Byte Stuffing Program in C
To ensure the secure transmission of binary data over networks that might interpret specific byte values as control characters or reserved patterns, the data communication technique known as "byte stuffing" is used. By adding extra bytes to distinguish them, byte stuffing stops these control characters from interfering with the data.
Byte stuffing uses particular patterns as control characters or flags to indicate the beginning and end of frames or packets. When these control characters are present in the data, they are replaced by a unique escape character and then a modified version of the original byte. The escape character recognises and eliminates the packed bytes at the other end, regaining access to the original data.
Here's a theoretical explanation of byte stuffing in C:
Sender (Byte Stuffing)
- Byte by byte, iterate through the incoming data.
- Identify any control characters or flags that require filling by seeing if the current byte matches them.
- Insert the escape character and a modified version of the original byte into the output buffer if a control character is discovered.
- Copy the current byte immediately into the output buffer if it is not a control character.
- Till all input bytes have been handled, keep doing this.
- Send the info that has been stuffed via the communication channel.
Receiver (Byte Destuffing)
- Go byte-by-byte through the received data in iterations.
- Verify that the escape character is the current byte.
- If the escape character is located, the changed version of the initial byte should be in the next byte. Removing the escape character will return the byte value to its original state.
- Copy the byte (the original or the de-stuffed byte) into the output buffer.
- Once all received bytes, have been processed, carry on with this process.
- The final data is the original data that has been destuffed.
It's vital to remember that different control characters, escape characters, and stuffing and de-stuffing methods may be utilised depending on the specific protocol or file format being used. The preceding response's example shows a straightforward byte stuffing implementation utilising the XOR technique and the control characters 0x00, 0xFF, and 0xAB, but you might need to modify it to fit your needs.
Consider the restrictions and potential problems related to byte stuffing, including the overhead provided by the extra bytes and the requirement to manage situations where the escape character naturally appears in the data.
Byte Stuffing Algorithm in C
- Set up a blank output buffer.
- Insert the flag byte at the start of the output buffer (for instance, 0x7E).
- Go over each byte of the incoming data in iterations:
- If the byte is an escape or flag byte:
- Include the escape byte in the output buffer, 0x7D.
- Add the original byte that has been XORed to the output buffer with a specific value, such as 0x20.
- Otherwise (standard data byte):
- To the output buffer, add the byte.
- After the output buffer, add the flag byte.
- Please send back the output buffer with the packed data in it.
Code:
#include <stdio.h>
#include <string.h>
#define FLAG 0x7E
#define ESCAPE 0x7D
// Function to perform byte stuffing
void byteStuffing(char* input, int inputLength, char* output, int* outputLength) {
int i, j;
*outputLength = 0;
// Start with the FLAG byte
output[(*outputLength)++] = FLAG;
for (i = 0; i < inputLength; i++) {
if (input[i] == FLAG || input[i] == ESCAPE) {
// Insert ESCAPE byte before special bytes
output[(*outputLength)++] = ESCAPE;
output[(*outputLength)++] = input[i] ^ 0x20;
} else {
output[(*outputLength)++] = input[i];
}
}
// End with FLAG byte
output[(*outputLength)++] = FLAG;
}
// Function to perform byte destuffing
void byteDestuffing(char* input, int inputLength, char* output, int* outputLength) {
int i, j;
*outputLength = 0;
for (i = 0; i < inputLength; i++) {
if (input[i] == ESCAPE && input[i + 1] == (FLAG ^ 0x20)) {
// Unescape the special bytes
output[(*outputLength)++] = FLAG;
i++;
} else if (input[i] == ESCAPE && input[i + 1] == (ESCAPE ^ 0x20)) {
// Unescape the special bytes
output[(*outputLength)++] = ESCAPE;
i++;
} else {
output[(*outputLength)++] = input[i];
}
}
}
int main() {
char input[100];
char output[200];
int inputLength, outputLength;
printf("Enter the input data: ");
fgets(input, sizeof(input), stdin);
// Remove the trailing newline character from the input
input[strcspn(input, "\n")] = '\0';
// Perform byte stuffing
byteStuffing(input, strlen(input), output, &outputLength);
printf("\nByte-stuffed data: ");
for (int i = 0; i < outputLength; i++) {
printf("%02X ", output[i]);
}
// Perform byte destuffing
byteDestuffing(output, outputLength, input, &inputLength);
printf("\n\nByte-destuffed data: %s\n", input);
return 0;
}
Output:
![Byte Stuffing Program in C](https://static.tutorialandexample.com/c/byte-stuffing-program-in-c1.png)
In conclusion, the C programme known as "byte stuffing" offers a dependable and effective method for sending data via communication channels. The programme ensures that data may be reliably transferred and received without ambiguity by integrating byte stuffing techniques, such as inserting a flag byte and escape sequences. It manages special characters inside the data efficiently, preventing their erroneous interpretation as control characters. The C language in the program's implementation enables low-level control and optimisation, making it appropriate for applications requiring reliable data transmission. Overall, the C byte stuffing programme provides an essential tool for trustworthy communication, supporting the efficient information of data in different systems and businesses.