/* vi: set sw=4 ts=4: */ /* * Licensed under GPLv2 or later, see file LICENSE in this source tree. */ #include "libbb.h" #include <math.h> //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, eor,\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 * 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" #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 { \ base = 10; \ } while (0) static void push(double a) { if (pointer >= STACK_SIZE) bb_error_msg_and_die("stack overflow"); stack[pointer++] = a; } static double pop(void) { if (pointer == 0) bb_error_msg_and_die("stack underflow"); 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) { print_base(stack[pointer-1]); } struct op { const char name[4]; void (*function) (void); }; 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}, {"pow", power}, #endif {"%", mod}, {"mod", mod}, {"and", and}, {"or", or}, {"not", not}, {"eor", eor}, {"xor", eor}, {"p", print_no_pop}, {"f", print_stack_no_pop}, {"o", set_output_base}, { "", NULL } }; static void stack_machine(const char *argument) { char *endPointer; double d; const struct op *o = operators; d = strtod(argument, &endPointer); if (endPointer != argument && *endPointer == '\0') { push(d); return; } while (o->function) { if (strcmp(o->name, argument) == 0) { o->function(); return; } o++; } 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; char *cursor; char *token; while ((line = xmalloc_fgetline(stdin)) != NULL) { cursor = line; while (1) { token = skip_whitespace(cursor); if (*token == '\0') break; cursor = skip_non_whitespace(token); if (*cursor != '\0') *cursor++ = '\0'; stack_machine(token); } free(line); } } else { // why? it breaks "dc -2 2 + p" //if (argv[0][0] == '-') // bb_show_usage(); do { stack_machine(*argv); } while (*++argv); } return EXIT_SUCCESS; }