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AK: Don't restore the stream offset when failing to read an LEB128

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Pretty much no other read function does this, and getting rid of the
typename template parameter for the stream makes the transition to the
new AK::Stream a bit easier.
This commit is contained in:
Tim Schumacher 2023-01-29 13:05:06 +01:00 • committed by Andrew Kaster
parent 371c51f934
commit 31f59855b4
1 changed files with 12 additions and 25 deletions
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37
AK/LEB128.h
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@ -13,26 +13,19 @@
namespace AK { namespace AK {
struct LEB128 { struct LEB128 {
template<typename StreamT, typename ValueType = size_t> template<typename ValueType = size_t>
static bool read_unsigned(StreamT& stream, ValueType& result) static bool read_unsigned(DeprecatedInputStream& stream, ValueType& result)
{ {
[[maybe_unused]] size_t backup_offset = 0;
if constexpr (requires { stream.offset(); })
backup_offset = stream.offset();
DeprecatedInputStream& input_stream { stream };
result = 0; result = 0;
size_t num_bytes = 0; size_t num_bytes = 0;
while (true) { while (true) {
if (input_stream.unreliable_eof()) { if (stream.unreliable_eof()) {
if constexpr (requires { stream.seek(backup_offset); }) stream.set_fatal_error();
stream.seek(backup_offset);
input_stream.set_fatal_error();
return false; return false;
} }
u8 byte = 0; u8 byte = 0;
input_stream >> byte; stream >> byte;
if (input_stream.has_any_error()) if (stream.has_any_error())
return false; return false;
ValueType masked_byte = byte & ~(1 << 7); ValueType masked_byte = byte & ~(1 << 7);
@ -53,16 +46,12 @@ struct LEB128 {
return true; return true;
} }
template<typename StreamT, typename ValueType = ssize_t> template<typename ValueType = ssize_t>
static bool read_signed(StreamT& stream, ValueType& result) static bool read_signed(DeprecatedInputStream& stream, ValueType& result)
{ {
// Note: We read into a u64 to simplify the parsing logic; // Note: We read into a u64 to simplify the parsing logic;
// result is range checked into ValueType after parsing. // result is range checked into ValueType after parsing.
static_assert(sizeof(ValueType) <= sizeof(u64), "Error checking logic assumes 64 bits or less!"); static_assert(sizeof(ValueType) <= sizeof(u64), "Error checking logic assumes 64 bits or less!");
[[maybe_unused]] size_t backup_offset = 0;
if constexpr (requires { stream.offset(); })
backup_offset = stream.offset();
DeprecatedInputStream& input_stream { stream };
i64 temp = 0; i64 temp = 0;
size_t num_bytes = 0; size_t num_bytes = 0;
@ -70,15 +59,13 @@ struct LEB128 {
result = 0; result = 0;
do { do {
if (input_stream.unreliable_eof()) { if (stream.unreliable_eof()) {
if constexpr (requires { stream.seek(backup_offset); }) stream.set_fatal_error();
stream.seek(backup_offset);
input_stream.set_fatal_error();
return false; return false;
} }
input_stream >> byte; stream >> byte;
if (input_stream.has_any_error()) if (stream.has_any_error())
return false; return false;
// note: 64 bit assumptions! // note: 64 bit assumptions!