shrink sha hashing

function                                             old     new   delta
sha512_hash                                          262     281     +19
sha512_end                                           204     221     +17
sha1_hash                                            128     113     -15
static.mask                                           16       -     -16
static.bits                                           16       -     -16
sha1_end                                             160     136     -24
------------------------------------------------------------------------------
(add/remove: 0/2 grow/shrink: 2/2 up/down: 36/-71)            Total: -35 bytes

2 files changed, 34 insertions, 49 deletions

diff --git a/libbb/pw_encrypt_sha.c b/libbb/pw_encrypt_sha.c
index e71f96fdc..070e0d442 100644
--- a/libbb/pw_encrypt_sha.c
+++ b/libbb/pw_encrypt_sha.c
@@ -20,7 +20,7 @@ sha_crypt(/*const*/ char *key_data, /*const*/ char *salt_data)
 {
         void (*sha_begin)(void *ctx) FAST_FUNC;
         void (*sha_hash)(const void *buffer, size_t len, void *ctx) FAST_FUNC;
-        void* (*sha_end)(void *resbuf, void *ctx) FAST_FUNC;
+        void (*sha_end)(void *resbuf, void *ctx) FAST_FUNC;
         int _32or64;
 
         char *result, *resptr;
diff --git a/libbb/sha1.c b/libbb/sha1.c
index 5fc312393..38be575a6 100644
--- a/libbb/sha1.c
+++ b/libbb/sha1.c
@@ -406,22 +406,21 @@ void FAST_FUNC sha512_begin(sha512_ctx_t *ctx)
 /* hash_compile function as required.                                       */
 void FAST_FUNC sha1_hash(const void *buffer, size_t len, sha1_ctx_t *ctx)
 {
-        uint32_t pos = (uint32_t) (ctx->total64 & SHA1_MASK);
-        uint32_t freeb = SHA1_BLOCK_SIZE - pos;
-        const unsigned char *sp = buffer;
+        unsigned wbuflen = ctx->total64 & SHA1_MASK;
+        unsigned add = SHA1_BLOCK_SIZE - wbuflen;
 
         ctx->total64 += len;
 
-        while (len >= freeb) {  /* transfer whole blocks while possible  */
-                memcpy(((unsigned char *) ctx->wbuffer) + pos, sp, freeb);
-                sp += freeb;
-                len -= freeb;
-                freeb = SHA1_BLOCK_SIZE;
-                pos = 0;
+        while (len >= add) {    /* transfer whole blocks while possible  */
+                memcpy(((unsigned char *) ctx->wbuffer) + wbuflen, buffer, add);
+                buffer = (const char *)buffer + add;
+                len -= add;
+                add = SHA1_BLOCK_SIZE;
+                wbuflen = 0;
                 sha1_process_block64(ctx);
         }
 
-        memcpy(((unsigned char *) ctx->wbuffer) + pos, sp, len);
+        memcpy(((unsigned char *) ctx->wbuffer) + wbuflen, buffer, len);
 }
 
 void FAST_FUNC sha256_hash(const void *buffer, size_t len, sha256_ctx_t *ctx)
@@ -517,42 +516,24 @@ void FAST_FUNC sha512_hash(const void *buffer, size_t len, sha512_ctx_t *ctx)
 
 void FAST_FUNC sha1_end(void *resbuf, sha1_ctx_t *ctx)
 {
-        /* SHA1 Final padding and digest calculation  */
-#if BB_BIG_ENDIAN
-        static const uint32_t mask[4] = { 0x00000000, 0xff000000, 0xffff0000, 0xffffff00 };
-        static const uint32_t bits[4] = { 0x80000000, 0x00800000, 0x00008000, 0x00000080 };
-#else
-        static const uint32_t mask[4] = { 0x00000000, 0x000000ff, 0x0000ffff, 0x00ffffff };
-        static const uint32_t bits[4] = { 0x00000080, 0x00008000, 0x00800000, 0x80000000 };
-#endif
-
-        uint8_t *hval = resbuf;
-        uint32_t i, cnt = (uint32_t) (ctx->total64 & SHA1_MASK);
-
-        /* mask out the rest of any partial 32-bit word and then set    */
-        /* the next byte to 0x80. On big-endian machines any bytes in   */
-        /* the buffer will be at the top end of 32 bit words, on little */
-        /* endian machines they will be at the bottom. Hence the AND    */
-        /* and OR masks above are reversed for little endian systems    */
-        ctx->wbuffer[cnt >> 2] =
-                (ctx->wbuffer[cnt >> 2] & mask[cnt & 3]) | bits[cnt & 3];
-
-        /* we need 9 or more empty positions, one for the padding byte  */
-        /* (above) and eight for the length count.  If there is not     */
-        /* enough space pad and empty the buffer                        */
-        if (cnt > SHA1_BLOCK_SIZE - 9) {
-                if (cnt < 60)
-                        ctx->wbuffer[15] = 0;
+        unsigned i, wbuflen, pad;
+
+        /* Pad the buffer to the next 64-byte boundary with 0x80,0,0,0... */
+        wbuflen = ctx->total64 & SHA1_MASK;
+        ((uint8_t *)ctx->wbuffer)[wbuflen++] = 0x80;
+        pad = SHA1_BLOCK_SIZE - wbuflen;
+        memset(((uint8_t *)ctx->wbuffer) + wbuflen, 0, pad);
+
+        /* We need 1+8 or more empty positions, one for the padding byte
+         * (above) and eight for the length count.
+         * If there is not enough space, empty the buffer. */
+        if (pad < 8) {
                 sha1_process_block64(ctx);
-                cnt = 0;
-        } else  /* compute a word index for the empty buffer positions */
-                cnt = (cnt >> 2) + 1;
-
-        while (cnt < 14)  /* and zero pad all but last two positions */
-                ctx->wbuffer[cnt++] = 0;
+                memset(ctx->wbuffer, 0, SHA1_BLOCK_SIZE - 8);
+                ((uint8_t *)ctx->wbuffer)[0] = 0x80;
+        }
 
-        /* assemble the 64-bit counter of bits in the buffer in BE      */
-        /* format                                                       */
+        /* Store the 64-bit counter of bits in the buffer in BE format */
         {
                 uint64_t t = ctx->total64 << 3;
                 t = hton64(t);
@@ -562,10 +543,14 @@ void FAST_FUNC sha1_end(void *resbuf, sha1_ctx_t *ctx)
 
         sha1_process_block64(ctx);
 
-        /* extract the hash value as bytes in case the hash buffer is   */
-        /* misaligned for 32-bit words                                  */
-        for (i = 0; i < SHA1_DIGEST_SIZE; ++i)
-                hval[i] = (unsigned char) (ctx->hash[i >> 2] >> 8 * (~i & 3));
+        /* Extract the hash value as bytes in case resbuf is
+         * misaligned for 32-bit words */
+        for (i = 0; i < ARRAY_SIZE(ctx->hash); ++i) {
+                uint32_t t = ctx->hash[i];
+                t = ntohl(t); /* paranoia. this can be a macro */
+                move_to_unaligned32(resbuf, t); /* ditto */
+                resbuf = (char*)resbuf + 4;
+        }
 }