ringbuf

A small, general-purpose ring buffer structure.

This particular implementation was created with logging applications in mind, though it can be used to store any kind of data.

Goals:

• Perform no memory allocations after initialization
• Provide a LIFO interface to "the last n" records inserted
• Execute reading and writing to the buffer in constant time
• Be easy to use and integrate into projects using the CMake build tools

Linking (CMake)

Use the variables RINGBUF_LIBRARY and RINGBUF_INCLUDE_DIR in your CMakeLists file.

Plural versions of those variable names are also defined if preferable.

Test (CMake)

Execute the following in order to run unit tests:

git subodule update --init
mkdir build && cd build
cmake .. && make test

Usage

Initialization:

#define CAPACITY 32     // the total number records in the data structure
#define BLOCK_SIZE 1024 // the maximum size of each record

rb_buffer_t* buffer = rb_create(CAPACITY, BLOCK_SIZE);

Write:

// copy a block of data into the tail of the structure
rb_insert(buffer, (void*)some_data, data_length);

Read:

unsigned char* result;
size_t length;

// get a pointer to the most recently-inserted data (i.e. the 'tail')...
rb_get_tail(buffer, (void*)&result, &length);

// ...or to the data at some offset from the tail
size_t offset = 4;
rb_get_at(buffer, offset, (void*)&result, &length);

Cleanup:

// free any resources allocated by the data structure
rb_destroy(buffer);