[wasi-libc.git] / libc-top-half / musl / src / internal / shgetc.h

#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. */

hidden void __shlim(FILE *, off_t);
hidden int __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)
Commit	Line	Data
320054e8 DG	1	#include "stdio_impl.h"
	2
	3	/* Scan helper "stdio" functions for use by scanf-family and strto*-family
	4	* functions. These accept either a valid stdio FILE, or a minimal pseudo
	5	* FILE whose buffer pointers point into a null-terminated string. In the
	6	* latter case, the sh_fromstring macro should be used to setup the FILE;
	7	* the rest of the structure can be left uninitialized.
	8	*
	9	* To begin using these functions, shlim must first be called on the FILE
	10	* to set a field width limit, or 0 for no limit. For string pseudo-FILEs,
	11	* a nonzero limit is not valid and produces undefined behavior. After that,
	12	* shgetc, shunget, and shcnt are valid as long as no other stdio functions
	13	* are called on the stream.
	14	*
	15	* When used with a real FILE object, shunget has only one byte of pushback
	16	* available. Further shunget (up to a limit of the stdio UNGET buffer size)
	17	* will adjust the position but will not restore the data to be read again.
	18	* This functionality is needed for the wcsto*-family functions, where it's
	19	* okay because the FILE will be discarded immediately anyway. When used
	20	* with string pseudo-FILEs, shunget has unlimited pushback, back to the
	21	* beginning of the string. */
	22
	23	hidden void __shlim(FILE *, off_t);
	24	hidden int __shgetc(FILE *);
	25
	26	#define shcnt(f) ((f)->shcnt + ((f)->rpos - (f)->buf))
	27	#define shlim(f, lim) __shlim((f), (lim))
	28	#define shgetc(f) (((f)->rpos != (f)->shend) ? *(f)->rpos++ : __shgetc(f))
f41256b6	29	#define shunget(f) ((f)->shlim>=0 ? (void)(f)->rpos-- : (void)0)
320054e8 DG	30
	31	#define sh_fromstring(f, s) \
	32	((f)->buf = (f)->rpos = (void )(s), (f)->rend = (void)-1)