text: /****************************************************************************
   *
   * Copyright 2020 Samsung Electronics All Rights Reserved.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   * http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
   * either express or implied. See the License for the specific
   * language governing permissions and limitations under the License.
   *
   ****************************************************************************/
  /****************************************************************************
   * lib/libc/stdio/lib_dtoa_engine.h
   *
   *   Copyright © 2018, Keith Packard
   *   All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   * 3. Neither the name NuttX nor the names of its contributors may be
   *    used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
   * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
   * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
   * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
   * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   *
   ****************************************************************************/
  
  #ifndef __LIBS_LIBC_STDIO_LIB_DTOA_ENGINE_H
  #define __LIBS_LIBC_STDIO_LIB_DTOA_ENGINE_H
  
  /****************************************************************************
   * Included Files
   ****************************************************************************/
  
  #include <sys/types.h>
  #include <stdint.h>
  #include <float.h>
  
  #include <tinyara/float.h>
  
  /****************************************************************************
   * Pre-processor Definitions
   ****************************************************************************/
  
  #define DTOA_MAX_DIG        DBL_DIG
  
  #define DTOA_MINUS          1
  #define DTOA_ZERO           2
  #define DTOA_INF            4
  #define DTOA_NAN            8
  #define DTOA_CARRY          16	/* Carry was to master position. */
  
  #if DBL_MAX_10_EXP >= 1 && DBL_MAX_10_EXP < 2
  #define DTOA_SCALE_UP_NUM 1
  #endif
  #if DBL_MAX_10_EXP >= 2 && DBL_MAX_10_EXP < 4
  #define DTOA_SCALE_UP_NUM 2
  #endif
  #if DBL_MAX_10_EXP >= 4 && DBL_MAX_10_EXP < 8
  #define DTOA_SCALE_UP_NUM 3
  #endif
  #if DBL_MAX_10_EXP >= 8 && DBL_MAX_10_EXP < 16
  #define DTOA_SCALE_UP_NUM 4
  #endif
  #if DBL_MAX_10_EXP >= 16 && DBL_MAX_10_EXP < 32
  #define DTOA_SCALE_UP_NUM 5
  #endif
  #if DBL_MAX_10_EXP >= 32 && DBL_MAX_10_EXP < 64
  #define DTOA_SCALE_UP_NUM 6
  #endif
  #if DBL_MAX_10_EXP >= 64 && DBL_MAX_10_EXP < 128
  #define DTOA_SCALE_UP_NUM 7
  #endif
  #if DBL_MAX_10_EXP >= 128 && DBL_MAX_10_EXP < 256
  #define DTOA_SCALE_UP_NUM 8
  #endif
  #if DBL_MAX_10_EXP >= 256 && DBL_MAX_10_EXP < 512
  #define DTOA_SCALE_UP_NUM 9
  #endif
  #if DBL_MAX_10_EXP >= 512 && DBL_MAX_10_EXP < 1024
  #define DTOA_SCALE_UP_NUM 10
  #endif
  #if DBL_MAX_10_EXP >= 1024 && DBL_MAX_10_EXP < 2048
  #define DTOA_SCALE_UP_NUM 11
  #endif
  #if DBL_MAX_10_EXP >= 2048 && DBL_MAX_10_EXP < 4096
  #define DTOA_SCALE_UP_NUM 12
  #endif
  #if DBL_MAX_10_EXP >= 4096 && DBL_MAX_10_EXP < 8192
  #define DTOA_SCALE_UP_NUM 13
  #endif
  #if DBL_MAX_10_EXP >= 8192 && DBL_MAX_10_EXP < 16384
  #define DTOA_SCALE_UP_NUM 14
  #endif
  #if DBL_MAX_10_EXP >= 16384 && DBL_MAX_10_EXP < 32768
  #define DTOA_SCALE_UP_NUM 15
  #endif
  #if DBL_MAX_10_EXP >= 32768 && DBL_MAX_10_EXP < 65536
  #define DTOA_SCALE_UP_NUM 16
  #endif
  #if DBL_MAX_10_EXP >= 65536 && DBL_MAX_10_EXP < 131072
  #define DTOA_SCALE_UP_NUM 17
  #endif
  #if DBL_MIN_10_EXP <= -1 && DBL_MIN_10_EXP > -2
  #define DTOA_SCALE_DOWN_NUM 1
  #endif
  #if DBL_MIN_10_EXP <= -2 && DBL_MIN_10_EXP > -4
  #define DTOA_SCALE_DOWN_NUM 2
  #endif
  #if DBL_MIN_10_EXP <= -4 && DBL_MIN_10_EXP > -8
  #define DTOA_SCALE_DOWN_NUM 3
  #endif
  #if DBL_MIN_10_EXP <= -8 && DBL_MIN_10_EXP > -16
  #define DTOA_SCALE_DOWN_NUM 4
  #endif
  #if DBL_MIN_10_EXP <= -16 && DBL_MIN_10_EXP > -32
  #define DTOA_SCALE_DOWN_NUM 5
  #endif
  #if DBL_MIN_10_EXP <= -32 && DBL_MIN_10_EXP > -64
  #define DTOA_SCALE_DOWN_NUM 6
  #endif
  #if DBL_MIN_10_EXP <= -64 && DBL_MIN_10_EXP > -128
  #define DTOA_SCALE_DOWN_NUM 7
  #endif
  #if DBL_MIN_10_EXP <= -128 && DBL_MIN_10_EXP > -256
  #define DTOA_SCALE_DOWN_NUM 8
  #endif
  #if DBL_MIN_10_EXP <= -256 && DBL_MIN_10_EXP > -512
  #define DTOA_SCALE_DOWN_NUM 9
  #endif
  #if DBL_MIN_10_EXP <= -512 && DBL_MIN_10_EXP > -1024
  #define DTOA_SCALE_DOWN_NUM 10
  #endif
  #if DBL_MIN_10_EXP <= -1024 && DBL_MIN_10_EXP > -2048
  #define DTOA_SCALE_DOWN_NUM 11
  #endif
  #if DBL_MIN_10_EXP <= -2048 && DBL_MIN_10_EXP > -4096
  #define DTOA_SCALE_DOWN_NUM 12
  #endif
  #if DBL_MIN_10_EXP <= -4096 && DBL_MIN_10_EXP > -8192
  #define DTOA_SCALE_DOWN_NUM 13
  #endif
  #if DBL_MIN_10_EXP <= -8192 && DBL_MIN_10_EXP > -16384
  #define DTOA_SCALE_DOWN_NUM 14
  #endif
  #if DBL_MIN_10_EXP <= -16384 && DBL_MIN_10_EXP > -32768
  #define DTOA_SCALE_DOWN_NUM 15
  #endif
  #if DBL_MIN_10_EXP <= -32768 && DBL_MIN_10_EXP > -65536
  #define DTOA_SCALE_DOWN_NUM 16
  #endif
  #if DBL_MIN_10_EXP <= -65536 && DBL_MIN_10_EXP > -131072
  #define DTOA_SCALE_DOWN_NUM 17
  #endif
  
  #define DTOA_ROUND_NUM        (DBL_DIG + 1)
  
  /****************************************************************************
   * Public Types
   ****************************************************************************/
  
  struct dtoa_s {
  	int32_t exp;
  	uint8_t flags;
  	char digits[DTOA_MAX_DIG + 1];
  };
  
  /****************************************************************************
   * Public Data
   ****************************************************************************/
  
  extern const double_t g_dtoa_scale_up[];
  extern const double_t g_dtoa_scale_down[];
  extern const double_t g_dtoa_round[];
  
  /****************************************************************************
   * Public Function Prototypes
   ****************************************************************************/
  
  int __dtoa_engine(double_t x, FAR struct dtoa_s *dtoa, int max_digits, int max_decimals);
  
  #endif							/* __LIBS_LIBC_STDIO_LIB_DTOA_ENGINE_H */
  