From 2f38636a277833d48bb093f27eb9db2fc194c5bc Mon Sep 17 00:00:00 2001
From: Milan Suman <>
Date: Wed, 20 Jul 2022 10:38:55 +0530
Subject: [PATCH] lib/javacompat: implement exportJavaString

---
 src/lib/javacompat.cpp  | 53 +++++++++++++++++++++++++++++++++++++----
 src/lib/javacompat.h++  |  3 ++-
 src/test/javacompat.cpp | 17 ++++++++++++-
 3 files changed, 66 insertions(+), 7 deletions(-)

diff --git a/src/lib/javacompat.cpp b/src/lib/javacompat.cpp
index 05e5dee..b60bc88 100644
--- a/src/lib/javacompat.cpp
+++ b/src/lib/javacompat.cpp
@@ -16,8 +16,18 @@
 #include <tinyutf8/tinyutf8.h>
 #include <string>
 #include "error.h++"
-
 #include "javacompat.h++"
+#include "../../.endianness"
+
+#ifdef FOSSVG_ENDIAN_BIG_WORD
+    #error "Honeywell-316-style endianness is not supported. If you feel like it should, feel free to participate in the project to maintain it."
+#endif
+#ifdef FOSSVG_ENDIAN_LITTLE_WORD
+    #error "PDP-11-style endianness is not supported. If you feel like it should, feel free to participate in the project to maintain it."
+#endif
+#ifdef FOSSVG_ENDIAN_UNKNOWN
+    #error "The endianness of your system could not be determined. Please set it manually. FOSS-VG is currently implemented using some endian-specific functions."
+#endif
 
 namespace JavaCompat {
     //FIXME: contrary to what I said, we need to explicitly pass the data
@@ -37,9 +47,42 @@ namespace JavaCompat {
         }
         return tiny_utf8::string(stdString);
     }
-    /*
-    ErrorOr<uint8_t*> exportJavaString(tiny_utf8::string data) {
-        return ErrorOr(nullptr);
+
+    ErrorOr<std::vector<uint8_t>> exportJavaString(tiny_utf8::string data) {
+        uint16_t* size = new uint16_t;
+        uint8_t* sizeBytes = reinterpret_cast<uint8_t*>(size);
+        std::vector<uint8_t> output = std::vector<uint8_t>();
+        std::string stdString = data.cpp_str();
+
+        *size = (uint16_t) stdString.size();
+
+        //placeholder size bytes
+        output.push_back(0x00);
+        output.push_back(0x00);
+        for(int i=0; i<stdString.size(); i++){
+            if((uint8_t) stdString[i] == 0x00){
+                *size += 1;
+                output.push_back(0xc0);
+                output.push_back(0x80);
+                continue;
+            }
+            output.push_back(stdString[i]);
+        }
+
+        #ifdef FOSSVG_BIG_ENDIAN
+            output[0] = *sizeBytes;
+            output[1] = *(sizeBytes+1);
+        #else
+            #ifdef FOSSVG_LITTLE_ENDIAN
+                output[0] = *(sizeBytes+1);
+                output[1] = *sizeBytes;
+            #else
+                #error "NBT::helper::writeInt16: An implementation for your endianness is unavailable."
+            #endif
+        #endif
+
+        
+        return ErrorOr(output);
     }
-    */
+
 }
diff --git a/src/lib/javacompat.h++ b/src/lib/javacompat.h++
index 24be799..c9eba00 100644
--- a/src/lib/javacompat.h++
+++ b/src/lib/javacompat.h++
@@ -15,10 +15,11 @@
 
 #include <tinyutf8/tinyutf8.h>
 #include "error.h++"
+#include <vector>
 
 namespace JavaCompat {
     //FIXME: contrary to what I said, we need to explicitly pass the data
     // size because files could have been tampered with or corrupted
     tiny_utf8::string importJavaString(uint8_t data[]);
-    ErrorOr<uint8_t*> exportJavaString(tiny_utf8::string data);
+    ErrorOr<std::vector<uint8_t>> exportJavaString(tiny_utf8::string data);
 }
diff --git a/src/test/javacompat.cpp b/src/test/javacompat.cpp
index 87d7862..49b1154 100644
--- a/src/test/javacompat.cpp
+++ b/src/test/javacompat.cpp
@@ -28,7 +28,7 @@ int main(){
     // java-style_unicode: 119 bytes, 85 characters ??
 
     std::cout << "################################################################################" << std::endl;
-    std::cout << "Java String Tests" << std::endl;
+    std::cout << "Import String Tests" << std::endl;
     std::cout << "################################################################################" << std::endl;
 
     char* nextChar = new char;
@@ -78,6 +78,21 @@ int main(){
     ASSERT(normalString == importedString);
     std::cout << "Passed Import Java string test." << std::endl;
 
+    std::cout << "################################################################################" << std::endl;
+    std::cout << "Export String Tests" << std::endl;
+    std::cout << "################################################################################" << std::endl;
+
+    //using normalString from when we read the file earlier
+    //there's no need to read the same file twice
+
+    std::vector<uint8_t> data = JavaCompat::exportJavaString(normalString).value;
+    std::string exportedString = std::string();
+    for(int i=0; i<data.size(); i++){
+        exportedString.push_back(data[i]);
+    }
+
+    ASSERT(exportedString == javaStdString);
+    std::cout << "Passed Export Java string test." << std::endl;
 
 return 0;
 }