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/* vi: set sw=4 ts=4: */
/*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
/* config/applet/usage bits are in bc.c */
//#include "libbb.h"
//#include "common_bufsiz.h"
#include <math.h>
#if 0
typedef unsigned data_t;
#define DATA_FMT ""
#elif 0
typedef unsigned long data_t;
#define DATA_FMT "l"
#else
typedef unsigned long long data_t;
#define DATA_FMT "ll"
#endif
struct globals {
unsigned pointer;
unsigned base;
double stack[1];
} FIX_ALIASING;
enum { STACK_SIZE = (COMMON_BUFSIZE - offsetof(struct globals, stack)) / sizeof(double) };
#define G (*(struct globals*)bb_common_bufsiz1)
#define pointer (G.pointer )
#define base (G.base )
#define stack (G.stack )
#define INIT_G() do { \
setup_common_bufsiz(); \
base = 10; \
} while (0)
static void check_under(void)
{
if (pointer == 0)
bb_error_msg_and_die("stack underflow");
}
static void push(double a)
{
if (pointer >= STACK_SIZE)
bb_error_msg_and_die("stack overflow");
stack[pointer++] = a;
}
static double pop(void)
{
check_under();
return stack[--pointer];
}
static void add(void)
{
push(pop() + pop());
}
static void sub(void)
{
double subtrahend = pop();
push(pop() - subtrahend);
}
static void mul(void)
{
push(pop() * pop());
}
#if ENABLE_FEATURE_DC_LIBM
static void power(void)
{
double topower = pop();
push(pow(pop(), topower));
}
#endif
static void divide(void)
{
double divisor = pop();
push(pop() / divisor);
}
static void mod(void)
{
data_t d = pop();
push((data_t) pop() % d);
}
static void and(void)
{
push((data_t) pop() & (data_t) pop());
}
static void or(void)
{
push((data_t) pop() | (data_t) pop());
}
static void eor(void)
{
push((data_t) pop() ^ (data_t) pop());
}
static void not(void)
{
push(~(data_t) pop());
}
static void set_output_base(void)
{
static const char bases[] ALIGN1 = { 2, 8, 10, 16, 0 };
unsigned b = (unsigned)pop();
base = *strchrnul(bases, b);
if (base == 0) {
bb_error_msg("error, base %u is not supported", b);
base = 10;
}
}
static void print_base(double print)
{
data_t x, i;
x = (data_t) print;
if (base == 10) {
if (x == print) /* exactly representable as unsigned integer */
printf("%"DATA_FMT"u\n", x);
else
printf("%g\n", print);
return;
}
switch (base) {
case 16:
printf("%"DATA_FMT"x\n", x);
break;
case 8:
printf("%"DATA_FMT"o\n", x);
break;
default: /* base 2 */
i = MAXINT(data_t) - (MAXINT(data_t) >> 1);
/* i is 100000...00000 */
do {
if (x & i)
break;
i >>= 1;
} while (i > 1);
do {
bb_putchar('1' - !(x & i));
i >>= 1;
} while (i);
bb_putchar('\n');
}
}
static void print_stack_no_pop(void)
{
unsigned i = pointer;
while (i)
print_base(stack[--i]);
}
static void print_no_pop(void)
{
check_under();
print_base(stack[pointer-1]);
}
struct op {
const char name[4];
void (*function) (void);
};
static const struct op operators[] = {
#if ENABLE_FEATURE_DC_LIBM
{"**", power},
{"exp", power},
{"pow", power},
#endif
{"%", mod},
{"mod", mod},
{"and", and},
{"or", or},
{"not", not},
{"eor", eor},
{"xor", eor},
{"+", add},
{"add", add},
{"-", sub},
{"sub", sub},
{"*", mul},
{"mul", mul},
{"/", divide},
{"div", divide},
{"p", print_no_pop},
{"f", print_stack_no_pop},
{"o", set_output_base},
};
/* Feed the stack machine */
static void stack_machine(const char *argument)
{
char *end;
double number;
const struct op *o;
next:
number = strtod(argument, &end);
if (end != argument) {
argument = end;
push(number);
goto next;
}
/* We might have matched a digit, eventually advance the argument */
argument = skip_whitespace(argument);
if (*argument == '\0')
return;
o = operators;
do {
char *after_name = is_prefixed_with(argument, o->name);
if (after_name) {
argument = after_name;
o->function();
goto next;
}
o++;
} while (o != operators + ARRAY_SIZE(operators));
bb_error_msg_and_die("syntax error at '%s'", argument);
}
int dc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int dc_main(int argc UNUSED_PARAM, char **argv)
{
INIT_G();
argv++;
if (!argv[0]) {
/* take stuff from stdin if no args are given */
char *line;
while ((line = xmalloc_fgetline(stdin)) != NULL) {
stack_machine(line);
free(line);
}
} else {
do {
stack_machine(*argv);
} while (*++argv);
}
return EXIT_SUCCESS;
}
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