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Overview
Comment:Slightly faster implementation of the length() SQL function.
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SHA3-256: 9a4199aedb039141a50a68943ef863d7df9637ada318793cce6c12b9d39bcdc5
User & Date: drh 2018-01-23 04:22:33
Context
2018-01-23
07:11
Skip defining WIN32_LEAN_AND_MEAN when it is already defined. check-in: 195f5323 user: mistachkin tags: trunk
04:22
Slightly faster implementation of the length() SQL function. check-in: 9a4199ae user: drh tags: trunk
03:44
Slightly faster function dispatch in the virtual machine by avoiding unnecessary reinitialization of variables that are already correctly initialized. check-in: edd4e687 user: drh tags: trunk
Changes
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Changes to src/func.c.

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** Implementation of the length() function
*/
static void lengthFunc(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  int len;

  assert( argc==1 );
  UNUSED_PARAMETER(argc);
  switch( sqlite3_value_type(argv[0]) ){
    case SQLITE_BLOB:
    case SQLITE_INTEGER:
    case SQLITE_FLOAT: {
      sqlite3_result_int(context, sqlite3_value_bytes(argv[0]));
      break;
    }
    case SQLITE_TEXT: {
      const unsigned char *z = sqlite3_value_text(argv[0]);


      if( z==0 ) return;
      len = 0;
      while( *z ){
        len++;
        SQLITE_SKIP_UTF8(z);


      }

      sqlite3_result_int(context, len);
      break;
    }
    default: {
      sqlite3_result_null(context);
      break;
    }
  }







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** Implementation of the length() function
*/
static void lengthFunc(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){


  assert( argc==1 );
  UNUSED_PARAMETER(argc);
  switch( sqlite3_value_type(argv[0]) ){
    case SQLITE_BLOB:
    case SQLITE_INTEGER:
    case SQLITE_FLOAT: {
      sqlite3_result_int(context, sqlite3_value_bytes(argv[0]));
      break;
    }
    case SQLITE_TEXT: {
      const unsigned char *z = sqlite3_value_text(argv[0]);
      const unsigned char *z0;
      unsigned char c;
      if( z==0 ) return;
      z0 = z;
      while( (c = *z)!=0 ){
        z++;

        if( c>=0xc0 ){
          while( (*z & 0xc0)==0x80 ){ z++; z0++; }
        }
      }
      sqlite3_result_int(context, (int)(z-z0));
      break;
    }
    default: {
      sqlite3_result_null(context);
      break;
    }
  }