From 8461d2f7c7685044649b2288bbcee0978d65995b Mon Sep 17 00:00:00 2001
From: Mathias Buus <mathiasbuus@gmail.com>
Date: Wed, 11 Nov 2015 16:21:04 -0800
Subject: [PATCH] externalize memory management and inline last_chunk

---
 bindings.cc  |  9 +++++----
 src/rabin.cc | 36 ++++--------------------------------
 src/rabin.h  | 14 ++++----------
 3 files changed, 13 insertions(+), 46 deletions(-)

diff --git a/bindings.cc b/bindings.cc
index 1ad4bba..c6259d4 100644
--- a/bindings.cc
+++ b/bindings.cc
@@ -1,3 +1,4 @@
+#include <stdlib.h>
 #include <nan.h>
 #include "src/rabin.h"
 
@@ -23,15 +24,15 @@ void get_fingerprints(rabin_t *hasher, Local<Array> bufs, Local<Array> lengths)
         len -= remaining;
         ptr += remaining;
 
-        lengths->Set(chunk_idx++, Nan::New<Number>(last_chunk.length));
+        lengths->Set(chunk_idx++, Nan::New<Number>(hasher->chunk_length));
     }
   }
 }
 
 NAN_METHOD(Initialize) {
   if (instance_counter >= 1024) return Nan::ThrowError("the value of instance_counter is too damn high");
-  struct rabin_t *hasher;
-  hasher = rabin_init();
+  struct rabin_t *hasher = (struct rabin_t *) malloc(sizeof(struct rabin_t));
+  rabin_init(hasher);
   instances[instance_counter++] = hasher;
   info.GetReturnValue().Set(instance_counter - 1);
 }
@@ -59,7 +60,7 @@ NAN_METHOD(End) {
     instance_counter--;
   }
 
-  delete fingerprint_ptr;
+  free(fingerprint_ptr);
 }
 
 NAN_MODULE_INIT(InitAll) {
diff --git a/src/rabin.cc b/src/rabin.cc
index eba7d12..d5c990c 100644
--- a/src/rabin.cc
+++ b/src/rabin.cc
@@ -6,8 +6,6 @@
 #define MASK ((1<<AVERAGE_BITS)-1)
 #define POL_SHIFT (POLYNOMIAL_DEGREE-8)
 
-struct chunk_t last_chunk;
-
 static bool tables_initialized = false;
 static uint64_t mod_table[256];
 static uint64_t out_table[256];
@@ -116,16 +114,11 @@ int rabin_next_chunk(struct rabin_t *h, uint8_t *buf, uint64_t len) {
         h->pos++;
 
         if ((h->count >= MINSIZE && ((h->digest & MASK) == 0)) || h->count >= MAXSIZE) {
-            last_chunk.start = h->start;
-            last_chunk.length = h->count;
-            last_chunk.cut_fingerprint = h->digest;
+            h->chunk_start = h->start;
+            h->chunk_length = h->count;
+            h->chunk_cut_fingerprint = h->digest;
 
-            // keep position
-            uint64_t pos = h->pos;
             rabin_reset(h);
-            h->start = pos;
-            h->pos = pos;
-
             return i+1;
         }
     }
@@ -133,36 +126,15 @@ int rabin_next_chunk(struct rabin_t *h, uint8_t *buf, uint64_t len) {
     return -1;
 }
 
-struct rabin_t *rabin_init(void) {
+struct rabin_t *rabin_init(struct rabin_t *h) {
     if (!tables_initialized) {
         calc_tables();
         tables_initialized = true;
     }
 
-    struct rabin_t *h;
-
-    if ((h = (struct rabin_t *) malloc(sizeof(struct rabin_t))) == NULL) {
-        errx(1, "malloc()");
-    }
-
     h->pos = 0;
     h->start = 0;
     rabin_reset(h);
 
     return h;
 }
-
-
-struct chunk_t *rabin_finalize(struct rabin_t *h) {
-    if (h->count == 0) {
-        last_chunk.start = 0;
-        last_chunk.length = 0;
-        last_chunk.cut_fingerprint = 0;
-        return NULL;
-    }
-
-    last_chunk.start = h->start;
-    last_chunk.length = h->count;
-    last_chunk.cut_fingerprint = h->digest;
-    return &last_chunk;
-}
diff --git a/src/rabin.h b/src/rabin.h
index 8168ec1..d9b4649 100644
--- a/src/rabin.h
+++ b/src/rabin.h
@@ -17,21 +17,15 @@ struct rabin_t {
   uint64_t pos;
   uint64_t start;
   uint64_t digest;
+  uint64_t chunk_start;
+  uint64_t chunk_length;
+  uint64_t chunk_cut_fingerprint;
 };
 
-struct chunk_t {
-  uint64_t start;
-  uint64_t length;
-  uint64_t cut_fingerprint;
-};
-
-extern struct chunk_t last_chunk;
-
-struct rabin_t *rabin_init(void);
+struct rabin_t *rabin_init(struct rabin_t *h);
 void rabin_reset(struct rabin_t *h);
 void rabin_slide(struct rabin_t *h, uint8_t b);
 void rabin_append(struct rabin_t *h, uint8_t b);
 int rabin_next_chunk(struct rabin_t *h, uint8_t *buf, uint64_t len);
-struct chunk_t *rabin_finalize(struct rabin_t *h);
 
 #endif