support both old and new fastText model

continuous_integration/travis/flake8_diff.sh

@@ -133,6 +133,6 @@ check_files() {
 if [[ "$MODIFIED_FILES" == "no_match" ]]; then
     echo "No file has been modified"
 else
-    check_files "$(echo "$MODIFIED_FILES" )" "--ignore=E501,E731,E12,W503 --exclude=*.sh,*.md,*.yml,*.rst,*.ipynb"
+    check_files "$(echo "$MODIFIED_FILES" )" "--ignore=E501,E731,E12,W503 --exclude=*.sh,*.md,*.yml,*.rst,*.ipynb,*.vec"
 fi
 echo -e "No problem detected by flake8\n"

gensim/models/wrappers/fasttext.py

@@ -42,6 +42,8 @@
 
 logger = logging.getLogger(__name__)
 
+FASTTEXT_FILEFORMAT_MAGIC = 793712314
+
 
 class FastTextKeyedVectors(KeyedVectors):
     """
@@ -257,7 +259,15 @@ def load_binary_data(self, model_binary_file, encoding='utf8'):
             self.load_vectors(f)
 
     def load_model_params(self, file_handle):
-        (dim, ws, epoch, minCount, neg, _, loss, model, bucket, minn, maxn, _, t) = self.struct_unpack(file_handle, '@12i1d')
+        magic, version = self.struct_unpack(file_handle, '@2i')
+        if magic == FASTTEXT_FILEFORMAT_MAGIC:  # newer format
+            self.new_format = True
+            dim, ws, epoch, minCount, neg, _, loss, model, bucket, minn, maxn, _, t = self.struct_unpack(file_handle, '@12i1d')
+        else:  # older format
+            self.new_format = False
+            dim = magic
+            ws = version
+            epoch, minCount, neg, _, loss, model, bucket, minn, maxn, _, t = self.struct_unpack(file_handle, '@10i1d')
         # Parameters stored by [Args::save](https://github.com/facebookresearch/fastText/blob/master/src/args.cc)
         self.vector_size = dim
         self.window = ws
@@ -272,11 +282,13 @@ def load_model_params(self, file_handle):
         self.sample = t
 
     def load_dict(self, file_handle, encoding='utf8'):
-        (vocab_size, nwords, _) = self.struct_unpack(file_handle, '@3i')
+        vocab_size, nwords, _ = self.struct_unpack(file_handle, '@3i')
         # Vocab stored by [Dictionary::save](https://github.com/facebookresearch/fastText/blob/master/src/dictionary.cc)
         assert len(self.wv.vocab) == nwords, 'mismatch between vocab sizes'
         assert len(self.wv.vocab) == vocab_size, 'mismatch between vocab sizes'
-        ntokens, = self.struct_unpack(file_handle, '@q')
+        self.struct_unpack(file_handle, '@1q') # number of tokens 
+        if self.new_format:
+            pruneidx_size, = self.struct_unpack(file_handle, '@q')
         for i in range(nwords):
             word_bytes = b''
             char_byte = file_handle.read(1)
@@ -285,12 +297,17 @@ def load_dict(self, file_handle, encoding='utf8'):
                 word_bytes += char_byte
                 char_byte = file_handle.read(1)
             word = word_bytes.decode(encoding)
-            count, _ = self.struct_unpack(file_handle, '@ib')
-            _ = self.struct_unpack(file_handle, '@i')
+            count, _ = self.struct_unpack(file_handle, '@qb')
             assert self.wv.vocab[word].index == i, 'mismatch between gensim word index and fastText word index'
             self.wv.vocab[word].count = count
 
+        if self.new_format:
+            for j in range(pruneidx_size):
+                self.struct_unpack(file_handle, '@2i')
+
     def load_vectors(self, file_handle):
+        if self.new_format:
+            self.struct_unpack(file_handle, '@?')  # bool quant_input in fasttext.cc
         num_vectors, dim = self.struct_unpack(file_handle, '@2q')
         # Vectors stored by [Matrix::save](https://github.com/facebookresearch/fastText/blob/master/src/matrix.cc)
         assert self.vector_size == dim, 'mismatch between model sizes'