change we can finally...

[thirdparty/pdns.git] / pdns / dnslabeltext.rl

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <unistd.h>
#include <string>
#include "namespaces.hh"

%%{
        machine dnstext;
        write data;
}%%

namespace {
void appendSplit(vector<string>& ret, string& segment, char c)
{
  if(segment.size()>254) {
    ret.push_back(segment);
    segment.clear();
  }
  segment.append(1, c);
}
}

vector<string> segmentDNSText(const string& input )
{
        const char *p = input.c_str(), *pe = input.c_str() + input.length();
        const char* eof = pe;
        int cs;
        char val = 0;

        string segment;
        vector<string> ret;

        %%{
                action segmentEnd { 
                        ret.push_back(segment);
                        segment.clear();
                }
                action segmentBegin { 
                        segment.clear();
                }

                action reportEscaped {
                  char c = *fpc;
                  appendSplit(ret, segment, c);
                }
                action reportEscapedNumber {
                  char c = *fpc;
                  val *= 10;
                  val += c-'0';
                  
                }
                action doneEscapedNumber {
                  appendSplit(ret, segment, val);
                  val=0;
                }
                
                action reportPlain {
                  appendSplit(ret, segment, *(fpc));
                }

                escaped = '\\' ((["\\]@reportEscaped) | ([0-9]{3}$reportEscapedNumber%doneEscapedNumber));
                plain = (print-'\\'-'"') $ reportPlain;
                labelElement = escaped | plain;
                

                main := (('"' labelElement* '"' space?) >segmentBegin %segmentEnd)+;

                # Initialize and execute.
                write init;
                write exec;
        }%%

        if ( cs < dnstext_first_final ) {
                throw runtime_error("Unable to parse DNS TXT '"+input+"'");
        }

        return ret;
};

#if 0
int main()
{
	//char blah[]="\"blah\" \"bleh\" \"bloeh\\\"bleh\" \"\\97enzo\"";
  char blah[]="\"v=spf1 ip4:67.106.74.128/25 ip4:63.138.42.224/28 ip4:65.204.46.224/27 \\013\\010ip4:66.104.217.176/28 \\013\\010ip4:209.48.147.0/27 ~all\"";
  //char blah[]="\"abc \\097\\098 def\"";
  printf("Input: '%s'\n", blah);
	vector<string> res=dnstext(blah);
  cerr<<res.size()<<" segments"<<endl;
  cerr<<res[0]<<endl;
}
#endif