diff --git a/src/graph.c b/src/graph.c
index 5e1a096a..c0f5fb9d 100644
--- a/src/graph.c
+++ b/src/graph.c
@@ -110,13 +110,14 @@ graph_t *graph_read(FILE *f) {
         goto exit_graph_allocated;
     }
 
-    g->indptr = indptr;
-
     for (int i = 0; i < len_indptr; i++) {
         if (!file_read_uint32(f, indptr->a + i)) {
             goto exit_graph_allocated;
         }
     }
+    indptr->n = (size_t)len_indptr;
+
+    g->indptr = indptr;
 
     uint64_t len_indices;
 
@@ -129,13 +130,15 @@ graph_t *graph_read(FILE *f) {
         goto exit_graph_allocated;
     }
 
-    g->indices = indices;
-
     for (int i = 0; i < len_indices; i++) {
         if (!file_read_uint32(f, indices->a + i)) {
             goto exit_graph_allocated;
         }
     }
+
+    indices->n = (size_t)len_indices;
+
+    g->indices = indices;
     
     return g;
 
@@ -155,7 +158,7 @@ bool graph_write(graph_t *self, FILE *f) {
         return false;
     }
 
-    uint64_t len_indptr = self->indptr->n;
+    uint64_t len_indptr = (uint64_t)self->indptr->n;
 
     if (!file_write_uint64(f, len_indptr)) {
         return false;
diff --git a/src/sparse_matrix.c b/src/sparse_matrix.c
index 82246cd2..a884ef41 100644
--- a/src/sparse_matrix.c
+++ b/src/sparse_matrix.c
@@ -284,8 +284,6 @@ sparse_matrix_t *sparse_matrix_read(FILE *f) {
         goto exit_sparse_matrix_allocated;
     }
 
-    sp->indptr = indptr;
-
     for (int i = 0; i < len_indptr; i++) {
         if (!file_read_uint32(f, indptr->a + i)) {
             printf("indptr\n");
@@ -293,6 +291,9 @@ sparse_matrix_t *sparse_matrix_read(FILE *f) {
         }
     }
 
+    indptr->n = (size_t)len_indptr;
+    sp->indptr = indptr;
+
     uint64_t len_indices;
 
     if (!file_read_uint64(f, &len_indices)) {
@@ -306,8 +307,6 @@ sparse_matrix_t *sparse_matrix_read(FILE *f) {
         goto exit_sparse_matrix_allocated;
     }
 
-    sp->indices = indices;
-
     for (int i = 0; i < len_indices; i++) {
         if (!file_read_uint32(f, indices->a + i)) {
             printf("indices\n");
@@ -315,6 +314,9 @@ sparse_matrix_t *sparse_matrix_read(FILE *f) {
         }
     }
 
+    indices->n = (size_t)len_indices;
+    sp->indices = indices;
+
     uint64_t len_data;
 
     if (!file_read_uint64(f, &len_data)) {
@@ -328,8 +330,6 @@ sparse_matrix_t *sparse_matrix_read(FILE *f) {
         goto exit_sparse_matrix_allocated;
     }
 
-    sp->data = data;
-
     for (int i = 0; i < len_data; i++) {
         if (!file_read_double(f, data->a + i)) {
             printf("data\n");
@@ -337,6 +337,9 @@ sparse_matrix_t *sparse_matrix_read(FILE *f) {
         }
     }
 
+    data->n = (size_t)len_data;
+    sp->data = data;
+
     return sp;
 
 exit_sparse_matrix_allocated: