Support the o, f and p options, patch by Magnus M�rtensson

2 files changed, 40 insertions, 2 deletions

diff --git a/include/usage.h b/include/usage.h
index 5b357a218..2ebf9ad43 100644
--- a/include/usage.h
+++ b/include/usage.h
@@ -245,7 +245,12 @@
 #define dc_full_usage \
         "This is a Tiny RPN calculator that understands the\n" \
         "following operations: +, -, /, *, and, or, not, eor.\n" \
-        "i.e., 'dc 2 2 add' -> 4, and 'dc 8 8 \\* 2 2 + /' -> 16"
+        "i.e., 'dc 2 2 add' -> 4, and 'dc 8 8 \\* 2 2 + /' -> 16" \
+        "p - Prints the value on the top of the stack, without altering the stack.\n" \
+        "f - Prints the entire contents of the stack without altering anything.\n" \
+        "o - Pops the value off the top of the stack and uses it to set the output radix.\n" \
+        "    Only 10 and 16 are supported.\n"
+
 #define dc_example_usage \
         "$ dc 2 2 +\n" \
         "4\n" \
diff --git a/miscutils/dc.c b/miscutils/dc.c
index f9020b360..c7b43ea0a 100644
--- a/miscutils/dc.c
+++ b/miscutils/dc.c
@@ -11,6 +11,7 @@
 
 static double stack[100];
 static unsigned int pointer;
+static unsigned char base;
 
 static void push(double a)
 {
@@ -70,9 +71,38 @@ static void not(void)
         push(~(unsigned int) 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 void print_base(double print)
+{
+        if (base == 16) 
+                printf("%x\n", (unsigned int)print);
+        else
+        printf("%g\n", print);
+}
+
+static void print_stack_no_pop(void)
+{
+        unsigned int i=pointer;
+        while (i)
+                print_base(stack[--i]);
+}
+
+static void print_no_pop(void)
+{
+        print_base(stack[pointer-1]);
+}
+
 static void print(void)
 {
-        printf("%g\n", pop());
+        print_base(pop());
 }
 
 struct op {
@@ -93,6 +123,9 @@ static const struct op operators[] = {
         {"or",  or},
         {"not", not},
         {"eor", eor},
+        {"p", print_no_pop},
+        {"f", print_stack_no_pop},
+        {"o", set_output_base},
         {0,     0}
 };