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Diffstat (limited to 'static/unix-v10/man3/bits.3')
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diff --git a/static/unix-v10/man3/bits.3 b/static/unix-v10/man3/bits.3 new file mode 100644 index 00000000..57318b39 --- /dev/null +++ b/static/unix-v10/man3/bits.3 @@ -0,0 +1,198 @@ +.TH BITS 3+ +.CT 2 datatype +.SH NAME +bits \- variable length bit strings +.SH SYNOPSIS +.nf +.B "#include <Bits.h>" +.PP +.B "typedef unsigned long Bits_chunk;" +.PP +.B "struct Bits {" +.B " Bits() { }" +.B " Bits(Bits_chunk, unsigned = 1);" +.B " Bits(const Bits&)" +.B " ~Bits(); +.BR " Bits& operator= (const Bits&); // " also " = &= |= ^= +.BR " Bits& operator<<= (int); // " also " >>= +.B " int operator[] (unsigned);" +.B " operator Bits_chunk();" +.B " unsigned size();" +.B " unsigned size(unsigned);" +.B " Bits& compl();" +.B " Bits& concat(const Bits&);" +.B " Bits& set(unsigned, unsigned long = 1);" +.B " Bits& reset(unsigned);" +.B " Bits& compl(unsigned);" +.B " unsigned count();" +.B " unsigned signif();" +.B " unsigned trim();" +.B "};" +.PP +.B "Bits operator~ (const Bits&); +.BR "Bits operator& (const Bits&, const Bits&); // " also " | ^ +.BR "Bits operator<< (const Bits&, int); // " also " >> +.BR "int operator< (const Bits&, const Bits&); // " also " > <= >= == != +.fi +.SH DESCRIPTION +A +.B Bits +object contains a variable-length bit string. +The bits of a +.B Bits +object +.I b +are numbered from 0 through +.IB b .size()\fR\-1,\fP +with the rightmost bit numbered 0. +.PP +.B Bits_chunk +is the largest unsigned integral type +acceptable for conversion to and from +.BR Bits , +.BR "unsigned long" +in this implementation. +.SS Constructors +.TP \w'\fIa\fL.concat(\fIb\fL)\ 'u +.B Bits() +An empty bit string. +.TP +.BI Bits( n ) +The bits are copied from the binary representation of +.I n +with the ones-digit of +.I n +becoming bit 0. +Leading zero-bits are removed, +except that +.B Bits(0) +is a one-bit string. +.TP +.BI Bits( n , m ) +The same, but padded with leading zeros to size +.I m +if necessary. +.SS Operators +Bit strings have +value semantics; +assigning a +.B Bits +object or passing it to or returning it from a function +creates a copy of its value. +The meanings of operators are mostly predictable from C. +.PP +Under binary and comparison operators, +the shorter operand +is considered to be padded on the left with zeros to the +length of the longer. +If, after padding, two strings of different length compare equal, +the shorter is deemed the smaller. +.PP +Negative shift amounts +reverse the sense of shift operators. +.PP +Under conversion (or assignment) to a +.BR Bits_chunk , +a +.B Bits +is interpreted as an unsigned integer. +If it has a value small enough to fit, +that value is assigned. +Otherwise, a non-zero value is +assigned. +Thus a +.B Bits +is considered `true' in an +.B if +test if it contains any one-bit, `false' otherwise. +.TP \w'\fIa\fL.concat(\fIb\fL)\ 'u +.IB a [ s ] +Bit number +.I s +of +.IR a ; +0 if +.I s +is out of bounds. +.SS Other functions +.TP \w'\fIa\fL.concat(\fIb\fL)\ 'u +.IB a .size( s ) +Set the size of +.I a +to +.I s +by truncating or padding with zeros on the left as necessary. +Return the new size. +.TP +.IB a .compl() +Complement the bits of +.I a. +Return +.I a. +.TP +.IB a .set( s ) +.PD 0 +.TP +.IB a .reset( s ) +.TP +.IB a .compl ( s ) +Set, reset, or complement bit +.I s +of +.I a. +No effect if +.IB a .size()<= s. +Return +.I a. +.PD +.TP +.IB a .set( s , n ) +If +.I n +is 0, reset bit +.I s +of +.I a, +otherwise set bit +.I s. +Equivalent to +.BR "n? a.set(s): a.reset(s)" . +.TP +.IB a .count() +Return the number of one-bits in +.I a. +.TP +.IB a .signif() +Return the number of significant bits in +.BR a : +one more than the +number of the leftmost one-bit, or +zero if there is no one-bit. +.TP +.IB a .trim() +Discard high-order zero-bits. +Equivalent to +.BR a.size(a.signif()) . +.TP +.IB a .concat( b ) +Concatenate the value of +.I b +to the right (low-order) end of +.I a. +Return +.I a. +.TP +.BI concat( a , b ) +Return a newly created concatenated object. +.SH DIAGNOSTICS +An operation that runs out of memory sets +the length of the affected +.B Bits +to zero. +.SH BUGS +Too bad C++ can't support +.BR "a[s] = n" . +.br +Things would be more consistent if +.B Bits(0).size() +were zero. |