summaryrefslogtreecommitdiffstats
path: root/ext/misc/randomjson.c
blob: cacc4feb68f84e3a7f225091a37a6e90e9f23c16 (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
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
/*
** 2023-04-28
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
******************************************************************************
**
** This SQLite extension implements a the random_json(SEED) and
** random_json5(SEED) functions.  Given a numeric SEED value, these
** routines generate pseudo-random JSON or JSON5, respectively.  The
** same value is always generated for the same seed.
**
** These SQL functions are intended for testing.  They do not have any
** practical real-world use, that we know of.
**
** COMPILE:
**
**     gcc --shared -fPIC -o randomjson.so -I. ext/misc/randomjson.c
**
** USING FROM THE CLI:
**
**     .load ./randomjson
**     SELECT random_json(1);
**     SELECT random_json5(1);
*/
#ifdef SQLITE_STATIC_RANDOMJSON
#  include "sqlite3.h"
#else
#  include "sqlite3ext.h"
   SQLITE_EXTENSION_INIT1
#endif
#include <assert.h>
#include <string.h>
#include <stdlib.h>

/* Pseudo-random number generator */
typedef struct Prng {
  unsigned int x, y;
} Prng;

/* Reseed the PRNG */
static void prngSeed(Prng *p, unsigned int iSeed){
  p->x = iSeed | 1;
  p->y = iSeed;
}

/* Extract a random number */
static unsigned int prngInt(Prng *p){
  p->x = (p->x>>1) ^ ((1+~(p->x&1)) & 0xd0000001);
  p->y = p->y*1103515245 + 12345;
  return p->x ^ p->y;
}

static char *azJsonAtoms[] = {
  /* JSON                    JSON-5 */
  "0",                       "0",
  "1",                       "1",
  "-1",                      "-1",
  "2",                       "+2",
  "3DDDD",                   "3DDDD",
  "2.5DD",                   "2.5DD",
  "0.75",                    ".75",
  "-4.0e2",                  "-4.e2",
  "5.0e-3",                  "+5e-3",
  "6.DDe+0DD",                "6.DDe+0DD",
  "0",                       "0x0",
  "512",                     "0x200",
  "256",                     "+0x100",
  "-2748",                   "-0xabc",
  "true",                    "true",
  "false",                   "false",
  "null",                    "null",
  "9.0e999",                 "Infinity",
  "-9.0e999",                "-Infinity",
  "9.0e999",                 "+Infinity",
  "null",                    "NaN",
  "-0.0005DD",              "-0.0005DD",
  "4.35e-3",                 "+4.35e-3",
  "\"gem\\\"hay\"",          "\"gem\\\"hay\"",
  "\"icy'joy\"",             "'icy\\'joy\'",
  "\"keylog\"",              "\"key\\\nlog\"",
  "\"mix\\\\\\tnet\"",       "\"mix\\\\\\tnet\"",
  "\"oat\\r\\n\"",           "\"oat\\r\\n\"",
  "\"\\fpan\\b\"",           "\"\\fpan\\b\"",
  "{}",                      "{}",
  "[]",                      "[]",
  "[]",                      "[/*empty*/]",
  "{}",                      "{//empty\n}",
  "\"ask\"",                 "\"ask\"",
  "\"bag\"",                 "\"bag\"",
  "\"can\"",                 "\"can\"",
  "\"day\"",                 "\"day\"",
  "\"end\"",                 "'end'",
  "\"fly\"",                 "\"fly\"",
  "\"\\u00XX\\u00XX\"",      "\"\\xXX\\xXX\"",
  "\"y\\uXXXXz\"",           "\"y\\uXXXXz\"",
  "\"\"",                    "\"\"",
};
static char *azJsonTemplate[] = {
  /* JSON                                      JSON-5 */
  "{\"a\":%,\"b\":%,\"cDD\":%}",               "{a:%,b:%,cDD:%}",
  "{\"a\":%,\"b\":%,\"c\":%,\"d\":%,\"e\":%}", "{a:%,b:%,c:%,d:%,e:%}",
  "{\"a\":%,\"b\":%,\"c\":%,\"d\":%,\"\":%}",  "{a:%,b:%,c:%,d:%,'':%}",
  "{\"d\":%}",                                 "{d:%}",
  "{\"eeee\":%, \"ffff\":%}",                  "{eeee:% /*and*/, ffff:%}",
  "{\"$g\":%,\"_h_\":%,\"a b c d\":%}",        "{$g:%,_h_:%,\"a b c d\":%}",
  "{\"x\":%,\n  \"y\":%}",                     "{\"x\":%,\n  \"y\":%}",
  "{\"\\u00XX\":%,\"\\uXXXX\":%}",             "{\"\\xXX\":%,\"\\uXXXX\":%}",
  "{\"Z\":%}",                                 "{Z:%,}",
  "[%]",                                       "[%,]",
  "[%,%]",                                     "[%,%]",
  "[%,%,%]",                                   "[%,%,%,]",
  "[%,%,%,%]",                                 "[%,%,%,%]",
  "[%,%,%,%,%]",                               "[%,%,%,%,%]",
};

#define count(X)  (sizeof(X)/sizeof(X[0]))

#define STRSZ 10000

static void jsonExpand(
  const char *zSrc,
  char *zDest,
  Prng *p,
  int eType,            /* 0 for JSON, 1 for JSON5 */
  unsigned int r        /* Growth probability 0..1000.  0 means no growth */
){
  unsigned int i, j, k;
  char *z;
  char *zX;
  size_t n;
  char zBuf[200];

  j = 0;
  if( zSrc==0 ) zSrc = "%";
  if( strlen(zSrc)>=STRSZ/10 ) r = 0;
  for(i=0; zSrc[i]; i++){
    if( zSrc[i]!='%' ){
      if( j<STRSZ ) zDest[j++] = zSrc[i];
      continue;
    }
    if( r==0 || (r<1000 && (prngInt(p)%1000)<=r) ){
      /* Fill in without values without any new % */
      k = prngInt(p)%(count(azJsonAtoms)/2);
      k = k*2 + eType;
      z = azJsonAtoms[k];
    }else{
      /* Add new % terms */
      k = prngInt(p)%(count(azJsonTemplate)/2);
      k = k*2 + eType;
      z = azJsonTemplate[k];
    }
    n = strlen(z);
    if( (zX = strstr(z,"XX"))!=0 ){
      unsigned int y = prngInt(p);
      if( (y&0xff)==((y>>8)&0xff) ) y += 0x100;
      while( (y&0xff)==((y>>16)&0xff) || ((y>>8)&0xff)==((y>>16)&0xff) ){
        y += 0x10000;
      }
      memcpy(zBuf, z, n+1);
      z = zBuf;
      zX = strstr(z,"XX");
      while( zX!=0 ){
        zX[0] = "0123456789abcdef"[y%16];  y /= 16;
        zX[1] = "0123456789abcdef"[y%16];  y /= 16;
        zX = strstr(zX, "XX");
      }
    }else if( (zX = strstr(z,"DD"))!=0 ){
      unsigned int y = prngInt(p);
      memcpy(zBuf, z, n+1);
      z = zBuf;
      zX = strstr(z,"DD");
      while( zX!=0 ){
        zX[0] = "0123456789"[y%10];  y /= 10;
        zX[1] = "0123456789"[y%10];  y /= 10;
        zX = strstr(zX, "DD");
      }
    }
    assert( strstr(z, "XX")==0 );
    assert( strstr(z, "DD")==0 );
    if( j+n<STRSZ ){
      memcpy(&zDest[j], z, n);
      j += (int)n;
    }
  }
  zDest[STRSZ-1] = 0;
  if( j<STRSZ ) zDest[j] = 0;
}

static void randJsonFunc(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  unsigned int iSeed;
  int eType = *(int*)sqlite3_user_data(context);
  Prng prng;
  char z1[STRSZ+1], z2[STRSZ+1];

  iSeed = (unsigned int)sqlite3_value_int(argv[0]);
  prngSeed(&prng, iSeed);
  jsonExpand(0, z2, &prng, eType, 1000);
  jsonExpand(z2, z1, &prng, eType, 1000);
  jsonExpand(z1, z2, &prng, eType, 100);
  jsonExpand(z2, z1, &prng, eType, 0);
  sqlite3_result_text(context, z1, -1, SQLITE_TRANSIENT);
}

#ifdef _WIN32
  __declspec(dllexport)
#endif
int sqlite3_randomjson_init(
  sqlite3 *db, 
  char **pzErrMsg, 
  const sqlite3_api_routines *pApi
){
  static int cOne = 1;
  static int cZero = 0;
  int rc = SQLITE_OK;
#ifdef SQLITE_STATIC_RANDOMJSON
  (void)pApi;      /* Unused parameter */
#else
  SQLITE_EXTENSION_INIT2(pApi);
#endif
  (void)pzErrMsg;  /* Unused parameter */
  rc = sqlite3_create_function(db, "random_json", 1,
                   SQLITE_UTF8|SQLITE_INNOCUOUS|SQLITE_DETERMINISTIC,
                   &cZero, randJsonFunc, 0, 0);
  if( rc==SQLITE_OK ){
    rc = sqlite3_create_function(db, "random_json5", 1,
                   SQLITE_UTF8|SQLITE_INNOCUOUS|SQLITE_DETERMINISTIC,
                   &cOne, randJsonFunc, 0, 0);
  }
  return rc;
}