Skip to content

Optimize leavings management in decoding. #44

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
sciencesakura merged 2 commits into from
Jun 28, 2025
Merged

Optimize leavings management in decoding. #44

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
a3f88a9
Optimize leavings management in decoding.
sciencesakura Jun 28, 2025
0fb31f5
Mark instance fields as readonly.
sciencesakura Jun 28, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
2 changes: 1 addition & 1 deletion packages/mutf-8-stream/src/index.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -26,7 +26,7 @@ import { type AllowSharedBufferSource, MUtf8Decoder, MUtf8Encoder, type TextDeco
* @since v1.2.0
*/
export class MUtf8DecoderStream extends TransformStream<AllowSharedBufferSource, string> {
#decoder: MUtf8Decoder;
readonly #decoder: MUtf8Decoder;

/**
* The encoding name for this decoder.
Expand Down
29 changes: 18 additions & 11 deletions packages/mutf-8/src/index.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -124,11 +124,13 @@ export type AllowSharedBufferSource = ArrayBuffer | SharedArrayBuffer | ArrayBuf
* @see {@link https://docs.oracle.com/javase/specs/jvms/se21/html/jvms-4.html#jvms-4.4.7 | The Java Virtual Machine Specification, Java SE 21 Edition, Section 4.4.7}
*/
export class MUtf8Decoder {
#fatal: boolean;
readonly #fatal: boolean;

#ignoreBOM: boolean;
readonly #ignoreBOM: boolean;

#leavings?: Uint8Array;
readonly #leavings = new Uint8Array(3);

#leavingsLength = 0;

/**
* The encoding name for this decoder.
Expand Down Expand Up @@ -211,7 +213,7 @@ export class MUtf8Decoder {
// U+0000, U+0080-07FF
if (length <= bp) {
if (stream) {
this.#leavings = bytes.slice(bp - 1);
this.#setLeavings(bytes, bp - 1);
break;
}
codes[cp++] = this.#handleError();
Expand All @@ -228,7 +230,7 @@ export class MUtf8Decoder {
// U+0800-FFFF
if (length <= bp + 1) {
if (stream) {
this.#leavings = bytes.slice(bp - 1);
this.#setLeavings(bytes, bp - 1);
break;
}
codes[cp++] = this.#handleError();
Expand Down Expand Up @@ -265,17 +267,22 @@ export class MUtf8Decoder {
} else {
bin = new Uint8Array("buffer" in input ? input.buffer : input);
}
if (!this.#leavings) {
if (!this.#leavingsLength) {
return bin;
}
const combined = new Uint8Array(this.#leavings.length + bin.length);
combined.set(this.#leavings, 0);
combined.set(bin, this.#leavings.length);
this.#leavings = undefined;
const combined = new Uint8Array(this.#leavingsLength + bin.length);
combined.set(this.#leavings.subarray(0, this.#leavingsLength));
combined.set(bin, this.#leavingsLength);
this.#leavingsLength = 0;
return combined;
}

#handleError() {
#setLeavings(bytes: Uint8Array, startIndex: number): void {
this.#leavings.set(bytes.subarray(startIndex));
this.#leavingsLength = bytes.length - startIndex;
}

#handleError(): number {
if (this.fatal) {
throw new TypeError("MUtf8Decoder.decode: Decoding failed.");
}
Expand Down