Working on passing structs through the cffi

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "pihash"
-version = "0.4.0"
+version = "0.4.1"
 authors = ["Drew Short <warrick@sothr.com>"]
 description = "A simple library for generating perceptual hashes for images and comparing images based on their perceptual hashes."
 repository = "https://github.com/warricksothr/Perceptual-Image-Hashing/"

FFI-tests/ffi_test.py

@@ -41,6 +41,13 @@ else:
 	lib = cdll.LoadLibrary("libpihash.so")
 
 
+class PIHashes(Structure):
+	_fields_ = [
+		("ahash", c_ulonglong),
+		("dhash", c_ulonglong),
+		("phash", c_ulonglong)]
+	
+
 # Setting the ctypes return type references for the foreign functions
 # returns a pointer to the library that we'll need to pass to all function calls
 lib.ext_init.restype = c_void_p
@@ -51,6 +58,9 @@ lib.ext_get_dhash.restype = c_ulonglong
 lib.ext_get_dhash.argtypes = [c_void_p, c_char_p]
 lib.ext_get_phash.restype = c_ulonglong
 lib.ext_get_phash.argtypes = [c_void_p, c_char_p]
+lib.ext_get_phashes.restype = c_void_p
+lib.ext_get_phashes.argtypes = [c_void_p, c_char_p]
+lib.ext_free_phashes.argtypes = [c_void_p]
 # Takes a pointer and frees the struct at that memory location
 lib.ext_free.argtypes = [c_void_p]
 
@@ -65,9 +75,15 @@ lib_struct = lib.ext_init("./.hash_cache".encode(encoding="utf-8"))
 
 for image in test_images:
 	print("Requesting hashes for: %s"% image)
-    print("ahash: %i"% unsigned64(lib.ext_get_ahash(lib_struct, image)))
-    print("dhash: %i"% unsigned64(lib.ext_get_dhash(lib_struct, image)))
-    print("phash: %i"% unsigned64(lib.ext_get_phash(lib_struct, image)))
+	phashes = lib.ext_get_phashes(lib_struct, image)
+	pihashes = PIHashes.from_address(phashes)
+	lib.ext_free_phashes(phashes)
+	print("ahash: %i"% unsigned64(pihashes.ahash))
+	print("dhash: %i"% unsigned64(pihashes.dhash))
+	print("phash: %i"% unsigned64(pihashes.phash))
+	# print("ahash: %i"% unsigned64(lib.ext_get_ahash(lib_struct, image)))
+	# print("dhash: %i"% unsigned64(lib.ext_get_dhash(lib_struct, image)))
+	# print("phash: %i"% unsigned64(lib.ext_get_phash(lib_struct, image)))
 
 # Do cleanup
 # Makes sure that the heap is cleaned up

ffi/pihash.h

@@ -5,3 +5,4 @@ void ext_free();
 uint64_t ext_get_ahash(void *, const char *);
 uint64_t ext_get_dhash(void *, const char *);
 uint64_t ext_get_phash(void *, const char *);
+void *ext_get_phashes(void *, const char *);

src/lib.rs

@@ -56,7 +56,9 @@ impl<'a> PIHash<'a> {
     }
 
     pub fn get_phashes(&self, path: &'a Path) -> hash::PerceptualHashes {
-        hash::get_perceptual_hashes(path, &hash::Precision::Medium, &self.cache)
+        hash::get_perceptual_hashes(&path,
+                                    &hash::Precision::Medium,
+                                    &self.cache)
     }
 
 
@@ -128,7 +130,7 @@ pub extern "C" fn ext_get_ahash(lib: &PIHash, path_char: *const libc::c_char) ->
             }
         };
         let path = Path::new(&image_path);
-        lib.get_ahash(&path)
+        lib.get_ahash(path)
     }
 }
 
@@ -146,7 +148,7 @@ pub extern "C" fn ext_get_dhash(lib: &PIHash, path_char: *const libc::c_char) ->
             }
         };
         let path = Path::new(&image_path);
-        lib.get_dhash(&path)
+        lib.get_dhash(path)
     }
 }
 
@@ -164,10 +166,48 @@ pub extern "C" fn ext_get_phash(lib: &PIHash, path_char: *const libc::c_char) ->
             }
         };
         let path = Path::new(&image_path);
-        lib.get_phash(&path)
+        lib.get_phash(path)
     }
 }
 
+#[repr(C)]
+pub struct PIHashes {
+    ahash: libc::uint64_t,
+    dhash: libc::uint64_t,
+    phash: libc::uint64_t
+}
+
+#[no_mangle]
+pub extern "C" fn ext_get_phashes(lib: &PIHash, path_char: *const libc::c_char) -> * mut PIHashes {
+    unsafe {
+        let path_str = CStr::from_ptr(path_char);
+        let image_path = match path_str.to_str() {
+            Ok(result) => result,
+            Err(e) => {
+                println!("Error: {}. Unable to parse '{}'",
+                         e,
+                         to_hex_string(path_str.to_bytes()));
+                panic!("Unable to parse path")
+            }
+        };
+        let path = Path::new(&image_path);
+        let phashes = lib.get_phashes(path);
+        Box::into_raw(Box::new(PIHashes {
+            ahash: phashes.ahash,
+            dhash: phashes.dhash,
+            phash: phashes.phash
+        }))
+    }
+}
+
+#[no_mangle]
+pub extern "C" fn ext_free_phashes(raw_phashes: *const libc::c_void) {
+    unsafe {
+        drop(Box::from_raw(raw_phashes as *mut PIHashes));
+    }
+}
+
+
 fn to_hex_string(bytes: &[u8]) -> String {
     println!("length: {}", bytes.len());
     let mut strs: Vec<String> = Vec::new();