omni::structuredlog::BlobReader

Defined in omni/structuredlog/BinarySerializer.h

template<bool validate = false, OnBlobWriterValidationErrorFunc onValidationError = ignoreBlobWriterValidationError>
class BlobReader

A class to read binary blobs produced by the BlobWriter.

You’ll need some sort of external schema or fixed layout to be able to read the blob.

Param validate

If this parameter is true, then the read position will be tracked while reading the blob and attempting to read past the end of the buffer will cause methods to fail. Note that a message will not be logged because this class is used in the log system. This is needed for the tests.

Public Functions

inline BlobReader(const void *blob, size_t blobSize)

Constructor.

Parameters

  • blob – [in] The buffer to read from.

  • blobSize – [in] The length of buffer.

template<typename T>
inline bool read(T *out)

read a primitive type element out of the buffer.

Parameters

out – [out] The value will be written to this. This may not be nullptr.

Returns

true if the value was successfully read.

Returns

false if the end of the buffer was reached.

inline bool read(const char **out, uint16_t *outLen, uint16_t maxLen)

Read an array of strings out of the buffer.

Parameters

  • out – [out] Receives the array of strings from the blob if maxLen is not 0. This may be nullptr if maxLen is 0. Note that the strings pointed to will point into the data blob that’s being read from.

  • outLen – [out] Receives the length of the output array. This may not be nullptr.

  • maxLen – [in] The maximum length that can be read into out in this call. If this is set to 0, then the array length with be read into outLen and the buffer pointer will not increment to point at the next member, so that an array can be allocated and read in the next call to this function. An exception to this is the case where outLen is set to 0; the buffer pointer will be incremented to point at the next member in this case.

Returns

true if the value was successfully read.

Returns

false if the end of the buffer was reached.

template<typename T>
inline bool read(const T **out, uint16_t *outLen)

Read a string out of the buffer.

Parameters

  • out – [out] Receives the array from the binary blob. This will be pointing to data from within the blob. This may not be nullptr.

  • outLen – [out] Receives the length of the array that was read. This includes the null terminator if this was as string. This may not be nullptr.

Returns

true if the value was successfully read.

Returns

false if the end of the buffer was reached.

template<typename T>
inline bool read(const T **out, uint16_t fixedLen)

Read a fixed length array out of the buffer.

Parameters

  • out – [out] Receives the array from the binary blob. This will be pointing to data from within the blob. This may not be nullptr.

  • fixedLen – [out] The fixed length of the array/string. This should not be 0.

Returns

true if the value was successfully read.

Returns

false if the end of the buffer was reached.

template<typename T>
inline void alignBuffer()

Align the buffer for a given type.

Remark

This will advance the buffer so that the next write is aligned for the specified type.

Public Static Attributes

static constexpr uint32_t kVersion = 0

The version of binary blob ABI that this reader was built to read.

Protected Functions

inline void outOfMemoryErrorMessage(size_t size)

Send an error message to the onValidationError callback when the end of the buffer has been reached.

Parameters

size – [in] The size that was requested that would have extended past the end of the buffer.

Protected Attributes

const uint8_t *m_buffer = nullptr

The buffer being written.

size_t m_bufferLen = 0

The length of m_buffer.

size_t m_read = 0

The amount that has been read from m_buffer.