Task 216: .FB File Format
Task 216: .FB File Format
1. List of All Properties of the .FB File Format Intrinsic to Its File System
The .FB file format refers to the Gforth Forth blocks file format, which is a simple block-based "file system" used in Forth implementations for storing source code or data in fixed-size blocks. It emulates a disk-like structure without complex metadata. Based on the official Gforth manual and Forth standards, the intrinsic properties are:
- Block Size: Fixed at 1024 bytes per block.
- Block Storage Structure: Blocks are stored sequentially in the file with no header, footer, directory, or metadata; the entire file is a direct concatenation of blocks.
- Block Count: Dynamically determined by the file size divided by the block size (must result in an integer; i.e., file size must be a multiple of 1024 bytes).
- Block Numbering: Blocks are numbered starting from 1 up to the block count.
- Line Format per Block: Each block is conventionally structured as 16 lines of exactly 64 characters each (1024 bytes total), suitable for Forth source code (lines 0-13 for code, line 14 for naming, line 15 for optional checksum), though the format does not enforce content validation.
- File Size Requirement: Must be an exact multiple of 1024 bytes; non-compliant files are invalid.
- Data Encoding: Binary file, but typically contains ASCII/UTF-8 text for Forth source; no compression or encryption.
- Access Model: Random access by block number (seek to (block_num - 1) * 1024); supports read/write at block level, mimicking a flat file system.
These properties define the format's simplicity and portability across Forth systems.
2. Two Direct Download Links for Files of Format .FB
- https://raw.githubusercontent.com/forthy42/gforth/master/blocked.fb (A sample blocked editor source file from the official Gforth repository; 16 blocks, 16384 bytes.)
- https://raw.githubusercontent.com/earl/gforth-mirror/master/blocked.fb (Mirror of the same sample from an automated Gforth Git mirror; identical content.)
3. Ghost Blog Embedded HTML JavaScript for Drag-and-Drop .FB File Analysis
This is a self-contained HTML snippet with embedded JavaScript, suitable for embedding in a Ghost blog post (e.g., via the HTML card). It creates a drag-and-drop zone that reads the dropped .FB file, validates the format, computes and dumps the properties to the screen (in a <div> below the drop zone), and decodes the first block's content as a preview (full dump omitted for large files to avoid performance issues).
Drag and drop a .FB file here to analyze its properties.
4. Python Class for .FB File Handling
import os
class FBFile:
BLOCK_SIZE = 1024
def read(self, filename):
if not os.path.exists(filename):
print("Error: File not found.")
return None
with open(filename, 'rb') as f:
data = f.read()
size = len(data)
if size % self.BLOCK_SIZE != 0:
print("Invalid format: File size must be a multiple of 1024 bytes.")
return None
num_blocks = size // self.BLOCK_SIZE
self.blocks = [data[i * self.BLOCK_SIZE:(i + 1) * self.BLOCK_SIZE] for i in range(num_blocks)]
print("FB File Properties:")
print(f"Block Size: {self.BLOCK_SIZE} bytes")
print(f"Block Count: {num_blocks}")
print("File Size Requirement Met: Yes")
print(f"Block Numbering: 1 to {num_blocks}")
print("Block Storage Structure: Sequential concatenation without header/footer")
print("Line Format per Block: 16 lines of 64 characters each")
print("Data Encoding: Binary (ASCII text expected)")
print("Access Model: Random access by block number")
return self.blocks
def write(self, filename, blocks):
if not blocks:
print("Error: No blocks to write.")
return
data = b''.join(blocks)
if len(data) % self.BLOCK_SIZE != 0:
print("Error: Total data size must be a multiple of 1024 bytes.")
return
with open(filename, 'wb') as f:
f.write(data)
print(f"Written {len(blocks)} blocks to {filename}.")
# Example usage:
# fb = FBFile()
# blocks = fb.read('example.fb')
# if blocks:
# fb.write('output.fb', blocks)
5. Java Class for .FB File Handling
import java.io.*;
import java.nio.file.*;
import java.util.*;
public class FBFile {
private static final int BLOCK_SIZE = 1024;
private List<byte[]> blocks = new ArrayList<>();
public List<byte[]> read(String filename) {
try {
Path path = Paths.get(filename);
byte[] data = Files.readAllBytes(path);
long size = data.length;
if (size % BLOCK_SIZE != 0) {
System.out.println("Invalid format: File size must be a multiple of 1024 bytes.");
return null;
}
int numBlocks = (int) (size / BLOCK_SIZE);
blocks.clear();
for (int i = 0; i < numBlocks; i++) {
byte[] block = new byte[BLOCK_SIZE];
System.arraycopy(data, i * BLOCK_SIZE, block, 0, BLOCK_SIZE);
blocks.add(block);
}
System.out.println("FB File Properties:");
System.out.println("Block Size: " + BLOCK_SIZE + " bytes");
System.out.println("Block Count: " + numBlocks);
System.out.println("File Size Requirement Met: Yes");
System.out.println("Block Numbering: 1 to " + numBlocks);
System.out.println("Block Storage Structure: Sequential concatenation without header/footer");
System.out.println("Line Format per Block: 16 lines of 64 characters each");
System.out.println("Data Encoding: Binary (ASCII text expected)");
System.out.println("Access Model: Random access by block number");
return blocks;
} catch (IOException e) {
System.out.println("Error reading file: " + e.getMessage());
return null;
}
}
public void write(String filename, List<byte[]> blocks) {
if (blocks == null || blocks.isEmpty()) {
System.out.println("Error: No blocks to write.");
return;
}
try {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
for (byte[] block : blocks) {
baos.write(block);
}
byte[] data = baos.toByteArray();
if (data.length % BLOCK_SIZE != 0) {
System.out.println("Error: Total data size must be a multiple of 1024 bytes.");
return;
}
Files.write(Paths.get(filename), data);
System.out.println("Written " + blocks.size() + " blocks to " + filename + ".");
} catch (IOException e) {
System.out.println("Error writing file: " + e.getMessage());
}
}
// Example usage:
// FBFile fb = new FBFile();
// List<byte[]> blocks = fb.read("example.fb");
// if (blocks != null) {
// fb.write("output.fb", blocks);
// }
}
6. JavaScript Class for .FB File Handling (Node.js)
const fs = require('fs').promises;
const path = require('path');
class FBFile {
constructor() {
this.BLOCK_SIZE = 1024;
this.blocks = [];
}
async read(filename) {
try {
const data = await fs.readFile(filename);
const size = data.length;
if (size % this.BLOCK_SIZE !== 0) {
console.log('Invalid format: File size must be a multiple of 1024 bytes.');
return null;
}
const numBlocks = Math.floor(size / this.BLOCK_SIZE);
this.blocks = [];
for (let i = 0; i < numBlocks; i++) {
const start = i * this.BLOCK_SIZE;
this.blocks.push(data.slice(start, start + this.BLOCK_SIZE));
}
console.log('FB File Properties:');
console.log(`Block Size: ${this.BLOCK_SIZE} bytes`);
console.log(`Block Count: ${numBlocks}`);
console.log('File Size Requirement Met: Yes');
console.log(`Block Numbering: 1 to ${numBlocks}`);
console.log('Block Storage Structure: Sequential concatenation without header/footer');
console.log('Line Format per Block: 16 lines of 64 characters each');
console.log('Data Encoding: Binary (ASCII text expected)');
console.log('Access Model: Random access by block number');
return this.blocks;
} catch (err) {
console.log('Error reading file: ' + err.message);
return null;
}
}
async write(filename, blocks) {
if (!blocks || blocks.length === 0) {
console.log('Error: No blocks to write.');
return;
}
const data = Buffer.concat(blocks);
if (data.length % this.BLOCK_SIZE !== 0) {
console.log('Error: Total data size must be a multiple of 1024 bytes.');
return;
}
await fs.writeFile(filename, data);
console.log(`Written ${blocks.length} blocks to ${filename}.`);
}
}
// Example usage:
// const fb = new FBFile();
// fb.read('example.fb').then(blocks => {
// if (blocks) {
// fb.write('output.fb', blocks);
// }
// });
7. C Class (Struct with Functions) for .FB File Handling
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define BLOCK_SIZE 1024
typedef struct {
unsigned char **blocks;
int num_blocks;
} FBFile;
FBFile *fbfile_new() {
FBFile *fb = malloc(sizeof(FBFile));
fb->blocks = NULL;
fb->num_blocks = 0;
return fb;
}
void fbfile_free(FBFile *fb) {
if (fb) {
if (fb->blocks) {
for (int i = 0; i < fb->num_blocks; i++) {
free(fb->blocks[i]);
}
free(fb->blocks);
}
free(fb);
}
}
unsigned char **fbfile_read(FBFile *fb, const char *filename) {
FILE *f = fopen(filename, "rb");
if (!f) {
printf("Error: File not found.\n");
return NULL;
}
fseek(f, 0, SEEK_END);
long size = ftell(f);
fseek(f, 0, SEEK_SET);
if (size % BLOCK_SIZE != 0) {
printf("Invalid format: File size must be a multiple of 1024 bytes.\n");
fclose(f);
return NULL;
}
int num_blocks = size / BLOCK_SIZE;
fb->num_blocks = num_blocks;
fb->blocks = malloc(num_blocks * sizeof(unsigned char *));
for (int i = 0; i < num_blocks; i++) {
fb->blocks[i] = malloc(BLOCK_SIZE);
fread(fb->blocks[i], 1, BLOCK_SIZE, f);
}
fclose(f);
printf("FB File Properties:\n");
printf("Block Size: %d bytes\n", BLOCK_SIZE);
printf("Block Count: %d\n", num_blocks);
printf("File Size Requirement Met: Yes\n");
printf("Block Numbering: 1 to %d\n", num_blocks);
printf("Block Storage Structure: Sequential concatenation without header/footer\n");
printf("Line Format per Block: 16 lines of 64 characters each\n");
printf("Data Encoding: Binary (ASCII text expected)\n");
printf("Access Model: Random access by block number\n");
return fb->blocks;
}
int fbfile_write(FBFile *fb, const char *filename, unsigned char **blocks, int num_blocks) {
if (!blocks || num_blocks == 0) {
printf("Error: No blocks to write.\n");
return -1;
}
FILE *f = fopen(filename, "wb");
if (!f) {
printf("Error: Cannot create file.\n");
return -1;
}
for (int i = 0; i < num_blocks; i++) {
fwrite(blocks[i], 1, BLOCK_SIZE, f);
}
fclose(f);
printf("Written %d blocks to %s.\n", num_blocks, filename);
return 0;
}
int main() {
FBFile *fb = fbfile_new();
unsigned char **blocks = fbfile_read(fb, "example.fb");
if (blocks) {
fbfile_write(fb, "output.fb", blocks, fb->num_blocks);
}
fbfile_free(fb);
return 0;
}