/* vi: set sw=4 ts=4: */
/*
- * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
+//config:config DC
+//config: bool "dc (4.2 kb)"
+//config: default y
+//config: help
+//config: Dc is a reverse-polish desk calculator which supports unlimited
+//config: precision arithmetic.
+//config:
+//config:config FEATURE_DC_LIBM
+//config: bool "Enable power and exp functions (requires libm)"
+//config: default y
+//config: depends on DC
+//config: help
+//config: Enable power and exp functions.
+//config: NOTE: This will require libm to be present for linking.
+
+//applet:IF_DC(APPLET(dc, BB_DIR_USR_BIN, BB_SUID_DROP))
+
+//kbuild:lib-$(CONFIG_DC) += dc.o
+
+//usage:#define dc_trivial_usage
+//usage: "EXPRESSION..."
+//usage:
+//usage:#define dc_full_usage "\n\n"
+//usage: "Tiny RPN calculator. Operations:\n"
+//usage: "+, add, -, sub, *, mul, /, div, %, mod, "IF_FEATURE_DC_LIBM("**, exp, ")"and, or, not, xor,\n"
+//usage: "p - print top of the stack (without popping),\n"
+//usage: "f - print entire stack,\n"
+//usage: "o - pop the value and set output radix (must be 10, 16, 8 or 2).\n"
+//usage: "Examples: 'dc 2 2 add p' -> 4, 'dc 8 8 mul 2 2 + / p' -> 16"
+//usage:
+//usage:#define dc_example_usage
+//usage: "$ dc 2 2 + p\n"
+//usage: "4\n"
+//usage: "$ dc 8 8 \\* 2 2 + / p\n"
+//usage: "16\n"
+//usage: "$ dc 0 1 and p\n"
+//usage: "0\n"
+//usage: "$ dc 0 1 or p\n"
+//usage: "1\n"
+//usage: "$ echo 72 9 div 8 mul p | dc\n"
+//usage: "64\n"
#include "libbb.h"
+#include "common_bufsiz.h"
#include <math.h>
-/* Tiny RPN calculator, because "expr" didn't give me bitwise operations. */
+#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 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)
static double pop(void)
{
- if (pointer == 0)
- bb_error_msg_and_die("stack underflow");
+ check_under();
return stack[--pointer];
}
static void mod(void)
{
- unsigned d = pop();
+ data_t d = pop();
- push((unsigned) pop() % d);
+ push((data_t) pop() % d);
}
static void and(void)
{
- push((unsigned) pop() & (unsigned) pop());
+ push((data_t) pop() & (data_t) pop());
}
static void or(void)
{
- push((unsigned) pop() | (unsigned) pop());
+ push((data_t) pop() | (data_t) pop());
}
static void eor(void)
{
- push((unsigned) pop() ^ (unsigned) pop());
+ push((data_t) pop() ^ (data_t) pop());
}
static void not(void)
{
- push(~(unsigned) pop());
+ push(~(data_t) pop());
}
static void set_output_base(void)
static void print_base(double print)
{
- unsigned x, i;
+ data_t x, i;
+ x = (data_t) print;
if (base == 10) {
- printf("%g\n", print);
+ if (x == print) /* exactly representable as unsigned integer */
+ printf("%"DATA_FMT"u\n", x);
+ else
+ printf("%g\n", print);
return;
}
- x = (unsigned)print;
switch (base) {
case 16:
- printf("%x\n", x);
+ printf("%"DATA_FMT"x\n", x);
break;
case 8:
- printf("%o\n", x);
+ printf("%"DATA_FMT"o\n", x);
break;
default: /* base 2 */
- i = (unsigned)INT_MAX + 1;
+ i = MAXINT(data_t) - (MAXINT(data_t) >> 1);
+ /* i is 100000...00000 */
do {
- if (x & i) break;
+ if (x & i)
+ break;
i >>= 1;
} while (i > 1);
do {
static void print_no_pop(void)
{
+ check_under();
print_base(stack[pointer-1]);
}
};
static const struct op operators[] = {
- {"+", add},
- {"add", add},
- {"-", sub},
- {"sub", sub},
- {"*", mul},
- {"mul", mul},
- {"/", divide},
- {"div", divide},
#if ENABLE_FEATURE_DC_LIBM
{"**", power},
{"exp", power},
{"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},
- { /* zero filled */ }
};
+/* Feed the stack machine */
static void stack_machine(const char *argument)
{
- char *endPointer;
- double d;
- const struct op *o = operators;
-
- if (argument == 0)
- return;
+ char *end;
+ double number;
+ const struct op *o;
+
+ next:
+ number = strtod(argument, &end);
+ if (end != argument) {
+ argument = end;
+ push(number);
+ goto next;
+ }
- d = strtod(argument, &endPointer);
+ /* We might have matched a digit, eventually advance the argument */
+ argument = skip_whitespace(argument);
- if (endPointer != argument) {
- push(d);
+ if (*argument == '\0')
return;
- }
- while (o->name[0]) {
- if (strcmp(o->name, argument) == 0) {
+ o = operators;
+ do {
+ char *after_name = is_prefixed_with(argument, o->name);
+ if (after_name) {
+ argument = after_name;
o->function();
- return;
+ goto next;
}
o++;
- }
- bb_error_msg_and_die("%s: syntax error", argument);
-}
+ } while (o != operators + ARRAY_SIZE(operators));
-/* return pointer to next token in buffer and set *buffer to one char
- * past the end of the above mentioned token
- */
-static char *get_token(char **buffer)
-{
- char *current = skip_whitespace(*buffer);
- if (*current != '\0') {
- *buffer = skip_non_whitespace(current);
- return current;
- }
- return NULL;
+ bb_error_msg_and_die("syntax error at '%s'", argument);
}
int dc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
if (!argv[0]) {
/* take stuff from stdin if no args are given */
char *line;
- char *cursor;
- char *token;
while ((line = xmalloc_fgetline(stdin)) != NULL) {
- cursor = line;
- while (1) {
- token = get_token(&cursor);
- if (!token) break;
- *cursor++ = '\0';
- stack_machine(token);
- }
+ stack_machine(line);
free(line);
}
} else {
- if (argv[0][0] == '-')
- bb_show_usage();
do {
stack_machine(*argv);
} while (*++argv);
projects / oweals / busybox.git / blobdiff