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#include "gbos.h"
/* xxd [-c N] [file]: hex dump a file, or stdin.
*
* Eight bytes per line, not the usual sixteen: offset + 8 hex pairs + the
* ASCII column is 38 of the terminal's 40 columns, where 16 would wrap every
* line and make the dump unreadable. -c overrides it anyway.
*
* There is no seek syscall, so this streams from the start - which is also
* why there is no -s (skip). -l stops after N bytes, which is how you look at
* a program image: /bin/<prog> is a whole 16 KiB ROM bank, and dumping all of
* it is 2048 lines (and more than a pipe's temp file can hold). */
#define MAXC 16
/* atou() is 8-bit; -l wants up to 16 KiB */
static unsigned int atou16(const char *s) {
unsigned int n = 0;
while (*s >= '0' && *s <= '9') {
n = n * 10 + (unsigned char)(*s - '0');
s++;
}
return n;
}
static char hexd(unsigned char v) { return (char)(v < 10 ? '0' + v : 'a' + (v - 10)); }
static void hex2(unsigned char v) {
putc(hexd((unsigned char)(v >> 4)));
putc(hexd((unsigned char)(v & 15)));
}
static void hex4(unsigned int v) {
hex2((unsigned char)(v >> 8));
hex2((unsigned char)v);
}
void main(void) {
char *argv[8];
unsigned char buf[MAXC];
unsigned char argc = argv_parse(argv, 8);
char *cv = optval(argv, argc, 'c');
char *lv = optval(argv, argc, 'l');
unsigned int limit = 0; /* 0 = no limit */
unsigned char cols = 8, fd = NOFD, n = 0, i;
unsigned int off = 0;
char *fname = 0;
int ch;
if (cv) {
cols = atou(cv);
if (cols == 0 || cols > MAXC) cols = 8;
}
if (lv) limit = atou16(lv);
for (i = 0; i < argc; i++) {
if (argv[i][0] == '-') continue;
if (cv == argv[i] || lv == argv[i]) continue;
fname = argv[i];
break;
}
if (fname) {
fd = open(fname, O_READ);
if (fd == EISDIR) {
puts("xxd: is a directory");
nl();
sexit(2);
}
if (fd == NOFD) {
puts("xxd: no such file");
nl();
sexit(2);
}
}
for (;;) {
if (limit && off + n >= limit) ch = -1; /* -l: stop after N bytes */
else if (fd == NOFD) {
char c = readc();
ch = (c == EOF) ? -1 : c;
} else ch = fgetc(fd);
if (ch >= 0) buf[n++] = (unsigned char)ch;
if (n == cols || (ch < 0 && n)) { /* full line, or the last one */
hex4(off);
puts(": ");
for (i = 0; i < cols; i++) {
if (i < n) hex2(buf[i]);
else {
putc(' ');
putc(' ');
} /* pad so ASCII stays aligned */
putc(' ');
}
for (i = 0; i < n; i++) putc((buf[i] >= 32 && buf[i] < 127) ? (char)buf[i] : '.');
nl();
off += n;
n = 0;
}
if (ch < 0) break;
}
if (fd != NOFD) close(fd);
}
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