diff --git a/src/algorithms/linear_congruential_gen.c b/src/algorithms/linear_congruential_gen.c
index d16a01b..e5a0705 100644
--- a/src/algorithms/linear_congruential_gen.c
+++ b/src/algorithms/linear_congruential_gen.c
@@ -1,11 +1,11 @@
 // ISC License
-// 
+//
 // Copyright (c) 2024 Stephen Seo
-// 
+//
 // Permission to use, copy, modify, and/or distribute this software for any
 // purpose with or without fee is hereby granted, provided that the above
 // copyright notice and this permission notice appear in all copies.
-// 
+//
 // THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
 // REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 // AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
diff --git a/src/algorithms/linear_congruential_gen.h b/src/algorithms/linear_congruential_gen.h
index a9b63f1..93714f3 100644
--- a/src/algorithms/linear_congruential_gen.h
+++ b/src/algorithms/linear_congruential_gen.h
@@ -1,11 +1,11 @@
 // ISC License
-// 
+//
 // Copyright (c) 2024 Stephen Seo
-// 
+//
 // Permission to use, copy, modify, and/or distribute this software for any
 // purpose with or without fee is hereby granted, provided that the above
 // copyright notice and this permission notice appear in all copies.
-// 
+//
 // THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
 // REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 // AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
diff --git a/src/archiver.c b/src/archiver.c
index 0b30f3d..c35b676 100644
--- a/src/archiver.c
+++ b/src/archiver.c
@@ -1,11 +1,11 @@
 // ISC License
-// 
+//
 // Copyright (c) 2024 Stephen Seo
-// 
+//
 // Permission to use, copy, modify, and/or distribute this software for any
 // purpose with or without fee is hereby granted, provided that the above
 // copyright notice and this permission notice appear in all copies.
-// 
+//
 // THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
 // REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 // AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
diff --git a/src/archiver.h b/src/archiver.h
index 9299291..b8b035a 100644
--- a/src/archiver.h
+++ b/src/archiver.h
@@ -1,11 +1,11 @@
 // ISC License
-// 
+//
 // Copyright (c) 2024 Stephen Seo
-// 
+//
 // Permission to use, copy, modify, and/or distribute this software for any
 // purpose with or without fee is hereby granted, provided that the above
 // copyright notice and this permission notice appear in all copies.
-// 
+//
 // THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
 // REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 // AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
diff --git a/src/data_structures/hash_map.c b/src/data_structures/hash_map.c
index 68d91f6..001c2ec 100644
--- a/src/data_structures/hash_map.c
+++ b/src/data_structures/hash_map.c
@@ -1,11 +1,11 @@
 // ISC License
-// 
+//
 // Copyright (c) 2024 Stephen Seo
-// 
+//
 // Permission to use, copy, modify, and/or distribute this software for any
 // purpose with or without fee is hereby granted, provided that the above
 // copyright notice and this permission notice appear in all copies.
-// 
+//
 // THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
 // REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 // AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
@@ -36,6 +36,12 @@ typedef struct SDArchiverHashMapKeyData {
   unsigned int key_size;
 } SDArchiverHashMapKeyData;
 
+typedef struct SDArchiverInternalIterContext {
+  int (*iter_check_fn)(void *, unsigned int, void *, void *);
+  int ret;
+  void *user_data;
+} SDArchiverInternalIterContext;
+
 void simple_archiver_hash_map_internal_cleanup_data(void *data) {
   SDArchiverHashMapData *hash_map_data = data;
   if (hash_map_data->value) {
@@ -248,3 +254,32 @@ int simple_archiver_hash_map_remove(SDArchiverHashMap *hash_map, void *key,
     return 2;
   }
 }
+
+int simple_archiver_internal_hash_map_bucket_iter_fn(void *data, void *ud) {
+  SDArchiverHashMapData *hash_map_data = data;
+  SDArchiverInternalIterContext *ctx = ud;
+
+  ctx->ret = ctx->iter_check_fn(hash_map_data->key, hash_map_data->key_size,
+                                hash_map_data->value, ctx->user_data);
+  if (ctx->ret != 0) {
+    return 1;
+  } else {
+    return 0;
+  }
+}
+
+int simple_archiver_hash_map_iter(const SDArchiverHashMap *hash_map,
+                                  int (*iter_check_fn)(void *, unsigned int,
+                                                       void *, void *),
+                                  void *user_data) {
+  SDArchiverInternalIterContext ctx;
+  ctx.iter_check_fn = iter_check_fn;
+  ctx.ret = 0;
+  ctx.user_data = user_data;
+  for (unsigned int idx = 0; idx < hash_map->buckets_size; ++idx) {
+    simple_archiver_list_get(hash_map->buckets[idx],
+                             simple_archiver_internal_hash_map_bucket_iter_fn,
+                             &ctx);
+  }
+  return ctx.ret;
+}
diff --git a/src/data_structures/hash_map.h b/src/data_structures/hash_map.h
index 60f1524..5691249 100644
--- a/src/data_structures/hash_map.h
+++ b/src/data_structures/hash_map.h
@@ -1,11 +1,11 @@
 // ISC License
-// 
+//
 // Copyright (c) 2024 Stephen Seo
-// 
+//
 // Permission to use, copy, modify, and/or distribute this software for any
 // purpose with or without fee is hereby granted, provided that the above
 // copyright notice and this permission notice appear in all copies.
-// 
+//
 // THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
 // REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 // AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
@@ -53,4 +53,15 @@ void *simple_archiver_hash_map_get(SDArchiverHashMap *hash_map, void *key,
 int simple_archiver_hash_map_remove(SDArchiverHashMap *hash_map, void *key,
                                     unsigned int key_size);
 
+/// Iterates through the hash map with the "iter_check_fn", which is passed the
+/// key, key-size, value, and user_data. This function will call "iter_check_fn"
+/// on every entry in the given hash_map. If "iter_check_fn" returns non-zero,
+/// iteration will halt and this function will return the same value. If
+/// "iter_check_fn" returns zero for every call, then this function will return
+/// zero after having iterated through every key-value pair.
+int simple_archiver_hash_map_iter(const SDArchiverHashMap *hash_map,
+                                  int (*iter_check_fn)(void *, unsigned int,
+                                                       void *, void *),
+                                  void *user_data);
+
 #endif
diff --git a/src/data_structures/linked_list.c b/src/data_structures/linked_list.c
index a37bd1f..475ca2b 100644
--- a/src/data_structures/linked_list.c
+++ b/src/data_structures/linked_list.c
@@ -1,11 +1,11 @@
 // ISC License
-// 
+//
 // Copyright (c) 2024 Stephen Seo
-// 
+//
 // Permission to use, copy, modify, and/or distribute this software for any
 // purpose with or without fee is hereby granted, provided that the above
 // copyright notice and this permission notice appear in all copies.
-// 
+//
 // THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
 // REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 // AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
diff --git a/src/data_structures/linked_list.h b/src/data_structures/linked_list.h
index 0c38135..7471b18 100644
--- a/src/data_structures/linked_list.h
+++ b/src/data_structures/linked_list.h
@@ -1,11 +1,11 @@
 // ISC License
-// 
+//
 // Copyright (c) 2024 Stephen Seo
-// 
+//
 // Permission to use, copy, modify, and/or distribute this software for any
 // purpose with or without fee is hereby granted, provided that the above
 // copyright notice and this permission notice appear in all copies.
-// 
+//
 // THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
 // REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 // AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
diff --git a/src/data_structures/priority_heap.c b/src/data_structures/priority_heap.c
index ea9f41e..c7b179f 100644
--- a/src/data_structures/priority_heap.c
+++ b/src/data_structures/priority_heap.c
@@ -1,11 +1,11 @@
 // ISC License
-// 
+//
 // Copyright (c) 2024 Stephen Seo
-// 
+//
 // Permission to use, copy, modify, and/or distribute this software for any
 // purpose with or without fee is hereby granted, provided that the above
 // copyright notice and this permission notice appear in all copies.
-// 
+//
 // THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
 // REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 // AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
diff --git a/src/data_structures/priority_heap.h b/src/data_structures/priority_heap.h
index f0413cd..8e9e303 100644
--- a/src/data_structures/priority_heap.h
+++ b/src/data_structures/priority_heap.h
@@ -1,11 +1,11 @@
 // ISC License
-// 
+//
 // Copyright (c) 2024 Stephen Seo
-// 
+//
 // Permission to use, copy, modify, and/or distribute this software for any
 // purpose with or without fee is hereby granted, provided that the above
 // copyright notice and this permission notice appear in all copies.
-// 
+//
 // THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
 // REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 // AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
diff --git a/src/data_structures/test.c b/src/data_structures/test.c
index 6dc9e00..cd0ab51 100644
--- a/src/data_structures/test.c
+++ b/src/data_structures/test.c
@@ -1,11 +1,11 @@
 // ISC License
-// 
+//
 // Copyright (c) 2024 Stephen Seo
-// 
+//
 // Permission to use, copy, modify, and/or distribute this software for any
 // purpose with or without fee is hereby granted, provided that the above
 // copyright notice and this permission notice appear in all copies.
-// 
+//
 // THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
 // REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 // AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
@@ -63,6 +63,19 @@ int get_three_fn(void *data, __attribute__((unused)) void *ud) {
 
 int more_fn(long long a, long long b) { return a > b ? 1 : 0; }
 
+int hash_map_iter_check_fn(__attribute__((unused)) void *key,
+                           __attribute__((unused)) unsigned int key_size,
+                           void *value, void *ud) {
+  char *found_buf = ud;
+  size_t real_value = (size_t)value;
+  if (real_value < 5) {
+    found_buf[real_value] += 1;
+    return 0;
+  } else {
+    return 1;
+  }
+}
+
 int main(void) {
   // Test LinkedList.
   {
@@ -166,6 +179,27 @@ int main(void) {
                                       sizeof(unsigned int), NULL, NULL);
     }
     simple_archiver_hash_map_free(&hash_map);
+
+    // Hash map iter test.
+    hash_map = simple_archiver_hash_map_init();
+
+    for (size_t idx = 0; idx < 5; ++idx) {
+      simple_archiver_hash_map_insert(&hash_map, (void *)idx, &idx,
+                                      sizeof(size_t), no_free_fn, no_free_fn);
+    }
+
+    char found[5] = {0, 0, 0, 0, 0};
+
+    CHECK_TRUE(simple_archiver_hash_map_iter(hash_map, hash_map_iter_check_fn,
+                                             found) == 0);
+
+    CHECK_TRUE(found[0] == 1);
+    CHECK_TRUE(found[1] == 1);
+    CHECK_TRUE(found[2] == 1);
+    CHECK_TRUE(found[3] == 1);
+    CHECK_TRUE(found[4] == 1);
+
+    simple_archiver_hash_map_free(&hash_map);
   }
 
   // Test PriorityHeap.
diff --git a/src/helpers.c b/src/helpers.c
index 4954e21..828faf0 100644
--- a/src/helpers.c
+++ b/src/helpers.c
@@ -1,11 +1,11 @@
 // ISC License
-// 
+//
 // Copyright (c) 2024 Stephen Seo
-// 
+//
 // Permission to use, copy, modify, and/or distribute this software for any
 // purpose with or without fee is hereby granted, provided that the above
 // copyright notice and this permission notice appear in all copies.
-// 
+//
 // THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
 // REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 // AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
diff --git a/src/helpers.h b/src/helpers.h
index 42c1867..3181370 100644
--- a/src/helpers.h
+++ b/src/helpers.h
@@ -1,11 +1,11 @@
 // ISC License
-// 
+//
 // Copyright (c) 2024 Stephen Seo
-// 
+//
 // Permission to use, copy, modify, and/or distribute this software for any
 // purpose with or without fee is hereby granted, provided that the above
 // copyright notice and this permission notice appear in all copies.
-// 
+//
 // THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
 // REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 // AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
diff --git a/src/main.c b/src/main.c
index 1234d20..fef432f 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1,11 +1,11 @@
 // ISC License
-// 
+//
 // Copyright (c) 2024 Stephen Seo
-// 
+//
 // Permission to use, copy, modify, and/or distribute this software for any
 // purpose with or without fee is hereby granted, provided that the above
 // copyright notice and this permission notice appear in all copies.
-// 
+//
 // THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
 // REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 // AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
diff --git a/src/parser.c b/src/parser.c
index 9286230..70ec84b 100644
--- a/src/parser.c
+++ b/src/parser.c
@@ -1,11 +1,11 @@
 // ISC License
-// 
+//
 // Copyright (c) 2024 Stephen Seo
-// 
+//
 // Permission to use, copy, modify, and/or distribute this software for any
 // purpose with or without fee is hereby granted, provided that the above
 // copyright notice and this permission notice appear in all copies.
-// 
+//
 // THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
 // REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 // AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
diff --git a/src/parser.h b/src/parser.h
index 3548f24..9d7017c 100644
--- a/src/parser.h
+++ b/src/parser.h
@@ -1,11 +1,11 @@
 // ISC License
-// 
+//
 // Copyright (c) 2024 Stephen Seo
-// 
+//
 // Permission to use, copy, modify, and/or distribute this software for any
 // purpose with or without fee is hereby granted, provided that the above
 // copyright notice and this permission notice appear in all copies.
-// 
+//
 // THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
 // REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 // AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
diff --git a/src/parser_internal.h b/src/parser_internal.h
index 229db22..4741abb 100644
--- a/src/parser_internal.h
+++ b/src/parser_internal.h
@@ -1,11 +1,11 @@
 // ISC License
-// 
+//
 // Copyright (c) 2024 Stephen Seo
-// 
+//
 // Permission to use, copy, modify, and/or distribute this software for any
 // purpose with or without fee is hereby granted, provided that the above
 // copyright notice and this permission notice appear in all copies.
-// 
+//
 // THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
 // REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 // AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
diff --git a/src/platforms.h b/src/platforms.h
index d8614c4..f08e4ac 100644
--- a/src/platforms.h
+++ b/src/platforms.h
@@ -1,11 +1,11 @@
 // ISC License
-// 
+//
 // Copyright (c) 2024 Stephen Seo
-// 
+//
 // Permission to use, copy, modify, and/or distribute this software for any
 // purpose with or without fee is hereby granted, provided that the above
 // copyright notice and this permission notice appear in all copies.
-// 
+//
 // THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
 // REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 // AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
diff --git a/src/test.c b/src/test.c
index d97cd84..1dcd93c 100644
--- a/src/test.c
+++ b/src/test.c
@@ -1,11 +1,11 @@
 // ISC License
-// 
+//
 // Copyright (c) 2024 Stephen Seo
-// 
+//
 // Permission to use, copy, modify, and/or distribute this software for any
 // purpose with or without fee is hereby granted, provided that the above
 // copyright notice and this permission notice appear in all copies.
-// 
+//
 // THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
 // REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 // AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,