X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=miscutils%2Fdc.c;h=b922a7184d7d2fe2934662fca61b7ad50dd5cef6;hb=d72e804e6db1bd6eb2417961004b4fe33aba9384;hp=777ec1654c332dc8c08cdc12b660ec75ddc89123;hpb=0ef64bdb40c54681e8dd5ab8df42ac88e4ab1d4a;p=oweals%2Fbusybox.git

diff --git a/miscutils/dc.c b/miscutils/dc.c
index 777ec1654..b922a7184 100644
--- a/miscutils/dc.c
+++ b/miscutils/dc.c
@@ -2,20 +2,35 @@
 /*
  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
-
-#include "libbb.h"
-#include <math.h>
+//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, **, exp, and, or, not, eor,\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' -> 4, 'dc 8 8 * 2 2 + /' -> 16"
+//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"
@@ -29,6 +44,10 @@
 //usage:       "$ echo 72 9 div 8 mul p | dc\n"
 //usage:       "64\n"
 
+#include "libbb.h"
+#include "common_bufsiz.h"
+#include <math.h>
+
 #if 0
 typedef unsigned data_t;
 #define DATA_FMT ""
@@ -47,15 +66,22 @@ struct globals {
 	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)
 {
 	if (pointer >= STACK_SIZE)
@@ -65,8 +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];
 }
 
@@ -187,6 +212,7 @@ static void print_stack_no_pop(void)
 
 static void print_no_pop(void)
 {
+	check_under();
 	print_base(stack[pointer-1]);
 }
 
@@ -196,14 +222,6 @@ 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},
@@ -216,46 +234,52 @@ 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},
-	{ "", NULL }
 };
 
+/* Feed the stack machine */
 static void stack_machine(const char *argument)
 {
-	char *endPointer;
-	double d;
-	const struct op *o = operators;
+	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 && *endPointer == '\0') {
-		push(d);
+	if (*argument == '\0')
 		return;
-	}
 
-	while (o->function) {
-		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("syntax error at '%s'", 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;
@@ -267,23 +291,11 @@ int dc_main(int argc UNUSED_PARAM, char **argv)
 	if (!argv[0]) {
 		/* take stuff from stdin if no args are given */
 		char *line;
-		char *cursor;
-		char *token;
 		while ((line = xmalloc_fgetline(stdin)) != NULL) {
-			cursor = line;
-			while (1) {
-				token = get_token(&cursor);
-				if (!token)
-					break;
-				*cursor++ = '\0';
-				stack_machine(token);
-			}
+			stack_machine(line);
 			free(line);
 		}
 	} else {
-		// why? it breaks "dc -2 2 * p"
-		//if (argv[0][0] == '-')
-		//	bb_show_usage();
 		do {
 			stack_machine(*argv);
 		} while (*++argv);