Implement more sophisticated readline-mode

luprex/core/cpp/util.cpp

@@ -8,6 +8,7 @@
 #include <cmath>
 #include <iomanip>
 #include <cassert>
+#include <algorithm>
 
 #ifndef WIN32
 #include <unistd.h>
@@ -141,6 +142,25 @@ StringVec split(const std::string &s, char sep) {
     return result;
 }
 
+std::string repeat_string(const std::string &a, int n) {
+    int len = a.size();
+    std::string result(len * n, ' ');
+    for (int i = 0; i < n; i++) {
+        for (int j = 0; j < len; j++) {
+            result[i*len + j] = a[j];
+        }
+    }
+    return result;
+}
+
+int common_prefix_length(const std::string &a, const std::string &b) {
+    int minlen = std::min(a.size(), b.size());
+    for (int i = 0; i < minlen; i++) {
+        if (a[i] != b[i]) return i;
+    }
+    return minlen;
+}
+    
 std::string tolower(std::string input) {
     for (int i = 0; i < int(input.size()); i++) {
         input[i] = std::tolower(input[i]);
@@ -305,6 +325,9 @@ LuaDefine(unittests_util, "c") {
     LuaAssert(L, sv2[2]=="");
     LuaAssert(L, sv2[3]=="bar");
 
+    // Test the repeat string routine.
+    LuaAssertStrEq(L, util::repeat_string("abc", 3), "abcabcabc");
+
     // test toupper and tolower
     LuaAssert(L, util::toupper("fooBar") == "FOOBAR");
     LuaAssert(L, util::tolower("fooBar") == "foobar");