X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=miscutils%2Fdc.c;h=b922a7184d7d2fe2934662fca61b7ad50dd5cef6;hb=d72e804e6db1bd6eb2417961004b4fe33aba9384;hp=fd5390143f2a59959e9cd84daab04f31d4699a3d;hpb=2d5ca60bfb66e0ba7340ab9b4696b872f00adf7c;p=oweals%2Fbusybox.git diff --git a/miscutils/dc.c b/miscutils/dc.c index fd5390143..b922a7184 100644 --- a/miscutils/dc.c +++ b/miscutils/dc.c @@ -1,33 +1,97 @@ /* 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 "busybox.h" -#include -#include -#include -#include -#include +//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 -/* Tiny RPN calculator, because "expr" didn't give me bitwise operations. */ - -static double stack[100]; -static unsigned int pointer; -static unsigned char base; +#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 >= (sizeof(stack) / sizeof(*stack))) + 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"); + check_under(); return stack[--pointer]; } @@ -48,12 +112,14 @@ 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) { @@ -64,77 +130,103 @@ static void divide(void) static void mod(void) { - unsigned int d = pop(); + data_t d = pop(); - push((unsigned int) pop() % d); + push((data_t) pop() % d); } static void and(void) { - push((unsigned int) pop() & (unsigned int) pop()); + push((data_t) pop() & (data_t) pop()); } static void or(void) { - push((unsigned int) pop() | (unsigned int) pop()); + push((data_t) pop() | (data_t) pop()); } static void eor(void) { - push((unsigned int) pop() ^ (unsigned int) pop()); + push((data_t) pop() ^ (data_t) pop()); } static void not(void) { - push(~(unsigned int) pop()); + push(~(data_t) pop()); } static void set_output_base(void) { - base=(unsigned char)pop(); - if ((base != 10) && (base != 16)) { - fprintf(stderr, "Error: base = %d is not supported.\n", base); - base=10; + 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) { - if (base == 16) - printf("%x\n", (unsigned int)print); - else - printf("%g\n", 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 int i=pointer; + 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; + 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}, @@ -142,90 +234,71 @@ static const struct op operators[] = { {"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}, - {0, 0} }; +/* Feed the stack machine */ static void stack_machine(const char *argument) { - char *endPointer = 0; - 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->function)) (); - return; + o = operators; + do { + char *after_name = is_prefixed_with(argument, o->name); + if (after_name) { + argument = after_name; + o->function(); + goto next; } o++; - } - bb_error_msg_and_die("%s: syntax error", argument); + } while (o != operators + ARRAY_SIZE(operators)); + + 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) +int dc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; +int dc_main(int argc UNUSED_PARAM, char **argv) { - char *start = NULL; - char *current = *buffer; - - while (isspace(*current)) { current++; } - if (*current != 0) { - start = current; - while (!isspace(*current) && *current != 0) { current++; } - *buffer = current; - } - return start; -} - -/* In Perl one might say, scalar m|\s*(\S+)\s*|g */ -static int number_of_tokens(char *buffer) -{ - int i = 0; - char *b = buffer; - while (get_token(&b)) { i++; } - return i; -} - -int dc_main(int argc, char **argv) -{ - /* take stuff from stdin if no args are given */ - if (argc <= 1) { - int i, len; - char *line = NULL; - char *cursor = NULL; - char *token = NULL; - while ((line = xmalloc_getline(stdin))) { - cursor = line; - len = number_of_tokens(line); - for (i = 0; i < len; i++) { - token = get_token(&cursor); - *cursor++ = 0; - stack_machine(token); - } + 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 { - if (*argv[1]=='-') - bb_show_usage(); - while (argc >= 2) { - stack_machine(argv[1]); - argv++; - argc--; - } + do { + stack_machine(*argv); + } while (*++argv); } return EXIT_SUCCESS; }