/*

* Jooby https://jooby.io

* Apache License Version 2.0 https://jooby.io/LICENSE.txt

* Copyright 2014 Edgar Espina

*/

package io.jooby;

import java.io.IOException;

import java.io.InputStream;

import org.jspecify.annotations.Nullable;

import io.jooby.internal.NoByteRange;

import io.jooby.internal.NotSatisfiableByteRange;

import io.jooby.internal.SingleByteRange;

/**

* Utility class to compute single byte range requests when response content length is known. Jooby

* support single byte range requests on file responses, like: assets, input stream, files, etc.

*

* <p>Single byte range request looks like: <code>bytes=0-100</code>, <code>bytes=100-</code>,

* <code>bytes=-100</code>.

*

* <p>Multiple byte range request are not supported.

*

* @since 2.0.0

* @author edgar

*/

public interface ByteRange {

/** Byte range prefix. */

String BYTES_RANGE = "bytes=";

/**

* Parse a byte range request value. Example of valid values:

*

* <p>- bytes=0-100 - bytes=-100 - bytes=100-

*

* <p>Any non-matching values produces a not satisfiable response.

*

* <p>If value is null or content length less or equal to <code>0</code>, produces an empty/NOOP

* response.

*

* @param value Valid byte range request value.

* @param contentLength Content length.

* @return Byte range instance.

*/

static ByteRange parse(@Nullable String value, long contentLength) {

if (contentLength <= 0 || value == null) {

// NOOP

return new NoByteRange(contentLength);

}

if (!value.startsWith(SingleByteRange.BYTES_RANGE)) {

return new NotSatisfiableByteRange(value, contentLength);

}

try {

long[] range = {-1, -1};

int r = 0;

int len = value.length();

int i = SingleByteRange.BYTES_RANGE.length();

int offset = i;

char ch;

// Only Single Byte Range Requests:

while (i < len && (ch = value.charAt(i)) != ',') {

if (ch == '-') {

if (offset < i) {

range[r] = Long.parseLong(value.substring(offset, i).trim());

}

offset = i + 1;

r += 1;

}

i += 1;

}

if (offset < i) {

if (r == 0) {

return new NotSatisfiableByteRange(value, contentLength);

}

range[r++] = Long.parseLong(value.substring(offset, i).trim());

}

if (r == 0 || (range[0] == -1 && range[1] == -1)) {

return new NotSatisfiableByteRange(value, contentLength);

}

long start = range[0];

long end = range[1];

if (start == -1) {

start = contentLength - end;

end = contentLength - 1;

}

if (end == -1 || end > contentLength - 1) {

end = contentLength - 1;

}

if (start > end) {

return new NotSatisfiableByteRange(value, contentLength);

}

// offset

long limit = (end - start + 1);

return new SingleByteRange(

value, start, limit, limit, "bytes " + start + "-" + end + "/" + contentLength);

} catch (NumberFormatException expected) {

return new NotSatisfiableByteRange(value, contentLength);

}

}

/**

* Start range or <code>-1</code>.

*

* @return Start range or <code>-1</code>.

*/

long getStart();

/**

* End range or <code>-1</code>.

*

* @return End range or <code>-1</code>.

*/

long getEnd();

/**

* New content length.

*

* @return New content length.

*/

long getContentLength();

/**

* Value for <code>Content-Range</code> response header.

*

* @return Value for <code>Content-Range</code> response header.

*/

String getContentRange();

/**

* For partial requests this method returns {@link StatusCode#PARTIAL_CONTENT}.

*

* <p>For not satisfiable requests this returns {@link

* StatusCode#REQUESTED_RANGE_NOT_SATISFIABLE}..

*

* <p>Otherwise just returns {@link StatusCode#OK}.

*

* @return Status code.

*/

StatusCode getStatusCode();

/**

* For partial request this method set the following byte range response headers:

*

* <p>- Accept-Ranges - Content-Range - Content-Length

*

* <p>For not satisfiable requests:

*

* <p>- Throws a {@link StatusCode#REQUESTED_RANGE_NOT_SATISFIABLE}

*

* <p>Otherwise this method does nothing.

*

* @param ctx Web context.

* @return This byte range request.

*/

ByteRange apply(Context ctx);

/**

* For partial requests this method generates a new truncated input stream.

*

* <p>For not satisfiable requests this method throws an exception.

*

* <p>If there is no range to apply this method returns the given input stream.

*

* @param input Input stream.

* @return A truncated input stream for partial request or same input stream.

* @throws IOException When truncation fails.

*/

InputStream apply(InputStream input) throws IOException;

}