#include "stdio_impl.h"/* Scan helper "stdio" functions for use by scanf-family and strto*-family * functions. These accept either a valid stdio FILE, or a minimal pseudo * FILE whose buffer pointers point into a null-terminated string. In the * latter case, the sh_fromstring macro should be used to setup the FILE; * the rest of the structure can be left uninitialized. * * To begin using these functions, shlim must first be called on the FILE * to set a field width limit, or 0 for no limit. For string pseudo-FILEs, * a nonzero limit is not valid and produces undefined behavior. After that, * shgetc, shunget, and shcnt are valid as long as no other stdio functions * are called on the stream. * * When used with a real FILE object, shunget has only one byte of pushback * available. Further shunget (up to a limit of the stdio UNGET buffer size) * will adjust the position but will not restore the data to be read again. * This functionality is needed for the wcsto*-family functions, where it's * okay because the FILE will be discarded immediately anyway. When used * with string pseudo-FILEs, shunget has unlimited pushback, back to the * beginning of the string. */hiddenvoid__shlim(FILE*,off_t);hiddenint__shgetc(FILE*);#define shcnt(f) ((f)->shcnt + ((f)->rpos - (f)->buf))#define shlim(f, lim) __shlim((f), (lim))#define shgetc(f) (((f)->rpos != (f)->shend) ? *(f)->rpos++ : __shgetc(f))#define shunget(f) ((f)->shlim>=0 ? (void)(f)->rpos-- : (void)0)#define sh_fromstring(f, s) \ ((f)->buf = (f)->rpos = (void *)(s), (f)->rend = (void*)-1)
