krishan prajapat
lele
Diff: convolution.h
- Revision:
- 0:984643af7d81
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/convolution.h Fri Jul 31 12:30:28 2015 +0000
@@ -0,0 +1,170 @@
+
+
+class Convolution{
+
+private:
+ typedef struct ConvNode{
+ //next state
+ //format : 8 bits mapped as [1]xxxx [0]xxxx
+ unsigned char nextState;
+
+ //output
+ // format : 8 bits mapped as
+ // **** xxxx{2} [1]-[0] {1} [1]-[0] i.e. ****xxxx
+ // x = data, * = junk
+ unsigned char output;
+ }ConvNode;
+
+ ConvNode convStateList[16];
+
+public:
+ /*
+ @brief: Constructor : Initialise all the variables
+ @param: none
+ @return: none
+ */
+ Convolution(){
+
+ convStateList[0].nextState = 0x10;
+ convStateList[1].nextState = 0x32;
+ convStateList[2].nextState = 0x54;
+ convStateList[3].nextState = 0x76;
+ convStateList[4].nextState = 0x98;
+ convStateList[5].nextState = 0xBA;
+ convStateList[6].nextState = 0xDC;
+ convStateList[7].nextState = 0xFE;
+ convStateList[8].nextState = 0x10;
+ convStateList[9].nextState = 0x32;
+ convStateList[10].nextState = 0x54;
+ convStateList[11].nextState = 0x76;
+ convStateList[12].nextState = 0x98;
+ convStateList[13].nextState = 0xBA;
+ convStateList[14].nextState = 0xDC;
+ convStateList[15].nextState = 0xFE;
+
+ convStateList[0].output = 0x0A;
+ convStateList[1].output = 0x06;
+ convStateList[2].output = 0x06;
+ convStateList[3].output = 0x0A;
+ convStateList[4].output = 0x09;
+ convStateList[5].output = 0x05;
+ convStateList[6].output = 0x05;
+ convStateList[7].output = 0x09;
+ convStateList[8].output = 0x05;
+ convStateList[9].output = 0x09;
+ convStateList[10].output = 0x09;
+ convStateList[11].output = 0x05;
+ convStateList[12].output = 0x06;
+ convStateList[13].output = 0x0A;
+ convStateList[14].output = 0x0A;
+ convStateList[15].output = 0x06;
+ }
+
+
+ /*
+ @brief: convolution encode the input bytes : in sync with => (1-TM-Frame -> 2-T-Frame)
+ @param: inPtr : pointer to input unsigned char array
+ inLength : length in bytes of input array
+ outPtr : pointer to the output bytes, define it outside the function
+ outLength : length of output array in bytes [call by reference, edited inside the function]
+ @return: none
+ */
+ void convolutionEncode(unsigned char *input, unsigned char *output){
+
+// cout << "inside convolution" << endl;
+
+ unsigned int convState = 0;
+
+ int inBit = 7;
+ unsigned int inByte = 0;
+
+ unsigned int outState = 0;
+ unsigned int outByte = 0;
+
+ for(unsigned int j = 0 ; j < 536 ; ++j){
+// printf("j = %u, inByte = %u\n", j, inByte);
+ // read a new bit from input stream
+// cout << "inByte " <<inByte;
+ unsigned char tempBit = (input[inByte] >> inBit) & 1;
+ --inBit;
+
+ // convolute and write output
+ switch(outState){
+ case 0:
+ outState = 2;
+ output[outByte] = ( (convStateList[convState].output >> tempBit) & 1 ) << 7;
+ output[outByte] += ( (convStateList[convState].output >> (tempBit + 2)) & 1 ) << 6;
+ break;
+ case 2:
+ outState = 4;
+ output[outByte] += ( (convStateList[convState].output >> tempBit) & 1 ) << 5;
+ output[outByte] += ( (convStateList[convState].output >> (tempBit + 2)) & 1 ) << 4;
+ break;
+ case 4:
+ outState = 6;
+ output[outByte] += ( (convStateList[convState].output >> tempBit) & 1 ) << 3;
+ output[outByte] += ( (convStateList[convState].output >> (tempBit + 2)) & 1 ) << 2;
+ break;
+ case 6:
+ outState = 0;
+ output[outByte] += ( (convStateList[convState].output >> tempBit) & 1 ) << 1;
+ output[outByte] += ( (convStateList[convState].output >> (tempBit + 2)) & 1 );
+ ++outByte;
+ output[outByte] = 0x00;
+ break;
+ }
+
+ // next state transition
+ switch(tempBit){
+ case 0:
+ convState = (convStateList[convState].nextState) & 0xF;
+ break;
+ case 1:
+ convState = (convStateList[convState].nextState >> 4) & 0xF;
+ break;
+ }
+
+ if(inBit == -1){
+// printf("in byte = %u\n", inByte);
+ ++inByte;
+ inBit = 7;
+ }
+
+ }
+
+// printf("normal iteration complete, outByte = %u\n", outByte);
+
+ for(unsigned int j = 0 ; j < 4 ; ++j){
+// printf("j = %u\n, outByte = %u\n", j, outByte);
+ // append zero at the end
+ switch(outState){
+ case 0:
+ outState = 2;
+ output[outByte] = ( (convStateList[convState].output) & 1 ) << 7;
+ output[outByte] += ( (convStateList[convState].output >> 2) & 1 ) << 6;
+ break;
+ case 2:
+ outState = 4;
+ output[outByte] += ( (convStateList[convState].output) & 1 ) << 5;
+ output[outByte] += ( (convStateList[convState].output >> 2) & 1 ) << 4;
+ break;
+ case 4:
+ outState = 6;
+ output[outByte] += ( (convStateList[convState].output ) & 1 ) << 3;
+ output[outByte] += ( (convStateList[convState].output >> 2) & 1 ) << 2;
+ break;
+ case 6:
+ outState = 0;
+ output[outByte] += ( (convStateList[convState].output ) & 1 ) << 1;
+ output[outByte] += ( (convStateList[convState].output >> 2) & 1 );
+ ++outByte;
+// printf("outByte @ end of switch = %u\n", outByte);
+ break;
+ }
+ // next state transition
+ convState = (convStateList[convState].nextState) & 0xF;
+ }
+// printf("complete\n");
+ }
+
+};