Initial - all functions working

Author: Marcin Gomulak

LZ77.c

@@ -0,0 +1,112 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "Compressions.h"
+
+int localindex = 0;
+int outbuffindex = 0;
+
+unsigned char ReadByte(unsigned char * buffer);
+unsigned short ReadUInt16(unsigned char * buffer);
+void WriteByte(unsigned char * buffer, unsigned char _value);
+void WriteBytes(unsigned char * buffer, unsigned char * _value, int offset,int length);
+unsigned char * buff;
+
+
+unsigned char * LZ77 (char*buffer, int buffsize)
+{
+    if(buffsize > 0xFFFFFF)
+    {
+        printf("Error, too big input file!");
+        exit(1);
+    }
+
+    return _LZ77((unsigned char*)buffer, buffsize);
+
+    /*int compressedLength = 4;
+
+    unsigned char * outbuff = (unsigned char*)malloc(8*2+1);
+    *(outbuff) = 0x00;
+    int bufferlength = 1, bufferedblocks = 0;
+    int readBytes = 0;
+    while(readBytes < buffsize)
+    {
+        if(bufferedblocks==8)
+        {
+            writebytes(outbuffer, outbuff, 0, bufferlength);
+            compressedLength += bufferlength;
+            *outbuff = 0;
+            bufferlength = 1;
+            bufferedblocks = 0;
+        }
+    }
+*/
+}
+
+
+unsigned char * UNLZ77(unsigned char*buffer, int buffsize)
+{
+    localindex = 1;
+    int size = ReadUInt16(buffer) | (ReadByte(buffer) << 16);
+    unsigned char * outbuff = (unsigned char*)malloc(size);
+
+    int i = 0;
+    int j = 0;
+    while(outbuffindex < size)
+    {
+        int flagByte = ReadByte(buffer);
+        for(i = 0; i<8; i++)
+        {
+            if((flagByte & (0x80 >> i)) == 0)
+            {
+                *(outbuff+outbuffindex++) = ReadByte(buffer);
+            }
+            else
+                {
+                    unsigned short block = ReadUInt16(buffer);
+                    int count = ((block>>4) & 0xF) + 3;
+                    int disp = ((block & 0xF) << 8) | ((block >> 8)&0xFF);
+                    long outPos = outbuffindex;
+                    long copyPos = outbuffindex - disp - 1;
+
+                    for (j = 0; j<count; j++)
+                    {
+                        outbuffindex = copyPos++;
+                        unsigned char b = *(outbuff+outbuffindex++);
+                        outbuffindex = outPos++;
+                        *(outbuff+outbuffindex++) = b;
+                    }
+                }
+                if(outbuffindex >= size)
+                    break;
+        }
+    }
+    outbuffindex = 0;
+    mysize = size;
+    return outbuff;
+}
+
+unsigned char ReadByte(unsigned char * buffer)
+{
+    localindex++;
+    return (unsigned char)*(buffer+localindex-1);
+}
+
+unsigned short ReadUInt16(unsigned char * buffer)
+{
+    unsigned char byte1 = ReadByte(buffer);
+    unsigned char byte2= ReadByte(buffer);
+    return (byte2 << 8) | byte1;
+}
+
+void WriteByte(unsigned char * buffer, unsigned char _value)
+{
+    *(buffer + localindex++) = _value;
+}
+
+void WriteBytes(unsigned char * buffer, unsigned char * _value, int offset,int length)
+{
+int i;
+for(i = 0; i<length; i++)
+    *(buffer+offset++) = *(_value+i);
+}