freebsd-dev/gnu/usr.bin/dc/dc.c
1993-07-31 01:10:24 +00:00

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/*
* `dc' desk calculator utility.
*
* Copyright (C) 1984, 1993 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 either send email to this
* program's author (see below) or write to: The Free Software Foundation,
* Inc.; 675 Mass Ave. Cambridge, MA 02139, USA.
*/
#include <stdio.h>
#include "decimal.h" /* definitions for our decimal arithmetic package */
FILE *open_file; /* input file now open */
int file_count; /* Number of input files not yet opened */
char **next_file; /* Pointer to vector of names of input files left */
struct regstack
{
decimal value; /* Saved value of register */
struct regstack *rest; /* Tail of list */
};
typedef struct regstack *regstack;
regstack freeregstacks; /* Chain of free regstack structures for fast realloc */
decimal regs[128]; /* "registers", with single-character names */
regstack regstacks[128]; /* For each register, a stack of previous values */
int stacktop; /* index of last used element in stack */
int stacksize; /* Current allocates size of stack */
decimal *stack; /* Pointer to computation stack */
/* A decimal number can be regarded as a string by
treating its contents as characters and ignoring the
position of its decimal point.
Decimal numbers are marked as strings by having an `after' field of -1
One use of strings is to execute them as macros.
*/
#define STRING -1
int macrolevel; /* Current macro nesting; 0 if taking keyboard input */
int macrostacksize; /* Current allocated size of macrostack and macroindex */
decimal *macrostack; /* Pointer to macro stack array */
int *macroindex; /* Pointer to index-within-macro stack array */
/* Note that an empty macro is popped from the stack
only when an trying to read a character from it
or trying to push another macro. */
int ibase; /* Radix for numeric input. */
int obase; /* Radix for numeric output. */
int precision; /* Number of digits to keep in multiply and divide. */
char *buffer; /* Address of buffer used for reading numbers */
int bufsize; /* Current size of buffer (made bigger when nec) */
decimal dec_read ();
regstack get_regstack ();
int fetch ();
int fgetchar ();
char *concat ();
void pushsqrt ();
void condop ();
void setibase ();
void setobase ();
void setprecision ();
void pushmacro ();
decimal read_string ();
void pushlength ();
void pushscale ();
void unfetch ();
void popmacros ();
void popmacro ();
void popstack ();
void print_obj ();
void print_string ();
void free_regstack ();
void pushreg ();
void execute ();
void fputchar ();
void push ();
void incref ();
void decref ();
void binop ();
main (argc, argv, env)
int argc;
char **argv, **env;
{
ibase = 10;
obase = 10;
precision = 0;
freeregstacks = 0;
bzero (regs, sizeof regs);
bzero (regstacks, sizeof regstacks);
bufsize = 40;
buffer = (char *) xmalloc (40);
stacksize = 40;
stack = (decimal *) xmalloc (stacksize * sizeof (decimal));
stacktop = -1;
macrostacksize = 40;
macrostack = (decimal *) xmalloc (macrostacksize * sizeof (decimal));
macroindex = (int *) xmalloc (macrostacksize * sizeof (int));
macrolevel = 0;
/* Initialize for reading input files if any */
open_file = 0;
file_count = argc - 1;
next_file = argv + 1;
while (1)
{
execute ();
}
}
/* Read and execute one command from the current source of input */
void
execute ()
{
int c = fetch ();
if (c < 0) exit (0);
{
switch (c)
{
case '+': /* Arithmetic operators... */
binop (decimal_add);
break;
case '-':
binop (decimal_sub);
break;
case '*':
binop (decimal_mul_dc); /* Like decimal_mul but hairy
way of deciding precision to keep */
break;
case '/':
binop (decimal_div);
break;
case '%':
binop (decimal_rem);
break;
case '^':
binop (decimal_expt);
break;
case '_': /* Begin a negative decimal constant */
{
decimal tem = dec_read (stdin);
tem->sign = !tem->sign;
push (tem);
}
break;
case '.':
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9': /* All these begin decimal constants */
unfetch (c);
push (dec_read (stdin));
break;
case 'A':
case 'B':
case 'C':
case 'D':
case 'E':
case 'F':
unfetch (c);
push (dec_read (stdin));
break;
case 'c': /* Clear the stack */
while (stacktop >= 0)
decref (stack[stacktop--]);
break;
case 'd': /* Duplicate top of stack */
if (stacktop < 0)
error ("stack empty", 0);
else push (stack[stacktop]);
break;
case 'f': /* Describe all registers and stack contents */
{
int regno;
int somereg = 0; /* set to 1 if we print any registers */
for (regno = 0; regno < 128; regno++)
{
if (regs[regno])
{
printf ("register %c: ", regno);
print_obj (regs[regno]);
somereg = 1;
printf ("\n");
}
}
if (somereg)
printf ("\n");
if (stacktop < 0)
printf ("stack empty\n");
else
{
int i;
printf ("stack:\n");
for (i = 0; i <= stacktop; i++)
{
print_obj (stack[stacktop - i]);
printf ("\n");
}
}
}
break;
case 'i': /* ibase <- top of stack */
popstack (setibase);
break;
case 'I': /* Push current ibase */
push (decimal_from_int (ibase));
break;
case 'k': /* like i, I but for precision instead of ibase */
popstack (setprecision);
break;
case 'K':
push (decimal_from_int (precision));
break;
case 'l': /* l<x> load register <x> onto stack */
{
char c1 = fetch ();
if (c1 < 0) exit (0);
if (!regs[c1])
error ("register %c empty", c1);
else
push (regs[c1]);
}
break;
case 'L': /* L<x> load register <x> to stack, pop <x>'s own stack */
{
char c1 = fetch ();
if (c1 < 0) exit (0);
if (!regstacks[c1])
error ("nothing pushed on register %c", c1);
else
{
regstack r = regstacks[c1];
if (!regs[c1])
error ("register %c empty after pop", c1);
else
push (regs[c1]);
regs[c1] = r->value;
regstacks[c1] = r->rest;
free_regstack (r);
}
}
break;
case 'o': /* o, O like i, I but for obase instead of ibase */
popstack (setobase);
break;
case 'O':
push (decimal_from_int (obase));
break;
case 'p': /* Print tos, don't pop, do print newline afterward */
if (stacktop < 0)
error ("stack empty", 0);
else
{
print_obj (stack[stacktop]);
printf ("\n");
}
break;
case 'P': /* Print tos, do pop, no newline afterward */
popstack (print_obj);
break;
case 'q': /* Exit */
if (macrolevel)
{ popmacro (); popmacro (); } /* decrease recursion level by 2 */
else
exit (0); /* If not in a macro, exit the program. */
break;
case 'Q': /* Tos says how many levels to exit */
popstack (popmacros);
break;
case 's': /* s<x> -- Pop stack and set register <x> */
if (stacktop < 0)
empty ();
else
{
int c1 = fetch ();
if (c1 < 0) exit (0);
if (regs[c1]) decref (regs[c1]);
regs[c1] = stack[stacktop--];
}
break;
case 'S': /* S<x> -- pop stack and push as new value of register <x> */
if (stacktop < 0)
empty ();
else
{
int c1 = fetch ();
if (c1 < 0) exit (0);
pushreg (c1);
regs[c1] = stack[stacktop--];
}
break;
case 'v': /* tos gets square root of tos */
popstack (pushsqrt);
break;
case 'x': /* pop stack , call as macro */
popstack (pushmacro);
break;
case 'X': /* Pop stack, get # fraction digits, push that */
popstack (pushscale);
break;
case 'z': /* Compute depth of stack, push that */
push (decimal_from_int (stacktop + 1));
break;
case 'Z': /* Pop stack, get # digits, push that */
popstack (pushlength);
break;
case '<': /* Conditional: pop two numbers, compare, maybe execute register */
/* Note: for no obvious reason, the standard Unix `dc'
considers < to be true if the top of stack is less
than the next-to-top of stack,
and vice versa for >.
This seems backwards to me, but I am preserving compatibility. */
condop (1);
break;
case '>':
condop (-1);
break;
case '=':
condop (0);
break;
case '?': /* Read expression from terminal and execute it */
/* First ignore any leading newlines */
{
int c1;
while ((c1 = getchar ()) == '\n');
ungetc (c1, stdin);
}
/* Read a line from the terminal and execute it. */
pushmacro (read_string ('\n', fgetchar, 0));
break;
case '[': /* Begin string constant */
push (read_string (']', fetch, '['));
break;
case ' ':
case '\n':
break;
default:
error ("undefined command %c", c);
}
}
}
/* Functionals for performing arithmetic, etc */
/* Call the function `op', with the top of stack value as argument,
and then pop the stack.
If the stack is empty, print a message and do not call `op'. */
void
popstack (op)
void (*op) ();
{
if (stacktop < 0)
empty ();
else
{
decimal value = stack[stacktop--];
op (value);
decref (value);
}
}
/* Call the function `op' with two arguments taken from the stack top,
then pop those arguments and push the value returned by `op'.
`op' is assumed to return a decimal number.
If there are not two values on the stack, print a message
and do not call `op'. */
void
binop (op)
decimal (*op) ();
{
if (stacktop < 1)
error ("stack empty", 0);
else if (stack[stacktop]->after == STRING || stack[stacktop - 1]->after == STRING)
error ("operands not both numeric");
else
{
decimal arg2 = stack [stacktop--];
decimal arg1 = stack [stacktop--];
push (op (arg1, arg2, precision));
decref (arg1);
decref (arg2);
}
}
void
condop (cond)
int cond;
{
int regno = fetch ();
if (!regs[regno])
error ("register %c is empty", regno);
else if (stacktop < 1)
empty ();
else
{
decimal arg2 = stack[stacktop--];
decimal arg1 = stack[stacktop--];
int relation = decimal_compare (arg1, arg2);
decref (arg1);
decref (arg2);
if (cond == relation
|| (cond < 0 && relation < 0)
|| (cond > 0 && relation > 0))
pushmacro (regs[regno]);
}
}
/* Handle the command input source */
/* Fetch the next command character from a macro or from the terminal */
int
fetch()
{
int c = -1;
while (macrolevel &&
LENGTH (macrostack[macrolevel-1]) == macroindex[macrolevel-1])
popmacro();
if (macrolevel)
return macrostack[macrolevel - 1]->contents[macroindex[macrolevel-1]++];
while (1)
{
if (open_file)
{
c = getc (open_file);
if (c >= 0) break;
fclose (open_file);
open_file = 0;
}
else if (file_count)
{
open_file = fopen (*next_file++, "r");
file_count--;
if (!open_file)
perror_with_name (*(next_file - 1));
}
else break;
}
if (c >= 0) return c;
return getc (stdin);
}
/* Unread character c on command input stream, whatever it is */
void
unfetch (c)
char c;
{
if (macrolevel)
macroindex[macrolevel-1]--;
else if (open_file)
ungetc (c, open_file);
else
ungetc (c, stdin);
}
/* Begin execution of macro m. */
void
pushmacro (m)
decimal m;
{
while (macrolevel &&
LENGTH (macrostack[macrolevel-1]) == macroindex[macrolevel-1])
popmacro();
if (m->after == STRING)
{
if (macrolevel == macrostacksize)
{
macrostacksize *= 2;
macrostack = (decimal *) xrealloc (macrostack, macrostacksize * sizeof (decimal));
macroindex = (int *) xrealloc (macroindex, macrostacksize * sizeof (int));
}
macroindex[macrolevel] = 0;
macrostack[macrolevel++] = m;
incref (m);
}
else
{ /* Number supplied as a macro! */
push (m); /* Its effect wouyld be to push the number. */
}
}
/* Pop a specified number of levels of macro execution.
The number of levels is specified by a decimal number d. */
void
popmacros (d)
decimal d;
{
int num_pops = decimal_to_int (d);
int i;
for (i = 0; i < num_pops; i++)
popmacro ();
}
/* Exit one level of macro execution. */
void
popmacro ()
{
if (!macrolevel)
exit (0);
else
{
decref (macrostack[--macrolevel]);
}
}
void
push (d)
decimal d;
{
if (stacktop == stacksize - 1)
stack = (decimal *) xrealloc (stack, (stacksize *= 2) * sizeof (decimal));
incref (d);
stack[++stacktop] = d;
}
/* Reference counting and storage freeing */
void
decref (d)
decimal d;
{
if (!--d->refcnt)
free (d);
}
void
incref (d)
decimal d;
{
d->refcnt++;
}
empty ()
{
error ("stack empty", 0);
}
regstack
get_regstack ()
{
if (freeregstacks)
{
regstack r = freeregstacks;
freeregstacks = r ->rest;
return r;
}
else
return (regstack) xmalloc (sizeof (struct regstack));
}
void
free_regstack (r)
regstack r;
{
r->rest = freeregstacks;
freeregstacks = r;
}
void
pushreg (c)
char c;
{
regstack r = get_regstack ();
r->rest = regstacks[c];
r->value = regs[c];
regstacks[c] = r;
regs[c] = 0;
}
/* Input of numbers and strings */
/* Return a character read from the terminal. */
fgetchar ()
{
return getchar ();
}
void
fputchar (c)
char (c);
{
putchar (c);
}
/* Read text from command input source up to a close-bracket,
make a string out of it, and return it.
If STARTC is nonzero, then it and STOPC must balance when nested. */
decimal
read_string (stopc, inputfn, startc)
char stopc;
int (*inputfn) ();
int startc;
{
int c;
decimal result;
int i = 0;
int count = 0;
while (1)
{
c = inputfn ();
if (c < 0 || (c == stopc && count == 0))
{
if (count != 0)
error ("Unmatched `%c'", startc);
break;
}
if (c == stopc)
count--;
if (c == startc)
count++;
if (i + 1 >= bufsize)
buffer = (char *) xrealloc (buffer, bufsize *= 2);
buffer[i++] = c;
}
result = make_decimal (i, 0);
result->after = -1; /* Mark it as a string */
result->before++; /* but keep the length unchanged */
bcopy (buffer, result->contents, i);
return result;
}
/* Read a number from the current input source */
decimal
dec_read ()
{
int c;
int i = 0;
while (1)
{
c = fetch ();
if (! ((c >= '0' && c <= '9')
|| (c >= 'A' && c <= 'F')
|| c == '.'))
break;
if (i + 1 >= bufsize)
buffer = (char *) xrealloc (buffer, bufsize *= 2);
buffer[i++] = c;
}
buffer[i++] = 0;
unfetch (c);
return decimal_parse (buffer, ibase);
}
/* Output of numbers and strings */
/* Print the contents of obj, either numerically or as a string,
according to what obj says it is. */
void
print_obj (obj)
decimal obj;
{
if (obj->after == STRING)
print_string (obj);
else
decimal_print (obj, fputchar, obase);
}
/* Print the contents of the decimal number `string', treated as a string. */
void
print_string (string)
decimal string;
{
char *p = string->contents;
int len = LENGTH (string);
int i;
for (i = 0; i < len; i++)
{
putchar (*p++);
}
}
/* Set the input radix from the value of the decimal number d, if valid. */
void
setibase (d)
decimal d;
{
int value = decimal_to_int (d);
if (value < 2 || value > 36)
error ("input radix must be from 2 to 36", 0);
else
ibase = value;
}
/* Set the output radix from the value of the decimal number d, if valid. */
void
setobase (d)
decimal d;
{
int value = decimal_to_int (d);
if (value < 2 || value > 36)
error ("output radix must be from 2 to 36", 0);
else
obase = value;
}
/* Set the precision for mul and div from the value of the decimal number d, if valid. */
void
setprecision (d)
decimal d;
{
int value = decimal_to_int (d);
if (value < 0 || value > 30000)
error ("precision must be nonnegative and < 30000", 0);
else
precision = value;
}
/* Push the number of digits in decimal number d, as a decimal number. */
void
pushlength (d)
decimal d;
{
push (decimal_from_int (LENGTH (d)));
}
/* Push the number of fraction digits in d. */
void
pushscale (d)
decimal d;
{
push (decimal_from_int (d->after));
}
/* Push the square root of decimal number d. */
void
pushsqrt (d)
decimal d;
{
push (decimal_sqrt (d, precision));
}
/* Print error message and exit. */
fatal (s1, s2)
char *s1, *s2;
{
error (s1, s2);
exit (1);
}
/* Print error message. `s1' is printf control string, `s2' is arg for it. */
error (s1, s2)
char *s1, *s2;
{
printf ("dc: ");
printf (s1, s2);
printf ("\n");
}
decimal_error (s1, s2)
char *s1, *s2;
{
error (s1, s2);
}
perror_with_name (name)
char *name;
{
extern int errno, sys_nerr;
extern char *sys_errlist[];
char *s;
if (errno < sys_nerr)
s = concat ("", sys_errlist[errno], " for %s");
else
s = "cannot open %s";
error (s, name);
}
/* Return a newly-allocated string whose contents concatenate those of s1, s2, s3. */
char *
concat (s1, s2, s3)
char *s1, *s2, *s3;
{
int len1 = strlen (s1), len2 = strlen (s2), len3 = strlen (s3);
char *result = (char *) xmalloc (len1 + len2 + len3 + 1);
strcpy (result, s1);
strcpy (result + len1, s2);
strcpy (result + len1 + len2, s3);
*(result + len1 + len2 + len3) = 0;
return result;
}
/* Like malloc but get fatal error if memory is exhausted. */
int
xmalloc (size)
int size;
{
int result = malloc (size);
if (!result)
fatal ("virtual memory exhausted", 0);
return result;
}
int
xrealloc (ptr, size)
char *ptr;
int size;
{
int result = realloc (ptr, size);
if (!result)
fatal ("virtual memory exhausted");
return result;
}