Bit string functions allow bits to be set, cleared, or tested in arbitrarily sized byte arrays.
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#define | OSRTBYTEARRAYSIZE(numbits) ((numbits+7)/8) |
| | This macro is used to calculate the byte array size required to hold the given number of bits.
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| EXTERNRT OSUINT32 | rtxGetBitCount (OSUINT32 value) |
| | This function returns the minimum size of the bit field required to hold the given integer value. More...
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| EXTERNRT int | rtxSetBit (OSOCTET *pBits, OSSIZE numbits, OSSIZE bitIndex) |
| | This function sets the specified zero-counted bit in the bit string. More...
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| EXTERNRT OSUINT32 | rtxSetBitFlags (OSUINT32 flags, OSUINT32 mask, OSBOOL action) |
| | This function sets one or more bits to TRUE or FALSE in a 32-bit unsigned bit flag set. More...
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| EXTERNRT int | rtxClearBit (OSOCTET *pBits, OSSIZE numbits, OSSIZE bitIndex) |
| | This function clears the specified zero-counted bit in the bit string. More...
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| EXTERNRT OSBOOL | rtxTestBit (const OSOCTET *pBits, OSSIZE numbits, OSSIZE bitIndex) |
| | This function tests the specified zero-counted bit in the bit string. More...
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| EXTERNRT OSSIZE | rtxLastBitSet (const OSOCTET *pBits, OSSIZE numbits) |
| | This function returns the zero-counted index of the last bit set in a bit string. More...
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| EXTERNRT int | rtxCheckBitBounds (OSCTXT *pctxt, OSOCTET **ppBits, OSSIZE *pNumocts, OSSIZE minRequiredBits, OSSIZE preferredLimitBits) |
| | Check whether the given bit string is large enough, and expand it if necessary. More...
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| EXTERNRT int | rtxZeroUnusedBits (OSOCTET *pBits, OSSIZE numbits) |
| | This function zeros unused bits at the end of the given bit string. More...
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| EXTERNRT int | rtxCheckUnusedBitsZero (const OSOCTET *pBits, OSSIZE numbits) |
| | This function checks to see if unused bits at the end of the given bit string are zero. More...
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Bit string functions allow bits to be set, cleared, or tested in arbitrarily sized byte arrays.
◆ rtxCheckBitBounds()
| EXTERNRT int rtxCheckBitBounds |
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OSCTXT * |
pctxt, |
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OSOCTET ** |
ppBits, |
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OSSIZE * |
pNumocts, |
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OSSIZE |
minRequiredBits, |
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OSSIZE |
preferredLimitBits |
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Check whether the given bit string is large enough, and expand it if necessary.
- Parameters
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| pctxt | The context to use should memory need to be allocated. |
| ppBits | *ppBits is a pointer to the bit string, or NULL if one has not been created. If the string is expanded, *ppBits receives a pointer to the new bit string. |
| pNumocts | pNumocts points to the current size of the bit string in octets. If the bit string is expanded, *pNumocts receives the new size. |
| minRequiredBits | The minimum number of bits needed in the bit string. On return, pBits will point to a bit string with at least this many bits. |
| preferredLimitBits | The number of bits over which we prefer not to go. If nonzero, no more bytes will be allocated than necessary for this many bits, unless explicitly required by minRequiredBits. |
- Returns
- If successful, 0. Otherwise, an error code.
◆ rtxCheckUnusedBitsZero()
| EXTERNRT int rtxCheckUnusedBitsZero |
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const OSOCTET * |
pBits, |
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OSSIZE |
numbits |
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This function checks to see if unused bits at the end of the given bit string are zero.
- Parameters
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| pBits | Pointer to the octets of the bit string. |
| numbits | The number of bits in the bit string. |
- Returns
- Zero if the operation is successful, or a negative status code if the operation fails. RTERR_INVBINS will be returned if bits at end are not zero.
◆ rtxClearBit()
| EXTERNRT int rtxClearBit |
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OSOCTET * |
pBits, |
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OSSIZE |
numbits, |
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OSSIZE |
bitIndex |
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This function clears the specified zero-counted bit in the bit string.
- Parameters
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| pBits | Pointer to octets of bit string. |
| numbits | Number of bits in the bit string. |
| bitIndex | Index of bit to be cleared. The bit with index 0 is a most significant bit in the octet with index 0. |
- Returns
- If successful, returns the previous state of the bit. If bit was previously set, the return value is positive. If bit was not previously set, the return value is zero. Otherwise, return value is an error code:
- RTERR_OUTOFBND = bitIndex is out of bounds
◆ rtxGetBitCount()
| EXTERNRT OSUINT32 rtxGetBitCount |
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OSUINT32 |
value | ) |
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This function returns the minimum size of the bit field required to hold the given integer value.
- Parameters
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- Returns
- Minimum size of the the field in bits required to hold value.
◆ rtxLastBitSet()
| EXTERNRT OSSIZE rtxLastBitSet |
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const OSOCTET * |
pBits, |
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OSSIZE |
numbits |
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This function returns the zero-counted index of the last bit set in a bit string.
- Parameters
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| pBits | Pointer to the octets of the bit string. |
| numbits | The number of bits in the bit string. |
- Returns
- Index of the last bit set in the bit string. OSNULLINDEX if no bit is set.
◆ rtxSetBit()
| EXTERNRT int rtxSetBit |
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OSOCTET * |
pBits, |
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OSSIZE |
numbits, |
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OSSIZE |
bitIndex |
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This function sets the specified zero-counted bit in the bit string.
- Parameters
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| pBits | Pointer to octets of bit string. |
| numbits | Number of bits in the bit string. |
| bitIndex | Index of bit to be set. The bit with index 0 is a most significant bit in the octet with index 0. |
- Returns
- If successful, returns the previous state of the bit. If bit was previously set, the return value is positive. If bit was not previously set, the return value is zero. Otherwise, return value is an error code:
- RTERR_OUTOFBND = bitIndex is out of bounds
◆ rtxSetBitFlags()
| EXTERNRT OSUINT32 rtxSetBitFlags |
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OSUINT32 |
flags, |
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OSUINT32 |
mask, |
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OSBOOL |
action |
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This function sets one or more bits to TRUE or FALSE in a 32-bit unsigned bit flag set.
- Parameters
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| flags | Flags to which mask will be applied. |
| mask | Mask with one or more bits set that will be applied to pBitMask. |
| action | Boolean action indicating if bits in flags should be set (TRUE) or cleared (FALSE). |
- Returns
- Updated flags after mask is applied.
◆ rtxTestBit()
| EXTERNRT OSBOOL rtxTestBit |
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const OSOCTET * |
pBits, |
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OSSIZE |
numbits, |
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OSSIZE |
bitIndex |
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This function tests the specified zero-counted bit in the bit string.
- Parameters
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| pBits | Pointer to octets of bit string. |
| numbits | Number of bits in the bit string. |
| bitIndex | Index of bit to be tested. The bit with index 0 is a most significant bit in the octet with index 0. |
- Returns
- True if bit set or false if not set or array index is beyond range of number of bits in the string.
◆ rtxZeroUnusedBits()
| EXTERNRT int rtxZeroUnusedBits |
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OSOCTET * |
pBits, |
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OSSIZE |
numbits |
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This function zeros unused bits at the end of the given bit string.
- Parameters
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| pBits | Pointer to the octets of the bit string. |
| numbits | The number of bits in the bit string. |
- Returns
- Zero if the operation is successful, or a negative status code if the operation fails.