You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 
 

155 lines
4.2 KiB

// -*- mode: cpp; mode: fold -*-
// Description /*{{{*/
// $Id: tagfile.cc,v 1.7 1998/07/12 23:58:39 jgg Exp $
/* ######################################################################
Fast scanner for RFC-822 type header information
This uses a rotating 64K buffer to load the package information into.
The scanner runs over it and isolates and indexes a single section.
##################################################################### */
/*}}}*/
// Include Files /*{{{*/
#ifdef __GNUG__
#pragma implementation "apt-pkg/tagfile.h"
#endif
#include <apt-pkg/tagfile.h>
#include <apt-pkg/error.h>
#include <apt-pkg/init.h>
#include <string>
#include <stdio.h>
/*}}}*/
// TagFile::pkgTagFile - Constructor /*{{{*/
// ---------------------------------------------------------------------
/* */
pkgTagFile::pkgTagFile(File &Fd) : Fd(Fd)
{
Buffer = new char[64*1024];
Start = End = Buffer + 64*1024;
Left = Fd.Size();
iOffset = 0;
Fill();
}
/*}}}*/
// TagFile::Step - Advance to the next section /*{{{*/
// ---------------------------------------------------------------------
/* If the Section Scanner fails we refill the buffer and try again. */
bool pkgTagFile::Step(pkgTagSection &Tag)
{
if (Tag.Scan(Start,End - Start) == false)
{
if (Fill() == false)
return false;
if (Tag.Scan(Start,End - Start) == false)
return _error->Error("Unable to parse package file");
}
Start += Tag.size();
iOffset += Tag.size();
return true;
}
/*}}}*/
// TagFile::Fill - Top up the buffer /*{{{*/
// ---------------------------------------------------------------------
/* This takes the bit at the end of the buffer and puts it at the start
then fills the rest from the file */
bool pkgTagFile::Fill()
{
unsigned long Size = End - Start;
if (Left == 0)
{
if (Size <= 1)
return false;
return true;
}
memmove(Buffer,Start,Size);
Start = Buffer;
// See if only a bit of the file is left or if
if (Left < End - Buffer - Size)
{
if (Fd.Read(Buffer + Size,Left) == false)
return false;
End = Buffer + Size + Left;
Left = 0;
}
else
{
if (Fd.Read(Buffer + Size, End - Buffer - Size) == false)
return false;
Left -= End - Buffer - Size;
}
return true;
}
/*}}}*/
// TagSection::Scan - Scan for the end of the header information /*{{{*/
// ---------------------------------------------------------------------
/* This looks for the first double new line in the data stream. It also
indexes the tags in the section. */
bool pkgTagSection::Scan(const char *Start,unsigned long MaxLength)
{
const char *End = Start + MaxLength;
Stop = Section = Start;
TagCount = 0;
Indexes[TagCount++] = Stop - Section;
Stop++;
for (; Stop < End; Stop++)
{
if (Stop[-1] != '\n')
continue;
if (Stop[0] == '\n')
{
// Extra one at the end to simplify find
Indexes[TagCount] = Stop - Section;
for (; Stop[0] == '\n' && Stop < End; Stop++);
return true;
break;
}
if (isspace(Stop[0]) == 0)
Indexes[TagCount++] = Stop - Section;
// Just in case.
if (TagCount > sizeof(Indexes)/sizeof(Indexes[0]))
TagCount = sizeof(Indexes)/sizeof(Indexes[0]);
}
return false;
}
/*}}}*/
// TagSection::Find - Locate a tag /*{{{*/
// ---------------------------------------------------------------------
/* This searches the section for a tag that matches the given string. */
bool pkgTagSection::Find(const char *Tag,const char *&Start,
const char *&End)
{
unsigned int Length = strlen(Tag);
for (unsigned int I = 0; I != TagCount; I++)
{
if (strncasecmp(Tag,Section + Indexes[I],Length) != 0)
continue;
// Make sure the colon is in the right place
const char *C = Section + Length + Indexes[I];
for (; isspace(*C) != 0; C++);
if (*C != ':')
continue;
// Strip off the gunk from the start end
Start = C;
End = Section + Indexes[I+1];
for (; (isspace(*Start) != 0 || *Start == ':') && Start < End; Start++);
for (; isspace(End[-1]) != 0 && End > Start; End--);
return true;
}
Start = End = 0;
return false;
}
/*}}}*/