Add support for the string literal

contracts/eoslib/string.hpp

@@ -6,7 +6,21 @@
 #include <eoslib/print.hpp>
 
 namespace eosio {
-
+  /**
+   * @brief Count the length of null terminated string (excluding the null terminated symbol)
+   * Non-null terminated string need to be passed here, 
+   * Otherwise it will not give the right length
+   * @param cstr - null terminated string
+   */
+  inline uint32_t cstrlen(const char* cstr) {
+    uint32_t len = 0;
+    while(*cstr != '\0') {
+      len++;
+      cstr++;
+    }
+    return len;
+  }
+    
   class string {
 
   private:
@@ -63,6 +77,21 @@ namespace eosio {
       }
     }
 
+    /**
+     * @brief Constructor for string literal
+     * Non-null terminated string need to be passed here, 
+     * Otherwise it will have extraneous data
+     * @param cstr - null terminated string
+     */
+    string(const char* cstr) {
+      size = cstrlen(cstr) + 1;
+      data = (char *)malloc(size * sizeof(char));
+      memcpy(data, cstr, size * sizeof(char));
+      own_memory = true;
+      refcount = (uint32_t*)malloc(sizeof(uint32_t));
+      *refcount = 1;
+    }
+
     // Destructor
     ~string() {
       release_data_if_needed();
@@ -131,6 +160,7 @@ namespace eosio {
       return *(data + index);
     }
 
+    // Assignment operator
     string& operator = (const string& obj) {
       if (this != &obj) {
         release_data_if_needed();
@@ -143,6 +173,23 @@ namespace eosio {
       return *this;
     }
 
+    /**
+     * @brief Assignment operator for string literal
+     * Non-null terminated string need to be passed here, 
+     * Otherwise it will have extraneous data
+     * @param cstr - null terminated string
+     */
+    string& operator = (const char* cstr) {
+        release_data_if_needed();
+        size = cstrlen(cstr) + 1;
+        data = (char *)malloc(size * sizeof(char));
+        memcpy(data, cstr, size * sizeof(char));
+        own_memory = true;
+        refcount = (uint32_t*)malloc(sizeof(uint32_t));
+        *refcount = 1;
+        return *this;
+    }
+
     string& operator += (const string& str){
       assert((size + str.size > size) && (size + str.size > str.size), "overflow");
 

contracts/test_api/test_api.cpp

@@ -111,6 +111,7 @@ extern "C" {
       WASM_TEST_HANDLER(test_string, print_unicode);
       WASM_TEST_HANDLER(test_string, valid_utf8);
       WASM_TEST_HANDLER(test_string, invalid_utf8);
+      WASM_TEST_HANDLER(test_string, string_literal);
 
       //unhandled test call
       WASM_TEST_ERROR_CODE = WASM_TEST_FAIL;

contracts/test_api/test_api.hpp

@@ -149,4 +149,5 @@ struct test_string {
   static unsigned int print_unicode();
   static unsigned int valid_utf8();
   static unsigned int invalid_utf8();
+  static unsigned int string_literal();
 };

contracts/test_api/test_string.cpp

@@ -291,7 +291,6 @@ unsigned int test_string::print_unicode() {
   return WASM_TEST_PASS;
 }
 
-
 unsigned int test_string::valid_utf8() {
   // Roman alphabet is 1 byte UTF-8
   char data[] = "abcdefghij";
@@ -330,3 +329,28 @@ unsigned int test_string::invalid_utf8() {
 
   return WASM_TEST_PASS;
 }
+
+
+unsigned int test_string::string_literal() {
+  // Construct
+  char data1[] = "abcdefghij";
+  char data2[] = "klmnopqrstuvwxyz";
+
+  eos::string str = "abcdefghij";
+
+  WASM_ASSERT( str.get_size() == 11,  "data1 str.get_size() == 11" );
+  for (uint8_t i = 0; i < 11; i++) {
+    WASM_ASSERT( str[i] == data1[i],  "data1 str[i] == data1[i]" );
+  }
+  WASM_ASSERT( str.is_own_memory() == true,  "data1 str.is_own_memory() == true" );
+
+  str = "klmnopqrstuvwxyz";
+  
+  WASM_ASSERT( str.get_size() == 17,  "data2 str.get_size() == 17" );
+  for (uint8_t i = 0; i < 17; i++) {
+    WASM_ASSERT( str[i] == data2[i],  "data2 str[i] == data2[i]" );
+  }
+  WASM_ASSERT( str.is_own_memory() == true,  "data2 str.is_own_memory() == true" );
+
+  return WASM_TEST_PASS;
+}

tests/api_tests/api_tests.cpp

@@ -458,7 +458,8 @@ BOOST_FIXTURE_TEST_CASE(test_all, testing_fixture)
       BOOST_CHECK_EQUAL( capture[0], "你好，世界！");
       BOOST_CHECK_MESSAGE( CALL_TEST_FUNCTION( TEST_METHOD("test_string", "valid_utf8"), {}, {} ) == WASM_TEST_PASS, "test_string::valid_utf8()" );
       BOOST_CHECK_EXCEPTION( CALL_TEST_FUNCTION( TEST_METHOD("test_string", "invalid_utf8"), {}, {} ), fc::assert_exception, is_assert_exception );
-      
+      BOOST_CHECK_MESSAGE( CALL_TEST_FUNCTION( TEST_METHOD("test_string", "string_literal"), {}, {} ) == WASM_TEST_PASS, "test_string::string_literal()" );
+
 } FC_LOG_AND_RETHROW() }
 
 #define RUN_CODE_HANDLER_WITH_TRANSFER(account_name, test_wast)                                            \