// vim: filetype=c:tabstop=4:ai:expandtab
// SPDX-License-Identifier: ICU
// scspell-id: a8a24c0b-f62c-11ec-ae11-80ee73e9b8e7
/* ------------------------------------------------------------------ */
/* Decimal Context module header                                      */
/* ------------------------------------------------------------------ */
/* Copyright (c) IBM Corporation, 2000, 2010.  All rights reserved.   */
/*                                                                    */
/* This software is made available under the terms of the             */
/* ICU License -- ICU 1.8.1 and later.                                */
/*                                                                    */
/* The description and User's Guide ("The decNumber C Library") for   */
/* this software is called decNumber.pdf.  This document is           */
/* available, together with arithmetic and format specifications,     */
/* testcases, and Web links, on the General Decimal Arithmetic page.  */
/*                                                                    */
/* Please send comments, suggestions, and corrections to the author:  */
/*   mfc@uk.ibm.com                                                   */
/*   Mike Cowlishaw, IBM Fellow                                       */
/*   IBM UK, PO Box 31, Birmingham Road, Warwick CV34 5JL, UK         */
/* ------------------------------------------------------------------ */
/*                                                                    */
/* Context variables must always have valid values:                   */
/*                                                                    */
/*  status   -- [any bits may be cleared, but not set, by user]       */
/*  round    -- must be one of the enumerated rounding modes          */
/*                                                                    */
/* The following variables are implied for fixed size formats (i.e.,  */
/* they are ignored) but should still be set correctly in case used   */
/* with decNumber functions:                                          */
/*                                                                    */
/*  clamp    -- must be either 0 or 1                                 */
/*  digits   -- must be in the range 1 through 999999999              */
/*  emax     -- must be in the range 0 through 999999999              */
/*  emin     -- must be in the range 0 through -999999999             */
/*  extended -- must be either 0 or 1 [present only if DECSUBSET]     */
/*  traps    -- only defined bits may be set                          */
/*                                                                    */
/* ------------------------------------------------------------------ */

#if !defined(DECCONTEXT)
# define DECCONTEXT
# define DECCNAME     "decContext"                      /* Short name */
# define DECCFULLNAME "Decimal Context Descriptor"    /* Verbose name */
# define DECCAUTHOR   "Mike Cowlishaw"                /* Who to blame */

# if !defined(int32_t)
#  include <stdint.h>              /* C99 standard integers           */
# endif
# include <stdio.h>                /* for printf, etc.                */
# include <signal.h>               /* for traps                       */

  /* Extended flags setting -- set this to 0 to use only IEEE flags   */
# if !defined(DECEXTFLAG)
#  define DECEXTFLAG 1             /* 1=enable extended flags         */
# endif

  /* Conditional code flag -- set this to 0 for best performance      */
# if !defined(DECSUBSET)
#  define DECSUBSET  0             /* 1=enable subset arithmetic      */
# endif

  /* Context for operations, with associated constants                */
  enum rounding {
    DEC_ROUND_CEILING,             /* round towards +infinity         */
    DEC_ROUND_UP,                  /* round away from 0               */
    DEC_ROUND_HALF_UP,             /* 0.5 rounds up                   */
    DEC_ROUND_HALF_EVEN,           /* 0.5 rounds to nearest even      */
    DEC_ROUND_HALF_DOWN,           /* 0.5 rounds down                 */
    DEC_ROUND_DOWN,                /* round towards 0 (truncate)      */
    DEC_ROUND_FLOOR,               /* round towards -infinity         */
    DEC_ROUND_05UP,                /* round for reround               */
    DEC_ROUND_MAX                  /* enum must be less than this     */
    };
# define DEC_ROUND_DEFAULT DEC_ROUND_HALF_EVEN;

  typedef struct {
    int32_t  digits;               /* working precision               */
    int32_t  emax;                 /* maximum positive exponent       */
    int32_t  emin;                 /* minimum negative exponent       */
    enum     rounding round;       /* rounding mode                   */
    uint32_t traps;                /* trap-enabler flags              */
    uint32_t status;               /* status flags                    */
    uint8_t  clamp;                /* flag: apply IEEE exponent clamp */
# if DECSUBSET
    uint8_t  extended;             /* flag: special-values allowed    */
# endif
    } decContext;

  /* Maxima and Minima for context settings                           */
# define DEC_MAX_DIGITS 999999999
# define DEC_MIN_DIGITS         1
# define DEC_MAX_EMAX   999999999
# define DEC_MIN_EMAX           0
# define DEC_MAX_EMIN           0
# define DEC_MIN_EMIN  -999999999
# define DEC_MAX_MATH      999999  /* max emax, etc., for math funcs. */

  /* Classifications for decimal numbers, aligned with 754 (note that */
  /* 'normal' and 'subnormal' are meaningful only with a decContext   */
  /* or a fixed size format).                                         */
  enum decClass {
    DEC_CLASS_SNAN,
    DEC_CLASS_QNAN,
    DEC_CLASS_NEG_INF,
    DEC_CLASS_NEG_NORMAL,
    DEC_CLASS_NEG_SUBNORMAL,
    DEC_CLASS_NEG_ZERO,
    DEC_CLASS_POS_ZERO,
    DEC_CLASS_POS_SUBNORMAL,
    DEC_CLASS_POS_NORMAL,
    DEC_CLASS_POS_INF
    };
  /* Strings for the decClasses */
# define DEC_ClassString_SN  "sNaN"
# define DEC_ClassString_QN  "NaN"
# define DEC_ClassString_NI  "-Infinity"
# define DEC_ClassString_NN  "-Normal"
# define DEC_ClassString_NS  "-Subnormal"
# define DEC_ClassString_NZ  "-Zero"
# define DEC_ClassString_PZ  "+Zero"
# define DEC_ClassString_PS  "+Subnormal"
# define DEC_ClassString_PN  "+Normal"
# define DEC_ClassString_PI  "+Infinity"
# define DEC_ClassString_UN  "Invalid"

  /* Trap-enabler and Status flags (exceptional conditions), and      */
  /* their names.  The top byte is reserved for internal use          */
# if DECEXTFLAG
    /* Extended flags */
#  define DEC_Conversion_syntax    0x00000001
#  define DEC_Division_by_zero     0x00000002
#  define DEC_Division_impossible  0x00000004
#  define DEC_Division_undefined   0x00000008
#  define DEC_Insufficient_storage 0x00000010 /* [when malloc fails]  */
#  define DEC_Inexact              0x00000020
#  define DEC_Invalid_context      0x00000040
#  define DEC_Invalid_operation    0x00000080
#  if DECSUBSET
#   define DEC_Lost_digits          0x00000100
#  endif
#  define DEC_Overflow             0x00000200
#  define DEC_Clamped              0x00000400
#  define DEC_Rounded              0x00000800
#  define DEC_Subnormal            0x00001000
#  define DEC_Underflow            0x00002000
# else
    /* IEEE flags only */
#  define DEC_Conversion_syntax    0x00000010
#  define DEC_Division_by_zero     0x00000002
#  define DEC_Division_impossible  0x00000010
#  define DEC_Division_undefined   0x00000010
#  define DEC_Insufficient_storage 0x00000010 /* [when malloc fails]  */
#  define DEC_Inexact              0x00000001
#  define DEC_Invalid_context      0x00000010
#  define DEC_Invalid_operation    0x00000010
#  if DECSUBSET
#   define DEC_Lost_digits          0x00000000
#  endif
#  define DEC_Overflow             0x00000008
#  define DEC_Clamped              0x00000000
#  define DEC_Rounded              0x00000000
#  define DEC_Subnormal            0x00000000
#  define DEC_Underflow            0x00000004
# endif

  /* IEEE 754 groupings for the flags                                 */
  /* [DEC_Clamped, DEC_Lost_digits, DEC_Rounded, and DEC_Subnormal    */
  /* are not in IEEE 754]                                             */
# define DEC_IEEE_754_Division_by_zero  (DEC_Division_by_zero)
# if DECSUBSET
#  define DEC_IEEE_754_Inexact           (DEC_Inexact | DEC_Lost_digits)
# else
#  define DEC_IEEE_754_Inexact           (DEC_Inexact)
# endif
# define DEC_IEEE_754_Invalid_operation (DEC_Conversion_syntax |       \
                                          DEC_Division_impossible |    \
                                          DEC_Division_undefined |     \
                                          DEC_Insufficient_storage |   \
                                          DEC_Invalid_context |        \
                                          DEC_Invalid_operation)
# define DEC_IEEE_754_Overflow          (DEC_Overflow)
# define DEC_IEEE_754_Underflow         (DEC_Underflow)

  /* flags which are normally errors (result is qNaN, infinite, or 0) */
# define DEC_Errors (DEC_IEEE_754_Division_by_zero |                   \
                      DEC_IEEE_754_Invalid_operation |                 \
                      DEC_IEEE_754_Overflow | DEC_IEEE_754_Underflow)
  /* flags which cause a result to become qNaN                        */
# define DEC_NaNs    DEC_IEEE_754_Invalid_operation

  /* flags which are normally for information only (finite results)   */
# if DECSUBSET
#  define DEC_Information (DEC_Clamped | DEC_Rounded | DEC_Inexact     \
                          | DEC_Lost_digits)
# else
#  define DEC_Information (DEC_Clamped | DEC_Rounded | DEC_Inexact)
# endif

  /* IEEE 854 names (for compatibility with older decNumber versions) */
# define DEC_IEEE_854_Division_by_zero  DEC_IEEE_754_Division_by_zero
# define DEC_IEEE_854_Inexact           DEC_IEEE_754_Inexact
# define DEC_IEEE_854_Invalid_operation DEC_IEEE_754_Invalid_operation
# define DEC_IEEE_854_Overflow          DEC_IEEE_754_Overflow
# define DEC_IEEE_854_Underflow         DEC_IEEE_754_Underflow

  /* Name strings for the exceptional conditions                      */
# define DEC_Condition_CS "Conversion syntax"
# define DEC_Condition_DZ "Division by zero"
# define DEC_Condition_DI "Division impossible"
# define DEC_Condition_DU "Division undefined"
# define DEC_Condition_IE "Inexact"
# define DEC_Condition_IS "Insufficient storage"
# define DEC_Condition_IC "Invalid context"
# define DEC_Condition_IO "Invalid operation"
# if DECSUBSET
#  define DEC_Condition_LD "Lost digits"
# endif
# define DEC_Condition_OV "Overflow"
# define DEC_Condition_PA "Clamped"
# define DEC_Condition_RO "Rounded"
# define DEC_Condition_SU "Subnormal"
# define DEC_Condition_UN "Underflow"
# define DEC_Condition_ZE "No status"
# define DEC_Condition_MU "Multiple status"
# define DEC_Condition_Length 21   /* length of the longest string,   */
                                   /* including terminator            */

  /* Initialization descriptors, used by decContextDefault            */
# define DEC_INIT_BASE         0
# define DEC_INIT_DECIMAL32   32
# define DEC_INIT_DECIMAL64   64
# define DEC_INIT_DECIMAL128 128
  /* Synonyms */
# define DEC_INIT_DECSINGLE  DEC_INIT_DECIMAL32
# define DEC_INIT_DECDOUBLE  DEC_INIT_DECIMAL64
# define DEC_INIT_DECQUAD    DEC_INIT_DECIMAL128

  /* decContext routines                                              */
  extern decContext  * decContextClearStatus(decContext *, uint32_t);
  extern decContext  * decContextDefault(decContext *, int32_t);
  extern enum rounding decContextGetRounding(decContext *);
  extern uint32_t      decContextGetStatus(decContext *);
  extern decContext  * decContextRestoreStatus(decContext *, uint32_t, uint32_t);
  extern uint32_t      decContextSaveStatus(decContext *, uint32_t);
  extern decContext  * decContextSetRounding(decContext *, enum rounding);
  extern decContext  * decContextSetStatus(decContext *, uint32_t);
  extern decContext  * decContextSetStatusFromString(decContext *, const char *);
  extern decContext  * decContextSetStatusFromStringQuiet(decContext *, const char *);
  extern decContext  * decContextSetStatusQuiet(decContext *, uint32_t);
  extern const char  * decContextStatusToString(const decContext *);
  extern int32_t       decContextTestEndian(void);
  extern uint32_t      decContextTestSavedStatus(uint32_t, uint32_t);
  extern uint32_t      decContextTestStatus(decContext *, uint32_t);
  extern decContext  * decContextZeroStatus(decContext *);

#endif
