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/**************************************************************************
* *
* Regina - A Normal Surface Theory Calculator *
* Computational Engine *
* *
* Copyright (c) 1999-2009, Ben Burton *
* For further details contact Ben Burton (bab@debian.org). *
* *
* This program is free software; you can redistribute it and/or *
* modify it under the terms of the GNU General Public License as *
* published by the Free Software Foundation; either version 2 of the *
* License, or (at your option) any later version. *
* *
* This program is distributed in the hope that it will be useful, but *
* WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU *
* General Public License for more details. *
* *
* You should have received a copy of the GNU General Public *
* License along with this program; if not, write to the Free *
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, *
* MA 02110-1301, USA. *
* *
**************************************************************************/
/* end stub */
#include <cstdio>
#include <cstring>
#include <sstream>
#include "file/nfile.h"
#include "file/nfileinfo.h"
#include "utilities/zstream.h"
namespace regina {
#define STARTS_FALSE 0
#define STARTS_TRUE 1
#define STARTS_COULD_NOT_OPEN 2
const int NFileInfo::TYPE_BINARY = 1;
const int NFileInfo::TYPE_XML = 2;
namespace {
/**
* Does the given file begin with the given set of characters?
*
* Returns STARTS_FALSE, STARTS_TRUE or STARTS_COULD_NOT_OPEN.
*/
int fileStartsWith(const char* file, const char* prefix) {
FILE* f = fopen(file, "rb");
if (! f)
return STARTS_COULD_NOT_OPEN;
int ans = STARTS_FALSE;
unsigned len = strlen(prefix);
char* buf = new char[len];
if (fread(buf, sizeof(char), len, f) == len)
if (strncmp(buf, prefix, len) == 0)
ans = STARTS_TRUE;
delete[] buf;
fclose(f);
return ans;
}
}
NFileInfo* NFileInfo::identify(const std::string& idPathname) {
// Check for an old-style binary file.
int starts = fileStartsWith(idPathname.c_str(), "Normal");
if (starts == STARTS_FALSE)
starts = fileStartsWith(idPathname.c_str(), "Regina");
if (starts == STARTS_COULD_NOT_OPEN)
return 0;
else if (starts == STARTS_TRUE) {
NFileInfo* ans = new NFileInfo();
ans->pathname = idPathname;
ans->type = NFileInfo::TYPE_BINARY;
ans->typeDescription = "Binary Regina data file (obsolete format)";
ans->compressed = false;
regina::NFile file;
if (! file.open(idPathname.c_str(),
regina::NRandomAccessResource::READ)) {
ans->invalid = true;
} else {
std::ostringstream out;
out << file.getMajorVersion() << '.' << file.getMinorVersion();
ans->engine = out.str();
ans->invalid = false;
}
file.close();
return ans;
}
// Check for an XML file.
NFileInfo* ans = 0;
if (fileStartsWith(idPathname.c_str(), "<?xml") == STARTS_TRUE) {
ans = new NFileInfo();
ans->compressed = false;
} else {
regina::DecompressionStream in(idPathname.c_str());
if (in) {
std::string s;
in >> s;
if ((! in.eof()) && (s == "<?xml")) {
ans = new NFileInfo();
ans->compressed = true;
}
}
}
if (ans) {
ans->pathname = idPathname;
ans->type = NFileInfo::TYPE_XML;
ans->typeDescription = "XML Regina data file";
// Make it an invalid file until we know otherwise.
ans->invalid = true;
regina::DecompressionStream in(idPathname.c_str());
if (! in)
return ans;
std::string s;
// Start by slurping in the opening "<?xml".
if (in.eof())
return ans;
in >> s;
if (s != "<?xml")
return ans;
// Hunt for the matching "...?>".
// Try skipping through several strings in case there are extra
// arguments in the XML prologue (such as encoding or standalone
// declarations).
int i;
for (i = 0; ; i++) {
if (in.eof())
return ans;
in >> s;
if (s.length() >= 2 &&
s[s.length() - 2] == '?' &&
s[s.length() - 1] == '>')
break;
// If we can't find it after enough tries, just give up.
// Ten tries should be more than sufficient, since the current XML
// spec supports only version, encoding and standalone arguments
// at present.
if (i >= 10)
return ans;
}
// The next thing we see should be the <reginadata ...> element.
if (in.eof())
return ans;
in >> s;
if (s != "<reginadata")
return ans;
// Next should be the engine version.
if (in.eof())
return ans;
in >> s;
if (s.length() < 8)
return ans;
if (s.substr(0, 8).compare("engine=\"") != 0)
return ans;
// We've found the engine attribute; extract its value.
std::string::size_type pos = s.find('"', 8);
if (pos == std::string::npos)
return ans;
ans->engine = s.substr(8, pos - 8);
// That's as far as we need to go; we've extracted everything we want.
ans->invalid = false;
return ans;
}
// Unknown format.
return 0;
}
void NFileInfo::writeTextShort(std::ostream& out) const {
out << "File information: " << typeDescription;
if (compressed)
out << " (compressed)";
}
void NFileInfo::writeTextLong(std::ostream& out) const {
out << "Regina data\n" << typeDescription;
if (compressed)
out << " (compressed)";
out << '\n';
if (invalid)
out << "File contains invalid metadata.\n";
else
out << "Engine " << engine << '\n';
}
} // namespace regina
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