From 203fbb778e9cfe3aff8b4dee6da9a103a171ca0e Mon Sep 17 00:00:00 2001
From: dec05eba <dec05eba@protonmail.com>
Date: Fri, 28 Feb 2020 16:58:49 +0100
Subject: Update hash map comments

---
 README.md              |  2 ++
 include/std/hash_map.h |  1 +
 src/ir/ir.c            |  1 +
 src/std/file.c         |  4 ++++
 src/std/hash_map.c     | 11 +++++++++--
 5 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index 110709f..16f5252 100644
--- a/README.md
+++ b/README.md
@@ -68,6 +68,8 @@ All branch targets should be 16-byte aligned.
 ```
 * Reduce the number of branches by making memory allocation/reallocation throw instead of returning error.
 * Implement pub for imports and show compile error when using non-pub symbols in pub closures/structs/etc.
+* Use a list instead of a hash map for variable lookup, since the list will be small most of the time.
+* Optimize buffer_append by returning pre-allocated space which can be used directly, instead of adding data to a variable and then copying it to the buffer.
 # Documents
 Documents are located under doc. The file doc/Documentation.md is generated from source files by running doc/doc_extract.py
 but there is no need to run this script unless you are modifying documentation in the source.
diff --git a/include/std/hash_map.h b/include/std/hash_map.h
index 05755ce..19f97a2 100644
--- a/include/std/hash_map.h
+++ b/include/std/hash_map.h
@@ -12,6 +12,7 @@ typedef struct HashMap HashMap;
 typedef int(*HashMapCompare)(const void *a, const void *b);
 typedef usize(*HashMapHash)(const u8 *data, usize size);
 
+/* TODO: Optimize small hash maps by using the members of the struct instead of allocating on heap */
 struct HashMap {
     ArenaAllocator *allocator; /* borrowed */
     Buffer/*HashMapBucket*/ buckets;
diff --git a/src/ir/ir.c b/src/ir/ir.c
index 1ca154a..a6ed931 100644
--- a/src/ir/ir.c
+++ b/src/ir/ir.c
@@ -271,6 +271,7 @@ static CHECK_RESULT int ir_add_ins_form2(Ir *self, IrInstruction ins_type, IrReg
     ins_form_2.lhs = lhs;
     ins_form_2.rhs = rhs;
     amal_log_debug("r%d = r%d %s r%d", *result, lhs, binop_type_to_string(ins_type), rhs);
+    /* TODO: Store ins_type as an uint8_t instead of int */
     return_if_error(buffer_append(&self->instructions, &ins_type, 1));
     return buffer_append(&self->instructions, &ins_form_2, sizeof(ins_form_2));
 }
diff --git a/src/std/file.c b/src/std/file.c
index 84f4b0c..3ca94b0 100644
--- a/src/std/file.c
+++ b/src/std/file.c
@@ -176,6 +176,10 @@ typedef enum {
     OTHER
 } FileType;
 
+/*
+    TODO: Remove this and instead use fstat, and then read the file.
+    Otherwise this is not atomic and the file type can change between the calls
+*/
 static CHECK_RESULT int file_get_type(const char *filepath, FileType *type) {
     struct stat file_stats;
     if(stat(filepath, &file_stats) == -1) {
diff --git a/src/std/hash_map.c b/src/std/hash_map.c
index 234f3e3..b4bd4c1 100644
--- a/src/std/hash_map.c
+++ b/src/std/hash_map.c
@@ -3,8 +3,13 @@
 #include "../../include/std/mem.h"
 #include <assert.h>
 
+/* Basic hash map implementation */
+
 /*
-Basic hash map implementation. TODO: Improve performance
+    TODO: Improve performance. For example replace % with & by first making sure size of bucket is a power of two.
+    TODO: Instead of allocating space for the key, use the key data pointer and size directly.
+    TODO: Instead of allocating space for the data, allow the user to pass a pointer in the insert
+    method and use that directly.
 */
 
 #define HASH_MAP_INITIAL_SIZE 8
@@ -109,6 +114,7 @@ static void hash_map_reorder_nodes(HashMap *self, usize end_index) {
     usize bucket_size;
     usize index;
 
+    /* TODO: bucket_end should be the old capacity. There is no need to reorder the new buckets */
     bucket = (HashMapBucket*)self->buckets.data;
     bucket_end = ((HashMapBucket*)self->buckets.data) + end_index;
     bucket_size = buffer_get_size(&self->buckets, HashMapBucket);
@@ -177,6 +183,7 @@ int hash_map_insert(HashMap *self, BufferView key, void *value) {
     return 0;
 }
 
+/* TODO: Remove this. Use hash_map_get_ref instead */
 bool hash_map_get(HashMap *self, BufferView key, void *value) {
 #if 0
     usize bucket_size;
@@ -235,7 +242,7 @@ bool hash_map_get_ref(HashMap *self, BufferView key, void **value) {
 }
 
 bool hash_map_contains(HashMap *self, BufferView key) {
-    return hash_map_get(self, key, NULL);
+    return hash_map_get_ref(self, key, NULL);
 }
 
 #define MIN(a, b) ((a) < (b) ? (a) : (b))
-- 
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