ab60cd138
Denys Vlasenko
2010-06-10
Subject
utoa: shrink
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libbb/xfuncs.c+29 -15
| @@ -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; | |
| } | |