|
|
- #include <defs.h>
- #include <x86.h>
- #include <error.h>
- #include <stdio.h>
- #include <string.h>
-
- /* *
- * Space or zero padding and a field width are supported for the numeric
- * formats only.
- *
- * The special format %e takes an integer error code
- * and prints a string describing the error.
- * The integer may be positive or negative,
- * so that -E_NO_MEM and E_NO_MEM are equivalent.
- * */
-
- static const char * const error_string[MAXERROR + 1] = {
- [0] NULL,
- [E_UNSPECIFIED] "unspecified error",
- [E_BAD_PROC] "bad process",
- [E_INVAL] "invalid parameter",
- [E_NO_MEM] "out of memory",
- [E_NO_FREE_PROC] "out of processes",
- [E_FAULT] "segmentation fault",
- [E_INVAL_ELF] "invalid elf file",
- [E_KILLED] "process is killed",
- [E_PANIC] "panic failure",
- };
-
- /* *
- * printnum - print a number (base <= 16) in reverse order
- * @putch: specified putch function, print a single character
- * @putdat: used by @putch function
- * @num: the number will be printed
- * @base: base for print, must be in [1, 16]
- * @width: maximum number of digits, if the actual width is less than @width, use @padc instead
- * @padc: character that padded on the left if the actual width is less than @width
- * */
- static void
- printnum(void (*putch)(int, void*), void *putdat,
- unsigned long long num, unsigned base, int width, int padc) {
- unsigned long long result = num;
- unsigned mod = do_div(result, base);
-
- // first recursively print all preceding (more significant) digits
- if (num >= base) {
- printnum(putch, putdat, result, base, width - 1, padc);
- } else {
- // print any needed pad characters before first digit
- while (-- width > 0)
- putch(padc, putdat);
- }
- // then print this (the least significant) digit
- putch("0123456789abcdef"[mod], putdat);
- }
-
- /* *
- * getuint - get an unsigned int of various possible sizes from a varargs list
- * @ap: a varargs list pointer
- * @lflag: determines the size of the vararg that @ap points to
- * */
- static unsigned long long
- getuint(va_list *ap, int lflag) {
- if (lflag >= 2) {
- return va_arg(*ap, unsigned long long);
- }
- else if (lflag) {
- return va_arg(*ap, unsigned long);
- }
- else {
- return va_arg(*ap, unsigned int);
- }
- }
-
- /* *
- * getint - same as getuint but signed, we can't use getuint because of sign extension
- * @ap: a varargs list pointer
- * @lflag: determines the size of the vararg that @ap points to
- * */
- static long long
- getint(va_list *ap, int lflag) {
- if (lflag >= 2) {
- return va_arg(*ap, long long);
- }
- else if (lflag) {
- return va_arg(*ap, long);
- }
- else {
- return va_arg(*ap, int);
- }
- }
-
- /* *
- * printfmt - format a string and print it by using putch
- * @putch: specified putch function, print a single character
- * @putdat: used by @putch function
- * @fmt: the format string to use
- * */
- void
- printfmt(void (*putch)(int, void*), void *putdat, const char *fmt, ...) {
- va_list ap;
-
- va_start(ap, fmt);
- vprintfmt(putch, putdat, fmt, ap);
- va_end(ap);
- }
-
- /* *
- * vprintfmt - format a string and print it by using putch, it's called with a va_list
- * instead of a variable number of arguments
- * @putch: specified putch function, print a single character
- * @putdat: used by @putch function
- * @fmt: the format string to use
- * @ap: arguments for the format string
- *
- * Call this function if you are already dealing with a va_list.
- * Or you probably want printfmt() instead.
- * */
- void
- vprintfmt(void (*putch)(int, void*), void *putdat, const char *fmt, va_list ap) {
- register const char *p;
- register int ch, err;
- unsigned long long num;
- int base, width, precision, lflag, altflag;
-
- while (1) {
- while ((ch = *(unsigned char *)fmt ++) != '%') {
- if (ch == '\0') {
- return;
- }
- putch(ch, putdat);
- }
-
- // Process a %-escape sequence
- char padc = ' ';
- width = precision = -1;
- lflag = altflag = 0;
-
- reswitch:
- switch (ch = *(unsigned char *)fmt ++) {
-
- // flag to pad on the right
- case '-':
- padc = '-';
- goto reswitch;
-
- // flag to pad with 0's instead of spaces
- case '0':
- padc = '0';
- goto reswitch;
-
- // width field
- case '1' ... '9':
- for (precision = 0; ; ++ fmt) {
- precision = precision * 10 + ch - '0';
- ch = *fmt;
- if (ch < '0' || ch > '9') {
- break;
- }
- }
- goto process_precision;
-
- case '*':
- precision = va_arg(ap, int);
- goto process_precision;
-
- case '.':
- if (width < 0)
- width = 0;
- goto reswitch;
-
- case '#':
- altflag = 1;
- goto reswitch;
-
- process_precision:
- if (width < 0)
- width = precision, precision = -1;
- goto reswitch;
-
- // long flag (doubled for long long)
- case 'l':
- lflag ++;
- goto reswitch;
-
- // character
- case 'c':
- putch(va_arg(ap, int), putdat);
- break;
-
- // error message
- case 'e':
- err = va_arg(ap, int);
- if (err < 0) {
- err = -err;
- }
- if (err > MAXERROR || (p = error_string[err]) == NULL) {
- printfmt(putch, putdat, "error %d", err);
- }
- else {
- printfmt(putch, putdat, "%s", p);
- }
- break;
-
- // string
- case 's':
- if ((p = va_arg(ap, char *)) == NULL) {
- p = "(null)";
- }
- if (width > 0 && padc != '-') {
- for (width -= strnlen(p, precision); width > 0; width --) {
- putch(padc, putdat);
- }
- }
- for (; (ch = *p ++) != '\0' && (precision < 0 || -- precision >= 0); width --) {
- if (altflag && (ch < ' ' || ch > '~')) {
- putch('?', putdat);
- }
- else {
- putch(ch, putdat);
- }
- }
- for (; width > 0; width --) {
- putch(' ', putdat);
- }
- break;
-
- // (signed) decimal
- case 'd':
- num = getint(&ap, lflag);
- if ((long long)num < 0) {
- putch('-', putdat);
- num = -(long long)num;
- }
- base = 10;
- goto number;
-
- // unsigned decimal
- case 'u':
- num = getuint(&ap, lflag);
- base = 10;
- goto number;
-
- // (unsigned) octal
- case 'o':
- num = getuint(&ap, lflag);
- base = 8;
- goto number;
-
- // pointer
- case 'p':
- putch('0', putdat);
- putch('x', putdat);
- num = (unsigned long long)(uintptr_t)va_arg(ap, void *);
- base = 16;
- goto number;
-
- // (unsigned) hexadecimal
- case 'x':
- num = getuint(&ap, lflag);
- base = 16;
- number:
- printnum(putch, putdat, num, base, width, padc);
- break;
-
- // escaped '%' character
- case '%':
- putch(ch, putdat);
- break;
-
- // unrecognized escape sequence - just print it literally
- default:
- putch('%', putdat);
- for (fmt --; fmt[-1] != '%'; fmt --)
- /* do nothing */;
- break;
- }
- }
- }
-
- /* sprintbuf is used to save enough information of a buffer */
- struct sprintbuf {
- char *buf; // address pointer points to the first unused memory
- char *ebuf; // points the end of the buffer
- int cnt; // the number of characters that have been placed in this buffer
- };
-
- /* *
- * sprintputch - 'print' a single character in a buffer
- * @ch: the character will be printed
- * @b: the buffer to place the character @ch
- * */
- static void
- sprintputch(int ch, struct sprintbuf *b) {
- b->cnt ++;
- if (b->buf < b->ebuf) {
- *b->buf ++ = ch;
- }
- }
-
- /* *
- * snprintf - format a string and place it in a buffer
- * @str: the buffer to place the result into
- * @size: the size of buffer, including the trailing null space
- * @fmt: the format string to use
- * */
- int
- snprintf(char *str, size_t size, const char *fmt, ...) {
- va_list ap;
- int cnt;
- va_start(ap, fmt);
- cnt = vsnprintf(str, size, fmt, ap);
- va_end(ap);
- return cnt;
- }
-
- /* *
- * vsnprintf - format a string and place it in a buffer, it's called with a va_list
- * instead of a variable number of arguments
- * @str: the buffer to place the result into
- * @size: the size of buffer, including the trailing null space
- * @fmt: the format string to use
- * @ap: arguments for the format string
- *
- * The return value is the number of characters which would be generated for the
- * given input, excluding the trailing '\0'.
- *
- * Call this function if you are already dealing with a va_list.
- * Or you probably want snprintf() instead.
- * */
- int
- vsnprintf(char *str, size_t size, const char *fmt, va_list ap) {
- struct sprintbuf b = {str, str + size - 1, 0};
- if (str == NULL || b.buf > b.ebuf) {
- return -E_INVAL;
- }
- // print the string to the buffer
- vprintfmt((void*)sprintputch, &b, fmt, ap);
- // null terminate the buffer
- *b.buf = '\0';
- return b.cnt;
- }
-
|