#include "types.h" #include "stat.h" #include "user.h" static void putc(int fd, char c) { write(fd, &c, 1); } static void printint(int fd, int xx, int base, int sgn) { static char digits[] = "0123456789ABCDEF"; char buf[16]; int i, neg; uint x; neg = 0; if(sgn && xx < 0){ neg = 1; x = -xx; }else{ x = xx; } i = 0; do{ buf[i++] = digits[x % base]; }while((x /= base) != 0); if(neg) buf[i++] = '-'; while(--i >= 0) putc(fd, buf[i]); } // Print to the given fd. Only understands %d, %x, %p, %s. void printf(int fd, char *fmt, ...) { char *s; int c, i, state; uint *ap; state = 0; ap = (uint*)(void*)&fmt + 1; for(i = 0; fmt[i]; i++){ c = fmt[i] & 0xff; if(state == 0){ if(c == '%'){ state = '%'; }else{ putc(fd, c); } }else if(state == '%'){ if(c == 'd'){ printint(fd, *ap, 10, 1); ap++; }else if(c == 'x' || c == 'p'){ printint(fd, *ap, 16, 0); ap++; }else if(c == 's'){ s = (char*)*ap; ap++; if(s == 0) s = "(null)"; while(*s != 0){ putc(fd, *s); s++; } }else if(c == 'c'){ putc(fd, *ap); ap++; }else if(c == '%'){ putc(fd, c); }else{ // Unknown % sequence. Print it to draw attention. putc(fd, '%'); putc(fd, c); } state = 0; } } }