summaryrefslogtreecommitdiff
path: root/src/strpool.c
blob: 364f096f63de737604e20a7603d08e51731d2430 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
/*
 * Copyright (c) 2007, Novell Inc.
 *
 * This program is licensed under the BSD license, read LICENSE.BSD
 * for further information
 */

#include <string.h>
#include "util.h"
#include "strpool.h"

#define STRING_BLOCK      2047
#define STRINGSPACE_BLOCK 65535

void
stringpool_init(Stringpool *ss, const char *strs[])
{
  unsigned totalsize = 0;
  unsigned count;

  memset(ss, 0, sizeof(*ss));
  /* count number and total size of predefined strings */
  for (count = 0; strs[count]; count++)
    totalsize += strlen(strs[count]) + 1;

  /* alloc appropriate space */
  ss->stringspace = solv_extend_resize(0, totalsize, 1, STRINGSPACE_BLOCK);
  ss->strings = solv_extend_resize(0, count, sizeof(Offset), STRING_BLOCK);

  /* now copy predefined strings into allocated space */
  ss->sstrings = 0;
  for (count = 0; strs[count]; count++)
    {
      strcpy(ss->stringspace + ss->sstrings, strs[count]);
      ss->strings[count] = ss->sstrings;
      ss->sstrings += strlen(strs[count]) + 1;
    }
  ss->nstrings = count;
}

void
stringpool_free(Stringpool *ss)
{
  solv_free(ss->strings);
  solv_free(ss->stringspace);
  solv_free(ss->stringhashtbl);
}

void
stringpool_freehash(Stringpool *ss)
{
  ss->stringhashtbl = solv_free(ss->stringhashtbl);
  ss->stringhashmask = 0;
}

void
stringpool_init_empty(Stringpool *ss)
{
  const char *emptystrs[] = {
    "<NULL>",
    "",
    0,
  };
  stringpool_init(ss, emptystrs);
}

void
stringpool_clone(Stringpool *ss, Stringpool *from)
{
  memset(ss, 0, sizeof(*ss));
  ss->strings = solv_extend_resize(0, from->nstrings, sizeof(Offset), STRING_BLOCK);
  memcpy(ss->strings, from->strings, from->nstrings * sizeof(Offset));
  ss->stringspace = solv_extend_resize(0, from->sstrings, 1, STRINGSPACE_BLOCK);
  memcpy(ss->stringspace, from->stringspace, from->sstrings);
  ss->nstrings = from->nstrings;
  ss->sstrings = from->sstrings;
}

Id
stringpool_strn2id(Stringpool *ss, const char *str, unsigned int len, int create)
{
  Hashval h, hh, hashmask, oldhashmask;
  int i;
  Id id;
  Hashtable hashtbl;

  if (!str)
    return STRID_NULL;
  if (!len)
    return STRID_EMPTY;

  hashmask = oldhashmask = ss->stringhashmask;
  hashtbl = ss->stringhashtbl;

  /* expand hashtable if needed */
  if (ss->nstrings * 2 > hashmask)
    {
      solv_free(hashtbl);

      /* realloc hash table */
      ss->stringhashmask = hashmask = mkmask(ss->nstrings + STRING_BLOCK);
      ss->stringhashtbl = hashtbl = (Hashtable)solv_calloc(hashmask + 1, sizeof(Id));

      /* rehash all strings into new hashtable */
      for (i = 1; i < ss->nstrings; i++)
	{
	  h = strhash(ss->stringspace + ss->strings[i]) & hashmask;
	  hh = HASHCHAIN_START;
	  while (hashtbl[h] != 0)
	    h = HASHCHAIN_NEXT(h, hh, hashmask);
	  hashtbl[h] = i;
	}
    }

  /* compute hash and check for match */
  h = strnhash(str, len) & hashmask;
  hh = HASHCHAIN_START;
  while ((id = hashtbl[h]) != 0)
    {
      if(!memcmp(ss->stringspace + ss->strings[id], str, len)
         && ss->stringspace[ss->strings[id] + len] == 0)
	break;
      h = HASHCHAIN_NEXT(h, hh, hashmask);
    }
  if (id || !create)    /* exit here if string found */
    return id;

  /* this should be a test for a flag that tells us if the 
   * correct blocking is used, but adding a flag would break
   * the ABI. So we use the existance of the hash area as
   * indication instead */
  if (!oldhashmask)
    {
      ss->stringspace = solv_extend_resize(ss->stringspace, ss->sstrings + len + 1, 1, STRINGSPACE_BLOCK);
      ss->strings = solv_extend_resize(ss->strings, ss->nstrings + 1, sizeof(Offset), STRING_BLOCK);
    }

  /* generate next id and save in table */
  id = ss->nstrings++;
  hashtbl[h] = id;

  ss->strings = solv_extend(ss->strings, id, 1, sizeof(Offset), STRING_BLOCK);
  ss->strings[id] = ss->sstrings;	/* we will append to the end */

  /* append string to stringspace */
  ss->stringspace = solv_extend(ss->stringspace, ss->sstrings, len + 1, 1, STRINGSPACE_BLOCK);
  memcpy(ss->stringspace + ss->sstrings, str, len);
  ss->stringspace[ss->sstrings + len] = 0;
  ss->sstrings += len + 1;
  return id;
}

Id
stringpool_str2id(Stringpool *ss, const char *str, int create)
{
  if (!str)
    return STRID_NULL;
  if (!*str)
    return STRID_EMPTY;
  return stringpool_strn2id(ss, str, (unsigned int)strlen(str), create);
}

void
stringpool_shrink(Stringpool *ss)
{
  ss->stringspace = solv_extend_resize(ss->stringspace, ss->sstrings, 1, STRINGSPACE_BLOCK);
  ss->strings = solv_extend_resize(ss->strings, ss->nstrings, sizeof(Offset), STRING_BLOCK);
}