def deleteType(args):
fileList = fm.getFiles("meta")
typeToBeDeleted = args[0]
t = Type()
updateHeaderFlag = True
for fileName in reversed(fileList):
f = open(DIRECTORY + fileName, "r+b")
for i in reversed(range(0, fm.MAX_NUM_PAGES)):
p = Page(f, i, "meta")
if updateHeaderFlag == True and p.numOfElements > 0:
updateHeaderFlag = False
p.numOfElements -= 1
p.state = 0
for j in reversed(range(0, Page.MAX_NUM_OF_ELEMENTS["meta"])):
if p.elements[j].state != 0:
t, p.elements[j] = p.elements[j], t
if t.name == typeToBeDeleted:
p.write(f, i)
f.close()
fm.deleteAllFiles(typeToBeDeleted)
if fm.isEmpty("meta", fileList[-1]):
fm.deleteFile("meta", fileList[-1])
return
p.write(f, i)
f.close()
def createType(args):
t = Type()
t.name = args[0]
t.state = 1
t.numOfFields = int(args[1])
t.fieldNames = args[2:] + [""] * (10 - int(t.numOfFields))
if not fm.isAvailableFileExist("meta"):
fm.createFile("meta")
fileList = fm.getFiles("meta")
for fileName in fileList:
f = open(DIRECTORY + fileName, "r+b")
for i in range(0, fm.MAX_NUM_PAGES):
p = Page(f, i, "meta")
for j in range(0, Page.MAX_NUM_OF_ELEMENTS["meta"]):
if p.elements[j].state == 0:
p.elements[j] = t
p.numOfElements += 1
if p.numOfElements == Page.MAX_NUM_OF_ELEMENTS["meta"]:
p.state = 1
p.write(f, i)
f.close()
return
elif t.name < p.elements[j].name:
t, p.elements[j] = p.elements[j], t
p.write(f, i)
f.close()
def createRecord(args):
r = Record()
typeName = args[0]
r.state = 1
r.fields = [int(e) for e in args[1:]] + [0] * (10 - len(args[1:]))
if not fm.isAvailableFileExist("data", typeName):
fm.createFile("data", typeName)
fileList = fm.getFiles("data", typeName)
for fileName in fileList:
f = open(DIRECTORY + fileName, "r+b")
for i in range(0, fm.MAX_NUM_PAGES):
p = Page(f, i, "data")
for j in range(0, Page.MAX_NUM_OF_ELEMENTS["data"]):
if p.elements[j].state == 0:
p.elements[j] = r
p.numOfElements += 1
if p.numOfElements == Page.MAX_NUM_OF_ELEMENTS["data"]:
p.state = 1
p.write(f, i)
f.close()
return
elif r.fields[0] < p.elements[j].fields[0]:
r, p.elements[j] = p.elements[j], r
p.write(f, i)
f.close()
def deleteRecord(args):
typeName = args[0]
primaryKey = int(args[1])
fileList = fm.getFiles("data", typeName)
t = Record()
updateHeaderFlag = True
for fileName in reversed(fileList):
f = open(DIRECTORY + fileName, "r+b")
for i in reversed(range(0, fm.MAX_NUM_PAGES)):
p = Page(f, i, "data")
if updateHeaderFlag == True and p.numOfElements > 0:
updateHeaderFlag = False
p.numOfElements -= 1
p.state = 0
for j in reversed(range(0, Page.MAX_NUM_OF_ELEMENTS["data"])):
if p.elements[j].state != 0:
t, p.elements[j] = p.elements[j], t
if t.fields[0] == primaryKey:
p.write(f, i)
f.close()
if fm.isEmpty("data", fileList[-1]):
fm.deleteFile("data", fileList[-1])
return
p.write(f, i)
f.close()
def listType(args):
fileList = fm.getFiles("meta")
for fileName in fileList:
f = open(DIRECTORY + fileName, "r+b")
for i in range(0, fm.MAX_NUM_PAGES):
p = Page(f, i, "meta")
for j in range(0, Page.MAX_NUM_OF_ELEMENTS["meta"]):
if p.elements[j].state != 0:
print(p.elements[j].name)
f.close()
def listRecord(args):
typeName = args[0]
numOfFields = util.numberOfFields(typeName)
fileList = fm.getFiles("data", typeName)
for fileName in fileList:
f = open(DIRECTORY + fileName, "r+b")
for i in range(0, fm.MAX_NUM_PAGES):
p = Page(f, i, "data")
for j in range(0, Page.MAX_NUM_OF_ELEMENTS["data"]):
if p.elements[j].state != 0:
print(" ".join([str(i) for i in p.elements[j].fields[0:numOfFields]]))
f.close()
def numberOfFields(typeName):
fileList = fm.getFiles("meta")
for fileName in fileList:
f = open(DIRECTORY + fileName, "r+b")
for i in range(0, fm.MAX_NUM_PAGES):
p = Page(f, i, "meta")
for j in range(0, Page.MAX_NUM_OF_ELEMENTS["meta"]):
if p.elements[j].state != 0:
if p.elements[j].name == typeName:
return p.elements[j].numOfFields
f.close()
return -1