1 files changed, 51 insertions, 0 deletions
diff --git a/moses2/parameters/ContextParameters.cpp b/moses2/parameters/ContextParameters.cpp
new file mode 100644
index 000000000..3c5b894ee
--- /dev/null
+++ b/moses2/parameters/ContextParameters.cpp
@@ -0,0 +1,51 @@
+#include "ContextParameters.h"
+#include "../legacy/Parameter.h"
+
+namespace Moses2
+{
+
+ContextParameters::
+ContextParameters()
+  : look_ahead(0), look_back(0)
+{ }
+
+bool
+ContextParameters::
+init(Parameter const& params)
+{
+  look_back = look_ahead = 0;
+  params.SetParameter(context_string, "context-string", std::string(""));
+  std::string context_window;
+  params.SetParameter(context_window, "context-window", std::string(""));
+
+  if (context_window == "")
+    return true;
+
+  if (context_window.substr(0,3) == "all") {
+    look_back = look_ahead = std::numeric_limits<size_t>::max();
+    return true;
+  }
+
+  size_t p = context_window.find_first_of("0123456789");
+  if (p == 0)
+    look_back = look_ahead = atoi(context_window.c_str());
+
+  if (p == 1) {
+    if (context_window[0] == '-')
+      look_back  = atoi(context_window.substr(1).c_str());
+    else if (context_window[0] == '+')
+      look_ahead = atoi(context_window.substr(1).c_str());
+    else
+      UTIL_THROW2("Invalid specification of context window.");
+  }
+
+  if (p == 2) {
+    if (context_window.substr(0,2) == "+-" ||
+        context_window.substr(0,2) == "-+")
+      look_back = look_ahead = atoi(context_window.substr(p).c_str());
+    else
+      UTIL_THROW2("Invalid specification of context window.");
+  }
+  return true;
+}
+}