Add run length example

examples/CMakeLists.txt

@@ -102,6 +102,16 @@ if (BUILD_LIBFUZZER)
    set_target_properties(StreamingAndFormatting_LF PROPERTIES COMPILE_DEFINITIONS "LIBFUZZER")
 endif()
 
+add_executable(Runlen Runlen.cpp) 
+target_link_libraries(Runlen deepstate)
+
+if (BUILD_LIBFUZZER)
+   add_executable(Runlen_LF Runlen.cpp) 
+   target_link_libraries(Runlen_LF deepstate_LF)
+   target_link_libraries (Runlen_LF "-fsanitize=fuzzer,undefined")
+   set_target_properties(Runlen_LF PROPERTIES COMPILE_DEFINITIONS "LIBFUZZER")
+endif()
+
 if (NOT APPLE)
   add_executable(Squares Squares.c)
   target_link_libraries(Squares deepstate)

examples/Runlen.cpp

@@ -0,0 +1,62 @@
+#include <deepstate/DeepState.hpp>
+
+using namespace deepstate;
+
+char* encode(const char* input) {
+  unsigned int l = strlen(input);
+  char* encoded = (char*)malloc((l*2)+1);
+  if (l == 0) {
+    encoded[0] = '\0';
+    return encoded;
+  }
+  unsigned char last = input[0];
+  unsigned char current;
+  int count = 1;
+  int pos = 0;
+  for (int i = 1; i < l; i++) {
+    current = input[i];
+    if ((current == last) && (count < 26)) {
+      count++;
+    } else {
+      encoded[pos++] = last;
+      encoded[pos++] = 64 + count;
+      last = current;
+      count = 1;
+    }
+  }
+  encoded[pos++] = last;
+  encoded[pos++] = 64 + count;
+  encoded[pos] = '\0';
+  return encoded;
+}
+
+char* decode(const char* output) {
+  unsigned int l = strlen(output);
+  char* decoded = (char*)malloc(((l/2)*25)+1);
+  if (l == 0) {
+    decoded[0] = '\0';
+    return decoded;
+  }
+  int pos = 0;
+  unsigned char current;
+  for (int i = 0; i < l; i++) {
+    current = output[i++];
+    unsigned int count = output[i] - 64;
+    for (int j = 0; j < count; j++) {
+      decoded[pos++] = current;
+    }
+  }
+  decoded[pos] = '\0';
+  return decoded;
+}
+
+#define MAX_STR_LEN 100
+
+TEST(Runlength, EncodeDecode) {
+  char* original = DeepState_CStrUpToLen(MAX_STR_LEN, "abcde");
+  LOG(TRACE) << "original = `" << original << "`";
+  char* encoded = encode(original);
+  char* roundtrip = decode(encoded);
+  ASSERT (strncmp(roundtrip, original, MAX_STR_LEN) == 0) <<
+    "encode = `" << encoded << "`, decode(encode) = `" << roundtrip << "`";
+}