/* 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.
*/
#include "libbb.h"
+#include "common_bufsiz.h"
#include <math.h>
//usage:#define dc_trivial_usage
//usage:
//usage:#define dc_full_usage "\n\n"
//usage: "Tiny RPN calculator. Operations:\n"
-//usage: "+, add, -, sub, *, mul, /, div, %, mod, **, exp, and, or, not, eor,\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' -> 4, 'dc 8 8 * 2 2 + /' -> 16"
+//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"
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 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},
- { "", NULL }
};
+/* Feed the stack machine */
static void stack_machine(const char *argument)
{
- char *endPointer;
- double d;
- const struct op *o = operators;
+ 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 && *endPointer == '\0') {
- push(d);
+ if (*argument == '\0')
return;
- }
- while (o->function) {
- 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("syntax error at '%s'", 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 {
- // why? it breaks "dc -2 2 * p"
- //if (argv[0][0] == '-')
- // bb_show_usage();
do {
stack_machine(*argv);
} while (*++argv);