busybox/miscutils/dc.c

/* vi: set sw=4 ts=4: */
/*
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

#include "libbb.h"
#include <math.h>

/* Tiny RPN calculator, because "expr" didn't give me bitwise operations. */


struct globals {
	unsigned pointer;
	unsigned base;
	double stack[1];
};
enum { STACK_SIZE = (COMMON_BUFSIZE - offsetof(struct globals, stack)) / sizeof(double) };
#define G (*(struct globals*)&bb_common_bufsiz1)
#define pointer   (G.pointer   )
#define base      (G.base      )
#define stack     (G.stack     )
#define INIT_G() do { \
	base = 10; \
} while (0)


static void push(double a)
{
	if (pointer >= STACK_SIZE)
		bb_error_msg_and_die("stack overflow");
	stack[pointer++] = a;
}

static double pop(void)
{
	if (pointer == 0)
		bb_error_msg_and_die("stack underflow");
	return stack[--pointer];
}

static void add(void)
{
	push(pop() + pop());
}

static void sub(void)
{
	double subtrahend = pop();

	push(pop() - subtrahend);
}

static void mul(void)
{
	push(pop() * pop());
}

#if ENABLE_FEATURE_DC_LIBM
static void power(void)
{
	double topower = pop();

	push(pow(pop(), topower));
}
#endif

static void divide(void)
{
	double divisor = pop();

	push(pop() / divisor);
}

static void mod(void)
{
	unsigned d = pop();

	push((unsigned) pop() % d);
}

static void and(void)
{
	push((unsigned) pop() & (unsigned) pop());
}

static void or(void)
{
	push((unsigned) pop() | (unsigned) pop());
}

static void eor(void)
{
	push((unsigned) pop() ^ (unsigned) pop());
}

static void not(void)
{
	push(~(unsigned) pop());
}

static void set_output_base(void)
{
	static const char bases[] ALIGN1 = { 2, 8, 10, 16, 0 };
	unsigned b = (unsigned)pop();

	base = *strchrnul(bases, b);
	if (base == 0) {
		bb_error_msg("error, base %u is not supported", b);
		base = 10;
	}
}

static void print_base(double print)
{
	unsigned x, i;

	if (base == 10) {
		printf("%g\n", print);
		return;
	}

	x = (unsigned)print;
	switch (base) {
	case 16:
		printf("%x\n", x);
		break;
	case 8:
		printf("%o\n", x);
		break;
	default: /* base 2 */
		i = (unsigned)INT_MAX + 1;
		do {
			if (x & i) break;
			i >>= 1;
		} while (i > 1);
		do {
			bb_putchar('1' - !(x & i));
			i >>= 1;
		} while (i);
		bb_putchar('\n');
	}
}

static void print_stack_no_pop(void)
{
	unsigned i = pointer;
	while (i)
		print_base(stack[--i]);
}

static void print_no_pop(void)
{
	print_base(stack[pointer-1]);
}

struct op {
	const char name[4];
	void (*function) (void);
};

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},
	{"pow", power},
#endif
	{"%",   mod},
	{"mod", mod},
	{"and", and},
	{"or",  or},
	{"not", not},
	{"eor", eor},
	{"xor", eor},
	{"p", print_no_pop},
	{"f", print_stack_no_pop},
	{"o", set_output_base},
	{ "", NULL }
};

static void stack_machine(const char *argument)
{
	char *endPointer;
	double d;
	const struct op *o = operators;

	d = strtod(argument, &endPointer);

	if (endPointer != argument && *endPointer == '\0') {
		push(d);
		return;
	}

	while (o->function) {
		if (strcmp(o->name, argument) == 0) {
			o->function();
			return;
		}
		o++;
	}
	bb_error_msg_and_die("syntax error at '%s'", 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;
}

int dc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int dc_main(int argc UNUSED_PARAM, char **argv)
{
	INIT_G();

	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);
			}
			free(line);
		}
	} else {
		// why? it breaks "dc -2 2 * p"
		//if (argv[0][0] == '-')
		//	bb_show_usage();
		do {
			stack_machine(*argv);
		} while (*++argv);
	}
	return EXIT_SUCCESS;
}
1	/* vi: set sw=4 ts=4: */
2	/*
3	* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
4	*/
5
6	#include "libbb.h"
7	#include <math.h>
8
9	/* Tiny RPN calculator, because "expr" didn't give me bitwise operations. */
10
11
12	struct globals {
13	unsigned pointer;
14	unsigned base;
15	double stack[1];
16	};
17	enum { STACK_SIZE = (COMMON_BUFSIZE - offsetof(struct globals, stack)) / sizeof(double) };
18	#define G ((struct globals)&bb_common_bufsiz1)
19	#define pointer (G.pointer )
20	#define base (G.base )
21	#define stack (G.stack )
22	#define INIT_G() do { \
23	base = 10; \
24	} while (0)
25
26
27	static void push(double a)
28	{
29	if (pointer >= STACK_SIZE)
30	bb_error_msg_and_die("stack overflow");
31	stack[pointer++] = a;
32	}
33
34	static double pop(void)
35	{
36	if (pointer == 0)
37	bb_error_msg_and_die("stack underflow");
38	return stack[--pointer];
39	}
40
41	static void add(void)
42	{
43	push(pop() + pop());
44	}
45
46	static void sub(void)
47	{
48	double subtrahend = pop();
49
50	push(pop() - subtrahend);
51	}
52
53	static void mul(void)
54	{
55	push(pop() * pop());
56	}
57
58	#if ENABLE_FEATURE_DC_LIBM
59	static void power(void)
60	{
61	double topower = pop();
62
63	push(pow(pop(), topower));
64	}
65	#endif
66
67	static void divide(void)
68	{
69	double divisor = pop();
70
71	push(pop() / divisor);
72	}
73
74	static void mod(void)
75	{
76	unsigned d = pop();
77
78	push((unsigned) pop() % d);
79	}
80
81	static void and(void)
82	{
83	push((unsigned) pop() & (unsigned) pop());
84	}
85
86	static void or(void)
87	{
88	push((unsigned) pop() \| (unsigned) pop());
89	}
90
91	static void eor(void)
92	{
93	push((unsigned) pop() ^ (unsigned) pop());
94	}
95
96	static void not(void)
97	{
98	push(~(unsigned) pop());
99	}
100
101	static void set_output_base(void)
102	{
103	static const char bases[] ALIGN1 = { 2, 8, 10, 16, 0 };
104	unsigned b = (unsigned)pop();
105
106	base = *strchrnul(bases, b);
107	if (base == 0) {
108	bb_error_msg("error, base %u is not supported", b);
109	base = 10;
110	}
111	}
112
113	static void print_base(double print)
114	{
115	unsigned x, i;
116
117	if (base == 10) {
118	printf("%g\n", print);
119	return;
120	}
121
122	x = (unsigned)print;
123	switch (base) {
124	case 16:
125	printf("%x\n", x);
126	break;
127	case 8:
128	printf("%o\n", x);
129	break;
130	default: /* base 2 */
131	i = (unsigned)INT_MAX + 1;
132	do {
133	if (x & i) break;
134	i >>= 1;
135	} while (i > 1);
136	do {
137	bb_putchar('1' - !(x & i));
138	i >>= 1;
139	} while (i);
140	bb_putchar('\n');
141	}
142	}
143
144	static void print_stack_no_pop(void)
145	{
146	unsigned i = pointer;
147	while (i)
148	print_base(stack[--i]);
149	}
150
151	static void print_no_pop(void)
152	{
153	print_base(stack[pointer-1]);
154	}
155
156	struct op {
157	const char name[4];
158	void (*function) (void);
159	};
160
161	static const struct op operators[] = {
162	{"+", add},
163	{"add", add},
164	{"-", sub},
165	{"sub", sub},
166	{"*", mul},
167	{"mul", mul},
168	{"/", divide},
169	{"div", divide},
170	#if ENABLE_FEATURE_DC_LIBM
171	{"**", power},
172	{"exp", power},
173	{"pow", power},
174	#endif
175	{"%", mod},
176	{"mod", mod},
177	{"and", and},
178	{"or", or},
179	{"not", not},
180	{"eor", eor},
181	{"xor", eor},
182	{"p", print_no_pop},
183	{"f", print_stack_no_pop},
184	{"o", set_output_base},
185	{ "", NULL }
186	};
187
188	static void stack_machine(const char *argument)
189	{
190	char *endPointer;
191	double d;
192	const struct op *o = operators;
193
194	d = strtod(argument, &endPointer);
195
196	if (endPointer != argument && *endPointer == '\0') {
197	push(d);
198	return;
199	}
200
201	while (o->function) {
202	if (strcmp(o->name, argument) == 0) {
203	o->function();
204	return;
205	}
206	o++;
207	}
208	bb_error_msg_and_die("syntax error at '%s'", argument);
209	}
210
211	/* return pointer to next token in buffer and set *buffer to one char
212	* past the end of the above mentioned token
213	*/
214	static char get_token(char *buffer)
215	{
216	char current = skip_whitespace(buffer);
217	if (*current != '\0') {
218	*buffer = skip_non_whitespace(current);
219	return current;
220	}
221	return NULL;
222	}
223
224	int dc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
225	int dc_main(int argc UNUSED_PARAM, char **argv)
226	{
227	INIT_G();
228
229	argv++;
230	if (!argv[0]) {
231	/* take stuff from stdin if no args are given */
232	char *line;
233	char *cursor;
234	char *token;
235	while ((line = xmalloc_fgetline(stdin)) != NULL) {
236	cursor = line;
237	while (1) {
238	token = get_token(&cursor);
239	if (!token)
240	break;
241	*cursor++ = '\0';
242	stack_machine(token);
243	}
244	free(line);
245	}
246	} else {
247	// why? it breaks "dc -2 2 * p"
248	//if (argv[0][0] == '-')
249	// bb_show_usage();
250	do {
251	stack_machine(*argv);
252	} while (*++argv);
253	}
254	return EXIT_SUCCESS;
255	}