/*
* This method processes a block of rows in a single invocation.
*
* The inputs are retrieved via arg_reader
* The outputs are returned via arg_writer
*/
virtual void processBlock(ServerInterface &srvInterface,
BlockReader &arg_reader,
BlockWriter &res_writer)
{
// Basic error checking
if (arg_reader.getNumCols() != 2)
vt_report_error(0, "Function only accept 2 arguments, but %zu provided",
arg_reader.getNumCols());
// While we have inputs to process
do {
// Get a copy of the input string
const std::string& patternStr = arg_reader.getStringRef(0).str();
const std::string& inStr = arg_reader.getStringRef(1).str();
size_t m = patternStr.size();
size_t n = inStr.size();
size_t d[m+1][n+1];
for (size_t i = 0; i <= m; ++i)
d[i][0] = i; // the distance of any first string to an empty second string
for (size_t j = 0; j <= n; ++j)
d[0][j] = j; // the distance of any second string to an empty first string
for (size_t j = 1; j <= n; ++j)
for (size_t i = 1; i <= m; ++i)
{
if (patternStr[i-1] == inStr[j-1])
d[i][j] = d[i-1][j-1]; // no operation required
else
{
d[i][j] = std::min(std::min(d[i-1][j] + 1, // a deletion
d[i][j-1] + 1), // an insertion
d[i-1][j-1] + 1); // a substitution
}
}
res_writer.setInt(d[m][n]);
res_writer.next();
} while (arg_reader.next());
}
