SQLite

Check-in [f12c3a25ba]
Login

Many hyperlinks are disabled.
Use anonymous login to enable hyperlinks.

Overview
Comment:Modify the sqlite_encode_binary() routine to return the strlen() of the encoded string. Also fix a bug that occurs when attempting to encode a zero-length buffer. (CVS 751)
Downloads: Tarball | ZIP archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA1: f12c3a25ba5408c2a7c846a9f160416fd188cd26
User & Date: drh 2002-09-16 11:44:06.000
Context
2002-09-17
03:20
Fix a bug in the OP_MemStore operator of the VDBE. A realloc() might occur but pointer to the old buffer were not being moved over to the new buffer. (CVS 752) (check-in: 29145746f3 user: drh tags: trunk)
2002-09-16
11:44
Modify the sqlite_encode_binary() routine to return the strlen() of the encoded string. Also fix a bug that occurs when attempting to encode a zero-length buffer. (CVS 751) (check-in: f12c3a25ba user: drh tags: trunk)
2002-09-14
13:47
Do not put a write lock on the main database file when writing to a temporary table. (CVS 750) (check-in: 3f253afe15 user: drh tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/encode.c.
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
*************************************************************************
** This file contains helper routines used to translate binary data into
** a null-terminated string (suitable for use in SQLite) and back again.
** These are convenience routines for use by people who want to store binary
** data in an SQLite database.  The code in this file is used by any other
** part of the SQLite library.
**
** $Id: encode.c,v 1.2 2002/04/25 23:06:47 drh Exp $
*/

/*
** Encode a binary buffer "in" of size n bytes so that it contains
** no instances of characters '\'' or '\000'.  The output is 
** null-terminated and can be used as a string value in an INSERT
** or UPDATE statement.  Use sqlite_decode_binary() to convert the
** string back into its original binary.
**
** The result is written into a preallocated output buffer "out".
** "out" must be able to hold at least (256*n + 1262)/253 bytes.
** In other words, the output will be expanded by as much as 3
** bytes for every 253 bytes of input plus 2 bytes of fixed overhead.
** (This is approximately 2 + 1.019*n or about a 2% size increase.)



*/
void sqlite_encode_binary(const unsigned char *in, int n, unsigned char *out){
  int i, j, e, m;
  int cnt[256];





  memset(cnt, 0, sizeof(cnt));
  for(i=n-1; i>=0; i--){ cnt[in[i]]++; }
  m = n;
  for(i=1; i<256; i++){
    int sum;
    if( i=='\'' ) continue;
    sum = cnt[i] + cnt[(i+1)&0xff] + cnt[(i+'\'')&0xff];







|














>
>
>

|


>
>
>
>
>







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
*************************************************************************
** This file contains helper routines used to translate binary data into
** a null-terminated string (suitable for use in SQLite) and back again.
** These are convenience routines for use by people who want to store binary
** data in an SQLite database.  The code in this file is used by any other
** part of the SQLite library.
**
** $Id: encode.c,v 1.3 2002/09/16 11:44:06 drh Exp $
*/

/*
** Encode a binary buffer "in" of size n bytes so that it contains
** no instances of characters '\'' or '\000'.  The output is 
** null-terminated and can be used as a string value in an INSERT
** or UPDATE statement.  Use sqlite_decode_binary() to convert the
** string back into its original binary.
**
** The result is written into a preallocated output buffer "out".
** "out" must be able to hold at least (256*n + 1262)/253 bytes.
** In other words, the output will be expanded by as much as 3
** bytes for every 253 bytes of input plus 2 bytes of fixed overhead.
** (This is approximately 2 + 1.019*n or about a 2% size increase.)
**
** The return value is the number of characters in the encoded
** string, excluding the "\000" terminator.
*/
int sqlite_encode_binary(const unsigned char *in, int n, unsigned char *out){
  int i, j, e, m;
  int cnt[256];
  if( n<=0 ){
    out[0] = 'x';
    out[1] = 0;
    return 1;
  }
  memset(cnt, 0, sizeof(cnt));
  for(i=n-1; i>=0; i--){ cnt[in[i]]++; }
  m = n;
  for(i=1; i<256; i++){
    int sum;
    if( i=='\'' ) continue;
    sum = cnt[i] + cnt[(i+1)&0xff] + cnt[(i+'\'')&0xff];
60
61
62
63
64
65
66
67

68
69
70
71
72
73
74
    }else if( c=='\'' ){
      out[j++] = 1;
      out[j++] = 3;
    }else{
      out[j++] = c;
    }
  }
  out[j++] = 0;

}

/*
** Decode the string "in" into binary data and write it into "out".
** This routine reverses the encoded created by sqlite_encode_binary().
** The output will always be a few bytes less than the input.  The number
** of bytes of output is returned.  If the input is not a well-formed







|
>







68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
    }else if( c=='\'' ){
      out[j++] = 1;
      out[j++] = 3;
    }else{
      out[j++] = c;
    }
  }
  out[j] = 0;
  return j;
}

/*
** Decode the string "in" into binary data and write it into "out".
** This routine reverses the encoded created by sqlite_encode_binary().
** The output will always be a few bytes less than the input.  The number
** of bytes of output is returned.  If the input is not a well-formed
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
#ifdef ENCODER_TEST
/*
** The subroutines above are not tested by the usual test suite.  To test
** these routines, compile just this one file with a -DENCODER_TEST=1 option
** and run the result.
*/
int main(int argc, char **argv){
  int i, j, n, m;
  unsigned char in[30000];
  unsigned char out[33000];

  for(i=0; i<sizeof(in); i++){
    printf("Test %d: ", i+1);
    n = rand() % (i+1);
    if( i%100==0 ){
      int k;
      for(j=k=0; j<n; j++){
        /* if( k==0 || k=='\'' ) k++; */
        in[j] = k;
        k = (k+1)&0xff;
      }
    }else{
      for(j=0; j<n; j++) in[j] = rand() & 0xff;
    }
    sqlite_encode_binary(in, n, out);




    m = (256*n + 1262)/253;
    printf("size %d->%d (max %d)", n, strlen(out)+1, m);
    if( strlen(out)+1>m ){
      printf(" ERROR output too big\n");
      exit(1);
    }
    for(j=0; out[j]; j++){







|
















|
>
>
>
>







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
#ifdef ENCODER_TEST
/*
** The subroutines above are not tested by the usual test suite.  To test
** these routines, compile just this one file with a -DENCODER_TEST=1 option
** and run the result.
*/
int main(int argc, char **argv){
  int i, j, n, m, nOut;
  unsigned char in[30000];
  unsigned char out[33000];

  for(i=0; i<sizeof(in); i++){
    printf("Test %d: ", i+1);
    n = rand() % (i+1);
    if( i%100==0 ){
      int k;
      for(j=k=0; j<n; j++){
        /* if( k==0 || k=='\'' ) k++; */
        in[j] = k;
        k = (k+1)&0xff;
      }
    }else{
      for(j=0; j<n; j++) in[j] = rand() & 0xff;
    }
    nOut = sqlite_encode_binary(in, n, out);
    if( nOut!=strlen(out) ){
      printf(" ERROR return value is %d instead of %d\n", nOut, strlen(out));
      exit(1);
    }
    m = (256*n + 1262)/253;
    printf("size %d->%d (max %d)", n, strlen(out)+1, m);
    if( strlen(out)+1>m ){
      printf(" ERROR output too big\n");
      exit(1);
    }
    for(j=0; out[j]; j++){