From 52cdc7d36bd7089701e614c1622e3306f1a13ef7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Nils=20O=2E=20Sel=C3=A5sdal?= <nos@utel.tech>
Date: Fri, 31 Jul 2026 18:03:17 +0200
Subject: [PATCH] Bugfixes

---
 src/main.c   | 10 +++++-----
 src/string.c | 32 +++++++++++++++++++++-----------
 src/string.h |  2 +-
 3 files changed, 27 insertions(+), 17 deletions(-)

diff --git a/src/main.c b/src/main.c
index 63c6aa4..b486db5 100644
--- a/src/main.c
+++ b/src/main.c
@@ -433,7 +433,7 @@ void string_split_test_1(void)
 {
     TRACEF("\n");
 
-    Str str1 = S("a:bb|ccc");
+    Str str1 = S("|a:bb|ccc|");
     Str sep = S("|:");
     STRVEC_DEFINE(strings, 16);
 
@@ -470,13 +470,13 @@ void string_test_misc(void)
     Str str4_trim = str_ascii_trim(str4);
     printf("str4_trim: '%.*s'\n", str4_trim.len, str4_trim.str);
 
-    S64 found = str_substr(str1, S("World"));
+    S64 found = str_index(str1, S("World"));
     printf("1. found %ld\n", found);
-    found = str_substr(str_empty(), S("World"));
+    found = str_index(str_empty(), S("World"));
     printf("2. found %ld\n", found);
-    found = str_substr(str_empty(), S(""));
+    found = str_index(str_empty(), S(""));
     printf("3. found %ld\n", found);
-    found = str_substr(str1, S(" "));
+    found = str_index(str1, S(" "));
     printf("4. found %ld\n", found);
 
 }
diff --git a/src/string.c b/src/string.c
index d8a88d4..ad11d54 100644
--- a/src/string.c
+++ b/src/string.c
@@ -9,8 +9,8 @@ Str str_empty(void)
 
 Str str_slice(Str str, U32 start, U32 len)
 {
-    Assert(start < str.len);
-    Assert(len <= str.len);
+    Assert(start <= str.len);
+    Assert(len <= str.len - start);
 
     Str new_str = str_create(&str.str[start], len);
     return new_str;
@@ -78,15 +78,18 @@ Str str_ascii_trim(Str str)
     return new_str;
 }
 
-S64 str_substr(Str haystack, Str needle)
+S64 str_index(Str haystack, Str needle)
 {
     if (needle.len == 0) {
         return 0;
     }
 
-    if (needle.len == 0) {
+    if (needle.len == 1) {
         return str_find_byte(haystack, needle.str[0]);
     }
+    if (needle.len > haystack.len) {
+        return -1;
+    }
 
     U8 *found = MemFind(haystack.str, haystack.len, needle.str, needle.len);
     if (found != NULL) {
@@ -117,7 +120,7 @@ void str_split(Str str, Str separators, StrVec *vec)
             start_pos = i + 1;
         }
     }
-    if (start_pos < str.len && vec->len < vec->max_len) {
+    if (start_pos <= str.len && vec->len < vec->max_len) {
         Str sub_str = str_slice(str, start_pos, str.len - start_pos);
         vec->strings[vec->len] = sub_str;
         vec->len++;
@@ -127,21 +130,28 @@ void str_split(Str str, Str separators, StrVec *vec)
 Str str_join(Allocator *allocator, StrVec strings, Str separator)
 {
 
-    U32 str_len = 0;
+    U32 joined_str_len = 0;
 
     for (U32 i = 0; i < strings.len; i++) {
-        str_len += strings.strings[i].len;
+        U32 part_len = strings.strings[i].len;
+        Assert(joined_str_len <= U32_Max - part_len); // overflow
+        joined_str_len += part_len;
     }
-    if (strings.len > 0) {
-        str_len += separator.len * (strings.len - 1);
+    if (strings.len > 1) {
+        U32 separator_count = strings.len - 1;
+        Assert(separator.len <= U32_Max / separator_count); // overflow
+        Assert(joined_str_len <= U32_Max - separator.len * separator_count); // overflow
+        joined_str_len += separator.len * separator_count;
     }
 
-    U8 *joined_str = allocator_push(allocator, str_len, 1);
+    U8 *joined_str = allocator_push(allocator, joined_str_len, 1);
     if (strings.len > 0) {
         U32 pos = 0;
         Str *str = &strings.strings[0];
+
         MemCopy(&joined_str[pos], str->str, str->len);
         pos += str->len;
+
         for (U32 i = 1; i < strings.len; i++) {
             str = &strings.strings[i];
             MemCopy(&joined_str[pos], separator.str, separator.len);
@@ -151,5 +161,5 @@ Str str_join(Allocator *allocator, StrVec strings, Str separator)
         }
     }
 
-    return str_create(joined_str, str_len);
+    return str_create(joined_str, joined_str_len);
 }
diff --git a/src/string.h b/src/string.h
index f9bb00c..1b998bd 100644
--- a/src/string.h
+++ b/src/string.h
@@ -9,7 +9,7 @@ struct Str {
 
 Str str_empty(void);
 Str str_slice(Str str, U32 start, U32 len);
-S64 str_substr(Str haystack, Str needle);
+S64 str_index(Str haystack, Str needle);
 
 Str str_concat(Allocator *alloc, Str first, Str second);
 Str str_push(Allocator *alloc, Str str);