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authorJohn Beppu <beppu@lbox.org>2000-06-21 19:06:16 +0000
committerJohn Beppu <beppu@lbox.org>2000-06-21 19:06:16 +0000
commit0021679b0dc5767e0c023b28b36eeb1476dc2364 (patch)
tree04ff8031a2151a0f95040bbc4bdf2f616d68a540 /math.c
parentb405dfa54df117201d93dcb7d24e9e9873737da6 (diff)
downloadbusybox-0021679b0dc5767e0c023b28b36eeb1476dc2364.tar.gz
+ added dc (aka the function formerly known as math)
+ did all the housekeeping that this change requires.
Diffstat (limited to 'math.c')
-rw-r--r--math.c194
1 files changed, 0 insertions, 194 deletions
diff --git a/math.c b/math.c
deleted file mode 100644
index 15a826ce4..000000000
--- a/math.c
+++ /dev/null
@@ -1,194 +0,0 @@
-/* vi: set sw=4 ts=4: */
-#include "internal.h"
-#include <ctype.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <unistd.h>
-#include <math.h>
-
-/* Tiny RPN calculator, because "expr" didn't give me bitwise operations. */
-
-static const char math_usage[] = "math expression ...\n"
-#ifndef BB_FEATURE_TRIVIAL_HELP
- "\nThis is a Tiny RPN calculator that understands the\n"
- "following operations: +, -, /, *, and, or, not, eor.\n"
- "i.e. 'math 2 2 add' -> 4, and 'math 8 8 \\* 2 2 + /' -> 16\n"
-#endif
- ;
-
-static double stack[100];
-static unsigned int pointer;
-
-static void push(double a)
-{
- if (pointer >= (sizeof(stack) / sizeof(*stack))) {
- fprintf(stderr, "math: stack overflow\n");
- exit(-1);
- } else
- stack[pointer++] = a;
-}
-
-static double pop()
-{
- if (pointer == 0) {
- fprintf(stderr, "math: stack underflow\n");
- exit(-1);
- }
- return stack[--pointer];
-}
-
-static void add()
-{
- push(pop() + pop());
-}
-
-static void sub()
-{
- double subtrahend = pop();
-
- push(pop() - subtrahend);
-}
-
-static void mul()
-{
- push(pop() * pop());
-}
-
-static void divide()
-{
- double divisor = pop();
-
- push(pop() / divisor);
-}
-
-static void and()
-{
- push((unsigned int) pop() & (unsigned int) pop());
-}
-
-static void or()
-{
- push((unsigned int) pop() | (unsigned int) pop());
-}
-
-static void eor()
-{
- push((unsigned int) pop() ^ (unsigned int) pop());
-}
-
-static void not()
-{
- push(~(unsigned int) pop());
-}
-
-static void print()
-{
- printf("%g\n", pop());
-}
-
-struct op {
- const char *name;
- void (*function) ();
-};
-
-static const struct op operators[] = {
- {"+", add},
- {"add", add},
- {"-", sub},
- {"sub", sub},
- {"*", mul},
- {"mul", mul},
- {"/", divide},
- {"div", divide},
- {"and", and},
- {"or", or},
- {"not", not},
- {"eor", eor},
- {0, 0}
-};
-
-static void stack_machine(const char *argument)
-{
- char *endPointer = 0;
- double d;
- const struct op *o = operators;
-
- if (argument == 0) {
- print();
- return;
- }
-
- d = strtod(argument, &endPointer);
-
- if (endPointer != argument) {
- push(d);
- return;
- }
-
- while (o->name != 0) {
- if (strcmp(o->name, argument) == 0) {
- (*(o->function)) ();
- return;
- }
- o++;
- }
- fprintf(stderr, "math: %s: syntax error.\n", argument);
- exit(-1);
-}
-
-/* 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 *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 math_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 = cstring_lineFromFile(stdin))) {
- cursor = line;
- len = number_of_tokens(line);
- for (i = 0; i < len; i++) {
- token = get_token(&cursor);
- *cursor++ = 0;
- stack_machine(token);
- }
- free(line);
- }
- } else {
- if (*argv[1]=='-')
- usage(math_usage);
- while (argc >= 2) {
- stack_machine(argv[1]);
- argv++;
- argc--;
- }
- }
- stack_machine(0);
- return( TRUE);
-}