internal int ReadByteArrayFrom(IJournalledResource data, long position, byte[] buf, int off, int len)
{
int orig_len = len;
long page_number = position / page_size;
int start_offset = (int)(position % page_size);
int to_read = System.Math.Min(len, page_size - start_offset);
BMPage page = FetchPage(data, page_number);
lock (page) {
try {
page.Initialize();
page.Read(start_offset, buf, off, to_read);
} finally {
page.Dispose();
}
}
len -= to_read;
while (len > 0)
{
off += to_read;
position += to_read;
++page_number;
to_read = System.Math.Min(len, page_size);
page = FetchPage(data, page_number);
lock (page) {
try {
page.Initialize();
page.Read(0, buf, off, to_read);
} finally {
page.Dispose();
}
}
len -= to_read;
}
return(orig_len);
}
// ------
// Buffered access methods. These are all thread safe methods. When a page
// is accessed the page is synchronized so no 2 or more operations can
// Read/Write from the page at the same time. An operation can Read/Write to
// different pages at the same time, however, and this requires thread safety
// at a lower level (in the IJournalledResource implementation).
// ------
internal int ReadByteFrom(IJournalledResource data, long position)
{
long page_number = position / page_size;
int v;
BMPage page = FetchPage(data, page_number);
lock (page) {
try {
page.Initialize();
v = ((int)page.Read((int)(position % page_size))) & 0x0FF;
} finally {
page.Dispose();
}
}
return(v);
}