1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/algs4-c++/src/Buffer.cpp	Tue Jun 23 11:02:31 2015 -0500
     1.3 @@ -0,0 +1,84 @@
     1.4 +// Sedgewick and Wayne, Algorithms, 4th ed. problem 1.3.44
     1.5 +
     1.6 +// I would never use this in real life.  It's far too inefficient.
     1.7 +
     1.8 +#include "Buffer.hpp"
     1.9 +
    1.10 +Buffer::Buffer( void ) :
    1.11 +    cursor (0),
    1.12 +    use_s1 (true)
    1.13 +    {
    1.14 +    }
    1.15 +
    1.16 +void Buffer::insert( char c ) {
    1.17 +    if ( use_s1 ) {
    1.18 +        size_t i = 0;
    1.19 +        size_t max = s1.size();
    1.20 +        while ( i != cursor )
    1.21 +            s2.push( s1.pop() );
    1.22 +        s2.push( c );
    1.23 +        while ( i < max )
    1.24 +            s2.push( s1.pop() );
    1.25 +        }
    1.26 +    else {
    1.27 +        size_t i = 0;
    1.28 +        size_t max = s2.size();
    1.29 +        while ( i != cursor )
    1.30 +            s1.push( s2.pop() );
    1.31 +        s1.push( c );
    1.32 +        while ( i < max )
    1.33 +            s1.push( s2.pop() );
    1.34 +        }
    1.35 +    }
    1.36 +
    1.37 +char Buffer::get( void ) {
    1.38 +    if ( use_s1 )
    1.39 +        return s1.find( cursor );       // Need to add overloaded T find( size_t k) to Stack
    1.40 +    else
    1.41 +        return s2.find( cursor );
    1.42 +    }
    1.43 +
    1.44 +char Buffer::delete( void ) {
    1.45 +    if ( use_s1 ) {
    1.46 +        size_t i = 0;
    1.47 +        size_t max = s1.size();
    1.48 +        while ( i != cursor )
    1.49 +            s2.push( s1.pop() );
    1.50 +        ++i;
    1.51 +        while ( i < max )
    1.52 +            s2.push( s1.pop() );
    1.53 +        }
    1.54 +    else {
    1.55 +        size_t i = 0;
    1.56 +        size_t max = s2.size();
    1.57 +        while ( i != cursor )
    1.58 +            s1.push( s2.pop() );
    1.59 +        ++i;
    1.60 +        while ( i < max )
    1.61 +            s1.push( s2.pop() );
    1.62 +        }
    1.63 +
    1.64 +    if ( cursor > size() )
    1.65 +        cursor = size();
    1.66 +    }
    1.67 +
    1.68 +void Buffer::left( size_t k ) {
    1.69 +    if ( cursor < k )
    1.70 +        cursor = 0;
    1.71 +    else
    1.72 +        cursor -= k;
    1.73 +    }
    1.74 +
    1.75 +void Buffer::right( size_t k ) {
    1.76 +    if ( size() - cursor < k )
    1.77 +        cursor = size();
    1.78 +    else
    1.79 +        cursor += k;
    1.80 +    }
    1.81 +
    1.82 +size_t Buffer::size( void ) {
    1.83 +    if ( use_s1 )
    1.84 +        return s1.size();
    1.85 +    else
    1.86 +        return s2.size();
    1.87 +    }