From d90f91cda013e2d2b16a14d13bdea97ea77e5244 Mon Sep 17 00:00:00 2001
From: Camden Dixie O'Brien <cdo@wip.sh>
Date: Sun, 10 Aug 2025 16:38:59 +0100
Subject: [PATCH] Create print module

---
 lib/CMakeLists.txt   |  1 +
 lib/include/print.h  |  8 ++++++
 lib/print.c          | 26 +++++++++++++++++++
 tests/CMakeLists.txt |  1 +
 tests/print_tests.c  | 61 ++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 97 insertions(+)
 create mode 100644 lib/include/print.h
 create mode 100644 lib/print.c
 create mode 100644 tests/print_tests.c

diff --git a/lib/CMakeLists.txt b/lib/CMakeLists.txt
index 5d7cded..1e95c07 100644
--- a/lib/CMakeLists.txt
+++ b/lib/CMakeLists.txt
@@ -6,6 +6,7 @@ add_library(imp
   memory_stream.c
   parse.c
   prim.c
+  print.c
   store.c
   token.c
 )
diff --git a/lib/include/print.h b/lib/include/print.h
new file mode 100644
index 0000000..5172663
--- /dev/null
+++ b/lib/include/print.h
@@ -0,0 +1,8 @@
+#ifndef PRINT_H
+#define PRINT_H
+
+#include "am.h"
+
+size_t print(am_t *am, char *buffer, size_t buffer_size);
+
+#endif
diff --git a/lib/print.c b/lib/print.c
new file mode 100644
index 0000000..258346e
--- /dev/null
+++ b/lib/print.c
@@ -0,0 +1,26 @@
+#include "print.h"
+
+#include <assert.h>
+
+size_t print(am_t *am, char *buffer, size_t buffer_size)
+{
+	assert(am->val->is_atom);
+	assert(am->val->atom.type == ATOM_TYPE_INTEGER);
+
+	int64_t value = am->val->atom.integer;
+	int divisor = 10;
+	while (divisor <= value)
+		divisor *= 10;
+
+	size_t i = 0;
+	do {
+		divisor /= 10;
+		const int digit = value / divisor;
+		value = value % divisor;
+
+		assert(i < buffer_size);
+		buffer[i++] = '0' + (char)digit;
+	} while (divisor > 1);
+
+	return i;
+}
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index a530c7e..8d5f3a7 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -15,6 +15,7 @@ add_test_suites(
   expr_tests.c
   parse_tests.c
   prim_tests.c
+  print_tests.c
   store_tests.c
   token_tests.c
 )
diff --git a/tests/print_tests.c b/tests/print_tests.c
new file mode 100644
index 0000000..a0f366e
--- /dev/null
+++ b/tests/print_tests.c
@@ -0,0 +1,61 @@
+#include "print.h"
+#include "unity.h"
+
+#include <string.h>
+
+#define BUFFER_SIZE 256U
+
+static am_t am;
+static char buffer[BUFFER_SIZE];
+
+void setUp(void)
+{
+	memset(buffer, 0, BUFFER_SIZE);
+	am_init(&am);
+}
+
+void tearDown(void)
+{
+}
+
+static void test_integer_5(void)
+{
+	am.val = expr_integer(&am, 5);
+	const size_t len = print(&am, buffer, BUFFER_SIZE);
+	TEST_ASSERT_EQUAL(1, len);
+	TEST_ASSERT_EQUAL_MEMORY("5", buffer, 1);
+}
+
+static void test_integer_1234(void)
+{
+	am.val = expr_integer(&am, 1234);
+	const size_t len = print(&am, buffer, BUFFER_SIZE);
+	TEST_ASSERT_EQUAL(4, len);
+	TEST_ASSERT_EQUAL_MEMORY("1234", buffer, 4);
+}
+
+static void test_integer_0(void)
+{
+	am.val = expr_integer(&am, 0);
+	const size_t len = print(&am, buffer, BUFFER_SIZE);
+	TEST_ASSERT_EQUAL(1, len);
+	TEST_ASSERT_EQUAL_MEMORY("0", buffer, 1);
+}
+
+static void test_integer_10(void)
+{
+	am.val = expr_integer(&am, 10);
+	const size_t len = print(&am, buffer, BUFFER_SIZE);
+	TEST_ASSERT_EQUAL(2, len);
+	TEST_ASSERT_EQUAL_MEMORY("10", buffer, 2);
+}
+
+int main(void)
+{
+	UNITY_BEGIN();
+	RUN_TEST(test_integer_5);
+	RUN_TEST(test_integer_1234);
+	RUN_TEST(test_integer_0);
+	RUN_TEST(test_integer_10);
+	return UNITY_END();
+}