scheck.c (1275B)
1 /* 2 ** This file is in the public domain, so clarified as of 3 ** 2006-07-17 by Arthur David Olson. 4 */ 5 6 /*LINTLIBRARY*/ 7 8 #include "private.h" 9 10 const char * 11 scheck(const char *const string, const char *const format) 12 { 13 register char * fbuf; 14 register const char * fp; 15 register char * tp; 16 register int c; 17 register const char * result; 18 char dummy; 19 20 result = ""; 21 if (string == NULL || format == NULL) 22 return result; 23 fbuf = malloc(2 * strlen(format) + 4); 24 if (fbuf == NULL) 25 return result; 26 fp = format; 27 tp = fbuf; 28 29 /* 30 ** Copy directives, suppressing each conversion that is not 31 ** already suppressed. Scansets containing '%' are not 32 ** supported; e.g., the conversion specification "%[%]" is not 33 ** supported. Also, multibyte characters containing a 34 ** non-leading '%' byte are not supported. 35 */ 36 while ((*tp++ = c = *fp++) != '\0') { 37 if (c != '%') 38 continue; 39 if (is_digit(*fp)) { 40 char const *f = fp; 41 char *t = tp; 42 do { 43 *t++ = c = *f++; 44 } while (is_digit(c)); 45 if (c == '$') { 46 fp = f; 47 tp = t; 48 } 49 } 50 *tp++ = '*'; 51 if (*fp == '*') 52 ++fp; 53 if ((*tp++ = *fp++) == '\0') 54 break; 55 } 56 57 *(tp - 1) = '%'; 58 *tp++ = 'c'; 59 *tp = '\0'; 60 if (sscanf(string, fbuf, &dummy) != 1) 61 result = format; 62 free(fbuf); 63 return result; 64 }