Decompresses a pcsxr save state, pulls out the memory into it's own file, and any time that memory file is edited, the save ste is updated with new memory.

psx-extract-mem.js

// Imports
const { readFileSync, writeFileSync, watchFile } = require('fs')
const { gunzipSync, gzipSync } = require('zlib')

// Constants
const dir = "/home/benjamin/.pcsxr/sstates"
const src = "MEGAMAN_LEGENDS2-SLUS01140.002"
const dst = "MEGAMAN_LEGENDS2-SLUS01140.004"
const memPath = "./mem.bin"

// Read the save state
const compressedState = readFileSync(`${dir}/${src}`);
// Make a copy of the original
writeFileSync(`${dir}/${dst}`, compressedState);
// Decompress the state
const decompressedState = gunzipSync(compressedState);

// Split the memory into it's own file
const mem_len = 0x200000;
const mem_ofs = 0x9025;
const mem = decompressedState.slice(mem_ofs, mem_ofs + mem_len);

// Write the memory to it's own file
writeFileSync(memPath, mem);

// Set up a watcher to check for changes
const interval = 100;
const options = { interval }
watchFile(memPath, () => {

	console.log("File updated");
	const updatedMem = readFileSync(memPath)
	decompressedState.set(updatedMem, mem_ofs)
	const updatedState = gzipSync(decompressedState)
	writeFileSync(`${dir}/${dst}`, updatedState);

});