1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (C) Paul Mackerras 1997.
4 */
5#include <linux/string.h>
6#include <linux/stdarg.h>
7
8size_t strnlen(const char * s, size_t count)
9{
10	const char *sc;
11
12	for (sc = s; count-- && *sc != '\0'; ++sc)
13		/* nothing */;
14	return sc - s;
15}
16
17# define do_div(n, base) ({						\
18	unsigned int __base = (base);					\
19	unsigned int __rem;						\
20	__rem = ((unsigned long long)(n)) % __base;			\
21	(n) = ((unsigned long long)(n)) / __base;			\
22	__rem;								\
23})
24
25
26static int skip_atoi(const char **s)
27{
28	int i, c;
29
30	for (i = 0; '0' <= (c = **s) && c <= '9'; ++*s)
31		i = i*10 + c - '0';
32	return i;
33}
34
35#define ZEROPAD	1		/* pad with zero */
36#define SIGN	2		/* unsigned/signed long */
37#define PLUS	4		/* show plus */
38#define SPACE	8		/* space if plus */
39#define LEFT	16		/* left justified */
40#define SPECIAL	32		/* 0x */
41#define LARGE	64		/* use 'ABCDEF' instead of 'abcdef' */
42
43static char * number(char * str, unsigned long long num, int base, int size, int precision, int type)
44{
45	char c, sign, tmp[66];
46	const char *digits = "0123456789abcdefghijklmnopqrstuvwxyz";
47	int i;
48
49	if (type & LARGE)
50		digits = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
51	if (type & LEFT)
52		type &= ~ZEROPAD;
53	if (base < 2 || base > 36)
54		return 0;
55	c = (type & ZEROPAD) ? '0' : ' ';
56	sign = 0;
57	if (type & SIGN) {
58		if ((signed long long)num < 0) {
59			sign = '-';
60			num = - (signed long long)num;
61			size--;
62		} else if (type & PLUS) {
63			sign = '+';
64			size--;
65		} else if (type & SPACE) {
66			sign = ' ';
67			size--;
68		}
69	}
70	if (type & SPECIAL) {
71		if (base == 16)
72			size -= 2;
73		else if (base == 8)
74			size--;
75	}
76	i = 0;
77	if (num == 0)
78		tmp[i++]='0';
79	else while (num != 0) {
80		tmp[i++] = digits[do_div(num, base)];
81	}
82	if (i > precision)
83		precision = i;
84	size -= precision;
85	if (!(type&(ZEROPAD+LEFT)))
86		while (size-- > 0)
87			*str++ = ' ';
88	if (sign)
89		*str++ = sign;
90	if (type & SPECIAL) {
91		if (base==8)
92			*str++ = '0';
93		else if (base == 16) {
94			*str++ = '0';
95			*str++ = digits[33];
96		}
97	}
98	if (!(type & LEFT))
99		while (size-- > 0)
100			*str++ = c;
101	while (i < precision--)
102		*str++ = '0';
103	while (i-- > 0)
104		*str++ = tmp[i];
105	while (size-- > 0)
106		*str++ = ' ';
107	return str;
108}
109
110int vsprintf(char *buf, const char *fmt, va_list args)
111{
112	int len;
113	unsigned long long num;
114	int i, base;
115	char * str;
116	const char *s;
117
118	int flags;		/* flags to number() */
119
120	int field_width;	/* width of output field */
121	int precision;		/* min. # of digits for integers; max
122				   number of chars for from string */
123	int qualifier;		/* 'h', 'l', or 'L' for integer fields */
124	                        /* 'z' support added 23/7/1999 S.H.    */
125				/* 'z' changed to 'Z' --davidm 1/25/99 */
126
127
128	for (str = buf ; *fmt ; ++fmt) {
129		if (*fmt != '%') {
130			*str++ = *fmt;
131			continue;
132		}
133
134		/* process flags */
135		flags = 0;
136		repeat:
137			++fmt;		/* this also skips first '%' */
138			switch (*fmt) {
139				case '-': flags |= LEFT; goto repeat;
140				case '+': flags |= PLUS; goto repeat;
141				case ' ': flags |= SPACE; goto repeat;
142				case '#': flags |= SPECIAL; goto repeat;
143				case '0': flags |= ZEROPAD; goto repeat;
144				}
145
146		/* get field width */
147		field_width = -1;
148		if ('0' <= *fmt && *fmt <= '9')
149			field_width = skip_atoi(&fmt);
150		else if (*fmt == '*') {
151			++fmt;
152			/* it's the next argument */
153			field_width = va_arg(args, int);
154			if (field_width < 0) {
155				field_width = -field_width;
156				flags |= LEFT;
157			}
158		}
159
160		/* get the precision */
161		precision = -1;
162		if (*fmt == '.') {
163			++fmt;
164			if ('0' <= *fmt && *fmt <= '9')
165				precision = skip_atoi(&fmt);
166			else if (*fmt == '*') {
167				++fmt;
168				/* it's the next argument */
169				precision = va_arg(args, int);
170			}
171			if (precision < 0)
172				precision = 0;
173		}
174
175		/* get the conversion qualifier */
176		qualifier = -1;
177		if (*fmt == 'l' && *(fmt + 1) == 'l') {
178			qualifier = 'q';
179			fmt += 2;
180		} else if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L'
181			|| *fmt == 'Z') {
182			qualifier = *fmt;
183			++fmt;
184		}
185
186		/* default base */
187		base = 10;
188
189		switch (*fmt) {
190		case 'c':
191			if (!(flags & LEFT))
192				while (--field_width > 0)
193					*str++ = ' ';
194			*str++ = (unsigned char) va_arg(args, int);
195			while (--field_width > 0)
196				*str++ = ' ';
197			continue;
198
199		case 's':
200			s = va_arg(args, char *);
201			if (!s)
202				s = "<NULL>";
203
204			len = strnlen(s, precision);
205
206			if (!(flags & LEFT))
207				while (len < field_width--)
208					*str++ = ' ';
209			for (i = 0; i < len; ++i)
210				*str++ = *s++;
211			while (len < field_width--)
212				*str++ = ' ';
213			continue;
214
215		case 'p':
216			if (field_width == -1) {
217				field_width = 2*sizeof(void *);
218				flags |= ZEROPAD;
219			}
220			str = number(str,
221				(unsigned long) va_arg(args, void *), 16,
222				field_width, precision, flags);
223			continue;
224
225
226		case 'n':
227			if (qualifier == 'l') {
228				long * ip = va_arg(args, long *);
229				*ip = (str - buf);
230			} else if (qualifier == 'Z') {
231				size_t * ip = va_arg(args, size_t *);
232				*ip = (str - buf);
233			} else {
234				int * ip = va_arg(args, int *);
235				*ip = (str - buf);
236			}
237			continue;
238
239		case '%':
240			*str++ = '%';
241			continue;
242
243		/* integer number formats - set up the flags and "break" */
244		case 'o':
245			base = 8;
246			break;
247
248		case 'X':
249			flags |= LARGE;
250		case 'x':
251			base = 16;
252			break;
253
254		case 'd':
255		case 'i':
256			flags |= SIGN;
257		case 'u':
258			break;
259
260		default:
261			*str++ = '%';
262			if (*fmt)
263				*str++ = *fmt;
264			else
265				--fmt;
266			continue;
267		}
268		if (qualifier == 'l') {
269			num = va_arg(args, unsigned long);
270			if (flags & SIGN)
271				num = (signed long) num;
272		} else if (qualifier == 'q') {
273			num = va_arg(args, unsigned long long);
274			if (flags & SIGN)
275				num = (signed long long) num;
276		} else if (qualifier == 'Z') {
277			num = va_arg(args, size_t);
278		} else if (qualifier == 'h') {
279			num = (unsigned short) va_arg(args, int);
280			if (flags & SIGN)
281				num = (signed short) num;
282		} else {
283			num = va_arg(args, unsigned int);
284			if (flags & SIGN)
285				num = (signed int) num;
286		}
287		str = number(str, num, base, field_width, precision, flags);
288	}
289	*str = '\0';
290	return str-buf;
291}
292
293int sprintf(char * buf, const char *fmt, ...)
294{
295	va_list args;
296	int i;
297
298	va_start(args, fmt);
299	i = vsprintf(buf, fmt, args);
300	va_end(args);
301	return i;
302}
303