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Overview
Comment:Update the test logic and the comments on the encoder.c module. (CVS 546)
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SHA1:18c28519d973944756694b2c213bfef3153f4b1b
User & Date: drh 2002-04-25 23:06:47
Context
2002-04-26
09:47
Fix for ticket #28: Export the "sqlite_changes" function in Windows DLLs. (CVS 547) check-in: f7cea463 user: drh tags: trunk
2002-04-25
23:06
Update the test logic and the comments on the encoder.c module. (CVS 546) check-in: 18c28519 user: drh tags: trunk
11:45
Added the "encode.c" source file that contains two utility subroutines that can be used to encode binary data for use in INSERT and UPDATE statements. This is just an initial checking. The code has not yet been integrated into the library. (CVS 545) check-in: 57f7c597 user: drh tags: trunk
Changes
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Changes to src/encode.c.

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*************************************************************************
** 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 1.1 2002/04/25 11:45:42 drh Exp $
*/
#include "sqliteInt.h"
#include "encode.h"

/*
** 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.

**
** The result is written into a preallocated output buffer "out".
** "out" must be able to hold at least 2 + (n+255)*3/256 + n bytes.
** In other words, the output will be expanded by as much as 3
** bytes for every 256 bytes of input plus 2 bytes of fixed overhead.

*/
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;
................................................................................
/*
** 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[20000];
  unsigned char out[30000];

  for(i=0; i<10000; i++){
    printf("Test %d: ", i+1);
    n = rand() % sizeof(in);








    for(j=0; j<n; j++) in[j] = rand() & 0xff;

    sqlite_encode_binary(in, n, out);

    printf("size %d->%d ", n, strlen(out)+1);
    m = 2 + (n+255)*3/256 + n;
    if( strlen(out)+1>m ){
      printf(" ERROR output too big\n");
      exit(1);
    }
    for(j=0; out[j]; j++){
      if( out[j]=='\'' ){
        printf(" ERROR contains (')\n");







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*************************************************************************
** 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;
................................................................................
/*
** 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++){
      if( out[j]=='\'' ){
        printf(" ERROR contains (')\n");