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Commit	Line	Data
	1	// -- mode: cpp; mode: fold --
	2	// Description /{{{/
	3	// $Id: tagfile.h,v 1.20 2003/05/19 17:13:57 doogie 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 separated 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	#ifndef PKGLIB_TAGFILE_H
	21	#define PKGLIB_TAGFILE_H
	22
	23
	24	#include <apt-pkg/fileutl.h>
	25	#include <stdio.h>
	26
	27	class pkgTagSection
	28	{
	29	const char *Section;
	30
	31	// We have a limit of 256 tags per section.
	32	unsigned int Indexes[256];
	33	unsigned int AlphaIndexes[0x100];
	34
	35	unsigned int TagCount;
	36
	37	/* This very simple hash function for the last 8 letters gives
	38	very good performance on the debian package files */
	39	inline static unsigned long AlphaHash(const char Text, const char End = 0)
	40	{
	41	unsigned long Res = 0;
	42	for (; Text != End && Text != ':' && Text != 0; Text++)
	43	Res = ((unsigned long)(*Text) & 0xDF) ^ (Res << 1);
	44	return Res & 0xFF;
	45	}
	46
	47
	48	protected:
	49	const char *Stop;
	50
	51	public:
	52
	53	inline bool operator ==(const pkgTagSection &rhs) {return Section == rhs.Section;};
	54	inline bool operator !=(const pkgTagSection &rhs) {return Section != rhs.Section;};
	55
	56	bool Find(const char Tag,const char &Start, const char *&End) const;
	57	bool Find(const char *Tag,unsigned &Pos) const;
	58	string FindS(const char *Tag) const;
	59	signed int FindI(const char *Tag,signed long Default = 0) const ;
	60	bool FindFlag(const char *Tag,unsigned long &Flags,
	61	unsigned long Flag) const;
	62	bool Scan(const char *Start,unsigned long MaxLength);
	63	inline unsigned long size() const {return Stop - Section;};
	64	void Trim();
	65	virtual void TrimRecord(bool BeforeRecord, const char* &End);
	66
	67	inline unsigned int Count() const {return TagCount;};
	68	inline bool Exists(const char* const Tag) {return AlphaIndexes[AlphaHash(Tag)] != 0;}
	69
	70	inline void Get(const char &Start,const char &Stop,unsigned int I) const
	71	{Start = Section + Indexes[I]; Stop = Section + Indexes[I+1];}
	72
	73	inline void GetSection(const char &Start,const char &Stop) const
	74	{
	75	Start = Section;
	76	Stop = this->Stop;
	77	};
	78
	79	pkgTagSection() : Section(0), Stop(0) {};
	80	};
	81
	82	class pkgTagFile
	83	{
	84	FileFd &Fd;
	85	char *Buffer;
	86	char *Start;
	87	char *End;
	88	bool Done;
	89	unsigned long iOffset;
	90	unsigned long Size;
	91
	92	bool Fill();
	93	bool Resize();
	94
	95	public:
	96
	97	bool Step(pkgTagSection &Section);
	98	inline unsigned long Offset() {return iOffset;};
	99	bool Jump(pkgTagSection &Tag,unsigned long Offset);
	100
	101	pkgTagFile(FileFd F,unsigned long Size = 321024);
	102	~pkgTagFile();
	103	};
	104
	105	/* This is the list of things to rewrite. The rewriter
	106	goes through and changes or adds each of these headers
	107	to suit. A zero forces the header to be erased, an empty string
	108	causes the old value to be used. (rewrite rule ignored) */
	109	struct TFRewriteData
	110	{
	111	const char *Tag;
	112	const char *Rewrite;
	113	const char *NewTag;
	114	};
	115	extern const char **TFRewritePackageOrder;
	116	extern const char **TFRewriteSourceOrder;
	117
	118	bool TFRewrite(FILE Output,pkgTagSection const &Tags,const char Order[],
	119	TFRewriteData *Rewrite);
	120
	121	#endif