+ added dc (aka the function formerly known as math)

+ did all the housekeeping that this change requires.

8 files changed, 234 insertions, 28 deletions

diff --git a/Changelog b/Changelog
index 07fd30d50..8e8de9523 100644
--- a/Changelog
+++ b/Changelog
@@ -86,6 +86,8 @@
         * Fixed grep "Line too long" problem -- John Beppu
         * Fixed 'grep -q -i B some_file' so it works
         * math takes input from stdin if no args are given.  -- John Beppu
+        * math was renamed to dc.  Although it deviates from dc's behaviour,
+            this will probably be remedied in the future.  -- John Beppu
 
 
          -Erik Andersen
diff --git a/applets/busybox.c b/applets/busybox.c
index 191dee13f..221ef2a65 100644
--- a/applets/busybox.c
+++ b/applets/busybox.c
@@ -72,6 +72,9 @@ const struct BB_applet applets[] = {
 #ifdef BB_DATE
         {"date", date_main, _BB_DIR_BIN},
 #endif
+#ifdef BB_DC
+        {"dc", dc_main, _BB_DIR_USR_BIN},
+#endif
 #ifdef BB_DD
         {"dd", dd_main, _BB_DIR_BIN},
 #endif
diff --git a/busybox.c b/busybox.c
index 191dee13f..221ef2a65 100644
--- a/busybox.c
+++ b/busybox.c
@@ -72,6 +72,9 @@ const struct BB_applet applets[] = {
 #ifdef BB_DATE
         {"date", date_main, _BB_DIR_BIN},
 #endif
+#ifdef BB_DC
+        {"dc", dc_main, _BB_DIR_USR_BIN},
+#endif
 #ifdef BB_DD
         {"dd", dd_main, _BB_DIR_BIN},
 #endif
diff --git a/busybox.def.h b/busybox.def.h
index d7756a498..89172ea98 100644
--- a/busybox.def.h
+++ b/busybox.def.h
@@ -17,6 +17,7 @@
 #define BB_CP_MV
 #define BB_CUT
 #define BB_DATE
+#define BB_DC
 #define BB_DD
 #define BB_DEALLOCVT
 #define BB_DF
@@ -54,7 +55,6 @@
 #define BB_LS
 #define BB_LSMOD
 #define BB_MAKEDEVS
-#define BB_MATH
 //#define BB_MD5SUM
 #define BB_MKDIR
 #define BB_MKFIFO
diff --git a/math.c b/dc.c
index 15a826ce4..37c7731d2 100644
--- a/math.c
+++ b/dc.c
@@ -8,7 +8,7 @@
 
 /* Tiny RPN calculator, because "expr" didn't give me bitwise operations. */
 
-static const char math_usage[] = "math expression ...\n"
+static const char dc_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"
@@ -162,7 +162,7 @@ static int number_of_tokens(char *buffer)
         return i;
 }
 
-int math_main(int argc, char **argv)
+int dc_main(int argc, char **argv)
 {
         /* take stuff from stdin if no args are given */
         if (argc <= 1) {
@@ -182,7 +182,7 @@ int math_main(int argc, char **argv)
                 }
         } else {
                 if (*argv[1]=='-')
-                        usage(math_usage);
+                        usage(dc_usage);
                 while (argc >= 2) {
                         stack_machine(argv[1]);
                         argv++;
diff --git a/docs/busybox.pod b/docs/busybox.pod
index 8b1b7155f..75763d33f 100644
--- a/docs/busybox.pod
+++ b/docs/busybox.pod
@@ -313,6 +313,32 @@ Example:
 
 -------------------------------
 
+=item dc
+
+Usage: dc expression ...
+
+This is a Tiny RPN calculator that understands the
+following operations: +, -, /, *, and, or, not, eor.
+If no arguments are given, dc will process input from STDIN.
+
+The behaviour of BusyBox/dc deviates (just a little ;-) from
+GNU/dc, but this will be remedied in the future.
+
+Example:
+
+        $ dc 2 2 +
+        4
+        $ dc 8 8 \* 2 2 + /
+        16
+        $ dc 0 1 and
+        0
+        $ dc 0 1 or
+        1
+        $ echo 72 9 div 8 mul | dc
+        64
+
+-------------------------------
+
 =item dd
 
 Usage: dd [if=name] [of=name] [bs=n] [count=n] [skip=n] [seek=n]
@@ -1012,29 +1038,6 @@ Example:
 
 -------------------------------
 
-=item math
-
-Usage: math expression ...
-
-This is a Tiny RPN calculator that understands the
-following operations: +, -, /, *, and, or, not, eor.
-If no arguments are given, math will process input from STDIN.
-
-Example:
-
-        $ math 2 2 +
-        4
-        $ math 8 8 \* 2 2 + /
-        16
-        $ math 0 1 and
-        0
-        $ math 0 1 or
-        1
-        $ echo 72 9 / | math
-        8
-
--------------------------------
-
 =item md5sum
 
 Usage: md5sum [OPTION] [file ...]
@@ -2021,4 +2024,4 @@ Enrique Zanardi <ezanardi@ull.es>
 
 =cut
 
-# $Id: busybox.pod,v 1.43 2000/06/20 00:11:07 proski Exp $
+# $Id: busybox.pod,v 1.44 2000/06/21 19:06:16 beppu Exp $
diff --git a/internal.h b/internal.h
index 50bb17a10..58f68f59b 100644
--- a/internal.h
+++ b/internal.h
@@ -113,6 +113,7 @@ extern int clear_main(int argc, char** argv);
 extern int cp_mv_main(int argc, char** argv);
 extern int cut_main(int argc, char** argv);
 extern int date_main(int argc, char** argv);
+extern int dc_main(int argc, char** argv);
 extern int dd_main(int argc, char** argv);
 extern int dirname_main(int argc, char** argv);
 extern int deallocvt_main(int argc, char** argv);
diff --git a/miscutils/dc.c b/miscutils/dc.c
new file mode 100644
index 000000000..37c7731d2
--- /dev/null
+++ b/miscutils/dc.c
@@ -0,0 +1,194 @@
+/* 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 dc_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 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 = 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(dc_usage);
+                while (argc >= 2) {
+                        stack_machine(argv[1]);
+                        argv++;
+                        argc--;
+                }
+        }
+        stack_machine(0);
+        return( TRUE);
+}