From 8a190c9f10f7b4b4739c503c457aeeb7e48d3b62 Mon Sep 17 00:00:00 2001
From: optixx <david@optixx.org>
Date: Sun, 22 May 2016 17:49:07 +0200
Subject: [PATCH] Make ringbuffer work

---
 poc/fastlz/fastlz.c     | 23 ++++++++++++++++++-----
 poc/fastlz/poc.c        |  4 +++-
 poc/fastlz/ringbuffer.h |  8 ++++++++
 3 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/poc/fastlz/fastlz.c b/poc/fastlz/fastlz.c
index 26f92bb..ec6790d 100644
--- a/poc/fastlz/fastlz.c
+++ b/poc/fastlz/fastlz.c
@@ -328,10 +328,12 @@ int fastlz_decompress(const void* input, int length, void* output)
   return op - (flzuint8*)output;
 
 }
+
 #include <stdlib.h>
+#include <assert.h>
 #include "ringbuffer.h"
 
-#define log2(NUM) printf("%i op=%i(%x) ip=%i(%x) ref=%i(%x) dist=%i len=%i ctrl=%i ofs=%i(%i) limit=%i\n",NUM, output_addr,output[output_addr], input_addr,input[input_addr],ref_addr,input[ref_addr],output_addr - ref_addr, len, ctrl, ofs, ofs>>6,input_addr < ip_limit); 
+#define log2(NUM) printf("%i op=%i(%x) ip=%i(%x) ref=%i(%x) dist=%i buf->end=%i len=%i ctrl=%i ofs=%i(%i) limit=%i\n",NUM, output_addr,output[output_addr], input_addr,input[input_addr],ref_addr,input[ref_addr],output_addr - ref_addr,buffer_ptr->end, len, ctrl, ofs, ofs>>6,input_addr < ip_limit); 
 
 #define OUTPUT_INC(B)  do { \
     flzuint8 __b = B;\
@@ -340,6 +342,17 @@ int fastlz_decompress(const void* input, int length, void* output)
     output_addr++;\
 } while (0)
 
+#define OUTPUT_INC_FROM_REFINC()  do { \
+    flzuint8 __b = output[ref_addr]; \
+    flzuint16 __dist = (output_addr-ref_addr); \
+    flzuint8 __c = bufferGet(buffer_ptr, __dist); \
+    printf("output_addr=%i ref_addr=%i(%x) dist=%i(%x) buf->end=%i buf->size=%i position=%i\n", output_addr, ref_addr, __b, __dist, __c, buffer_ptr->end, buffer_ptr->size, __mod(buffer_ptr->end - __dist, buffer_ptr->size)); \
+    assert(__c == __b); \
+    output[output_addr] = __c;\
+    bufferWrite(buffer_ptr, __c);\
+    output_addr++;\
+    ref_addr++;\
+} while (0)
 
 
 ringBuffer_typedef(unsigned char, charBuffer);
@@ -396,11 +409,11 @@ int fastlz_decompress2(unsigned char* input, int length, unsigned char* output)
       {
         log2(3)
         ref_addr--;
-        OUTPUT_INC(output[ref_addr++]);
-        OUTPUT_INC(output[ref_addr++]);
-        OUTPUT_INC(output[ref_addr++]);
+        OUTPUT_INC_FROM_REFINC();
+        OUTPUT_INC_FROM_REFINC();
+        OUTPUT_INC_FROM_REFINC();
         for(; len; --len)
-          OUTPUT_INC(output[ref_addr++]);
+            OUTPUT_INC_FROM_REFINC();
       }
     }
     else
diff --git a/poc/fastlz/poc.c b/poc/fastlz/poc.c
index 9b633cf..51d4bf2 100644
--- a/poc/fastlz/poc.c
+++ b/poc/fastlz/poc.c
@@ -71,10 +71,11 @@ int main(int argc, char** argv){
     for(i = 0; i < MD5_DIGEST_LENGTH; i++) printf("%02x", c[i]);
     printf("\n");
     rlen = fastlz_compress(unpacked, len, packed);
-    hexdump(packed, rlen);
+    //hexdump(packed, rlen);
     printf("packed len=%i\n", rlen);
     memset(unpacked, 0, len);
     printf("-----\n");
+#if 0
     fastlz_decompress(packed, rlen, unpacked);
     MD5_Init (&md5_context); 
     MD5_Update (&md5_context, unpacked, len);
@@ -87,6 +88,7 @@ int main(int argc, char** argv){
     printf("Wrote out01.smc %l bytes\n", len);
     fclose(fp);
     memset(unpacked, 0, len);
+#endif 
     printf("-----\n");
     fastlz_decompress2(packed, rlen, unpacked);
     MD5_Init (&md5_context); 
diff --git a/poc/fastlz/ringbuffer.h b/poc/fastlz/ringbuffer.h
index 5e5e975..2cb9452 100644
--- a/poc/fastlz/ringbuffer.h
+++ b/poc/fastlz/ringbuffer.h
@@ -41,9 +41,16 @@
  *
  */
 
+
 #ifndef _ringbuffer_h
 #define _ringbuffer_h
 
+int __mod(int a, int b)
+{
+    int r = a % b;
+    return r < 0 ? r + b : r;
+}
+
 #define ringBuffer_typedef(T, NAME) \
   typedef struct { \
     int size; \
@@ -64,6 +71,7 @@
 #define nextEndIndex(BUF) ((BUF->end + 1) % BUF->size)
 #define isBufferEmpty(BUF) (BUF->end == BUF->start)
 #define isBufferFull(BUF) (nextEndIndex(BUF) == BUF->start)
+#define bufferGet(BUF, INDEX) (BUF->elems[__mod(BUF->end - INDEX, BUF->size)])
 
 #define bufferWrite(BUF, ELEM) \
   BUF->elems[BUF->end] = ELEM; \