printf.c

sqlite 嵌入式数据库的源码

        if( precision>etBUFSIZE-10 ) precision = etBUFSIZE-10;
        if( realvalue<0.0 ){
          realvalue = -realvalue;
          prefix = '-';
        }else{
          if( flag_plussign )          prefix = '+';
          else if( flag_blanksign )    prefix = ' ';
          else                         prefix = 0;
        }
        if( infop->type==etGENERIC && precision>0 ) precision--;
        rounder = 0.0;
#if 0
        /* 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 ){
          while( realvalue>=1e8 && exp<=350 ){ realvalue *= 1e-8; exp+=8; }
          while( realvalue>=10.0 && exp<=350 ){ realvalue *= 0.1; exp++; }
          while( realvalue<1e-8 && exp>=-350 ){ realvalue *= 1e8; exp-=8; }
          while( realvalue<1.0 && exp>=-350 ){ realvalue *= 10.0; exp--; }
          if( exp>350 || exp<-350 ){
            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++) = aDigits[infop->charset];
            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;
          int needQuote;
          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++;
          }
          needQuote = !isnull && xtype==etSQLESCAPE2;
          n += i + 1 + needQuote*2;
          if( n>etBUFSIZE ){
            bufpt = zExtra = sqliteMalloc( n );
            if( bufpt==0 ) return -1;
          }else{
            bufpt = buf;
          }
          j = 0;
          if( needQuote ) bufpt[j++] = '\'';
          for(i=0; (c=arg[i])!=0; i++){
            bufpt[j++] = c;
            if( c=='\'' ) bufpt[j++] = c;
          }
          if( needQuote ) bufpt[j++] = '\'';
          bufpt[j] = 0;
          length = j;
          if( precision>=0 && precision<length ) length = precision;
        }
        break;
      case etTOKEN: {
        Token *pToken = va_arg(ap, Token*);
        if( pToken && pToken->z ){
          (*func)(arg, pToken->z, pToken->n);
        }
        length = width = 0;
        break;
      }
      case etSRCLIST: {
        SrcList *pSrc = va_arg(ap, SrcList*);
        int k = va_arg(ap, int);
        struct SrcList_item *pItem = &pSrc->a[k];
        assert( k>=0 && k<pSrc->nSrc );
        if( pItem->zDatabase && pItem->zDatabase[0] ){
          (*func)(arg, pItem->zDatabase, strlen(pItem->zDatabase));
          (*func)(arg, ".", 1);
        }
        (*func)(arg, pItem->zName, strlen(pItem->zName));
        length = width = 0;
        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 ){
        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 ){
      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  nTotal;     /* Output size if unconstrained */
  int  nAlloc;     /* Amount of space allocated in zText */
  void *(*xRealloc)(void*,int);  /* Function used to realloc memory */
};

/* 
** 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, const char *zNewText, int nNewChar){
  struct sgMprintf *pM = (struct sgMprintf*)arg;
  pM->nTotal += nNewChar;
  if( pM->nChar + nNewChar + 1 > pM->nAlloc ){
    if( pM->xRealloc==0 ){
      nNewChar =  pM->nAlloc - pM->nChar - 1;
    }else{
      pM->nAlloc = pM->nChar + nNewChar*2 + 1;
      if( pM->zText==pM->zBase ){
        pM->zText = pM->xRealloc(0, pM->nAlloc);
        if( pM->zText && pM->nChar ){
          memcpy(pM->zText, pM->zBase, pM->nChar);
        }
      }else{
        pM->zText = pM->xRealloc(pM->zText, pM->nAlloc);
      }
    }
  }
  if( pM->zText ){
    if( nNewChar>0 ){
      memcpy(&pM->zText[pM->nChar], zNewText, nNewChar);
      pM->nChar += nNewChar;
    }
    pM->zText[pM->nChar] = 0;
  }
}

/*
** This routine is a wrapper around xprintf() that invokes mout() as
** the consumer.  
*/
static char *base_vprintf(
  void *(*xRealloc)(void*,int),   /* Routine to realloc memory. May be NULL */
  int useInternal,                /* Use internal %-conversions if true */
  char *zInitBuf,                 /* Initially write here, before mallocing */
  int nInitBuf,                   /* Size of zInitBuf[] */
  const char *zFormat,            /* format string */
  va_list ap                      /* arguments */
){
  struct sgMprintf sM;
  sM.zBase = sM.zText = zInitBuf;
  sM.nChar = sM.nTotal = 0;
  sM.nAlloc = nInitBuf;
  sM.xRealloc = xRealloc;
  vxprintf(mout, &sM, useInternal, zFormat, ap);
  if( xRealloc ){
    if( sM.zText==sM.zBase ){
      sM.zText = xRealloc(0, sM.nChar+1);
      if( sM.zText ){
        memcpy(sM.zText, sM.zBase, sM.nChar+1);
      }
    }else if( sM.nAlloc>sM.nChar+10 ){
      sM.zText = xRealloc(sM.zText, sM.nChar+1);
    }
  }
  return sM.zText;
}

/*
** Realloc that is a real function, not a macro.
*/
static void *printf_realloc(void *old, int size){
  return sqliteRealloc(old,size);
}

/*
** Print into memory obtained from sqliteMalloc().  Use the internal
** %-conversion extensions.
*/
char *sqlite3VMPrintf(const char *zFormat, va_list ap){
  char zBase[1000];
  return base_vprintf(printf_realloc, 1, zBase, sizeof(zBase), zFormat, ap);
}

/*
** Print into memory obtained from sqliteMalloc().  Use the internal
** %-conversion extensions.
*/
char *sqlite3MPrintf(const char *zFormat, ...){
  va_list ap;
  char *z;
  char zBase[1000];
  va_start(ap, zFormat);
  z = base_vprintf(printf_realloc, 1, zBase, sizeof(zBase), zFormat, ap);
  va_end(ap);
  return z;
}

/*
** Print into memory obtained from malloc().  Do not use the internal
** %-conversion extensions.  This routine is for use by external users.
*/
char *sqlite3_mprintf(const char *zFormat, ...){
  va_list ap;
  char *z;
  char zBuf[200];

  va_start(ap,zFormat);
  z = base_vprintf((void*(*)(void*,int))realloc, 0, 
                   zBuf, sizeof(zBuf), zFormat, ap);
  va_end(ap);
  return z;
}

/* This is the varargs version of sqlite3_mprintf.  
*/
char *sqlite3_vmprintf(const char *zFormat, va_list ap){
  char zBuf[200];
  return base_vprintf((void*(*)(void*,int))realloc, 0,
                      zBuf, sizeof(zBuf), zFormat, ap);
}

/*
** sqlite3_snprintf() works like snprintf() except that it ignores the
** current locale settings.  This is important for SQLite because we
** are not able to use a "," as the decimal point in place of "." as
** specified by some locales.
*/
char *sqlite3_snprintf(int n, char *zBuf, const char *zFormat, ...){
  char *z;
  va_list ap;

  va_start(ap,zFormat);
  z = base_vprintf(0, 0, zBuf, n, zFormat, ap);
  va_end(ap);
  return z;
}

#if defined(SQLITE_TEST) || defined(SQLITE_DEBUG)
/*
** A version of printf() that understands %lld.  Used for debugging.
** The printf() built into some versions of windows does not understand %lld
** and segfaults if you give it a long long int.
*/
void sqlite3DebugPrintf(const char *zFormat, ...){
  extern int getpid(void);
  va_list ap;
  char zBuf[500];
  va_start(ap, zFormat);
  base_vprintf(0, 0, zBuf, sizeof(zBuf), zFormat, ap);
  va_end(ap);
  fprintf(stdout,"%d: %s", getpid(), zBuf);
  fflush(stdout);
}
#endif