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lib/nbt: Fix a bug in nextTagTotalSize and significantly improve readability by removing redundant code

BodgeMaster-unfinished
BodgeMaster 2022-08-13 15:42:52 +02:00
parent 7a2c1d7d57
commit 027f324f03
1 changed files with 24 additions and 52 deletions
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76
src/lib/nbt.cpp
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@ -377,7 +377,7 @@ namespace NBT {
// //
// Does not work for compound tags and lists. This is an intended // Does not work for compound tags and lists. This is an intended
// feature as compound tags and lists need to be dealt with // feature as compound tags and lists need to be dealt with
// separately to avoid unnecessarily complex code. // separately to avoid unnecessarily long and complex code.
// //
// Regardinng lists specifically: The size of some lists can can // Regardinng lists specifically: The size of some lists can can
// be determined easily by looking at the contained data type and // be determined easily by looking at the contained data type and
@ -397,81 +397,53 @@ namespace NBT {
if (nextTag == TagType::COMPOUND || nextTag == TagType::LIST) return ErrorOr<uint64_t>(false, ErrorCodes::NOT_YET_KNOWN); if (nextTag == TagType::COMPOUND || nextTag == TagType::LIST) return ErrorOr<uint64_t>(false, ErrorCodes::NOT_YET_KNOWN);
// deal with end tag before trying to access the name // deal with end tag before trying to access the name
if (nextTag == TagType::END) return ErrorOr<uint64_t>(1); if (nextTag == TagType::END) return ErrorOr<uint64_t>(1);
// get name size
ErrorOr<int16_t> nameSize = helper::readInt16(data, dataSize, currentPosition+1); ErrorOr<int16_t> nameSize = helper::readInt16(data, dataSize, currentPosition+1);
if (nameSize.isError) { if (nameSize.isError) {
return ErrorOr<uint64_t>(true, nameSize.errorCode); return ErrorOr<uint64_t>(true, nameSize.errorCode);
} }
// add type byte and name size bytes
uint64_t prefixSize = (uint64_t) nameSize.value + 3;
switch (nextTag) { switch (nextTag) {
case TagType::INT8: case TagType::INT8:
// type byte + name size + data byte -> 4 bytes return ErrorOr<uint64_t>(prefixSize+1);
return ErrorOr<uint64_t>((uint64_t) nameSize.value+4);
case TagType::INT16: case TagType::INT16:
// type byte + name size + 2 data bytes -> 5 bytes return ErrorOr<uint64_t>(prefixSize+2);
return ErrorOr<uint64_t>((uint64_t) nameSize.value+5);
case TagType::INT32: case TagType::INT32:
// type byte + name size + 4 data bytes -> 7 bytes return ErrorOr<uint64_t>(prefixSize+4);
return ErrorOr<uint64_t>((uint64_t) nameSize.value+7);
case TagType::INT64: case TagType::INT64:
// type byte + name size + 8 data bytes -> 11 bytes return ErrorOr<uint64_t>(prefixSize+8);
return ErrorOr<uint64_t>((uint64_t) nameSize.value+11);
case TagType::FLOAT: case TagType::FLOAT:
// type byte + name size + 4 data bytes -> 7 bytes return ErrorOr<uint64_t>(prefixSize+4);
return ErrorOr<uint64_t>((uint64_t) nameSize.value+7);
case TagType::DOUBLE: case TagType::DOUBLE:
// type byte + name size + 8 data bytes -> 11 bytes return ErrorOr<uint64_t>(prefixSize+8);
return ErrorOr<uint64_t>((uint64_t) nameSize.value+11);
case TagType::INT8_ARRAY: { case TagType::INT8_ARRAY: {
// type byte + name size + 4 size bytes -> 7 bytes ErrorOr<int32_t> arrayLength = helper::readInt32(data, dataSize, currentPosition+prefixSize);
uint64_t totalSize = (uint64_t) nameSize.value+7; if (arrayLength.isError) {
return ErrorOr<uint64_t>(true, arrayLength.errorCode);
// add size of actual data (1 byte per entry)
ErrorOr<int32_t> arraySize = helper::readInt32(data, dataSize, currentPosition+totalSize);
if (arraySize.isError) {
return ErrorOr<uint64_t>(true, arraySize.errorCode);
} }
totalSize += (uint64_t) arraySize.value; return ErrorOr<uint64_t>((uint64_t) arrayLength.value + prefixSize + 4);
return ErrorOr<uint64_t>(totalSize);
} }
case TagType::STRING: { case TagType::STRING: {
// type byte + name size + 2 size bytes -> 5 bytes ErrorOr<int16_t> stringSize = helper::readInt16(data, dataSize, currentPosition+prefixSize);
uint64_t totalSize = (uint64_t) nameSize.value+5;
// add size of actual data
ErrorOr<int16_t> stringSize = helper::readInt16(data, dataSize, currentPosition+totalSize);
if (stringSize.isError) { if (stringSize.isError) {
return ErrorOr<uint64_t>(true, stringSize.errorCode); return ErrorOr<uint64_t>(true, stringSize.errorCode);
} }
totalSize += (uint64_t) stringSize.value; return ErrorOr<uint64_t>((uint64_t) stringSize.value + prefixSize + 2);
return ErrorOr<uint64_t>(totalSize);
} }
case TagType::INT32_ARRAY: { case TagType::INT32_ARRAY: {
// type byte + name size + 4 size bytes -> 7 bytes ErrorOr<int32_t> arrayLength = helper::readInt32(data, dataSize, currentPosition+prefixSize);
uint64_t totalSize = (uint64_t) nameSize.value+7; if (arrayLength.isError) {
return ErrorOr<uint64_t>(true, arrayLength.errorCode);
// add size of actual data (4 bytes per entry)
ErrorOr<int16_t> arraySize = helper::readInt16(data, dataSize, currentPosition+totalSize);
if (arraySize.isError) {
return ErrorOr<uint64_t>(true, arraySize.errorCode);
} }
totalSize += (uint64_t) arraySize.value*4; return ErrorOr<uint64_t>((uint64_t) arrayLength.value*4 + prefixSize + 4);
return ErrorOr<uint64_t>(totalSize);
} }
case TagType::INT64_ARRAY: { case TagType::INT64_ARRAY: {
// type byte + name size + 4 size bytes -> 7 bytes ErrorOr<int32_t> arrayLength = helper::readInt32(data, dataSize, currentPosition+prefixSize);
uint64_t totalSize = (uint64_t) nameSize.value+7; if (arrayLength.isError) {
return ErrorOr<uint64_t>(true, arrayLength.errorCode);
// add size of actual data (8 bytes per entry)
ErrorOr<int16_t> arraySize = helper::readInt16(data, dataSize, currentPosition+totalSize);
if (arraySize.isError) {
return ErrorOr<uint64_t>(true, arraySize.errorCode);
} }
totalSize += (uint64_t) arraySize.value*8; return ErrorOr<uint64_t>((uint64_t) arrayLength.value*8 + prefixSize + 4);
return ErrorOr<uint64_t>(totalSize);
} }
// unknown tag or parsing error // unknown tag or parsing error
default: default: