Merge branch 'master' of git+ssh://busybox.net/var/lib/git/busybox

[oweals/busybox.git] / miscutils / dc.c

diff --git a/miscutils/dc.c b/miscutils/dc.c
index ff2bc3bcef6869eacb8be7799cc97657b65e5d13..6903761e4f4b9983a7c31c5331fd5ce73aafae88 100644 (file)
--- a/miscutils/dc.c
+++ b/miscutils/dc.c
@@ -1,19 +1,51 @@
 /* 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 <math.h>
 
-/* Tiny RPN calculator, because "expr" didn't give me bitwise operations. */
+//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   )
@@ -73,29 +105,29 @@ 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)
@@ -112,25 +144,30 @@ static void set_output_base(void)
 
 static void print_base(double print)
 {
-       unsigned x, i;
+       data_t x, i;
 
+       x = (data_t) print;
        if (base == 10) {
-               printf("%g\n", print);
+               if (x == print) /* exactly representable as unsigned integer */
+                       printf("%"DATA_FMT"u\n", x);
+               else
+                       printf("%g\n", print);
                return;
        }
 
-       x = (unsigned)print;
        switch (base) {
        case 16:
-               printf("%x\n", x);
+               printf("%"DATA_FMT"x\n", x);
                break;
        case 8:
-               printf("%o\n", x);
+               printf("%"DATA_FMT"o\n", x);
                break;
        default: /* base 2 */
-               i = (unsigned)INT_MAX + 1;
+               i = MAXINT(data_t) - (MAXINT(data_t) >> 1);
+               /* i is 100000...00000 */
                do {
-                       if (x & i) break;
+                       if (x & i)
+                               break;
                        i >>= 1;
                } while (i > 1);
                do {
@@ -182,7 +219,7 @@ static const struct op operators[] = {
        {"p", print_no_pop},
        {"f", print_stack_no_pop},
        {"o", set_output_base},
-       { /* zero filled */ }
+       { "", NULL }
 };
 
 static void stack_machine(const char *argument)
@@ -191,37 +228,21 @@ static void stack_machine(const char *argument)
        double d;
        const struct op *o = operators;
 
-       if (argument == 0)
-               return;
-
        d = strtod(argument, &endPointer);
 
-       if (endPointer != argument) {
+       if (endPointer != argument && *endPointer == '\0') {
                push(d);
                return;
        }
 
-       while (o->name[0]) {
+       while (o->function) {
                if (strcmp(o->name, argument) == 0) {
                        o->function();
                        return;
                }
                o++;
        }
-       bb_error_msg_and_die("%s: syntax error", 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;
+       bb_error_msg_and_die("syntax error at '%s'", argument);
 }
 
 int dc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
@@ -238,16 +259,20 @@ int dc_main(int argc UNUSED_PARAM, char **argv)
                while ((line = xmalloc_fgetline(stdin)) != NULL) {
                        cursor = line;
                        while (1) {
-                               token = get_token(&cursor);
-                               if (!token) break;
-                               *cursor++ = '\0';
+                               token = skip_whitespace(cursor);
+                               if (*token == '\0')
+                                       break;
+                               cursor = skip_non_whitespace(token);
+                               if (*cursor != '\0')
+                                       *cursor++ = '\0';
                                stack_machine(token);
                        }
                        free(line);
                }
        } else {
-               if (argv[0][0] == '-')
-                       bb_show_usage();
+               // why? it breaks "dc -2 2 + p"
+               //if (argv[0][0] == '-')
+               //      bb_show_usage();
                do {
                        stack_machine(*argv);
                } while (*++argv);