Implement a sparse array / set.

src/sprs.c

@@ -0,0 +1,70 @@
+#include "sprs.h"
+#include <stdlib.h>
+
+void sprs_init(sprs* sprs){
+  sprs->capacity = 0;
+  sprs->size = 0;
+  sprs->dense = NULL;
+  sprs->sparse = NULL;
+}
+libds_result sprs_setup(sprs* sprs, int size){
+  libds_result result = LIBDS_SUCCESS;
+  sprs->sparse = malloc(sizeof(*(sprs->sparse)) * size);
+  sprs->dense = malloc(sizeof(*(sprs->dense)) * size);
+  if(sprs->sparse == NULL || sprs->dense == NULL){
+    free(sprs->sparse);
+    free(sprs->dense);
+    result = LIBDS_MALLOC;
+  } else {
+    sprs->capacity = size;
+  }
+  return result;
+}
+void sprs_free(sprs* sprs){
+  free(sprs->sparse);
+  free(sprs->dense);
+  sprs->capacity = 0;
+  sprs->size = 0;
+  sprs->dense = NULL;
+  sprs->sparse = NULL;
+}
+void sprs_put(sprs* sprs, int index, void* data){
+  if(index < sprs->capacity && sprs->size < sprs->capacity){
+    sprs->dense[sprs->size++] = index;
+    sprs->sparse[index].index = sprs->size - 1;
+    sprs->sparse[index].data = data;
+  }
+}
+int sprs_contains(sprs* sprs, int index){
+  return sprs->sparse[index].index < sprs->size && sprs->dense[sprs->sparse[index].index] == index;
+}
+void* sprs_get(sprs* sprs, int index){
+  void* data = NULL;
+  if(sprs_contains(sprs, index)){
+    data = sprs->sparse[index].data;
+  }
+  return data;
+}
+void* sprs_find(sprs* sprs, void* data, compare_func compare){
+  int index = 0;
+  void* to_return = NULL;
+  for(; index < sprs->size && to_return == NULL; index++){
+    if(compare(data, sprs->sparse[sprs->dense[index]].data)) {
+      to_return = sprs->sparse[sprs->dense[index]].data;
+    }
+  }
+  return to_return;
+}
+int sprs_foreach(sprs* sprs, void* data, compare_func compare, foreach_func foreach, ...){
+  int index = 0;
+  int return_code = 0;
+  va_list args;
+  for(; index < sprs->size && return_code == 0; index++){
+    if(compare(data, sprs->sparse[sprs->dense[index]].data)) {
+      va_start(args, foreach);
+      return_code = foreach(sprs->sparse[sprs->dense[index]].data, args);
+      va_end(args);
+    }
+  }
+  return return_code;
+}