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option to set minimum number of bytes (makeSizeDenotation())

This commit is contained in:
Martchus 2015-11-21 01:10:04 +01:00
parent 5a15d956e8
commit 10bc8516ee
2 changed files with 15 additions and 13 deletions
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26
matroska/ebmlelement.cpp
View File

@ -258,35 +258,37 @@ byte EbmlElement::makeId(GenericFileElement::identifierType id, char *buff)
}
/*!
* \brief Makes the size denotation for the specified \a size and stores it to \a buff
* which must be at least 8 bytes long.
* \returns Returns the number of bytes written to \a buff.
* \brief Makes the size denotation for the specified \a size and stores it to \a buff.
* \param size Specifies the size to be denoted.
* \param buff Specifies the buffer to store the denotation. Must be at least 8 bytes long.
* \param minBytes Specifies the minimum number of bytes to use. Might be use allow subsequent element growth.
* \returns Returns the number of bytes written to \a buff. Always in the range of \a minBytes and 8.
* \throws Throws InvalidDataException() if \a size can not be represented.
*/
byte EbmlElement::makeSizeDenotation(uint64 size, char *buff)
byte EbmlElement::makeSizeDenotation(uint64 size, char *buff, byte minBytes)
{
if(size < 126) {
if(minBytes <= 1 && size < 126) {
*buff = static_cast<byte>(size | 0x80);
return 1;
} else if(size <= 16382ul) {
} else if(minBytes <= 2 && size <= 16382ul) {
BE::getBytes(static_cast<uint16>(size | 0x4000), buff);
return 2;
} else if(size <= 2097150ul) {
} else if(minBytes <= 3 && size <= 2097150ul) {
BE::getBytes(static_cast<uint32>((size | 0x200000) << 0x08), buff);
return 3;
} else if(size <= 268435454ul) {
} else if(minBytes <= 4 && size <= 268435454ul) {
BE::getBytes(static_cast<uint32>(size | 0x10000000), buff);
return 4;
} else if(size <= 34359738366ul) {
} else if(minBytes <= 5 && size <= 34359738366ul) {
BE::getBytes(static_cast<uint64>((size | 0x800000000) << 0x18), buff);
return 5;
} else if(size <= 4398046511102ul) {
} else if(minBytes <= 6 && size <= 4398046511102ul) {
BE::getBytes(static_cast<uint64>((size | 0x40000000000) << 0x10), buff);
return 6;
} else if(size <= 562949953421310ul) {
} else if(minBytes <= 7 && size <= 562949953421310ul) {
BE::getBytes(static_cast<uint64>((size | 0x2000000000000) << 0x08), buff);
return 7;
} else if(size <= 72057594037927934ul) {
} else if(minBytes <= 8 && size <= 72057594037927934ul) {
BE::getBytes(static_cast<uint64>(size | 0x100000000000000), buff);
return 8;
}

2
matroska/ebmlelement.h
View File

@ -65,7 +65,7 @@ public:
static byte calculateIdLength(identifierType id);
static byte calculateSizeDenotationLength(uint64 size);
static byte makeId(identifierType id, char *buff);
static byte makeSizeDenotation(uint64 size, char *buff);
static byte makeSizeDenotation(uint64 size, char *buff, byte minBytes = 1);
static byte calculateUIntegerLength(uint64 integer);
static byte makeUInteger(uint64 value, char *buff);
static void makeSimpleElement(std::ostream &stream, identifierType id, uint64 content);