public boolean readLine()

in httpcore5/src/main/java/org/apache/hc/core5/http/impl/nio/SessionInputBufferImpl.java [209:315]
89 lines of code
22 McCabe index (conditional complexity)

    public boolean readLine(
            final CharArrayBuffer lineBuffer,
            final boolean endOfStream) throws IOException {

        setOutputMode();
        // See if there is LF char present in the buffer
        int pos = -1;
        for (int i = buffer().position(); i < buffer().limit(); i++) {
            final int b = buffer().get(i);
            if (b == Chars.LF) {
                pos = i + 1;
                break;
            }
        }

        if (this.maxLineLen > 0) {
            final int currentLen = (pos > 0 ? pos : buffer().limit()) - buffer().position();
            if (currentLen >= this.maxLineLen) {
                throw new MessageConstraintException("Maximum line length limit exceeded");
            }
        }

        if (pos == -1) {
            if (endOfStream && buffer().hasRemaining()) {
                // No more data. Get the rest
                pos = buffer().limit();
            } else {
                // Either no complete line present in the buffer
                // or no more data is expected
                return false;
            }
        }
        final int origLimit = buffer().limit();
        buffer().limit(pos);

        final int requiredCapacity = buffer().limit() - buffer().position();
        // Ensure capacity of len assuming ASCII as the most likely charset
        lineBuffer.ensureCapacity(requiredCapacity);

        if (this.charDecoder == null) {
            if (buffer().hasArray()) {
                final byte[] b = buffer().array();
                final int off = buffer().position();
                final int len = buffer().remaining();
                lineBuffer.append(b, buffer().arrayOffset() + off, len);
                buffer().position(off + len);
            } else {
                while (buffer().hasRemaining()) {
                    lineBuffer.append((char) (buffer().get() & 0xff));
                }
            }
        } else {
            if (this.charbuffer == null) {
                this.charbuffer = CharBuffer.allocate(this.lineBuffersize);
            }
            this.charDecoder.reset();

            for (;;) {
                final CoderResult result = this.charDecoder.decode(
                        buffer(),
                        this.charbuffer,
                        true);
                if (result.isError()) {
                    result.throwException();
                }
                if (result.isOverflow()) {
                    this.charbuffer.flip();
                    lineBuffer.append(
                            this.charbuffer.array(),
                            this.charbuffer.arrayOffset() + this.charbuffer.position(),
                            this.charbuffer.remaining());
                    this.charbuffer.clear();
                }
                if (result.isUnderflow()) {
                    break;
                }
            }

            // flush the decoder
            this.charDecoder.flush(this.charbuffer);
            this.charbuffer.flip();
            // append the decoded content to the line buffer
            if (this.charbuffer.hasRemaining()) {
                lineBuffer.append(
                        this.charbuffer.array(),
                        this.charbuffer.arrayOffset() + this.charbuffer.position(),
                        this.charbuffer.remaining());
            }

        }
        buffer().limit(origLimit);

        // discard LF if found
        int l = lineBuffer.length();
        if (l > 0) {
            if (lineBuffer.charAt(l - 1) == Chars.LF) {
                l--;
                lineBuffer.setLength(l);
            }
            // discard CR if found
            if (l > 0 && lineBuffer.charAt(l - 1) == Chars.CR) {
                l--;
                lineBuffer.setLength(l);
            }
        }
        return true;
    }