From 1a59e2b190a9d05e34914041e855d2a35cbc9509 Mon Sep 17 00:00:00 2001
From: Ivar Fatland <fatland99@hotmail.com>
Date: Sat, 13 Dec 2025 16:30:27 +0100
Subject: [PATCH] file io

---
 cig.h     |  5 +++++
 file_io.c | 37 +++++++++++++++++++++++++++++++++++++
 2 files changed, 42 insertions(+)
 create mode 100644 file_io.c

diff --git a/cig.h b/cig.h
index edbbcab..a7d9611 100644
--- a/cig.h
+++ b/cig.h
@@ -339,6 +339,10 @@ void sb_add_substring(string_builder_t *this, const char *string, size_t substri
 const char *sb_build_and_clear(string_builder_t *this, allocator_t output_allocator);
 void sb_fprint_and_clear(string_builder_t *this, FILE *dest);
 
+// file_io /////////////////////////////////////////////////////////////////////
+char *read_entire_file(const char *path, allocator_t allocator);
+char **read_all_file_lines(const char *path, allocator_t allocator);
+
 #ifdef CIG_IMPL
 
 void *allocator_alloc_func(allocator_t this, size_t bytes, const char *file, int line) {
@@ -369,6 +373,7 @@ void allocator_reset(allocator_t this) {
 #include "cli.c"
 #include "scanner.c"
 #include "string_builder.c"
+#include "file_io.c"
 
 #endif // CIG_IMPL
 
diff --git a/file_io.c b/file_io.c
new file mode 100644
index 0000000..de2d1a9
--- /dev/null
+++ b/file_io.c
@@ -0,0 +1,37 @@
+#include "cig.h"
+#include <assert.h>
+
+char *read_entire_file(const char *path, allocator_t allocator) {
+	FILE *fp = fopen(path, "rb");
+	assert(fp != NULL);
+	fseek(fp, 0, SEEK_END);
+	long size = ftell(fp);
+	rewind(fp);
+	char *buf = allocator_alloc(allocator, size+1);
+	assert(buf != NULL);
+	size_t read = fread(buf, 1, size, fp);
+	assert(read == (size_t)size);
+	fclose(fp);
+	buf[size] = '\0';
+	return buf;
+}
+
+// Returns dynamic array, of fixed char strings.
+char **read_all_file_lines(const char *path, allocator_t allocator) {
+	char *contents = read_entire_file(path, allocator);
+	char **lines = make_arr(allocator, char*);
+	arr_append(lines, contents);
+	bool just_split = false;
+	for (char *c = contents; (*c)!='\0'; c++) {
+		if ((*c) == '\n') {
+			*c = '\0';
+			just_split = true;
+			continue;
+		}
+		if (just_split) {
+			just_split = false;
+			arr_append(lines, c);
+		}
+	}
+	return lines;
+}