apt-pkg/tagfile.h

   1 // -*- mode: cpp; mode: fold -*-
   2 // Description                                                          /*{{{*/
   3 // $Id: tagfile.h,v 1.11 1998/11/28 03:54:31 jgg Exp $
   4 /* ######################################################################
   5
   6    Fast scanner for RFC-822 type header information
   7
   8    This parser handles Debian package files (and others). Their form is
   9    RFC-822 type header fields in groups seperated by a blank line.
  10
  11    The parser reads the file and provides methods to step linearly
  12    over it or to jump to a pre-recorded start point and read that record.
  13
  14    A second class is used to perform pre-parsing of the record. It works
  15    by indexing the start of each header field and providing lookup
  16    functions for header fields.
  17
  18    ##################################################################### */
  19                                                                         /*}}}*/
  20 // Header section: pkglib
  21 #ifndef PKGLIB_TAGFILE_H
  22 #define PKGLIB_TAGFILE_H
  23
  24 #ifdef __GNUG__
  25 #pragma interface "apt-pkg/tagfile.h"
  26 #endif
  27
  28 #include <apt-pkg/fileutl.h>
  29
  30 class pkgTagSection
  31 {
  32    const char *Section;
  33    const char *Stop;
  34
  35    // We have a limit of 256 tags per section.
  36    unsigned short Indexes[256];
  37    unsigned int TagCount;
  38
  39    public:
  40
  41    inline bool operator ==(const pkgTagSection &rhs) {return Section == rhs.Section;};
  42    inline bool operator !=(const pkgTagSection &rhs) {return Section != rhs.Section;};
  43
  44    bool Find(const char *Tag,const char *&Start, const char *&End);
  45    string FindS(const char *Tag);
  46    unsigned int FindI(const char *Tag);
  47    bool Scan(const char *Start,unsigned long MaxLength);
  48    inline unsigned long size() {return Stop - Section;};
  49
  50    inline unsigned int Count() {return TagCount;};
  51    inline void Get(const char *&Start,const char *&Stop,unsigned int I)
  52                    {Start = Section + Indexes[I]; Stop = Section + Indexes[I+1];}
  53
  54    inline void GetSection(const char *&Start,const char *&Stop)
  55    {
  56       Start = Section;
  57       Stop = this->Stop;
  58    };
  59
  60    pkgTagSection() : Section(0), Stop(0) {};
  61 };
  62
  63 class pkgTagFile
  64 {
  65    FileFd &Fd;
  66    char *Buffer;
  67    char *Start;
  68    char *End;
  69    unsigned long Left;
  70    unsigned long iOffset;
  71    unsigned long Size;
  72
  73    bool Fill();
  74
  75    public:
  76
  77    bool Step(pkgTagSection &Section);
  78    inline unsigned long Offset() {return iOffset;};
  79    bool Jump(pkgTagSection &Tag,unsigned long Offset);
  80
  81    pkgTagFile(FileFd &F,unsigned long Size = 32*1024);
  82 };
  83
  84 #endif