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numeric.c

/* 
 * interface dc to the bc numeric routines
 *
 * Copyright (C) 1994, 1997, 1998, 2000, 2005 Free Software Foundation, Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, you can write to:
 *   The Free Software Foundation, Inc.
 *   51 Franklin Street, Fifth Floor
 *   Boston, MA 02110-1301  USA
 */

/* This should be the only module that knows the internals of type dc_num */
/* In this particular implementation we just slather out some glue and
 * make use of bc's numeric routines.
 */

#include "config.h"

#include <stdio.h>
#include <ctype.h>
#ifdef HAVE_LIMITS_H
# include <limits.h>
#endif
#ifndef UCHAR_MAX
# define UCHAR_MAX ((unsigned char)~0)
#endif
#ifdef HAVE_STDLIB_H
# include <stdlib.h>
#endif
#ifdef HAVE_ERRNO_H
# include <errno.h>
#else
  extern int errno;
#endif

#include "number.h"
#include "dc.h"
#include "dc-proto.h"

#ifdef __GNUC__
# if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__-0 >= 7) 
#  define ATTRIB(x) __attribute__(x)
# endif
#endif
#ifndef ATTRIB
# define ATTRIB(x)
#endif

/* Forward prototype */
static void out_char (int);

/* there is no POSIX standard for dc, so we'll take the GNU definitions */
int std_only = FALSE;

/* convert an opaque dc_num into a real bc_num */
#define CastNum(x)      ((bc_num)(x))

/* add two dc_nums, place into *result;
 * return DC_SUCCESS on success, DC_DOMAIN_ERROR on domain error
 */
int
dc_add DC_DECLARG((a, b, kscale, result))
      dc_num a DC_DECLSEP
      dc_num b DC_DECLSEP
      int kscale ATTRIB((unused)) DC_DECLSEP
      dc_num *result DC_DECLEND
{
      bc_init_num((bc_num *)result);
      bc_add(CastNum(a), CastNum(b), (bc_num *)result, 0);
      return DC_SUCCESS;
}

/* subtract two dc_nums, place into *result;
 * return DC_SUCCESS on success, DC_DOMAIN_ERROR on domain error
 */
int
dc_sub DC_DECLARG((a, b, kscale, result))
      dc_num a DC_DECLSEP
      dc_num b DC_DECLSEP
      int kscale ATTRIB((unused)) DC_DECLSEP
      dc_num *result DC_DECLEND
{
      bc_init_num((bc_num *)result);
      bc_sub(CastNum(a), CastNum(b), (bc_num *)result, 0);
      return DC_SUCCESS;
}

/* multiply two dc_nums, place into *result;
 * return DC_SUCCESS on success, DC_DOMAIN_ERROR on domain error
 */
int
dc_mul DC_DECLARG((a, b, kscale, result))
      dc_num a DC_DECLSEP
      dc_num b DC_DECLSEP
      int kscale DC_DECLSEP
      dc_num *result DC_DECLEND
{
      bc_init_num((bc_num *)result);
      bc_multiply(CastNum(a), CastNum(b), (bc_num *)result, kscale);
      return DC_SUCCESS;
}

/* divide two dc_nums, place into *result;
 * return DC_SUCCESS on success, DC_DOMAIN_ERROR on domain error
 */
int
dc_div DC_DECLARG((a, b, kscale, result))
      dc_num a DC_DECLSEP
      dc_num b DC_DECLSEP
      int kscale DC_DECLSEP
      dc_num *result DC_DECLEND
{
      bc_init_num((bc_num *)result);
      if (bc_divide(CastNum(a), CastNum(b), (bc_num *)result, kscale)){
            fprintf(stderr, "%s: divide by zero\n", progname);
            checkferror_output(stderr);
            return DC_DOMAIN_ERROR;
      }
      return DC_SUCCESS;
}

/* divide two dc_nums, place quotient into *quotient and remainder
 * into *remainder;
 * return DC_SUCCESS on success, DC_DOMAIN_ERROR on domain error
 */
int
dc_divrem DC_DECLARG((a, b, kscale, quotient, remainder))
      dc_num a DC_DECLSEP
      dc_num b DC_DECLSEP
      int kscale DC_DECLSEP
      dc_num *quotient DC_DECLSEP
      dc_num *remainder DC_DECLEND
{
      bc_init_num((bc_num *)quotient);
      bc_init_num((bc_num *)remainder);
      if (bc_divmod(CastNum(a), CastNum(b),
                                    (bc_num *)quotient, (bc_num *)remainder, kscale)){
            fprintf(stderr, "%s: divide by zero\n", progname);
            checkferror_output(stderr);
            return DC_DOMAIN_ERROR;
      }
      return DC_SUCCESS;
}

/* place the reminder of dividing a by b into *result;
 * return DC_SUCCESS on success, DC_DOMAIN_ERROR on domain error
 */
int
dc_rem DC_DECLARG((a, b, kscale, result))
      dc_num a DC_DECLSEP
      dc_num b DC_DECLSEP
      int kscale DC_DECLSEP
      dc_num *result DC_DECLEND
{
      bc_init_num((bc_num *)result);
      if (bc_modulo(CastNum(a), CastNum(b), (bc_num *)result, kscale)){
            fprintf(stderr, "%s: remainder by zero\n", progname);
            checkferror_output(stderr);
            return DC_DOMAIN_ERROR;
      }
      return DC_SUCCESS;
}

int
dc_modexp DC_DECLARG((base, expo, mod, kscale, result))
      dc_num base DC_DECLSEP
      dc_num expo DC_DECLSEP
      dc_num mod DC_DECLSEP
      int kscale DC_DECLSEP
      dc_num *result DC_DECLEND
{
      bc_init_num((bc_num *)result);
      if (bc_raisemod(CastNum(base), CastNum(expo), CastNum(mod),
                              (bc_num *)result, kscale)){
            if (bc_is_zero(CastNum(mod))) {
                  fprintf(stderr, "%s: remainder by zero\n", progname);
                  checkferror_output(stderr);
            }
            return DC_DOMAIN_ERROR;
      }
      return DC_SUCCESS;
}

/* place the result of exponentiationg a by b into *result;
 * return DC_SUCCESS on success, DC_DOMAIN_ERROR on domain error
 */
int
dc_exp DC_DECLARG((a, b, kscale, result))
      dc_num a DC_DECLSEP
      dc_num b DC_DECLSEP
      int kscale DC_DECLSEP
      dc_num *result DC_DECLEND
{
      bc_init_num((bc_num *)result);
      bc_raise(CastNum(a), CastNum(b), (bc_num *)result, kscale);
      return DC_SUCCESS;
}

/* take the square root of the value, place into *result;
 * return DC_SUCCESS on success, DC_DOMAIN_ERROR on domain error
 */
int
dc_sqrt DC_DECLARG((value, kscale, result))
      dc_num value DC_DECLSEP
      int kscale DC_DECLSEP
      dc_num *result DC_DECLEND
{
      bc_num tmp;

      tmp = bc_copy_num(CastNum(value));
      if (!bc_sqrt(&tmp, kscale)){
            fprintf(stderr, "%s: square root of negative number\n", progname);
            checkferror_output(stderr);
            bc_free_num(&tmp);
            return DC_DOMAIN_ERROR;
      }
      *((bc_num *)result) = tmp;
      return DC_SUCCESS;
}

/* compare dc_nums a and b;
 *  return a negative value if a < b;
 *  return a positive value if a > b;
 *  return zero value if a == b
 */
int
dc_compare DC_DECLARG((a, b))
      dc_num a DC_DECLSEP
      dc_num b DC_DECLEND
{
      return bc_compare(CastNum(a), CastNum(b));
}

/* attempt to convert a dc_num to its corresponding int value
 * If discard_p is DC_TOSS then deallocate the value after use.
 */
int
dc_num2int DC_DECLARG((value, discard_p))
      dc_num value DC_DECLSEP
      dc_discard discard_p DC_DECLEND
{
      long result;

      result = bc_num2long(CastNum(value));
      if (result == 0 && !bc_is_zero(CastNum(value))) {
            fprintf(stderr, "%s: value overflows simple integer; punting...\n",
                        progname);
            result = -1; /* more appropriate for dc's purposes */
      }
      if (discard_p == DC_TOSS)
            dc_free_num(&value);
      return (int)result;
}

/* convert a C integer value into a dc_num */
/* For convenience of the caller, package the dc_num
 * into a dc_data result.
 */
dc_data
dc_int2data DC_DECLARG((value))
      int value DC_DECLEND
{
      dc_data result;

      bc_init_num((bc_num *)&result.v.number);
      bc_int2num((bc_num *)&result.v.number, value);
      result.dc_type = DC_NUMBER;
      return result;
}

/* get a dc_num from some input stream;
 *  input is a function which knows how to read the desired input stream
 *  ibase is the input base (2<=ibase<=DC_IBASE_MAX)
 *  *readahead will be set to the readahead character consumed while
 *   looking for the end-of-number
 */
/* For convenience of the caller, package the dc_num
 * into a dc_data result.
 */
dc_data
dc_getnum DC_DECLARG((input, ibase, readahead))
      int (*input) DC_PROTO((void)) DC_DECLSEP
      int ibase DC_DECLSEP
      int *readahead DC_DECLEND
{
      bc_num      base;
      bc_num      result;
      bc_num      build;
      bc_num      tmp;
      bc_num      divisor;
      dc_data     full_result;
      int         negative = 0;
      int         digit;
      int         decimal;
      int         c;

      bc_init_num(&tmp);
      bc_init_num(&build);
      bc_init_num(&base);
      result = bc_copy_num(_zero_);
      bc_int2num(&base, ibase);
      c = (*input)();
      while (isspace(c))
            c = (*input)();
      if (c == '_' || c == '-'){
            negative = c;
            c = (*input)();
      }else if (c == '+'){
            c = (*input)();
      }
      while (isspace(c))
            c = (*input)();
      for (;;){
            if (isdigit(c))
                  digit = c - '0';
            else if ('A' <= c && c <= 'F')
                  digit = 10 + c - 'A';
            else
                  break;
            c = (*input)();
            bc_int2num(&tmp, digit);
            bc_multiply(result, base, &result, 0);
            bc_add(result, tmp, &result, 0);
      }
      if (c == '.'){
            bc_free_num(&build);
            bc_free_num(&tmp);
            divisor = bc_copy_num(_one_);
            build = bc_copy_num(_zero_);
            decimal = 0;
            for (;;){
                  c = (*input)();
                  if (isdigit(c))
                        digit = c - '0';
                  else if ('A' <= c && c <= 'F')
                        digit = 10 + c - 'A';
                  else
                        break;
                  bc_int2num(&tmp, digit);
                  bc_multiply(build, base, &build, 0);
                  bc_add(build, tmp, &build, 0);
                  bc_multiply(divisor, base, &divisor, 0);
                  ++decimal;
            }
            bc_divide(build, divisor, &build, decimal);
            bc_add(result, build, &result, 0);
      }
      /* Final work. */
      if (negative)
            bc_sub(_zero_, result, &result, 0);

      bc_free_num(&tmp);
      bc_free_num(&build);
      bc_free_num(&base);
      if (readahead)
            *readahead = c;
      full_result.v.number = (dc_num)result;
      full_result.dc_type = DC_NUMBER;
      return full_result;
}


/* Return the "length" of the number, ignoring *all* leading zeros,
 * (including those to the right of the radix point!)
 */
int
dc_numlen DC_DECLARG((value))
      dc_num value DC_DECLEND
{
      /* XXX warning: unholy coziness with the internals of a bc_num! */
      bc_num num = CastNum(value);
      char *p = num->n_value;
      int i = num->n_len + num->n_scale;

      while (1<i && *p=='\0')
            --i, ++p;
      return i;
}

/* return the scale factor of the passed dc_num
 * If discard_p is DC_TOSS then deallocate the value after use.
 */
int
dc_tell_scale DC_DECLARG((value, discard_p))
      dc_num value DC_DECLSEP
      dc_discard discard_p DC_DECLEND
{
      int kscale;

      kscale = CastNum(value)->n_scale;
      if (discard_p == DC_TOSS)
            dc_free_num(&value);
      return kscale;
}


/* initialize the math subsystem */
void
dc_math_init DC_DECLVOID()
{
      bc_init_numbers();
}

/* print out a dc_num in output base obase to stdout;
 * if newline_p is DC_WITHNL, terminate output with a '\n';
 * if discard_p is DC_TOSS then deallocate the value after use
 */
void
dc_out_num DC_DECLARG((value, obase, newline_p, discard_p))
      dc_num value DC_DECLSEP
      int obase DC_DECLSEP
      dc_newline newline_p DC_DECLSEP
      dc_discard discard_p DC_DECLEND
{
      out_char('\0'); /* clear the column counter */
      bc_out_num(CastNum(value), obase, out_char, 0);
      if (newline_p == DC_WITHNL) {
            putchar ('\n');
            checkferror_output(stdout);
      }
      if (discard_p == DC_TOSS)
            dc_free_num(&value);
}

/* dump out the absolute value of the integer part of a
 * dc_num as a byte stream, without any line wrapping;
 * if discard_p is DC_TOSS then deallocate the value after use
 */
void
dc_dump_num DC_DECLARG((dcvalue, discard_p))
      dc_num dcvalue DC_DECLSEP
      dc_discard discard_p DC_DECLEND
{
      struct digit_stack { int digit; struct digit_stack *link;};
      struct digit_stack *top_of_stack = NULL;
      struct digit_stack *cur;
      struct digit_stack *next;
      bc_num value;
      bc_num obase;
      bc_num digit;

      bc_init_num(&value);
      bc_init_num(&obase);
      bc_init_num(&digit);

      /* we only handle the integer portion: */
      bc_divide(CastNum(dcvalue), _one_, &value, 0);
      /* we only handle the absolute value: */
      value->n_sign = PLUS;
      /* we're done with the dcvalue parameter: */
      if (discard_p == DC_TOSS)
            dc_free_num(&dcvalue);

      bc_int2num(&obase, 1+UCHAR_MAX);
      do {
            (void) bc_divmod(value, obase, &value, &digit, 0);
            cur = dc_malloc(sizeof *cur);
            cur->digit = (int)bc_num2long(digit);
            cur->link = top_of_stack;
            top_of_stack = cur;
      } while (!bc_is_zero(value));

      for (cur=top_of_stack; cur; cur=next) {
            putchar(cur->digit);
            checkferror_output(stdout);
            next = cur->link;
            free(cur);
      }

      bc_free_num(&digit);
      bc_free_num(&obase);
      bc_free_num(&value);
}

/* deallocate an instance of a dc_num */
void
dc_free_num DC_DECLARG((value))
      dc_num *value DC_DECLEND
{
      bc_free_num((bc_num *)value);
}

/* return a duplicate of the number in the passed value */
/* The mismatched data types forces the caller to deal with
 * bad dc_type'd dc_data values, and makes it more convenient
 * for the caller to not have to do the grunge work of setting
 * up a dc_type result.
 */
dc_data
dc_dup_num DC_DECLARG((value))
      dc_num value DC_DECLEND
{
      dc_data result;

      ++CastNum(value)->n_refs;
      result.v.number = value;
      result.dc_type = DC_NUMBER;
      return result;
}



/*---------------------------------------------------------------------------\
| The rest of this file consists of stubs for bc routines called by numeric.c|
| so as to minimize the amount of bc code needed to build dc.                |
| The bulk of the code was just lifted straight out of the bc source.        |
\---------------------------------------------------------------------------*/

#ifdef HAVE_STDARG_H
# include <stdarg.h>
#else
# include <varargs.h>
#endif

#ifndef HAVE_STRTOL
/* Maintain some of the error checking of a real strtol() on
 * ancient systems that lack one, but punting on the niceties
 * of supporting bases other than 10 and overflow checking.
 */
long
strtol(const char *s, char **end, int base)
{
      int sign = 1;
      long result = 0;

      for (;; ++s) {
            if (*s == '-')
                  sign = -sign;
            else if (*s != '+' && !isspace(*s))
                  break;
      }
      while (isdigit(*s))
            result = 10*result + (*s++ - '0');
      *end = s;
      return result * sign;
}
#endif /*!HAVE_STRTOL*/


static int out_col = 0;
static int line_max = -1;     /* negative means "need to check environment" */
#define DEFAULT_LINE_MAX 70

static void
set_line_max_from_environment(void)
{
      const char *env_line_len = getenv("DC_LINE_LENGTH");
      line_max = DEFAULT_LINE_MAX;
      errno = 0;
      if (env_line_len) {
            char *endptr;
            long proposed_line_len = strtol(env_line_len, &endptr, 0);
            line_max = (int)proposed_line_len;

            /* silently enforce sanity */
            while (isspace(*endptr))
                  ++endptr;
            if (*endptr || errno || line_max != proposed_line_len
                              || line_max < 0 || line_max == 1)
                  line_max = DEFAULT_LINE_MAX;
      }
}

/* Output routines: Write a character CH to the standard output.
   It keeps track of the number of characters output and may
   break the output with a "<cr>". */

static void
out_char (ch)
      int ch;
{
      if (ch == '\0') {
            out_col = 0;
      } else {
            if (line_max < 0)
                  set_line_max_from_environment();
            if (++out_col >= line_max && line_max != 0) {
                  putchar ('\\');
                  putchar ('\n');
                  out_col = 1;
            }
            putchar(ch);
            checkferror_output(stderr);
      }
}

/* Malloc could not get enough memory. */

void
out_of_memory()
{
      dc_memfail();
}

/* Runtime error --- will print a message and stop the machine. */

#ifdef HAVE_STDARG_H
#ifdef __STDC__
void
rt_error (char *mesg, ...)
#else
void
rt_error (mesg)
      char *mesg;
#endif
#else
void
rt_error (mesg, va_alist)
      char *mesg;
#endif
{
      va_list args;

      fprintf (stderr, "Runtime error: ");
#ifdef HAVE_STDARG_H
      va_start (args, mesg);
#else
      va_start (args);
#endif
      vfprintf (stderr, mesg, args);
      va_end (args);
      fprintf (stderr, "\n");
      checkferror_output(stderr);
}


/* A runtime warning tells of some action taken by the processor that
   may change the program execution but was not enough of a problem
   to stop the execution. */

#ifdef HAVE_STDARG_H
#ifdef __STDC__
void
rt_warn (char *mesg, ...)
#else
void
rt_warn (mesg)
      char *mesg;
#endif
#else
void
rt_warn (mesg, va_alist)
      char *mesg;
#endif
{
      va_list args;

      fprintf (stderr, "Runtime warning: ");
#ifdef HAVE_STDARG_H
      va_start (args, mesg);
#else
      va_start (args);
#endif
      vfprintf (stderr, mesg, args);
      va_end (args);
      fprintf (stderr, "\n");
      checkferror_output(stderr);
}


/*
 * Local Variables:
 * mode: C
 * tab-width: 4
 * End:
 * vi: set ts=4 :
 */

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