From c318aae32ce5425e74bfd5b08d4eac419d72df1c Mon Sep 17 00:00:00 2001
From: Danila Fedorin <danila.fedorin@gmail.com>
Date: Mon, 5 Feb 2018 13:54:47 -0800
Subject: [PATCH] Implement a growing insertion.

---
 include/sprs.h | 10 ++++++++++
 src/main.c     | 28 ++++++++++++++++++++++++----
 src/sprs.c     | 29 +++++++++++++++++++++++++++++
 3 files changed, 63 insertions(+), 4 deletions(-)

diff --git a/include/sprs.h b/include/sprs.h
index c7b1714..3435251 100644
--- a/include/sprs.h
+++ b/include/sprs.h
@@ -95,6 +95,16 @@ void sprs_free(sprs* sprs);
  * @param data the value to store.
  */
 void sprs_put(sprs* sprs, size_t index, void* data);
+/**
+ * Stores a value in the sparse set under a given index.
+ * If the capacity of the sparse set is smaller than the given index,
+ * this grows the sparse set by doubling its size.
+ * @param sprs the sparse set into which to store the value.
+ * @param index the index at which to store the value.
+ * @param data the value to store.
+ * @return LIBDS_SUCCESS if all goes well, or LIBDS_MALLOC if the growing failed.
+ */
+libds_result sprs_put_grow(sprs* sprs, size_t index, void* data);
 /**
  * Checks if the sparse set contains data under a given index.
  * @param sprs the sparse set to check.
diff --git a/src/main.c b/src/main.c
index b1a1f47..8463d1e 100644
--- a/src/main.c
+++ b/src/main.c
@@ -297,6 +297,26 @@ int test_sprs_put(){
   return return_code;
 }
 
+int test_sprs_put_grow(){
+  char* test_string_one = "test 1";
+  char* test_string_two = "test 2";
+  int return_code = 1;
+  sprs sprs;
+  sprs_init(&sprs);
+  sprs_setup(&sprs, 2);
+  sprs_put_grow(&sprs, 1, test_string_one);
+  return_code &= sprs.dense[0] == 1 && sprs.sparse[1].index == 0 && sprs.sparse[1].data == test_string_one;
+  return_code &= sprs.capacity == 2;
+  sprs_put_grow(&sprs, 3, test_string_two);
+  return_code &= sprs.dense[1] == 3 && sprs.sparse[3].index == 1 && sprs.sparse[3].data == test_string_two;
+  return_code &= sprs.capacity == 4;
+  sprs_put_grow(&sprs, 12, test_string_one);
+  return_code &= sprs.dense[2] == 12 && sprs.sparse[12].index == 2 && sprs.sparse[12].data == test_string_one;
+  return_code &= sprs.capacity == 16;
+  sprs_free(&sprs);
+  return return_code;
+}
+
 int test_sprs_contains(){
   int return_code;
   sprs sprs;
@@ -357,14 +377,14 @@ int run_test(char* test_name, int (*test_func)()) {
 }
 
 int main(int argc, char** argv) {
-  char* test_names[26] = {"vec_basic",   "vec_add",   "vec_remove", "vec_find",
+  char* test_names[27] = {"vec_basic",   "vec_add",   "vec_remove", "vec_find",
                           "vec_foreach", "vec_index", "vec_clear", "ht_basic",   "ht_put",
-                          "ht_get",      "ht_remove", "ht_foreach", "ll_basic", "ll_append", "ll_prepend", "ll_remove", "ll_find" , "ll_foreach", "ll_pophead", "ll_poptail", "sprs_basic", "sprs_put", "sprs_contains", "sprs_get", "sprs_find", "sprs_foreach"};
+                          "ht_get",      "ht_remove", "ht_foreach", "ll_basic", "ll_append", "ll_prepend", "ll_remove", "ll_find" , "ll_foreach", "ll_pophead", "ll_poptail", "sprs_basic", "sprs_put", "sprs_put_grow", "sprs_contains", "sprs_get", "sprs_find", "sprs_foreach"};
 
-  int (*test_functions[26])() = {
+  int (*test_functions[27])() = {
       test_vec_basic,   test_vec_add,   test_vec_remove, test_vec_find,
       test_vec_foreach, test_vec_index, test_vec_clear, test_ht_basic,   test_ht_put,
-      test_ht_get,      test_ht_remove, test_ht_foreach, test_ll_basic, test_ll_append, test_ll_prepend, test_ll_remove, test_ll_find, test_ll_foreach, test_ll_pophead, test_ll_poptail, test_sprs_basic, test_sprs_put, test_sprs_contains, test_sprs_get, test_sprs_find, test_sprs_foreach};
+      test_ht_get,      test_ht_remove, test_ht_foreach, test_ll_basic, test_ll_append, test_ll_prepend, test_ll_remove, test_ll_find, test_ll_foreach, test_ll_pophead, test_ll_poptail, test_sprs_basic, test_sprs_put, test_sprs_put_grow, test_sprs_contains, test_sprs_get, test_sprs_find, test_sprs_foreach};
 
   int test_index = 0;
   int result = 1;
diff --git a/src/sprs.c b/src/sprs.c
index 5939e0c..fc7c62b 100644
--- a/src/sprs.c
+++ b/src/sprs.c
@@ -41,6 +41,35 @@ void sprs_put(sprs* sprs, size_t index, void* data){
     }
   }
 }
+libds_result sprs_put_grow(sprs* sprs, size_t index, void* data) {
+  libds_result result = LIBDS_SUCCESS;
+  if(!sprs_contains(sprs, index) && (index >= sprs->capacity || sprs->size >= sprs->capacity)) {
+    int increase_required = 0;
+    size_t ratio = index / sprs->capacity;
+    size_t new_size;
+    void* new_sparse;
+    void* new_dense;
+    while(ratio >>= 1) {
+      increase_required++;
+    }
+    new_size = sprs->capacity * (1 << (increase_required + 1));
+    new_sparse = realloc(sprs->sparse, sizeof(*(sprs->sparse)) * new_size);
+    new_dense = realloc(sprs->dense, sizeof(*(sprs->dense)) * new_size);
+    if(new_sparse == NULL || new_dense == NULL){
+      free(new_sparse);
+      free(new_dense);
+      result = LIBDS_MALLOC;
+    } else {
+      sprs->sparse = new_sparse;
+      sprs->dense = new_dense;
+      sprs->capacity = new_size;
+    }
+  }
+  if(result == LIBDS_SUCCESS) {
+    sprs_put(sprs, index, data);
+  }
+  return result;
+}
 int sprs_contains(sprs* sprs, size_t index){
   return sprs->sparse[index].index < sprs->size && sprs->dense[sprs->sparse[index].index] == index;
 }