internal static void Purge(StorageImpl db, int pageId, int type, int height) { if (--height != 0) { Page pg = db.GetPage(pageId); int n = GetItemsCount(pg) + 1; if (type == ClassDescriptor.tpString || type == ClassDescriptor.tpArrayOfByte) { // page of strings while (--n >= 0) { Purge(db, GetKeyStrOid(pg, n), type, height); } } else { while (--n >= 0) { Purge(db, GetReference(pg, maxItems - n - 1), type, height); } } db.pool.Unfix(pg); } db.FreePage(pageId); }
internal static int HandlePageUnderflow(StorageImpl db, Page pg, int r, int type, BtreeKey rem, int height) { int nItems = GetItemsCount(pg); if (type == ClassDescriptor.tpString) { Page a = db.PutPage(GetKeyStrOid(pg, r)); int an = GetItemsCount(a); if (r < nItems) { // exists greater page Page b = db.GetPage(GetKeyStrOid(pg, r + 1)); int bn = GetItemsCount(b); int merged_size = (an + bn) * strKeySize + GetSize(a) + GetSize(b); if (height != 1) { merged_size += GetKeyStrSize(pg, r) * 2 + strKeySize * 2; } if (merged_size > keySpace) { // reallocation of nodes between pages a and b int i, j, k; db.pool.Unfix(b); b = db.PutPage(GetKeyStrOid(pg, r + 1)); int size_a = GetSize(a); int size_b = GetSize(b); int addSize, subSize; if (height != 1) { addSize = GetKeyStrSize(pg, r); subSize = GetKeyStrSize(b, 0); } else { addSize = subSize = GetKeyStrSize(b, 0); } i = 0; int prevDelta = (an * strKeySize + size_a) - (bn * strKeySize + size_b); while (true) { i += 1; int delta = ((an + i) * strKeySize + size_a + addSize * 2) - ((bn - i) * strKeySize + size_b - subSize * 2); if (delta >= 0) { if (delta >= -prevDelta) { i -= 1; } break; } size_a += addSize * 2; size_b -= subSize * 2; prevDelta = delta; if (height != 1) { addSize = subSize; subSize = GetKeyStrSize(b, i); } else { addSize = subSize = GetKeyStrSize(b, i); } } int result = Btree.op_done; if (i > 0) { k = i; if (height != 1) { int len = GetKeyStrSize(pg, r); SetSize(a, GetSize(a) + len * 2); SetKeyStrOffs(a, an, keySpace - GetSize(a)); SetKeyStrSize(a, an, len); MemCopy(a, GetKeyStrOffs(a, an), pg, GetKeyStrOffs(pg, r), len * 2, 1); k -= 1; an += 1; SetKeyStrOid(a, an + k, GetKeyStrOid(b, k)); SetSize(b, GetSize(b) - GetKeyStrSize(b, k) * 2); } for (j = 0; j < k; j++) { int len = GetKeyStrSize(b, j); SetSize(a, GetSize(a) + len * 2); SetSize(b, GetSize(b) - len * 2); SetKeyStrOffs(a, an, keySpace - GetSize(a)); SetKeyStrSize(a, an, len); SetKeyStrOid(a, an, GetKeyStrOid(b, j)); MemCopy(a, GetKeyStrOffs(a, an), b, GetKeyStrOffs(b, j), len * 2, 1); an += 1; } rem.GetStr(b, i - 1); result = ReplaceStrKey(db, pg, r, rem, height); SetItemsCount(a, an); SetItemsCount(b, CompactifyStrings(b, i)); } db.pool.Unfix(a); db.pool.Unfix(b); return result; } else { // merge page b to a if (height != 1) { int r_len = GetKeyStrSize(pg, r); SetKeyStrSize(a, an, r_len); SetSize(a, GetSize(a) + r_len * 2); SetKeyStrOffs(a, an, keySpace - GetSize(a)); MemCopy(a, GetKeyStrOffs(a, an), pg, GetKeyStrOffs(pg, r), r_len * 2, 1); an += 1; SetKeyStrOid(a, an + bn, GetKeyStrOid(b, bn)); } for (int i = 0; i < bn; i++, an++) { SetKeyStrSize(a, an, GetKeyStrSize(b, i)); SetKeyStrOffs(a, an, GetKeyStrOffs(b, i) - GetSize(a)); SetKeyStrOid(a, an, GetKeyStrOid(b, i)); } SetSize(a, GetSize(a) + GetSize(b)); SetItemsCount(a, an); MemCopy(a, keySpace - GetSize(a), b, keySpace - GetSize(b), GetSize(b), 1); db.pool.Unfix(a); db.pool.Unfix(b); db.FreePage(GetKeyStrOid(pg, r + 1)); SetKeyStrOid(pg, r + 1, GetKeyStrOid(pg, r)); return RemoveStrKey(pg, r); } } else { // page b is before a Page b = db.GetPage(GetKeyStrOid(pg, r - 1)); int bn = GetItemsCount(b); int merged_size = (an + bn) * strKeySize + GetSize(a) + GetSize(b); if (height != 1) { merged_size += GetKeyStrSize(pg, r - 1) * 2 + strKeySize * 2; } if (merged_size > keySpace) { // reallocation of nodes between pages a and b int i, j, k, len; db.pool.Unfix(b); b = db.PutPage(GetKeyStrOid(pg, r - 1)); int size_a = GetSize(a); int size_b = GetSize(b); int addSize, subSize; if (height != 1) { addSize = GetKeyStrSize(pg, r - 1); subSize = GetKeyStrSize(b, bn - 1); } else { addSize = subSize = GetKeyStrSize(b, bn - 1); } i = 0; int prevDelta = (an * strKeySize + size_a) - (bn * strKeySize + size_b); while (true) { i += 1; int delta = ((an + i) * strKeySize + size_a + addSize * 2) - ((bn - i) * strKeySize + size_b - subSize * 2); if (delta >= 0) { if (delta >= -prevDelta) { i -= 1; } break; } prevDelta = delta; size_a += addSize * 2; size_b -= subSize * 2; if (height != 1) { addSize = subSize; subSize = GetKeyStrSize(b, bn - i - 1); } else { addSize = subSize = GetKeyStrSize(b, bn - i - 1); } } int result = Btree.op_done; if (i > 0) { k = i; Assert.That(i < bn); if (height != 1) { SetSize(b, GetSize(b) - GetKeyStrSize(b, bn - k) * 2); MemCopy(a, i, a, 0, an + 1, strKeySize); k -= 1; SetKeyStrOid(a, k, GetKeyStrOid(b, bn)); len = GetKeyStrSize(pg, r - 1); SetKeyStrSize(a, k, len); SetSize(a, GetSize(a) + len * 2); SetKeyStrOffs(a, k, keySpace - GetSize(a)); MemCopy(a, GetKeyStrOffs(a, k), pg, GetKeyStrOffs(pg, r - 1), len * 2, 1); } else { MemCopy(a, i, a, 0, an, strKeySize); } for (j = 0; j < k; j++) { len = GetKeyStrSize(b, bn - k + j); SetSize(a, GetSize(a) + len * 2); SetSize(b, GetSize(b) - len * 2); SetKeyStrOffs(a, j, keySpace - GetSize(a)); SetKeyStrSize(a, j, len); SetKeyStrOid(a, j, GetKeyStrOid(b, bn - k + j)); MemCopy(a, GetKeyStrOffs(a, j), b, GetKeyStrOffs(b, bn - k + j), len * 2, 1); } an += i; SetItemsCount(a, an); rem.GetStr(b, bn - k - 1); result = ReplaceStrKey(db, pg, r - 1, rem, height); SetItemsCount(b, CompactifyStrings(b, -i)); } db.pool.Unfix(a); db.pool.Unfix(b); return result; } else { // merge page b to a if (height != 1) { MemCopy(a, bn + 1, a, 0, an + 1, strKeySize); int len = GetKeyStrSize(pg, r - 1); SetKeyStrSize(a, bn, len); SetSize(a, GetSize(a) + len * 2); SetKeyStrOffs(a, bn, keySpace - GetSize(a)); SetKeyStrOid(a, bn, GetKeyStrOid(b, bn)); MemCopy(a, GetKeyStrOffs(a, bn), pg, GetKeyStrOffs(pg, r - 1), len * 2, 1); an += 1; } else { MemCopy(a, bn, a, 0, an, strKeySize); } for (int i = 0; i < bn; i++) { SetKeyStrOid(a, i, GetKeyStrOid(b, i)); SetKeyStrSize(a, i, GetKeyStrSize(b, i)); SetKeyStrOffs(a, i, GetKeyStrOffs(b, i) - GetSize(a)); } an += bn; SetItemsCount(a, an); SetSize(a, GetSize(a) + GetSize(b)); MemCopy(a, keySpace - GetSize(a), b, keySpace - GetSize(b), GetSize(b), 1); db.pool.Unfix(a); db.pool.Unfix(b); db.FreePage(GetKeyStrOid(pg, r - 1)); return RemoveStrKey(pg, r - 1); } } } else if (type == ClassDescriptor.tpArrayOfByte) { Page a = db.PutPage(GetKeyStrOid(pg, r)); int an = GetItemsCount(a); if (r < nItems) { // exists greater page Page b = db.GetPage(GetKeyStrOid(pg, r + 1)); int bn = GetItemsCount(b); int merged_size = (an + bn) * strKeySize + GetSize(a) + GetSize(b); if (height != 1) { merged_size += GetKeyStrSize(pg, r) + strKeySize * 2; } if (merged_size > keySpace) { // reallocation of nodes between pages a and b int i, j, k; db.pool.Unfix(b); b = db.PutPage(GetKeyStrOid(pg, r + 1)); int size_a = GetSize(a); int size_b = GetSize(b); int addSize, subSize; if (height != 1) { addSize = GetKeyStrSize(pg, r); subSize = GetKeyStrSize(b, 0); } else { addSize = subSize = GetKeyStrSize(b, 0); } i = 0; int prevDelta = (an * strKeySize + size_a) - (bn * strKeySize + size_b); while (true) { i += 1; int delta = ((an + i) * strKeySize + size_a + addSize) - ((bn - i) * strKeySize + size_b - subSize); if (delta >= 0) { if (delta >= -prevDelta) { i -= 1; } break; } size_a += addSize; size_b -= subSize; prevDelta = delta; if (height != 1) { addSize = subSize; subSize = GetKeyStrSize(b, i); } else { addSize = subSize = GetKeyStrSize(b, i); } } int result = Btree.op_done; if (i > 0) { k = i; if (height != 1) { int len = GetKeyStrSize(pg, r); SetSize(a, GetSize(a) + len); SetKeyStrOffs(a, an, keySpace - GetSize(a)); SetKeyStrSize(a, an, len); MemCopy(a, GetKeyStrOffs(a, an), pg, GetKeyStrOffs(pg, r), len, 1); k -= 1; an += 1; SetKeyStrOid(a, an + k, GetKeyStrOid(b, k)); SetSize(b, GetSize(b) - GetKeyStrSize(b, k)); } for (j = 0; j < k; j++) { int len = GetKeyStrSize(b, j); SetSize(a, GetSize(a) + len); SetSize(b, GetSize(b) - len); SetKeyStrOffs(a, an, keySpace - GetSize(a)); SetKeyStrSize(a, an, len); SetKeyStrOid(a, an, GetKeyStrOid(b, j)); MemCopy(a, GetKeyStrOffs(a, an), b, GetKeyStrOffs(b, j), len, 1); an += 1; } rem.GetByteArray(b, i - 1); result = ReplaceByteArrayKey(db, pg, r, rem, height); SetItemsCount(a, an); SetItemsCount(b, CompactifyByteArrays(b, i)); } db.pool.Unfix(a); db.pool.Unfix(b); return result; } else { // merge page b to a if (height != 1) { int r_len = GetKeyStrSize(pg, r); SetKeyStrSize(a, an, r_len); SetSize(a, GetSize(a) + r_len); SetKeyStrOffs(a, an, keySpace - GetSize(a)); MemCopy(a, GetKeyStrOffs(a, an), pg, GetKeyStrOffs(pg, r), r_len, 1); an += 1; SetKeyStrOid(a, an + bn, GetKeyStrOid(b, bn)); } for (int i = 0; i < bn; i++, an++) { SetKeyStrSize(a, an, GetKeyStrSize(b, i)); SetKeyStrOffs(a, an, GetKeyStrOffs(b, i) - GetSize(a)); SetKeyStrOid(a, an, GetKeyStrOid(b, i)); } SetSize(a, GetSize(a) + GetSize(b)); SetItemsCount(a, an); MemCopy(a, keySpace - GetSize(a), b, keySpace - GetSize(b), GetSize(b), 1); db.pool.Unfix(a); db.pool.Unfix(b); db.FreePage(GetKeyStrOid(pg, r + 1)); SetKeyStrOid(pg, r + 1, GetKeyStrOid(pg, r)); return RemoveByteArrayKey(pg, r); } } else { // page b is before a Page b = db.GetPage(GetKeyStrOid(pg, r - 1)); int bn = GetItemsCount(b); int merged_size = (an + bn) * strKeySize + GetSize(a) + GetSize(b); if (height != 1) { merged_size += GetKeyStrSize(pg, r - 1) + strKeySize * 2; } if (merged_size > keySpace) { // reallocation of nodes between pages a and b int i, j, k, len; db.pool.Unfix(b); b = db.PutPage(GetKeyStrOid(pg, r - 1)); int size_a = GetSize(a); int size_b = GetSize(b); int addSize, subSize; if (height != 1) { addSize = GetKeyStrSize(pg, r - 1); subSize = GetKeyStrSize(b, bn - 1); } else { addSize = subSize = GetKeyStrSize(b, bn - 1); } i = 0; int prevDelta = (an * strKeySize + size_a) - (bn * strKeySize + size_b); while (true) { i += 1; int delta = ((an + i) * strKeySize + size_a + addSize) - ((bn - i) * strKeySize + size_b - subSize); if (delta >= 0) { if (delta >= -prevDelta) { i -= 1; } break; } prevDelta = delta; size_a += addSize; size_b -= subSize; if (height != 1) { addSize = subSize; subSize = GetKeyStrSize(b, bn - i - 1); } else { addSize = subSize = GetKeyStrSize(b, bn - i - 1); } } int result = Btree.op_done; if (i > 0) { k = i; Assert.That(i < bn); if (height != 1) { SetSize(b, GetSize(b) - GetKeyStrSize(b, bn - k)); MemCopy(a, i, a, 0, an + 1, strKeySize); k -= 1; SetKeyStrOid(a, k, GetKeyStrOid(b, bn)); len = GetKeyStrSize(pg, r - 1); SetKeyStrSize(a, k, len); SetSize(a, GetSize(a) + len); SetKeyStrOffs(a, k, keySpace - GetSize(a)); MemCopy(a, GetKeyStrOffs(a, k), pg, GetKeyStrOffs(pg, r - 1), len, 1); } else { MemCopy(a, i, a, 0, an, strKeySize); } for (j = 0; j < k; j++) { len = GetKeyStrSize(b, bn - k + j); SetSize(a, GetSize(a) + len); SetSize(b, GetSize(b) - len); SetKeyStrOffs(a, j, keySpace - GetSize(a)); SetKeyStrSize(a, j, len); SetKeyStrOid(a, j, GetKeyStrOid(b, bn - k + j)); MemCopy(a, GetKeyStrOffs(a, j), b, GetKeyStrOffs(b, bn - k + j), len, 1); } an += i; SetItemsCount(a, an); rem.GetByteArray(b, bn - k - 1); result = ReplaceByteArrayKey(db, pg, r - 1, rem, height); SetItemsCount(b, CompactifyByteArrays(b, -i)); } db.pool.Unfix(a); db.pool.Unfix(b); return result; } else { // merge page b to a if (height != 1) { MemCopy(a, bn + 1, a, 0, an + 1, strKeySize); int len = GetKeyStrSize(pg, r - 1); SetKeyStrSize(a, bn, len); SetSize(a, GetSize(a) + len); SetKeyStrOffs(a, bn, keySpace - GetSize(a)); SetKeyStrOid(a, bn, GetKeyStrOid(b, bn)); MemCopy(a, GetKeyStrOffs(a, bn), pg, GetKeyStrOffs(pg, r - 1), len, 1); an += 1; } else { MemCopy(a, bn, a, 0, an, strKeySize); } for (int i = 0; i < bn; i++) { SetKeyStrOid(a, i, GetKeyStrOid(b, i)); SetKeyStrSize(a, i, GetKeyStrSize(b, i)); SetKeyStrOffs(a, i, GetKeyStrOffs(b, i) - GetSize(a)); } an += bn; SetItemsCount(a, an); SetSize(a, GetSize(a) + GetSize(b)); MemCopy(a, keySpace - GetSize(a), b, keySpace - GetSize(b), GetSize(b), 1); db.pool.Unfix(a); db.pool.Unfix(b); db.FreePage(GetKeyStrOid(pg, r - 1)); return RemoveByteArrayKey(pg, r - 1); } } } else { // scalar types Page a = db.PutPage(GetReference(pg, maxItems - r - 1)); int an = GetItemsCount(a); int itemSize = ClassDescriptor.Sizeof[type]; if (r < nItems) { // exists greater page Page b = db.GetPage(GetReference(pg, maxItems - r - 2)); int bn = GetItemsCount(b); Assert.That(bn >= an); if (height != 1) { MemCopy(a, an, pg, r, 1, itemSize); an += 1; bn += 1; } int merged_size = (an + bn) * (4 + itemSize); if (merged_size > keySpace) { // reallocation of nodes between pages a and b int i = bn - ((an + bn) >> 1); db.pool.Unfix(b); b = db.PutPage(GetReference(pg, maxItems - r - 2)); MemCopy(a, an, b, 0, i, itemSize); MemCopy(b, 0, b, i, bn - i, itemSize); MemCopy(a, maxItems - an - i, b, maxItems - i, i, 4); MemCopy(b, maxItems - bn + i, b, maxItems - bn, bn - i, 4); MemCopy(pg, r, a, an + i - 1, 1, itemSize); SetItemsCount(b, GetItemsCount(b) - i); SetItemsCount(a, GetItemsCount(a) + i); db.pool.Unfix(a); db.pool.Unfix(b); return Btree.op_done; } else { // merge page b to a MemCopy(a, an, b, 0, bn, itemSize); MemCopy(a, maxItems - an - bn, b, maxItems - bn, bn, 4); db.FreePage(GetReference(pg, maxItems - r - 2)); MemCopy(pg, maxItems - nItems, pg, maxItems - nItems - 1, nItems - r - 1, 4); MemCopy(pg, r, pg, r + 1, nItems - r - 1, itemSize); SetItemsCount(a, GetItemsCount(a) + bn); SetItemsCount(pg, nItems - 1); db.pool.Unfix(a); db.pool.Unfix(b); return nItems * (itemSize + 4) < keySpace / 2 ? Btree.op_underflow : Btree.op_done; } } else { // page b is before a Page b = db.GetPage(GetReference(pg, maxItems - r)); int bn = GetItemsCount(b); Assert.That(bn >= an); if (height != 1) { an += 1; bn += 1; } int merged_size = (an + bn) * (4 + itemSize); if (merged_size > keySpace) { // reallocation of nodes between pages a and b int i = bn - ((an + bn) >> 1); db.pool.Unfix(b); b = db.PutPage(GetReference(pg, maxItems - r)); MemCopy(a, i, a, 0, an, itemSize); MemCopy(a, 0, b, bn - i, i, itemSize); MemCopy(a, maxItems - an - i, a, maxItems - an, an, 4); MemCopy(a, maxItems - i, b, maxItems - bn, i, 4); if (height != 1) { MemCopy(a, i - 1, pg, r - 1, 1, itemSize); } MemCopy(pg, r - 1, b, bn - i - 1, 1, itemSize); SetItemsCount(b, GetItemsCount(b) - i); SetItemsCount(a, GetItemsCount(a) + i); db.pool.Unfix(a); db.pool.Unfix(b); return Btree.op_done; } else { // merge page b to a MemCopy(a, bn, a, 0, an, itemSize); MemCopy(a, 0, b, 0, bn, itemSize); MemCopy(a, maxItems - an - bn, a, maxItems - an, an, 4); MemCopy(a, maxItems - bn, b, maxItems - bn, bn, 4); if (height != 1) { MemCopy(a, bn - 1, pg, r - 1, 1, itemSize); } db.FreePage(GetReference(pg, maxItems - r)); SetReference(pg, maxItems - r, GetReference(pg, maxItems - r - 1)); SetItemsCount(a, GetItemsCount(a) + bn); SetItemsCount(pg, nItems - 1); db.pool.Unfix(a); db.pool.Unfix(b); return nItems * (itemSize + 4) < keySpace / 2 ? Btree.op_underflow : Btree.op_done; } } } }
internal static int HandlePageUnderflow(StorageImpl db, Page pg, int r, int height) { int nItems = GetItemsCount(pg); Page a = db.PutPage(GetItem(pg, maxItems - r - 1)); int an = GetItemsCount(a); if (r < nItems) { // exists greater page Page b = db.GetPage(GetItem(pg, maxItems - r - 2)); int bn = GetItemsCount(b); Assert.That(bn >= an); if (height != 1) { MemCopy(a, an, pg, r, 1); an += 1; bn += 1; } if (an + bn > max) { // reallocation of nodes between pages a and b int i = bn - ((an + bn) >> 1); db.pool.Unfix(b); b = db.PutPage(GetItem(pg, maxItems - r - 2)); MemCopy(a, an, b, 0, i); MemCopy(b, 0, b, i, bn - i); MemCopy(a, maxItems - an - i, b, maxItems - i, i); MemCopy(b, maxItems - bn + i, b, maxItems - bn, bn - i); if (height != 1) { MemCopy(pg, r, a, an + i - 1, 1); } else { MemCopy(pg, r, a, maxItems - an - i, 1); } SetItemsCount(b, GetItemsCount(b) - i); SetItemsCount(a, GetItemsCount(a) + i); db.pool.Unfix(a); db.pool.Unfix(b); return TenderBaseImpl.Btree.op_done; } else { // merge page b to a MemCopy(a, an, b, 0, bn); MemCopy(a, maxItems - an - bn, b, maxItems - bn, bn); db.FreePage(GetItem(pg, maxItems - r - 2)); MemCopy(pg, maxItems - nItems, pg, maxItems - nItems - 1, nItems - r - 1); MemCopy(pg, r, pg, r + 1, nItems - r - 1); SetItemsCount(a, GetItemsCount(a) + bn); SetItemsCount(pg, nItems - 1); db.pool.Unfix(a); db.pool.Unfix(b); if (nItems < max / 2) return TenderBaseImpl.Btree.op_underflow; else return TenderBaseImpl.Btree.op_done; } } else { // page b is before a Page b = db.GetPage(GetItem(pg, maxItems - r)); int bn = GetItemsCount(b); Assert.That(bn >= an); if (height != 1) { an += 1; bn += 1; } if (an + bn > max) { // reallocation of nodes between pages a and b int i = bn - ((an + bn) >> 1); db.pool.Unfix(b); b = db.PutPage(GetItem(pg, maxItems - r)); MemCopy(a, i, a, 0, an); MemCopy(a, 0, b, bn - i, i); MemCopy(a, maxItems - an - i, a, maxItems - an, an); MemCopy(a, maxItems - i, b, maxItems - bn, i); if (height != 1) { MemCopy(a, i - 1, pg, r - 1, 1); MemCopy(pg, r - 1, b, bn - i - 1, 1); } else { MemCopy(pg, r - 1, b, maxItems - bn + i, 1); } SetItemsCount(b, GetItemsCount(b) - i); SetItemsCount(a, GetItemsCount(a) + i); db.pool.Unfix(a); db.pool.Unfix(b); return TenderBaseImpl.Btree.op_done; } else { // merge page b to a MemCopy(a, bn, a, 0, an); MemCopy(a, 0, b, 0, bn); MemCopy(a, maxItems - an - bn, a, maxItems - an, an); MemCopy(a, maxItems - bn, b, maxItems - bn, bn); if (height != 1) { MemCopy(a, bn - 1, pg, r - 1, 1); } db.FreePage(GetItem(pg, maxItems - r)); SetItem(pg, maxItems - r, GetItem(pg, maxItems - r - 1)); SetItemsCount(a, GetItemsCount(a) + bn); SetItemsCount(pg, nItems - 1); db.pool.Unfix(a); db.pool.Unfix(b); return nItems < max / 2 ? TenderBaseImpl.Btree.op_underflow : TenderBaseImpl.Btree.op_done; } } }