// -*- 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 <stdio.h> #include <string> class FileFd; 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; // dpointer placeholder (for later in case we need it) void *d; /* 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; std::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 static const FindFlag(unsigned long &Flags, unsigned long Flag, const char* Start, const char* Stop); 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), TagCount(0), Stop(0) {}; virtual ~pkgTagSection() {}; }; class pkgTagFilePrivate; class pkgTagFile { pkgTagFilePrivate *d; bool Fill(); bool Resize(); public: bool Step(pkgTagSection &Section); unsigned long Offset(); bool Jump(pkgTagSection &Tag,unsigned long long Offset); pkgTagFile(FileFd *F,unsigned long long Size = 32*1024); virtual ~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