From 0875f206cbafa4c8f963a32da4b7b9e022f19670 Mon Sep 17 00:00:00 2001
From: Ivar Fatland <fatland99@hotmail.com>
Date: Sat, 6 Dec 2025 22:27:20 +0100
Subject: [PATCH] add substring

---
 cig.h            |  1 +
 string_builder.c | 57 +++++++++++++++++++++++++++---------------------
 2 files changed, 33 insertions(+), 25 deletions(-)

diff --git a/cig.h b/cig.h
index 0b0f851..5bb6b0d 100644
--- a/cig.h
+++ b/cig.h
@@ -273,6 +273,7 @@ void sb_add_u64(string_builder_t *this, uint64_t u64);
 void sb_add_u32(string_builder_t *this, uint32_t u32);
 void sb_add_u16(string_builder_t *this, uint16_t u16);
 void sb_add_u8(string_builder_t *this, uint8_t u8);
+void sb_add_substring(string_builder_t *this, const char *string, size_t substring_length);
 const char *sb_build(string_builder_t *this, allocator_t output_allocator);
 
 #ifdef CIG_IMPL
diff --git a/string_builder.c b/string_builder.c
index 7e7d780..a50edc7 100644
--- a/string_builder.c
+++ b/string_builder.c
@@ -27,60 +27,67 @@ void sb_add_string(string_builder_t *this, const char *string) {
 	}
 }
 
+// 21 bytes is the max needed ever for a 64 bit integer, even unsigned.
+#define MAX_SIZE (21)
+
 void sb_add_i64(string_builder_t *this, int64_t i64) {
-	// 21 bytes is the max needed ever for a 64 bit integer, even unsigned.
-	const unsigned long max_size = 21;
-	char *buffer = allocator_alloc(this->allocator, max_size);
-	snprintf(buffer, max_size, "%"PRIi64, i64);
+	char *buffer = allocator_alloc(this->allocator, MAX_SIZE);
+	snprintf(buffer, MAX_SIZE, "%"PRIi64, i64);
 	sb_add_string(this, buffer);
 }
 
 void sb_add_i32(string_builder_t *this, int32_t i32) {
-	const unsigned long max_size = 21;
-	char *buffer = allocator_alloc(this->allocator, max_size);
-	snprintf(buffer, max_size, "%"PRIi32, i32);
+	char *buffer = allocator_alloc(this->allocator, MAX_SIZE);
+	snprintf(buffer, MAX_SIZE, "%"PRIi32, i32);
 	sb_add_string(this, buffer);
 }
 
 void sb_add_i16(string_builder_t *this, int16_t i16) {
-	const unsigned long max_size = 21;
-	char *buffer = allocator_alloc(this->allocator, max_size);
-	snprintf(buffer, max_size, "%"PRIi16, i16);
+	char *buffer = allocator_alloc(this->allocator, MAX_SIZE);
+	snprintf(buffer, MAX_SIZE, "%"PRIi16, i16);
 	sb_add_string(this, buffer);
 }
 
 void sb_add_i8(string_builder_t *this, int8_t i8) {
-	const unsigned long max_size = 21;
-	char *buffer = allocator_alloc(this->allocator, max_size);
-	snprintf(buffer, max_size, "%"PRIi8, i8);
+	char *buffer = allocator_alloc(this->allocator, MAX_SIZE);
+	snprintf(buffer, MAX_SIZE, "%"PRIi8, i8);
 	sb_add_string(this, buffer);
 }
 
 void sb_add_u64(string_builder_t *this, uint64_t u64) {
-	const unsigned long max_size = 21;
-	char *buffer = allocator_alloc(this->allocator, max_size);
-	snprintf(buffer, max_size, "%"PRIu64, u64);
+	char *buffer = allocator_alloc(this->allocator, MAX_SIZE);
+	snprintf(buffer, MAX_SIZE, "%"PRIu64, u64);
 	sb_add_string(this, buffer);
 }
 
 void sb_add_u32(string_builder_t *this, uint32_t u32) {
-	const unsigned long max_size = 21;
-	char *buffer = allocator_alloc(this->allocator, max_size);
-	snprintf(buffer, max_size, "%"PRIu32, u32);
+	char *buffer = allocator_alloc(this->allocator, MAX_SIZE);
+	snprintf(buffer, MAX_SIZE, "%"PRIu32, u32);
 	sb_add_string(this, buffer);
 }
 
 void sb_add_u16(string_builder_t *this, uint16_t u16) {
-	const unsigned long max_size = 21;
-	char *buffer = allocator_alloc(this->allocator, max_size);
-	snprintf(buffer, max_size, "%"PRIu16, u16);
+	char *buffer = allocator_alloc(this->allocator, MAX_SIZE);
+	snprintf(buffer, MAX_SIZE, "%"PRIu16, u16);
 	sb_add_string(this, buffer);
 }
 
 void sb_add_u8(string_builder_t *this, uint8_t u8) {
-	const unsigned long max_size = 21;
-	char *buffer = allocator_alloc(this->allocator, max_size);
-	snprintf(buffer, max_size, "%"PRIu8, u8);
+	char *buffer = allocator_alloc(this->allocator, MAX_SIZE);
+	snprintf(buffer, MAX_SIZE, "%"PRIu8, u8);
+	sb_add_string(this, buffer);
+}
+
+void sb_add_substring(string_builder_t *this, const char *string, size_t substring_length) {
+	size_t string_length = strlen(string);
+	size_t min_length = string_length < substring_length
+		? string_length
+		: substring_length;
+	char *buffer = allocator_alloc(this->allocator, min_length + 1);
+	for ( size_t i = 0; i < min_length; i++ ) {
+		buffer[i] = string[i];
+	}
+	buffer[min_length-1] = '\0';
 	sb_add_string(this, buffer);
 }