| /* vi: set sw=4 ts=4: */ |
| /* |
| * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. |
| */ |
| |
| #include "libbb.h" |
| #include <math.h> |
| |
| /* Tiny RPN calculator, because "expr" didn't give me bitwise operations. */ |
| |
| |
| 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) |
| { |
| unsigned d = pop(); |
| |
| push((unsigned) pop() % d); |
| } |
| |
| static void and(void) |
| { |
| push((unsigned) pop() & (unsigned) pop()); |
| } |
| |
| static void or(void) |
| { |
| push((unsigned) pop() | (unsigned) pop()); |
| } |
| |
| static void eor(void) |
| { |
| push((unsigned) pop() ^ (unsigned) pop()); |
| } |
| |
| static void not(void) |
| { |
| push(~(unsigned) 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) |
| { |
| unsigned x, i; |
| |
| if (base == 10) { |
| printf("%g\n", print); |
| return; |
| } |
| |
| x = (unsigned)print; |
| switch (base) { |
| case 16: |
| printf("%x\n", x); |
| break; |
| case 8: |
| printf("%o\n", x); |
| break; |
| default: /* base 2 */ |
| i = (unsigned)INT_MAX + 1; |
| 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); |
| } |
| |
| /* 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; |
| } |
| |
| 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 = get_token(&cursor); |
| if (!token) |
| break; |
| *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; |
| } |