From 9439c6f1caffd938673018f3af7460b33a12528e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Karel=20Ko=C4=8D=C3=AD?= <cynerd@email.cz>
Date: Sun, 20 Mar 2016 16:39:30 +0100
Subject: Another work progress

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+buffer
+======
+In whole project are used ring buffers. This is so common that handling them is
+exported to separated header file. In fact it contains two implementations of
+buffers. One implementation is defined using preprocessor macros. Another one is
+plain C code.
+
+## Preprocessor implementation
+Preprocessor implementation is expected to be faster and less memory intense. Also
+more suitable for buffers of simple types (such us int). But this buffer has to be
+defined with known size at compile time and can't be resized. All this makes it
+good implementation for IO devices input and output buffers, but less for more
+complicated tasks containing for example sorting.
+
+### Macros
+#### IOEBUFFER
+```C
+IOEBUFFER(type, name, size)
+```
+This macro defines buffer. Use it to define new buffer.
+##### Parameters
+| type | Specify type of elements in buffer. Can be any valid C type |
+| name | Name of buffer. This is C variable name.                    |
+| size | Numerical value of buffer size                              |
+
+#### IOEBUFFER_INIT
+```C
+IOEBUFFER_INIT(name, size)
+```
+Use this to initialize buffer. Parameter `size` must be same as for IOEBUFFER
+(definition of buffer). You can use this also to reset buffer (remove all data
+from buffer).
+##### Parameters
+| name | Name if buffer. This is C variable name. |
+| size | Numerical value of buffer size           |
+
+#### IOEBUFFER_PUT
+```C
+IOEBUFFER_PUT(name, size, data, mode)
+```
+Use this macro to add new data to buffer.
+##### Parameters
+| name | Name of buffer. This is C variable name. |
+| size | Numerical value of buffer size           |
+| data | Data to be stored to buffer              |
+| mode | This specifies action if buffer is full. |
+##### Modes
+| IOEBUFFER_MODE_BLOCK     | Block execution until buffer has some free space. |
+| IOEBUFFER_MODE_OVERWRITE | Overwrites oldest added (fist to be read)         |
+| IOEBUFFER_MODE_DROP      | New data won't be stored to buffer if full        |
+
+#### IOEBUFFER_GET
+```C
+IOEBUFFER_GET(name, size, variable)
+```
+Get value from buffer. Value is stored in `variable` (it is variable of same type
+as buffer data, not pointer to variable of same type). If no data is in buffer,
+variable is set to NULL.
+##### Parameters
+| name     | Name of buffer. This is C variable name.  |
+| size     | Numerical value of buffer size.           |
+| variable | Variable in which data will be stored in. |
+
+#### IOEBUFFER_CNT
+```C
+IOEBUFFER_CNT(name, size, variable)
+```
+Counts number of data entries in buffer and saves value to variable.
+##### Parameters
+| name     | Name of buffer. This is C variable name.                    |
+| size     | Numerical value of buffer size.                             |
+| variable | Int/Unsigned type variable where data count will be stored. |
+
+## C implementation
+C implementation is more general. Size is defined by calling initialization
+function. But it is using general pointers, so it is only able store pointers.
+
+As buffer identification is used defined type `IOEBuffer`. All functions takes
+pointer to this type as parameter. Because of this, it won't be described for
+every function.
+
+### Functions
+#### ioebuffer_init
+```C
+int8_t ioebuffer_init(IOEBuffer *buf, uint8_t size, uint8_t flags)
+```
+Initialized buffer and allocates required resources.
+##### Parameters
+| size  | Number of elements to be maximally stored in buffer |
+| flags | TODO
+##### Flags
+TODO
+
+#### ioebuffer_uninit
+```C
+void ioebuffer_uninit(IOEBuffer *buf)
+```
+Frees all resources allocated during initialization of buffer. Use this every time
+you are freeing buffer.
+
+#### ioebuffer_put
+```C
+int8_t ioebuffer_put(IOEBuffer *buf, void *data)
+```
+Add `data` to buffer
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