printf.c

SQLite 2.8.6 源代码,用来在Linux/Unix/Windows上编译安装.它是一个小型的数据库,但是非常好用,速度也快,一般的数据库查询之类的操作据统计比MySQL,PostgreSQL

          if( flag_plussign )          prefix = '+';
          else if( flag_blanksign )    prefix = ' ';
          else                         prefix = 0;
        }
        if( infop->type==etGENERIC && precision>0 ) precision--;
        rounder = 0.0;
#ifdef COMPATIBILITY
        /* Rounding works like BSD when the constant 0.4999 is used.  Wierd! */
        for(idx=precision, rounder=0.4999; idx>0; idx--, rounder*=0.1);
#else
        /* It makes more sense to use 0.5 */
        for(idx=precision, rounder=0.5; idx>0; idx--, rounder*=0.1);
#endif
        if( infop->type==etFLOAT ) realvalue += rounder;
        /* Normalize realvalue to within 10.0 > realvalue >= 1.0 */
        exp = 0;
        if( realvalue>0.0 ){
          int k = 0;
          while( realvalue>=1e8 && k++<100 ){ realvalue *= 1e-8; exp+=8; }
          while( realvalue>=10.0 && k++<100 ){ realvalue *= 0.1; exp++; }
          while( realvalue<1e-8 && k++<100 ){ realvalue *= 1e8; exp-=8; }
          while( realvalue<1.0 && k++<100 ){ realvalue *= 10.0; exp--; }
          if( k>=100 ){
            bufpt = "NaN";
            length = 3;
            break;
          }
        }
        bufpt = buf;
        /*
        ** If the field type is etGENERIC, then convert to either etEXP
        ** or etFLOAT, as appropriate.
        */
        flag_exp = xtype==etEXP;
        if( xtype!=etFLOAT ){
          realvalue += rounder;
          if( realvalue>=10.0 ){ realvalue *= 0.1; exp++; }
        }
        if( xtype==etGENERIC ){
          flag_rtz = !flag_alternateform;
          if( exp<-4 || exp>precision ){
            xtype = etEXP;
          }else{
            precision = precision - exp;
            xtype = etFLOAT;
          }
        }else{
          flag_rtz = 0;
        }
        /*
        ** The "exp+precision" test causes output to be of type etEXP if
        ** the precision is too large to fit in buf[].
        */
        nsd = 0;
        if( xtype==etFLOAT && exp+precision<etBUFSIZE-30 ){
          flag_dp = (precision>0 || flag_alternateform);
          if( prefix ) *(bufpt++) = prefix;         /* Sign */
          if( exp<0 )  *(bufpt++) = '0';            /* Digits before "." */
          else for(; exp>=0; exp--) *(bufpt++) = et_getdigit(&realvalue,&nsd);
          if( flag_dp ) *(bufpt++) = '.';           /* The decimal point */
          for(exp++; exp<0 && precision>0; precision--, exp++){
            *(bufpt++) = '0';
          }
          while( (precision--)>0 ) *(bufpt++) = et_getdigit(&realvalue,&nsd);
          *(bufpt--) = 0;                           /* Null terminate */
          if( flag_rtz && flag_dp ){     /* Remove trailing zeros and "." */
            while( bufpt>=buf && *bufpt=='0' ) *(bufpt--) = 0;
            if( bufpt>=buf && *bufpt=='.' ) *(bufpt--) = 0;
          }
          bufpt++;                            /* point to next free slot */
        }else{    /* etEXP or etGENERIC */
          flag_dp = (precision>0 || flag_alternateform);
          if( prefix ) *(bufpt++) = prefix;   /* Sign */
          *(bufpt++) = et_getdigit(&realvalue,&nsd);  /* First digit */
          if( flag_dp ) *(bufpt++) = '.';     /* Decimal point */
          while( (precision--)>0 ) *(bufpt++) = et_getdigit(&realvalue,&nsd);
          bufpt--;                            /* point to last digit */
          if( flag_rtz && flag_dp ){          /* Remove tail zeros */
            while( bufpt>=buf && *bufpt=='0' ) *(bufpt--) = 0;
            if( bufpt>=buf && *bufpt=='.' ) *(bufpt--) = 0;
          }
          bufpt++;                            /* point to next free slot */
          if( exp || flag_exp ){
            *(bufpt++) = infop->charset[0];
            if( exp<0 ){ *(bufpt++) = '-'; exp = -exp; } /* sign of exp */
            else       { *(bufpt++) = '+'; }
            if( exp>=100 ){
              *(bufpt++) = (exp/100)+'0';                /* 100's digit */
              exp %= 100;
            }
            *(bufpt++) = exp/10+'0';                     /* 10's digit */
            *(bufpt++) = exp%10+'0';                     /* 1's digit */
          }
        }
        /* The converted number is in buf[] and zero terminated. Output it.
        ** Note that the number is in the usual order, not reversed as with
        ** integer conversions. */
        length = bufpt-buf;
        bufpt = buf;

        /* Special case:  Add leading zeros if the flag_zeropad flag is
        ** set and we are not left justified */
        if( flag_zeropad && !flag_leftjustify && length < width){
          int i;
          int nPad = width - length;
          for(i=width; i>=nPad; i--){
            bufpt[i] = bufpt[i-nPad];
          }
          i = prefix!=0;
          while( nPad-- ) bufpt[i++] = '0';
          length = width;
        }
#endif
        break;
      case etSIZE:
        *(va_arg(ap,int*)) = count;
        length = width = 0;
        break;
      case etPERCENT:
        buf[0] = '%';
        bufpt = buf;
        length = 1;
        break;
      case etCHARLIT:
      case etCHARX:
        c = buf[0] = (xtype==etCHARX ? va_arg(ap,int) : *++fmt);
        if( precision>=0 ){
          for(idx=1; idx<precision; idx++) buf[idx] = c;
          length = precision;
        }else{
          length =1;
        }
        bufpt = buf;
        break;
      case etSTRING:
      case etDYNSTRING:
        bufpt = va_arg(ap,char*);
        if( bufpt==0 ){
          bufpt = "";
        }else if( xtype==etDYNSTRING ){
          zExtra = bufpt;
        }
        length = strlen(bufpt);
        if( precision>=0 && precision<length ) length = precision;
        break;
      case etSQLESCAPE:
      case etSQLESCAPE2:
        {
          int i, j, n, c, isnull;
          char *arg = va_arg(ap,char*);
          isnull = arg==0;
          if( isnull ) arg = (xtype==etSQLESCAPE2 ? "NULL" : "(NULL)");
          for(i=n=0; (c=arg[i])!=0; i++){
            if( c=='\'' )  n++;
          }
          n += i + 1 + ((!isnull && xtype==etSQLESCAPE2) ? 2 : 0);
          if( n>etBUFSIZE ){
            bufpt = zExtra = sqliteMalloc( n );
            if( bufpt==0 ) return -1;
          }else{
            bufpt = buf;
          }
          j = 0;
          if( !isnull && xtype==etSQLESCAPE2 ) bufpt[j++] = '\'';
          for(i=0; (c=arg[i])!=0; i++){
            bufpt[j++] = c;
            if( c=='\'' ) bufpt[j++] = c;
          }
          if( !isnull && xtype==etSQLESCAPE2 ) bufpt[j++] = '\'';
          bufpt[j] = 0;
          length = j;
          if( precision>=0 && precision<length ) length = precision;
        }
        break;
      case etERROR:
        buf[0] = '%';
        buf[1] = c;
        errorflag = 0;
        idx = 1+(c!=0);
        (*func)(arg,"%",idx);
        count += idx;
        if( c==0 ) fmt--;
        break;
    }/* 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 ){
        if( flag_center ){
          nspace = nspace/2;
          width -= nspace;
          flag_leftjustify = 1;
        }
        count += nspace;
        while( nspace>=etSPACESIZE ){
          (*func)(arg,spaces,etSPACESIZE);
          nspace -= etSPACESIZE;
        }
        if( nspace>0 ) (*func)(arg,spaces,nspace);
      }
    }
    if( length>0 ){
      (*func)(arg,bufpt,length);
      count += length;
    }
    if( flag_leftjustify ){
      register int nspace;
      nspace = width-length;
      if( nspace>0 ){
        count += nspace;
        while( nspace>=etSPACESIZE ){
          (*func)(arg,spaces,etSPACESIZE);
          nspace -= etSPACESIZE;
        }
        if( nspace>0 ) (*func)(arg,spaces,nspace);
      }
    }
    if( zExtra ){
      if( xtype==etDYNSTRING ){
        free(zExtra);
      }else{
        sqliteFree(zExtra);
      }
    }
  }/* End for loop over the format string */
  return errorflag ? -1 : count;
} /* End of function */


/* This structure is used to store state information about the
** write to memory that is currently in progress.
*/
struct sgMprintf {
  char *zBase;     /* A base allocation */
  char *zText;     /* The string collected so far */
  int  nChar;      /* Length of the string so far */
  int  nAlloc;     /* Amount of space allocated in zText */
};

/* 
** This function implements the callback from vxprintf. 
**
** This routine add nNewChar characters of text in zNewText to
** the sgMprintf structure pointed to by "arg".
*/
static void mout(void *arg, char *zNewText, int nNewChar){
  struct sgMprintf *pM = (struct sgMprintf*)arg;
  if( pM->nChar + nNewChar + 1 > pM->nAlloc ){
    pM->nAlloc = pM->nChar + nNewChar*2 + 1;
    if( pM->zText==pM->zBase ){
      pM->zText = sqliteMalloc(pM->nAlloc);
      if( pM->zText && pM->nChar ) memcpy(pM->zText,pM->zBase,pM->nChar);
    }else{
      char *z = sqliteRealloc(pM->zText, pM->nAlloc);
      if( z==0 ){
        sqliteFree(pM->zText);
        pM->nChar = 0;
        pM->nAlloc = 0;
      }
      pM->zText = z;
    }
  }
  if( pM->zText ){
    memcpy(&pM->zText[pM->nChar], zNewText, nNewChar);
    pM->nChar += nNewChar;
    pM->zText[pM->nChar] = 0;
  }
}

/*
** sqlite_mprintf() works like printf(), but allocations memory to hold the
** resulting string and returns a pointer to the allocated memory.  Use
** sqliteFree() to release the memory allocated.
*/
char *sqliteMPrintf(const char *zFormat, ...){
  va_list ap;
  struct sgMprintf sMprintf;
  char zBuf[200];

  sMprintf.nChar = 0;
  sMprintf.nAlloc = sizeof(zBuf);
  sMprintf.zText = zBuf;
  sMprintf.zBase = zBuf;
  va_start(ap,zFormat);
  vxprintf(mout,&sMprintf,zFormat,ap);
  va_end(ap);
  sMprintf.zText[sMprintf.nChar] = 0;
  return sqliteRealloc(sMprintf.zText, sMprintf.nChar+1);
}

/*
** sqlite_mprintf() works like printf(), but allocations memory to hold the
** resulting string and returns a pointer to the allocated memory.  Use
** sqliteFree() to release the memory allocated.
*/
char *sqlite_mprintf(const char *zFormat, ...){
  va_list ap;
  struct sgMprintf sMprintf;
  char *zNew;
  char zBuf[200];

  sMprintf.nChar = 0;
  sMprintf.nAlloc = sizeof(zBuf);
  sMprintf.zText = zBuf;
  sMprintf.zBase = zBuf;
  va_start(ap,zFormat);
  vxprintf(mout,&sMprintf,zFormat,ap);
  va_end(ap);
  sMprintf.zText[sMprintf.nChar] = 0;
  zNew = malloc( sMprintf.nChar+1 );
  if( zNew ) strcpy(zNew,sMprintf.zText);
  if( sMprintf.zText!=sMprintf.zBase ){
    sqliteFree(sMprintf.zText);
  }
  return zNew;
}

/* This is the varargs version of sqlite_mprintf.  
*/
char *sqlite_vmprintf(const char *zFormat, va_list ap){
  struct sgMprintf sMprintf;
  char *zNew;
  char zBuf[200];
  sMprintf.nChar = 0;
  sMprintf.zText = zBuf;
  sMprintf.nAlloc = sizeof(zBuf);
  sMprintf.zBase = zBuf;
  vxprintf(mout,&sMprintf,zFormat,ap);
  sMprintf.zText[sMprintf.nChar] = 0;
  zNew = malloc( sMprintf.nChar+1 );
  if( zNew ) strcpy(zNew,sMprintf.zText);
  if( sMprintf.zText!=sMprintf.zBase ){
    sqliteFree(sMprintf.zText);
  }
  return zNew;
}

/*
** The following four routines implement the varargs versions of the
** sqlite_exec() and sqlite_get_table() interfaces.  See the sqlite.h
** header files for a more detailed description of how these interfaces
** work.
**
** These routines are all just simple wrappers.
*/
int sqlite_exec_printf(
  sqlite *db,                   /* An open database */
  const char *sqlFormat,        /* printf-style format string for the SQL */
  sqlite_callback xCallback,    /* Callback function */
  void *pArg,                   /* 1st argument to callback function */
  char **errmsg,                /* Error msg written here */
  ...                           /* Arguments to the format string. */
){
  va_list ap;
  int rc;

  va_start(ap, errmsg);
  rc = sqlite_exec_vprintf(db, sqlFormat, xCallback, pArg, errmsg, ap);
  va_end(ap);
  return rc;
}
int sqlite_exec_vprintf(
  sqlite *db,                   /* An open database */
  const char *sqlFormat,        /* printf-style format string for the SQL */
  sqlite_callback xCallback,    /* Callback function */
  void *pArg,                   /* 1st argument to callback function */
  char **errmsg,                /* Error msg written here */
  va_list ap                    /* Arguments to the format string. */
){
  char *zSql;
  int rc;

  zSql = sqlite_vmprintf(sqlFormat, ap);
  rc = sqlite_exec(db, zSql, xCallback, pArg, errmsg);
  free(zSql);
  return rc;
}
int sqlite_get_table_printf(
  sqlite *db,            /* An open database */
  const char *sqlFormat, /* printf-style format string for the SQL */
  char ***resultp,       /* Result written to a char *[]  that this points to */
  int *nrow,             /* Number of result rows written here */
  int *ncol,             /* Number of result columns written here */
  char **errmsg,         /* Error msg written here */
  ...                    /* Arguments to the format string */
){
  va_list ap;
  int rc;

  va_start(ap, errmsg);
  rc = sqlite_get_table_vprintf(db, sqlFormat, resultp, nrow, ncol, errmsg, ap);
  va_end(ap);
  return rc;
}
int sqlite_get_table_vprintf(
  sqlite *db,            /* An open database */
  const char *sqlFormat, /* printf-style format string for the SQL */
  char ***resultp,       /* Result written to a char *[]  that this points to */
  int *nrow,             /* Number of result rows written here */
  int *ncolumn,          /* Number of result columns written here */
  char **errmsg,         /* Error msg written here */
  va_list ap             /* Arguments to the format string */
){
  char *zSql;
  int rc;

  zSql = sqlite_vmprintf(sqlFormat, ap);
  rc = sqlite_get_table(db, zSql, resultp, nrow, ncolumn, errmsg);
  free(zSql);
  return rc;
}