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// -*- mode: cpp; mode: fold -*-
// Description /*{{{*/
// $Id: tagfile.h,v 1.20 2003/05/19 17:13:57 doogie Exp $
/* ######################################################################
Fast scanner for RFC-822 type header information
This parser handles Debian package files (and others). Their form is
RFC-822 type header fields in groups separated by a blank line.
The parser reads the file and provides methods to step linearly
over it or to jump to a pre-recorded start point and read that record.
A second class is used to perform pre-parsing of the record. It works
by indexing the start of each header field and providing lookup
functions for header fields.
##################################################################### */
/*}}}*/
#ifndef PKGLIB_TAGFILE_H
#define PKGLIB_TAGFILE_H
#include <apt-pkg/fileutl.h>
#include <stdio.h>
class pkgTagSection
{
const char *Section;
// We have a limit of 256 tags per section.
unsigned int Indexes[256];
unsigned int AlphaIndexes[0x100];
unsigned int TagCount;
/* This very simple hash function for the last 8 letters gives
very good performance on the debian package files */
inline static unsigned long AlphaHash(const char *Text, const char *End = 0)
{
unsigned long Res = 0;
for (; Text != End && *Text != ':' && *Text != 0; Text++)
Res = ((unsigned long)(*Text) & 0xDF) ^ (Res << 1);
return Res & 0xFF;
}
protected:
const char *Stop;
public:
inline bool operator ==(const pkgTagSection &rhs) {return Section == rhs.Section;};
inline bool operator !=(const pkgTagSection &rhs) {return Section != rhs.Section;};
bool Find(const char *Tag,const char *&Start, const char *&End) const;
bool Find(const char *Tag,unsigned &Pos) const;
string FindS(const char *Tag) const;
signed int FindI(const char *Tag,signed long Default = 0) const ;
unsigned long long FindULL(const char *Tag, unsigned long long const &Default = 0) const;
bool FindFlag(const char *Tag,unsigned long &Flags,
unsigned long Flag) const;
bool Scan(const char *Start,unsigned long MaxLength);
inline unsigned long size() const {return Stop - Section;};
void Trim();
virtual void TrimRecord(bool BeforeRecord, const char* &End);
inline unsigned int Count() const {return TagCount;};
inline bool Exists(const char* const Tag) {return AlphaIndexes[AlphaHash(Tag)] != 0;}
inline void Get(const char *&Start,const char *&Stop,unsigned int I) const
{Start = Section + Indexes[I]; Stop = Section + Indexes[I+1];}
inline void GetSection(const char *&Start,const char *&Stop) const
{
Start = Section;
Stop = this->Stop;
};
pkgTagSection() : Section(0), Stop(0) {};
};
class pkgTagFile
{
FileFd &Fd;
char *Buffer;
char *Start;
char *End;
bool Done;
unsigned long iOffset;
unsigned long Size;
bool Fill();
bool Resize();
public:
bool Step(pkgTagSection &Section);
inline unsigned long Offset() {return iOffset;};
bool Jump(pkgTagSection &Tag,unsigned long Offset);
pkgTagFile(FileFd *F,unsigned long Size = 32*1024);
~pkgTagFile();
};
/* This is the list of things to rewrite. The rewriter
goes through and changes or adds each of these headers
to suit. A zero forces the header to be erased, an empty string
causes the old value to be used. (rewrite rule ignored) */
struct TFRewriteData
{
const char *Tag;
const char *Rewrite;
const char *NewTag;
};
extern const char **TFRewritePackageOrder;
extern const char **TFRewriteSourceOrder;
bool TFRewrite(FILE *Output,pkgTagSection const &Tags,const char *Order[],
TFRewriteData *Rewrite);
#endif