From 640bf57b604b015d11c8e836df1c6001ab0c870f Mon Sep 17 00:00:00 2001
From: Max Wash <mbswash@gmail.com>
Date: Fri, 11 Apr 2025 13:55:36 +0100
Subject: [PATCH] object: add b_string_substr

---
 object/include/blue/object/string.h |  2 +-
 object/string.c                     | 22 ++++++++++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/object/include/blue/object/string.h b/object/include/blue/object/string.h
index 9b1a813..9c23086 100644
--- a/object/include/blue/object/string.h
+++ b/object/include/blue/object/string.h
@@ -37,7 +37,6 @@ BLUE_API b_status b_string_replace_all(b_string *str, const char *new_data);
 BLUE_API void b_string_append_s(b_string *dest, const b_string *src);
 BLUE_API void b_string_append_cstr(b_string *dest, const char *src);
 BLUE_API void b_string_append_cstrf(b_string *dest, const char *format, ...);
-BLUE_API void b_string_prepend_s(b_string *dest, const b_string *src);
 BLUE_API void b_string_prepend_cstr(b_string *dest, const char *src);
 BLUE_API void b_string_prepend_cstrf(b_string *dest, const char *format, ...);
 BLUE_API void b_string_insert_s(b_string *dest, const b_string *src, size_t at);
@@ -57,6 +56,7 @@ BLUE_API char b_string_back(const b_string *str);
 BLUE_API void b_string_pop_back(b_string *str);
 
 BLUE_API const char *b_string_ptr(const b_string *str);
+BLUE_API b_string *b_string_substr(const b_string *str, size_t start, size_t len);
 
 BLUE_API char *b_strdup(const char *s);
 BLUE_API size_t b_strlen(const char *s, b_strlen_flags flags);
diff --git a/object/string.c b/object/string.c
index d662ece..e1ab6e0 100644
--- a/object/string.c
+++ b/object/string.c
@@ -365,6 +365,28 @@ const char *b_string_ptr(const struct b_string *str)
 	return str->s_data.d_external;
 }
 
+struct b_string *b_string_substr(const struct b_string *str, size_t start, size_t len)
+{
+	if (start > b_string_get_size(str, B_STRLEN_NORMAL)) {
+		return NULL;
+	}
+
+	if (start + len > b_string_get_size(str, B_STRLEN_NORMAL)) {
+		len = b_string_get_size(str, B_STRLEN_NORMAL) - start;
+	}
+
+	struct b_string *newstr = b_string_create();
+	b_string_reserve(newstr, len);
+
+	const char *src = b_string_ptr(str) + start;
+	char *dest = string_ptr(newstr);
+
+	memcpy(dest, src, len);
+	newstr->s_len = len;
+
+	return newstr;
+}
+
 static void string_release(struct b_object *obj)
 {
 	struct b_string *str = B_STRING(obj);