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#include <unistd.h>
#include <errno.h>
struct mini_buffer {
char *x;
unsigned int p, n;
int fd;
};
static char buf_space[512];
struct mini_buffer b = { buf_space, 0, sizeof(buf_space), 1 };
static void s_write(int fd, char *s, int n) {
int w;
while (n) {
w = write(fd,s,n);
if (w==0) _exit(1);
if (w==-1) {
if (errno == EINTR) continue;
_exit(1);
}
s += w;
n -= w;
}
}
void out_flush() { s_write(b.fd, b.x, b.p); b.p=0; }
void out_char(char ch) { if (b.p==b.n) out_flush(); b.x[b.p] = ch; b.p++; }
void outs(char *s) { while (*s) { out_char(*s); ++s; } }
static void bad(char *fmt, char *s) {
if (b.fd==1) out_flush();
b.fd=2;
outs("\nbad format: "); outs(fmt); outs("\nstart: ");
outs(s); outs("\n"); out_flush(); _exit(2);
}
char *conv_esc(char *x, char *pr_char) {
char *e0 = "ntrabfvEe\\";
char *e1 = "\n\t\r\a\b\f\v\033\033\\";
char ch;
int k;
for (k=0; k<10; k++)
if (e0[k] == *x)
{ *pr_char = e1[k]; return x; }
for (k=0, ch=0; '0'<=*x && *x<'8' && k<3; k++, x++)
ch = ch*8 + (*x-'0');
if (k == 0) return 0;
*pr_char = ch;
return --x;
}
int main(int argc, char **argv) {
char *fmt, *s, *x, ch;
if (argc<2) _exit(100);
fmt = argv[1];
argv += 2;
for (s=fmt; (ch=*s); s++) {
if (ch != '%' && ch != '\\') goto print_char;
if ((ch = *++s) == 0) goto bad_fmt;
if (s[-1] == '\\') {
if ((x=conv_esc(s,&ch)) == 0) goto bad_fmt;
s = x;
print_char:
out_char(ch);
} else { /* % */
switch (ch) {
case '%': goto print_char;
case 's':
case 'b':
if ((x=*argv++)) {
if (ch=='s') outs(x);
else { /* %b */
char *y, *tmp;
for (tmp=x; (ch=*x); x++) {
if (ch == '\\') {
if ((y=conv_esc(++x,&ch)) == 0) bad(tmp, x-1);
x = y;
}
out_char(ch);
}
}
break;
}
out_flush(); b.fd=2;
outs("\nmissing argument");
default:
bad_fmt:
bad(fmt,s-1);
}
}
}
out_flush();
fsync(1);
_exit(close(1));
}
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