libbb/pw_encrypt_sha: -28 bytes

diff --git a/libbb/pw_encrypt_sha.c b/libbb/pw_encrypt_sha.c
index 08b0647501e7938484323ba3e98b5ce287cbfd8b..3dbaeabc93284f96c109af19bfe1216e9a1643c8 100644 (file)
--- a/libbb/pw_encrypt_sha.c
+++ b/libbb/pw_encrypt_sha.c
@@ -196,25 +196,23 @@ do {                                                      \
        resptr = to64(resptr, w, N);                    \
 } while (0)
        if (is_sha512 == '5') {
-               unsigned i = 0;
-               unsigned j = 10;
-               unsigned k = 20;
-               /* strange swap of one byte (see below why) */
-               unsigned char alt_result_31 = alt_result[31];
-               alt_result[31] = alt_result[1];
+               int i = 0;
+               int j = 10;
+               int k = 20;
                while (1) {
                        b64_from_24bit(alt_result[i], alt_result[j], alt_result[k], 4);
                        if (i == 9)
                                break;
-                       i += 21; i = (((i >> 4) & 2) + i) & 0x1f;
-                       j += 21; j = (((j >> 4) & 2) + j) & 0x1f;
-                       k += 21; k = (((k >> 4) & 2) + k) & 0x1f;
+                       /* if x - 9 produces < 0, subtract 2 more:
+                        * ((i >> 8) << 1) is either 0 or binary 111111...1110 */
+                       i -= 9; i = (i & 0x1f) + ((i >> 8) << 1);
+                       j -= 9; j = (j & 0x1f) + ((j >> 8) << 1);
+                       k -= 9; k = (k & 0x1f) + ((k >> 8) << 1);
                }
-               b64_from_24bit(0, alt_result_31, alt_result[30], 3);
+               b64_from_24bit(0, alt_result[31], alt_result[30], 3);
                /* was:
                b64_from_24bit(alt_result[0], alt_result[10], alt_result[20], 4);
                b64_from_24bit(alt_result[21], alt_result[1], alt_result[11], 4);
-               ...............................^^^^^^^^^^^^^ why [1] and not [31]?
                b64_from_24bit(alt_result[12], alt_result[22], alt_result[2], 4);
                b64_from_24bit(alt_result[3], alt_result[13], alt_result[23], 4);
                b64_from_24bit(alt_result[24], alt_result[4], alt_result[14], 4);