diff options
Diffstat (limited to 'base85.c')
| -rw-r--r-- | base85.c | 24 |
1 files changed, 8 insertions, 16 deletions
@@ -7,9 +7,9 @@ #define say1(a,b) fprintf(stderr, a, b) #define say2(a,b,c) fprintf(stderr, a, b, c) #else -#define say(a) do {} while(0) -#define say1(a,b) do {} while(0) -#define say2(a,b,c) do {} while(0) +#define say(a) do { /* nothing */ } while (0) +#define say1(a,b) do { /* nothing */ } while (0) +#define say2(a,b,c) do { /* nothing */ } while (0) #endif static const char en85[] = { @@ -41,7 +41,7 @@ int decode_85(char *dst, const char *buffer, int len) { prep_base85(); - say2("decode 85 <%.*s>", len/4*5, buffer); + say2("decode 85 <%.*s>", len / 4 * 5, buffer); while (len) { unsigned acc = 0; int de, cnt = 4; @@ -57,14 +57,8 @@ int decode_85(char *dst, const char *buffer, int len) de = de85[ch]; if (--de < 0) return error("invalid base85 alphabet %c", ch); - /* - * Detect overflow. The largest - * 5-letter possible is "|NsC0" to - * encode 0xffffffff, and "|NsC" gives - * 0x03030303 at this point (i.e. - * 0xffffffff = 0x03030303 * 85). - */ - if (0x03030303 < acc || + /* Detect overflow. */ + if (0xffffffff / 85 < acc || 0xffffffff - de < (acc *= 85)) return error("invalid base85 sequence %.5s", buffer-5); acc += de; @@ -84,14 +78,12 @@ int decode_85(char *dst, const char *buffer, int len) void encode_85(char *buf, const unsigned char *data, int bytes) { - prep_base85(); - say("encode 85"); while (bytes) { unsigned acc = 0; int cnt; for (cnt = 24; cnt >= 0; cnt -= 8) { - int ch = *data++; + unsigned ch = *data++; acc |= ch << cnt; if (--bytes == 0) break; @@ -118,7 +110,7 @@ int main(int ac, char **av) int len = strlen(av[2]); encode_85(buf, av[2], len); if (len <= 26) len = len + 'A' - 1; - else len = len + 'a' - 26 + 1; + else len = len + 'a' - 26 - 1; printf("encoded: %c%s\n", len, buf); return 0; } |