stdio.c 6.0 KB

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