diff options
| -rw-r--r-- | libbb/xfuncs.c | 44 |
1 files changed, 29 insertions, 15 deletions
diff --git a/libbb/xfuncs.c b/libbb/xfuncs.c index 1cd8d7c01..65437211d 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; } |