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Improve GET_UTF{8,16} documentation

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Originally committed as revision 23909 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Måns Rullgård 2010-06-30 20:09:48 +00:00
parent 12633044b1
commit c2a5b4731b
1 changed files with 18 additions and 23 deletions
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41
libavutil/common.h
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@ -192,18 +192,16 @@ static inline av_const int av_ceil_log2(int x)
#define MKTAG(a,b,c,d) ((a) | ((b) << 8) | ((c) << 16) | ((d) << 24))
#define MKBETAG(a,b,c,d) ((d) | ((c) << 8) | ((b) << 16) | ((a) << 24))
/*!
* \def GET_UTF8(val, GET_BYTE, ERROR)
* Convert a UTF-8 character (up to 4 bytes long) to its 32-bit UCS-4 encoded form
* \param val is the output and should be of type uint32_t. It holds the converted
* UCS-4 character and should be a left value.
* \param GET_BYTE gets UTF-8 encoded bytes from any proper source. It can be
* a function or a statement whose return value or evaluated value is of type
* uint8_t. It will be executed up to 4 times for values in the valid UTF-8 range,
* and up to 7 times in the general case.
* \param ERROR action that should be taken when an invalid UTF-8 byte is returned
* from GET_BYTE. It should be a statement that jumps out of the macro,
* like exit(), goto, return, break, or continue.
/**
* Convert a UTF-8 character (up to 4 bytes) to its 32-bit UCS-4 encoded form.
*
* @param val Output value, must be an lvalue of type uint32_t.
* @param GET_BYTE Expression reading one byte from the input.
* Evaluated up to 7 times (4 for the currently
* assigned Unicode range). With a memory buffer
* input, this could be *ptr++.
* @param ERROR Expression to be evaluated on invalid input,
* typically a goto statement.
*/
#define GET_UTF8(val, GET_BYTE, ERROR)\
val= GET_BYTE;\
@ -220,17 +218,14 @@ static inline av_const int av_ceil_log2(int x)
}\
}
/*!
* \def GET_UTF16(val, GET_16BIT, ERROR)
* Convert a UTF-16 character (2 or 4 bytes) to its 32-bit UCS-4 encoded form
* \param val is the output and should be of type uint32_t. It holds the converted
* UCS-4 character and should be a left value.
* \param GET_16BIT gets two bytes of UTF-16 encoded data converted to native endianness.
* It can be a function or a statement whose return value or evaluated value is of type
* uint16_t. It will be executed up to 2 times.
* \param ERROR action that should be taken when an invalid UTF-16 surrogate is
* returned from GET_BYTE. It should be a statement that jumps out of the macro,
* like exit(), goto, return, break, or continue.
/**
* Convert a UTF-16 character (2 or 4 bytes) to its 32-bit UCS-4 encoded form.
*
* @param val Output value, must be an lvalue of type uint32_t.
* @param GET_16BIT Expression returning two bytes of UTF-16 data converted
* to native byte order. Evaluated one or two times.
* @param ERROR Expression to be evaluated on invalid input,
* typically a goto statement.
*/
#define GET_UTF16(val, GET_16BIT, ERROR)\
val = GET_16BIT;\