From df7b2982d37220998cd1195fa83b8c263ecd90db Mon Sep 17 00:00:00 2001
From: Peter Barker <pbarker@barker.dropbear.id.au>
Date: Wed, 29 Sep 2021 13:01:26 +1000
Subject: [PATCH] AP_Filesystem: add fgets

---
 libraries/AP_Filesystem/AP_Filesystem.cpp | 17 +++++++++++++++++
 libraries/AP_Filesystem/AP_Filesystem.h   |  3 +++
 2 files changed, 20 insertions(+)

diff --git a/libraries/AP_Filesystem/AP_Filesystem.cpp b/libraries/AP_Filesystem/AP_Filesystem.cpp
index dbc036e502..bf983977d5 100644
--- a/libraries/AP_Filesystem/AP_Filesystem.cpp
+++ b/libraries/AP_Filesystem/AP_Filesystem.cpp
@@ -246,6 +246,23 @@ FileData *AP_Filesystem::load_file(const char *filename)
     return backend.fs.load_file(filename);
 }
 
+// returns null-terminated string; cr or lf terminates line
+bool AP_Filesystem::fgets(char *buf, uint8_t buflen, int fd)
+{
+    const Backend &backend = backend_by_fd(fd);
+
+    uint8_t i = 0;
+    for (; i<buflen-1; i++) {
+        if (backend.fs.read(fd, &buf[i], 1) != 1) {
+            break;
+        }
+        if (buf[i] == '\r' || buf[i] == '\n') {
+            break;
+        }
+    }
+    buf[i] = '\0';
+    return i != 0;
+}
 
 namespace AP
 {
diff --git a/libraries/AP_Filesystem/AP_Filesystem.h b/libraries/AP_Filesystem/AP_Filesystem.h
index 0708a56c7e..d40b9a447c 100644
--- a/libraries/AP_Filesystem/AP_Filesystem.h
+++ b/libraries/AP_Filesystem/AP_Filesystem.h
@@ -89,6 +89,9 @@ public:
     // unmount filesystem for reboot
     void unmount(void);
 
+    // returns null-terminated string; cr or lf terminates line
+    bool fgets(char *buf, uint8_t buflen, int fd);
+
     /*
       load a full file. Use delete to free the data
      */