torrentd

commit d143e24f86f4e99fd78b22706c2d7354d4b73bc6
parent f6916ef2743377b69e380ef464740609d2d5a2ad
Author: sin <sin@2f30.org>
Date:   Sun, 27 Dec 2015 10:40:30 +0000

Add pack/unpack functions

Diffstat:
M
storrent.h
 | 
2
++
M
util.c
 | 
123
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

2 files changed, 125 insertions(+), 0 deletions(-)
diff --git a/storrent.h b/storrent.h
@@ -111,3 +111,5 @@ size_t strlcat(char *, const char *, size_t);
 void initbuf(struct buf *);
 void freebuf(struct buf *);
 size_t fillbuf(struct buf *, void *, size_t);
+int unpack(uint8_t *, size_t, char *, ...);
+int pack(uint8_t *, size_t, char *, ...);
diff --git a/util.c b/util.c
@@ -5,6 +5,7 @@
 #include <ctype.h>
 #include <err.h>
 #include <fcntl.h>
+#include <stdarg.h>
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
@@ -245,3 +246,125 @@ fillbuf(struct buf *b, void *ptr, size_t n)
 	b->n += n;
 	return b->n;
 }
+
+int
+unpack(uint8_t *s, size_t n, char *fmt, ...)
+{
+	va_list arg;
+	uint8_t *b, *e;
+
+	b = s;
+	e = b + n;
+	va_start(arg, fmt);
+	for (; *fmt; fmt++) {
+		switch (*fmt) {
+		case '_':
+			s++;
+			break;
+		case 'b':
+			if (s + 1 > e)
+				goto err;
+			*va_arg(arg, int *) = *s++;
+			break;
+		case 'w':
+			if (s + 2 > e)
+				goto err;
+			*va_arg(arg, int *) = s[0] << 8 | s[1];
+			s += 2;
+			break;
+		case 'l':
+			if (s + 4 > e)
+				goto err;
+			*va_arg(arg, int *) = s[0] << 24 | s[1] << 16 | s[2] << 8 | s[3];
+			s += 4;
+			break;
+		case 'v':
+			if (s + 4 > e)
+				goto err;
+			*va_arg(arg, long long *) =
+				(long long)s[0] << 56 |
+				(long long)s[1] << 48 |
+				(long long)s[2] << 40 |
+				(long long)s[3] << 32 |
+				(long long)s[4] << 24 |
+				(long long)s[5] << 16 |
+				(long long)s[6] << 8 |
+				(long long)s[7];
+			s += 8;
+			break;
+		}
+	}
+	va_end(arg);
+	return s - b;
+err:
+	va_end(arg);
+	return -1;
+}
+
+int
+pack(uint8_t *s, size_t n, char *fmt, ...)
+{
+	va_list arg;
+	uint8_t *b, *e;
+	long long v;
+	int i;
+
+	b = s;
+	e = b + n;
+	va_start(arg, fmt);
+	for (; *fmt; fmt++) {
+		switch (*fmt) {
+		case '_':
+			i = 0;
+			if (0) {
+		case 'b':
+			i = va_arg(arg, int);
+			}
+			if (s + 1 > e)
+				goto err;
+			*s++ = i & 0xff;
+			break;
+		case 'w':
+			i = va_arg(arg, int);
+			if (s + 2 > e)
+				goto err;
+			*s++ = (i >> 8) & 0xff;
+			*s++ = i & 0xff;
+			break;
+		case 'l':
+			i = va_arg(arg, int);
+			if (s + 4 > e)
+				goto err;
+			*s++ = (i >> 24) & 0xff;
+			*s++ = (i >> 16) & 0xff;
+			*s++ = (i >> 8) & 0xff;
+			*s++ = i & 0xff;
+			break;
+		case 'v':
+			v = va_arg(arg, long long);
+			if (s + 8 > e)
+				goto err;
+			*s++ = (v >> 56) & 0xff;
+			*s++ = (v >> 48) & 0xff;
+			*s++ = (v >> 40) & 0xff;
+			*s++ = (v >> 32) & 0xff;
+			*s++ = (v >> 24) & 0xff;
+			*s++ = (v >> 16) & 0xff;
+			*s++ = (v >> 8) & 0xff;
+			*s++ = v & 0xff;
+			break;
+		case '*':
+			i = va_arg(arg, int);
+			if (s + i > e)
+				goto err;
+			memmove(s, va_arg(arg, void *), i);
+			s += i;
+			break;
+		}
+	}
+	va_end(arg);
+	return s - b;
+err:
+	va_end(arg);
+	return -1;
+}