server/include/dynbuf.h

#ifndef DYNBUF_H__
#define DYNBUF_H__

#include <cstring>
#include <cassert>

#include "shstr.h"

// this is a "buffer" that can grow fast
// and is still somewhat space-efficient.
// unlike obstacks or other data structures,
// it never moves data around. basically,
// this is a fast strstream without the overhead.

struct dynbuf
{
protected:
  struct chunk
  {
    chunk *next;
    int size;
    char data[0];
  };

  char *ptr;
  int room;
  int ext;
  int _size;

  chunk *first, *last;

  void _reserve (int size);
  void clear ();
  void finish ();

public:
  
  dynbuf (int initial = 4096, int extend = 16384);
  ~dynbuf ();

  int size () { return _size + (ptr - last->data); }

  void linearise (void *data);
  char *linearise ();

  char *force (int size)
  {
    if (room < size)
      _reserve (size);

    return ptr;
  }

  char *alloc (int size)
  {
    char *res = force (size);

    room -= size;
    ptr += size;

    return res;
  }

  void fadd (char c) { --room; *ptr++ = c; }
  void fadd (unsigned char c) { fadd (char (c)); }

  void add (const void *p, int len)
  {
    memcpy (alloc (len), p, len);
  }

  void add (char c)
  {
    alloc (1)[0] = c;
  }

  void add (const char *s)
  {
     add (s, strlen (s));
  }

  void add (const shstr &s)
  {
    add (s.s, s.length ());
  }

  //TODO
  //void add_destructive (dynbuf &buf);

  dynbuf &operator << (char c) { add (c); return *this; }
  dynbuf &operator << (unsigned char c) { return *this << char (c); }
  dynbuf &operator << (const char *s) { add (s); return *this; }
  dynbuf &operator << (const std::string &s) { add (s.data(), s.size ()); return *this; }

  operator std::string ();
};

struct dynbuf_text : dynbuf
{
  dynbuf_text (int initial = 4096, int extend = 16384)
  : dynbuf (initial, extend)
  { }

  using dynbuf::add;

  static const int max_sint32_size = 11;
  static const int max_sint64_size = 20;

  void add (sint32 i);
  void add (sint64 i);

  void printf (const char *format, ...);
};

#endif
Revision:	1.4
Committed:	Mon Apr 23 18:09:57 2007 UTC (17 years, 2 months ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.3:	+28 -6 lines
Log Message:	- add format utility function. - split dynbuf into dynbuf and dynbuf_text. - use dynbuf_text for examine strings instead of outputting each line seperately. tried to use stringstreams but they add insane overheads (as does std::string, but less so).
#	User	Rev	Content
1	root	1.1	#ifndef DYNBUF_H__
2			#define DYNBUF_H__
3
4			#include <cstring>
5			#include <cassert>
6
7	root	1.4	#include "shstr.h"
8
9	root	1.1	// this is a "buffer" that can grow fast
10			// and is still somewhat space-efficient.
11			// unlike obstacks or other data structures,
12			// it never moves data around. basically,
13			// this is a fast strstream without the overhead.
14
15	root	1.4	struct dynbuf
16	root	1.1	{
17	root	1.4	protected:
18	root	1.1	struct chunk
19			{
20			chunk *next;
21			int size;
22			char data[0];
23			};
24
25			char *ptr;
26			int room;
27			int ext;
28			int _size;
29
30			chunk first, last;
31
32			void _reserve (int size);
33			void clear ();
34			void finish ();
35
36			public:
37
38	root	1.2	dynbuf (int initial = 4096, int extend = 16384);
39	root	1.1	~dynbuf ();
40
41			int size () { return _size + (ptr - last->data); }
42
43			void linearise (void *data);
44			char *linearise ();
45
46			char *force (int size)
47			{
48			if (room < size)
49			_reserve (size);
50
51			return ptr;
52			}
53
54			char *alloc (int size)
55			{
56			char *res = force (size);
57
58			room -= size;
59			ptr += size;
60
61			return res;
62			}
63
64			void fadd (char c) { --room; *ptr++ = c; }
65	root	1.2	void fadd (unsigned char c) { fadd (char (c)); }
66	root	1.1
67			void add (const void *p, int len)
68			{
69			memcpy (alloc (len), p, len);
70			}
71
72			void add (char c)
73			{
74	root	1.3	alloc (1)[0] = c;
75	root	1.1	}
76
77			void add (const char *s)
78			{
79			add (s, strlen (s));
80			}
81
82	root	1.4	void add (const shstr &s)
83			{
84			add (s.s, s.length ());
85			}
86	root	1.1
87			//TODO
88			//void add_destructive (dynbuf &buf);
89
90			dynbuf &operator << (char c) { add (c); return *this; }
91			dynbuf &operator << (unsigned char c) { return *this << char (c); }
92			dynbuf &operator << (const char s) { add (s); return this; }
93	root	1.4	dynbuf &operator << (const std::string &s) { add (s.data(), s.size ()); return *this; }
94
95			operator std::string ();
96			};
97
98			struct dynbuf_text : dynbuf
99			{
100			dynbuf_text (int initial = 4096, int extend = 16384)
101			: dynbuf (initial, extend)
102			{ }
103
104			using dynbuf::add;
105
106			static const int max_sint32_size = 11;
107			static const int max_sint64_size = 20;
108
109			void add (sint32 i);
110			void add (sint64 i);
111
112			void printf (const char *format, ...);
113	root	1.1	};
114
115			#endif