/** Sets the current size */
static void setCurrentSize(final PageIo page, final short pos, int value) {
if (value == 0) {
page.writeByte(pos + O_CURRENTSIZE, (byte) (MAX_SIZE_SPACE + 1));
return;
}
int availSize = getAvailableSize(page, pos);
if (value < (availSize - MAX_SIZE_SPACE) || value > availSize)
throw new IllegalArgumentException(
"currentSize out of bounds, need to realocate " + value + " - " + availSize);
page.writeByte(pos + O_CURRENTSIZE, (byte) (availSize - value));
}
/** Sets the available size */
static void setAvailableSize(final PageIo page, final short pos, int value) {
if (value != roundAvailableSize(value))
throw new IllegalArgumentException("value is not rounded");
int oldCurrSize = getCurrentSize(page, pos);
page.writeShort(pos + O_AVAILABLESIZE, convertAvailSize(value));
setCurrentSize(page, pos, oldCurrSize);
}
/** Returns the available size */
static int getAvailableSize(final PageIo page, final short pos) {
return deconvertAvailSize(page.readShort(pos + O_AVAILABLESIZE));
}
/** Returns the current size */
static int getCurrentSize(final PageIo page, final short pos) {
int s = page.readByte(pos + O_CURRENTSIZE) & 0xFF;
if (s == MAX_SIZE_SPACE + 1) return 0;
return getAvailableSize(page, pos) - s;
}