// memory available to scavenge.
type scavengeIndex struct {
	// chunks is a scavChunkData-per-chunk structure that indicates the presence of pages
	// available for scavenging. Updates to the index are serialized by the pageAlloc lock.
	//
	// It tracks chunk occupancy and a generation counter per chunk. If a chunk's occupancy

	testSysStat.add(-int64(p.summaryMappedReady))

	// Free the mapped space for chunks.
	for i := range p.chunks {
		if x := p.chunks[i]; x != nil {
			p.chunks[i] = nil
			// This memory comes from sysAlloc and will always be page-aligned.
			sysFree(unsafe.Pointer(x), unsafe.Sizeof(*p.chunks[0]), testSysStat)
		}
	}
}

// BaseChunkIdx is a convenient chunkIdx value which works on both

				chunks = append(chunks, c)
			}

			if !chunkEqual(chunks, tc.chunks) {
				t.Errorf("Chunk(%v, %d) = %v, want %v", tc.s, tc.n, chunks, tc.chunks)
			}

			if len(chunks) == 0 {
				return
			}

			// Verify that appending to the end of the first chunk does not
			// clobber the beginning of the next chunk.
			s := Clone(tc.s)
			chunks[0] = append(chunks[0], -1)
			if !Equal(s, tc.s) {

// lineTooLong is generated as chunk header is bigger than 4KiB.
var errLineTooLong = errors.New("header line too long")

// malformed encoding is generated when chunk header is wrongly formed.
var errMalformedEncoding = errors.New("malformed chunked encoding")

// chunk is considered too big if its bigger than > 16MiB.
var errChunkTooBig = errors.New("chunk too big: choose chunk size <= 16MiB")

//
// In summary, there are 2 resources: arenas, and arena chunks. They exist in the
// following lifecycle:
//
// (1) A new arena is created via newArena.
// (2) Chunks are allocated to hold memory allocated into the arena with new or slice.
//    (a) Chunks are first allocated from the reuse list of partially-used chunks.
//    (b) If there are no such chunks, then chunks on the ready list are taken.

        for (byte[] buf : listOfByteArrays) {
            addChunk(new StreamByteBufferChunk(buf));
        }
    }

    private void addChunk(StreamByteBufferChunk chunk) {
        chunks.add(chunk);
        totalBytesUnreadInList += chunk.bytesUnread();
    }

    static class StreamByteBufferChunk {
        private int pointer;
        private byte[] buffer;
        private int size;

			{"MZXW", "6YTB"},
			{"MZXW", "6Y", "TB"},
		}, nil},
	}

	for _, testcase := range testcases {
		for _, chunks := range testcase.chunkCombinations {
			pr, pw := io.Pipe()

			// Write the encoded chunks into the pipe
			go func() {
				for _, chunk := range chunks {
					pw.Write([]byte(chunk))
				}
				pw.Close()
			}()

			decoder := NewDecoder(StdEncoding, pr)
			_, err := io.ReadAll(decoder)

        out.write(TEST_STRING_BYTES)

        then:
        byteBuffer.readAsString("UTF-8") == TEST_STRING

        where:
        // make sure that multi-byte unicode characters get split in different chunks
        [chunkSize, preUseBuffer] << [(1..(TEST_STRING_BYTES.length * 3)).toList() + [100, 1000], [false, true]].combinations()
    }

    def "empty buffer to String returns empty String"() {
        given:

                nested.writeSmallInt(12)
                nested.writeString("chunked")
            }
            encoder.writeString("done")
        }

        then:
        decode(bytes) { Decoder decoder ->
            decoder.decodeChunked { Decoder nested ->
                assert nested.readSmallInt() == 12
                assert nested.readString() == "chunked"
            }
            assert decoder.readString() == "done"

//
//go:nosplit
func inPersistentAlloc(p uintptr) bool {
	chunk := atomic.Loaduintptr((*uintptr)(unsafe.Pointer(&persistentChunks)))
	for chunk != 0 {
		if p >= chunk && p < chunk+persistentChunkSize {
			return true
		}
		chunk = *(*uintptr)(unsafe.Pointer(chunk))
	}
	return false
}

// linearAlloc is a simple linear allocator that pre-reserves a region