Zlib ng

libs/zlibng/arch/arm/insert_string_acle.c

@@ -0,0 +1,53 @@
+/* insert_string_acle.c -- insert_string variant using ACLE's CRC instructions
+ *
+ * Copyright (C) 1995-2013 Jean-loup Gailly and Mark Adler
+ * For conditions of distribution and use, see copyright notice in zlib.h
+ *
+ */
+
+#if defined(__ARM_FEATURE_CRC32) && defined(ARM_ACLE_CRC_HASH)
+#include <arm_acle.h>
+#include "zbuild.h"
+#include "deflate.h"
+
+/* ===========================================================================
+ * Insert string str in the dictionary and set match_head to the previous head
+ * of the hash chain (the most recent string with same hash key). Return
+ * the previous length of the hash chain.
+ * IN  assertion: all calls to to INSERT_STRING are made with consecutive
+ *    input characters and the first MIN_MATCH bytes of str are valid
+ *    (except for the last MIN_MATCH-1 bytes of the input file).
+ */
+Pos insert_string_acle(deflate_state *const s, const Pos str, unsigned int count) {
+    Pos p, lp, ret;
+
+    if (unlikely(count == 0)) {
+        return s->prev[str & s->w_mask];
+    }
+
+    ret = 0;
+    lp = str + count - 1; /* last position */
+
+    for (p = str; p <= lp; p++) {
+        uint32_t val, h, hm;
+        memcpy(&val, &s->window[p], sizeof(val));
+
+        if (s->level >= TRIGGER_LEVEL)
+            val &= 0xFFFFFF;
+
+        h = __crc32w(0, val);
+        hm = h & s->hash_mask;
+
+        Pos head = s->head[hm];
+        if (head != p) {
+            s->prev[p & s->w_mask] = head;
+            s->head[hm] = p;
+            if (p == lp)
+              ret = head;
+        } else if (p == lp) {
+          ret = p;
+        }
+    }
+    return ret;
+}
+#endif