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Overview
Comment:Performance enhancements and size reduction for sqlite3VXPrintf()
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SHA1: eb071eb58cf675bd6cd9dd46aed9d57fbb7a77e8
User & Date: drh 2014-03-17 14:24:27.523
Context
2014-03-17
15:06
Clean up some obsolete "register" declarations in printf.c. (check-in: ecd9d3f945 user: drh tags: trunk)
14:24
Performance enhancements and size reduction for sqlite3VXPrintf() (check-in: eb071eb58c user: drh tags: trunk)
2014-03-14
11:46
Fix a harmless compiler warning that crops up with SQLITE_MAX_MMAP_SIZE=0. (check-in: 1277932b7e user: drh tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/printf.c.
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  d = digit;
  digit += '0';
  *val = (*val - d)*10.0;
  return (char)digit;
}
#endif /* SQLITE_OMIT_FLOATING_POINT */

/*
** Append N space characters to the given string buffer.
*/
void sqlite3AppendSpace(StrAccum *pAccum, int N){
  static const char zSpaces[] = "                             ";
  while( N>=(int)sizeof(zSpaces)-1 ){
    sqlite3StrAccumAppend(pAccum, zSpaces, sizeof(zSpaces)-1);
    N -= sizeof(zSpaces)-1;
  }
  if( N>0 ){
    sqlite3StrAccumAppend(pAccum, zSpaces, N);
  }
}

/*
** Set the StrAccum object to an error mode.
*/
static void setStrAccumError(StrAccum *p, u8 eError){
  p->accError = eError;
  p->nAlloc = 0;
}







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  d = digit;
  digit += '0';
  *val = (*val - d)*10.0;
  return (char)digit;
}
#endif /* SQLITE_OMIT_FLOATING_POINT */















/*
** Set the StrAccum object to an error mode.
*/
static void setStrAccumError(StrAccum *p, u8 eError){
  p->accError = eError;
  p->nAlloc = 0;
}
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    }
    useIntern = bFlags & SQLITE_PRINTF_INTERNAL;
  }else{
    bArgList = useIntern = 0;
  }
  for(; (c=(*fmt))!=0; ++fmt){
    if( c!='%' ){
      int amt;
      bufpt = (char *)fmt;
      amt = 1;
      while( (c=(*++fmt))!='%' && c!=0 ) amt++;
      sqlite3StrAccumAppend(pAccum, bufpt, amt);
      if( c==0 ) break;
    }
    if( (c=(*++fmt))==0 ){
      sqlite3StrAccumAppend(pAccum, "%", 1);
      break;
    }
    /* Find out what flags are present */







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    }
    useIntern = bFlags & SQLITE_PRINTF_INTERNAL;
  }else{
    bArgList = useIntern = 0;
  }
  for(; (c=(*fmt))!=0; ++fmt){
    if( c!='%' ){

      bufpt = (char *)fmt;

      while( (c=(*++fmt))!='%' && c!=0 ){};
      sqlite3StrAccumAppend(pAccum, bufpt, (int)(fmt - bufpt));
      if( c==0 ) break;
    }
    if( (c=(*++fmt))==0 ){
      sqlite3StrAccumAppend(pAccum, "%", 1);
      break;
    }
    /* Find out what flags are present */
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      }
    }/* End switch over the format type */
    /*
    ** The text of the conversion is pointed to by "bufpt" and is
    ** "length" characters long.  The field width is "width".  Do
    ** the output.
    */
    if( !flag_leftjustify ){
      register int nspace;
      nspace = width-length;
      if( nspace>0 ){
        sqlite3AppendSpace(pAccum, nspace);
      }
    }
    if( length>0 ){
      sqlite3StrAccumAppend(pAccum, bufpt, length);
    }
    if( flag_leftjustify ){
      register int nspace;
      nspace = width-length;
      if( nspace>0 ){
        sqlite3AppendSpace(pAccum, nspace);
      }
    }
    if( zExtra ) sqlite3_free(zExtra);
  }/* End for loop over the format string */
} /* End of function */

/*







































































** Append N bytes of text from z to the StrAccum object.

*/
void sqlite3StrAccumAppend(StrAccum *p, const char *z, int N){
  assert( z!=0 );
  assert( p->zText!=0 || p->nChar==0 || p->accError );
  assert( N>=0 );
  assert( p->accError==0 || p->nAlloc==0 );
  if( p->nChar+N >= p->nAlloc ){
    char *zNew;
    if( p->accError ){
      testcase(p->accError==STRACCUM_TOOBIG);
      testcase(p->accError==STRACCUM_NOMEM);
      return;
    }
    if( !p->useMalloc ){
      N = p->nAlloc - p->nChar - 1;
      setStrAccumError(p, STRACCUM_TOOBIG);
      if( N<=0 ){
        return;
      }
    }else{
      char *zOld = (p->zText==p->zBase ? 0 : p->zText);
      i64 szNew = p->nChar;
      szNew += N + 1;
      if( szNew > p->mxAlloc ){
        sqlite3StrAccumReset(p);
        setStrAccumError(p, STRACCUM_TOOBIG);
        return;
      }else{
        p->nAlloc = (int)szNew;
      }
      if( p->useMalloc==1 ){
        zNew = sqlite3DbRealloc(p->db, zOld, p->nAlloc);
      }else{
        zNew = sqlite3_realloc(zOld, p->nAlloc);
      }
      if( zNew ){
        if( zOld==0 && p->nChar>0 ) memcpy(zNew, p->zText, p->nChar);
        p->zText = zNew;
      }else{
        sqlite3StrAccumReset(p);
        setStrAccumError(p, STRACCUM_NOMEM);
        return;
      }
    }
  }
  assert( p->zText );
  memcpy(&p->zText[p->nChar], z, N);
  p->nChar += N;
}

/*







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      }
    }/* End switch over the format type */
    /*
    ** The text of the conversion is pointed to by "bufpt" and is
    ** "length" characters long.  The field width is "width".  Do
    ** the output.
    */


    width -= length;

    if( width>0 && !flag_leftjustify ) sqlite3AppendSpace(pAccum, width);



    sqlite3StrAccumAppend(pAccum, bufpt, length);





    if( width>0 && flag_leftjustify ) sqlite3AppendSpace(pAccum, width);


    if( zExtra ) sqlite3_free(zExtra);
  }/* End for loop over the format string */
} /* End of function */

/*
** Enlarge the memory allocation on a StrAccum object so that it is
** able to accept at least N more bytes of text.
**
** Return the number of bytes of text that StrAccum is able to accept
** after the attempted enlargement.  The value returned might be zero.
*/
static int sqlite3StrAccumEnlarge(StrAccum *p, int N){
  char *zNew;
  assert( p->nChar+N >= p->nAlloc ); /* Only called if really needed */
  if( p->accError ){
    testcase(p->accError==STRACCUM_TOOBIG);
    testcase(p->accError==STRACCUM_NOMEM);
    return 0;
  }
  if( !p->useMalloc ){
    N = p->nAlloc - p->nChar - 1;
    setStrAccumError(p, STRACCUM_TOOBIG);
    return N;
  }else{
    char *zOld = (p->zText==p->zBase ? 0 : p->zText);
    i64 szNew = p->nChar;
    szNew += N + 1;
    if( szNew > p->mxAlloc ){
      sqlite3StrAccumReset(p);
      setStrAccumError(p, STRACCUM_TOOBIG);
      return 0;
    }else{
      p->nAlloc = (int)szNew;
    }
    if( p->useMalloc==1 ){
      zNew = sqlite3DbRealloc(p->db, zOld, p->nAlloc);
    }else{
      zNew = sqlite3_realloc(zOld, p->nAlloc);
    }
    if( zNew ){
      if( zOld==0 && p->nChar>0 ) memcpy(zNew, p->zText, p->nChar);
      p->zText = zNew;
    }else{
      sqlite3StrAccumReset(p);
      setStrAccumError(p, STRACCUM_NOMEM);
      return 0;
    }
  }
  return N;
}

/*
** Append N space characters to the given string buffer.
*/
void sqlite3AppendSpace(StrAccum *p, int N){
  if( p->nChar+N >= p->nAlloc && (N = sqlite3StrAccumEnlarge(p, N))<=0 ) return;
  while( (N--)>0 ) p->zText[p->nChar++] = ' ';
}

/*
** The StrAccum "p" is not large enough to accept N new bytes of z[].
** So enlarge if first, then do the append.
**
** This is a helper routine to sqlite3StrAccumAppend() that does special-case
** work (enlarging the buffer) using tail recursion, so that the
** sqlite3StrAccumAppend() routine can use fast calling semantics.
*/
static void enlargeAndAppend(StrAccum *p, const char *z, int N){
  N = sqlite3StrAccumEnlarge(p, N);
  if( N>0 ){
    memcpy(&p->zText[p->nChar], z, N);
    p->nChar += N;
  }
}

/*
** Append N bytes of text from z to the StrAccum object.  Increase the
** size of the memory allocation for StrAccum if necessary.
*/
void sqlite3StrAccumAppend(StrAccum *p, const char *z, int N){
  assert( z!=0 );
  assert( p->zText!=0 || p->nChar==0 || p->accError );
  assert( N>=0 );
  assert( p->accError==0 || p->nAlloc==0 );
  if( p->nChar+N >= p->nAlloc ){
    enlargeAndAppend(p,z,N);



    return;
































  }
  assert( p->zText );
  memcpy(&p->zText[p->nChar], z, N);
  p->nChar += N;
}

/*