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authorDenys Vlasenko <vda.linux@googlemail.com>2010-06-10 08:54:44 (GMT)
committer Denys Vlasenko <vda.linux@googlemail.com>2010-06-10 08:54:44 (GMT)
commitab60cd13828896febb6c5c44046610f2c75a11f5 (patch)
tree87ee10c35ebe37781b35ddd688ec31af180d2ae4
parent7fdf5a88b4aaabb88624e66cd31d589a5b7280f6 (diff)
downloadbusybox-ab60cd13828896febb6c5c44046610f2c75a11f5.tar.gz
busybox-ab60cd13828896febb6c5c44046610f2c75a11f5.tar.bz2
utoa: shrink
function old new delta itoa_to_buf 20 23 +3 utoa_to_buf 117 101 -16 Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
-rw-r--r--libbb/xfuncs.c44
1 files changed, 29 insertions, 15 deletions
diff --git a/libbb/xfuncs.c b/libbb/xfuncs.c
index 1cd8d7c..6543721 100644
--- a/libbb/xfuncs.c
+++ b/libbb/xfuncs.c
@@ -49,23 +49,35 @@ char* FAST_FUNC strncpy_IFNAMSIZ(char *dst, const char *src)
}
-// Convert unsigned integer to ascii, writing into supplied buffer.
-// A truncated result contains the first few digits of the result ala strncpy.
-// Returns a pointer past last generated digit, does _not_ store NUL.
-void BUG_sizeof_unsigned_not_4(void);
+/* Convert unsigned integer to ascii, writing into supplied buffer.
+ * A truncated result contains the first few digits of the result ala strncpy.
+ * Returns a pointer past last generated digit, does _not_ store NUL.
+ */
+void BUG_sizeof(void);
char* FAST_FUNC utoa_to_buf(unsigned n, char *buf, unsigned buflen)
{
unsigned i, out, res;
- if (sizeof(unsigned) != 4)
- BUG_sizeof_unsigned_not_4();
+
if (buflen) {
out = 0;
- for (i = 1000000000; i; i /= 10) {
+ if (sizeof(n) == 4)
+ // 2^32-1 = 4294967295
+ i = 1000000000;
+#if UINT_MAX > 4294967295 /* prevents warning about "const too large" */
+ else
+ if (sizeof(n) == 8)
+ // 2^64-1 = 18446744073709551615
+ i = 10000000000000000000;
+#endif
+ else
+ BUG_sizeof();
+ for (; i; i /= 10) {
res = n / i;
+ n = n % i;
if (res || out || i == 1) {
- if (!--buflen) break;
+ if (--buflen == 0)
+ break;
out++;
- n -= res*i;
*buf++ = '0' + res;
}
}
@@ -76,7 +88,9 @@ char* FAST_FUNC utoa_to_buf(unsigned n, char *buf, unsigned buflen)
/* Convert signed integer to ascii, like utoa_to_buf() */
char* FAST_FUNC itoa_to_buf(int n, char *buf, unsigned buflen)
{
- if (buflen && n < 0) {
+ if (!buflen)
+ return buf;
+ if (n < 0) {
n = -n;
*buf++ = '-';
buflen--;
@@ -87,16 +101,16 @@ char* FAST_FUNC itoa_to_buf(int n, char *buf, unsigned buflen)
// The following two functions use a static buffer, so calling either one a
// second time will overwrite previous results.
//
-// The largest 32 bit integer is -2 billion plus null terminator, or 12 bytes.
-// It so happens that sizeof(int) * 3 is enough for 32+ bits.
+// The largest 32 bit integer is -2 billion plus NUL, or 1+10+1=12 bytes.
+// It so happens that sizeof(int) * 3 is enough for 32+ bit ints.
// (sizeof(int) * 3 + 2 is correct for any width, even 8-bit)
static char local_buf[sizeof(int) * 3];
-// Convert unsigned integer to ascii using a static buffer (returned).
+/* Convert unsigned integer to ascii using a static buffer (returned). */
char* FAST_FUNC utoa(unsigned n)
{
- *(utoa_to_buf(n, local_buf, sizeof(local_buf))) = '\0';
+ *(utoa_to_buf(n, local_buf, sizeof(local_buf) - 1)) = '\0';
return local_buf;
}
@@ -104,7 +118,7 @@ char* FAST_FUNC utoa(unsigned n)
/* Convert signed integer to ascii using a static buffer (returned). */
char* FAST_FUNC itoa(int n)
{
- *(itoa_to_buf(n, local_buf, sizeof(local_buf))) = '\0';
+ *(itoa_to_buf(n, local_buf, sizeof(local_buf) - 1)) = '\0';
return local_buf;
}