X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=miscutils%2Fdc.c;h=b922a7184d7d2fe2934662fca61b7ad50dd5cef6;hb=d72e804e6db1bd6eb2417961004b4fe33aba9384;hp=68ecd8a3f8e690325bcdb77c0da3effc77c0fff7;hpb=b44c790e41e281965955a83408f35ea53ecdb3d2;p=oweals%2Fbusybox.git diff --git a/miscutils/dc.c b/miscutils/dc.c index 68ecd8a3f..b922a7184 100644 --- a/miscutils/dc.c +++ b/miscutils/dc.c @@ -1,25 +1,86 @@ /* 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 -/* 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) { @@ -30,8 +91,7 @@ static void push(double a) static double pop(void) { - if (pointer == 0) - bb_error_msg_and_die("stack underflow"); + check_under(); return stack[--pointer]; } @@ -52,12 +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) { @@ -68,46 +130,77 @@ static void divide(void) 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) { - base = (unsigned)pop(); - if ((base != 10) && (base != 16)) { - bb_error_msg("error, base %d is not supported", base); + 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)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) @@ -119,6 +212,7 @@ static void print_stack_no_pop(void) static void print_no_pop(void) { + check_under(); print_base(stack[pointer-1]); } @@ -128,17 +222,11 @@ struct op { }; 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}, @@ -146,73 +234,68 @@ 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}, - { /* 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; -int dc_main(int argc ATTRIBUTE_UNUSED, char **argv) +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_getline(stdin)) != NULL) { - cursor = line; - while (1) { - token = get_token(&cursor); - if (!token) break; - *cursor++ = '\0'; - stack_machine(token); - } + while ((line = xmalloc_fgetline(stdin)) != NULL) { + stack_machine(line); free(line); } } else { - if (argv[0][0] == '-') - bb_show_usage(); do { stack_machine(*argv); } while (*++argv);