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Support for ROMs whose size isn't a multiple of 1024 bytes #59

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40 changes: 24 additions & 16 deletions js/PicoCart64.js
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Original file line number Diff line number Diff line change
Expand Up @@ -82,7 +82,7 @@ function compileUF2(headerAndMappingU8, payload) {
let offset = 0;

// Calculate the output size
var blocks = Math.floor(((payload.fileSize + 255) / 256) + 0x8000 / 256);
var blocks = Math.ceil(payload.fileSize / 256 + 0x8000 / 256);
var outSize = blocks * 512;
var dataOut = new Uint8Array(outSize);

Expand All @@ -96,35 +96,41 @@ function compileUF2(headerAndMappingU8, payload) {
};

// Write header
for (i = 0; i < headerAndMappingU8.length / 256; i++) {
block.payload = headerAndMappingU8.slice(i * 256, (i + 1) * 256);
i = 0;
while (i < headerAndMappingU8.length) {
len = Math.min(headerAndMappingU8.length - i, 256)
block.payload = headerAndMappingU8.slice(i, i + len);
encodeBlock(block, dataOut, offset);
block.blockNumber++;
block.flashAddress += 256;
offset += 512;
i += len
}

// Write payload
payload.seek(0);
while (!payload.isEOF()) {
block.payload = payload.readBytes(256);
i = 0;
while (i < payload.fileSize) {
len = Math.min(payload.fileSize - i, 256)
block.payload = payload.readBytes(len);
encodeBlock(block, dataOut, offset);
block.blockNumber++;
block.flashAddress += 256;
offset += 512;
i += len
}

return dataOut;
}

// Compares two Uint8Array
function Uint8ArrayCompare(buf1, buf2) {
if (buf1.byteLength != buf2.byteLength) {
function Uint8ArrayHasPrefix(buf, prefix) {
if (buf.byteLength < prefix.byteLength) {
return false;
}

for (var i = 0; i < buf1.byteLength; i++) {
if (buf1[i] != buf2[i]) {
for (var i = 0; i < prefix.byteLength; i++) {
if (buf[i] != prefix[i]) {
return false;
}
}
Expand All @@ -135,7 +141,7 @@ function Uint8ArrayCompare(buf1, buf2) {
// Returns the index of the Uint8Array needle in the array of Uint8Arrays haystack
function indexOfUint8Array(needle, haystack) {
for (var i = 0; i < haystack.length; i++) {
if (Uint8ArrayCompare(haystack[i], needle)) {
if (Uint8ArrayHasPrefix(haystack[i], needle)) {
return i;
}
}
Expand All @@ -152,7 +158,7 @@ function generateAndSaveUF2(rom, compress) {
var headerAndMappingU8 = new Uint8Array(headerAndMapping, 0);
headerAndMappingU8.set(stringToUint8Array("picocartcompress"));

var mappingU16 = new Uint16Array(headerAndMapping, 16, Math.floor((0x8000 - 16) / 2));
var mapping = new DataView(headerAndMapping, 16);

chunk_size_pot = 10
chunk_size = 1 << chunk_size_pot
Expand All @@ -163,10 +169,11 @@ function generateAndSaveUF2(rom, compress) {
unique_chunks = []
chunk_mapping = []
chunk_idx = 0
num_chunks = Math.floor(rom.fileSize / chunk_size)
num_chunks = Math.ceil(rom.fileSize / chunk_size)
rom.seek(0)
for (var i = 0; i < num_chunks; i++) {
chunk_data = rom.slice(i * chunk_size, chunk_size)._u8array;
len = Math.min(rom.fileSize - i*chunk_size, chunk_size)
chunk_data = rom.slice(i * chunk_size, len)._u8array;

// Check if chunk_data is in unique_chunks
var index = indexOfUint8Array(chunk_data, unique_chunks);
Expand All @@ -183,12 +190,13 @@ function generateAndSaveUF2(rom, compress) {

// Flatten chunk_mapping into a Uint8Array
for (var i = 0; i < chunk_mapping.length; i++) {
mappingU16[i] = chunk_mapping[i];
mapping.setUint16(i*2, chunk_mapping[i], true); // little-endian
}

// Flatten unique_chunks into a Uint8Array
var compressedROM = new Uint8Array(chunk_size * unique_chunks.length);
for (var i = 0; i < unique_chunks.length; i++) {
ucn = unique_chunks.length
var compressedROM = new Uint8Array(chunk_size * (ucn - 1) + unique_chunks[ucn - 1].byteLength);
for (var i = 0; i < ucn; i++) {
compressedROM.set(unique_chunks[i], chunk_size * i);
}

Expand Down