add z_whatami_to_str api

examples/z_scout.c

@@ -33,13 +33,9 @@ void fprintpid(FILE *stream, z_id_t pid) {
 }
 
 void fprintwhatami(FILE *stream, unsigned int whatami) {
-    if (whatami == Z_ROUTER) {
-        fprintf(stream, "\"Router\"");
-    } else if (whatami == Z_PEER) {
-        fprintf(stream, "\"Peer\"");
-    } else {
-        fprintf(stream, "\"Other\"");
-    }
+    char buf[64];
+    z_whatami_to_str(whatami, buf, sizeof(buf));
+    fprintf(stream, "%s", buf);
 }
 
 void fprintlocators(FILE *stream, const z_str_array_t *locs) {

include/zenoh_commons.h

@@ -2129,6 +2129,18 @@ ZENOHC_API int8_t z_undeclare_queryable(struct z_owned_queryable_t *qable);
  */
 ZENOHC_API
 int8_t z_undeclare_subscriber(struct z_owned_subscriber_t *sub);
+/**
+ * Converts the kind of zenoh entity into a string.
+ *
+ * Parameters:
+ *     whatami: A whatami bitmask of zenoh entity kind.
+ *     buf: Buffer to write a null-terminated string to.
+ *     len: Maximum number of bytes that can be written to the `buf`.
+ *
+ * Returns 0 if successful, negative values if whatami contains an invalid bitmask or `buf` is null,
+ * or number of remaining bytes, if the null-terminated string size exceeds `len`.
+ */
+ZENOHC_API int8_t z_whatami_to_str(uint8_t whatami, char *buf, size_t len);
 /**
  * Constructs a configuration by parsing a file at `path`. Currently supported format is JSON5, a superset of JSON.
  */

src/lib.rs

@@ -15,6 +15,9 @@
 #![allow(non_camel_case_types)]
 
 mod collections;
+use std::cmp::min;
+use std::slice;
+
 pub use crate::collections::*;
 mod config;
 pub use crate::config::*;
@@ -43,6 +46,7 @@ pub use crate::publisher::*;
 mod closures;
 pub use closures::*;
 mod liveliness;
+use libc::c_void;
 pub use liveliness::*;
 mod publication_cache;
 pub use publication_cache::*;
@@ -122,3 +126,26 @@ fn test_no_default_features() {
         )
     );
 }
+
+trait CopyableToCArray {
+    fn copy_to_c_array(&self, buf: *mut c_void, len: usize) -> usize;
+}
+
+impl CopyableToCArray for &[u8] {
+    fn copy_to_c_array(&self, buf: *mut c_void, len: usize) -> usize {
+        if buf.is_null() || (len == 0 && !self.is_empty()) {
+            return 0;
+        }
+
+        let max_len = min(len, self.len());
+        let b = unsafe { slice::from_raw_parts_mut(buf as *mut u8, max_len) };
+        b[0..max_len].copy_from_slice(&self[0..max_len]);
+        max_len
+    }
+}
+
+impl CopyableToCArray for &str {
+    fn copy_to_c_array(&self, buf: *mut c_void, len: usize) -> usize {
+        self.as_bytes().copy_to_c_array(buf, len)
+    }
+}

src/platform/clock.rs

@@ -1,12 +1,11 @@
 use chrono::{DateTime, Local};
 use libc::c_char;
 use std::{
-    cmp::min,
     os::raw::c_void,
-    slice,
     time::{Duration, Instant, SystemTime, UNIX_EPOCH},
 };
 
+use crate::CopyableToCArray;
 use lazy_static::lazy_static;
 
 // Use initial time stored in static variable as a reference time,
@@ -77,16 +76,13 @@ pub struct z_time_t {
 #[no_mangle]
 #[allow(clippy::missing_safety_doc)]
 pub unsafe extern "C" fn z_time_now_as_str(buf: *const c_char, len: usize) -> *const c_char {
-    if len == 0 {
+    if len == 0 || buf.is_null() {
         return buf;
     }
     let datetime: DateTime<Local> = SystemTime::now().into();
     let s = datetime.format("%Y-%m-%dT%H:%M:%SZ").to_string();
-    let sb = s.as_bytes();
-    let max_len = min(len - 1, s.len());
-    let b = slice::from_raw_parts_mut(buf as *mut u8, max_len + 1);
-    b[0..max_len].copy_from_slice(&sb[0..max_len]);
-    b[max_len] = 0;
+    let res = s.as_str().copy_to_c_array(buf as *mut c_void, len - 1);
+    *((buf as usize + res) as *mut c_char) = 0;
     buf
 }
 

src/scouting.rs

@@ -13,11 +13,11 @@
 //
 use crate::{
     z_closure_hello_call, z_config_check, z_config_default, z_config_null, z_config_t, z_id_t,
-    z_owned_closure_hello_t, z_owned_config_t, zc_init_logger,
+    z_owned_closure_hello_t, z_owned_config_t, zc_init_logger, CopyableToCArray,
 };
 use async_std::task;
 use libc::{c_char, c_uint, c_ulong, size_t};
-use std::ffi::CString;
+use std::{ffi::CString, os::raw::c_void};
 use zenoh::scouting::Hello;
 use zenoh_protocol::core::{whatami::WhatAmIMatcher, WhatAmI};
 use zenoh_util::core::AsyncResolve;
@@ -268,3 +268,30 @@ pub extern "C" fn z_scout(
     });
     0
 }
+
+/// Converts the kind of zenoh entity into a string.
+///
+/// Parameters:
+///     whatami: A whatami bitmask of zenoh entity kind.
+///     buf: Buffer to write a null-terminated string to.
+///     len: Maximum number of bytes that can be written to the `buf`.
+///
+/// Returns 0 if successful, negative values if whatami contains an invalid bitmask or `buf` is null,
+/// or number of remaining bytes, if the null-terminated string size exceeds `len`.
+#[no_mangle]
+pub extern "C" fn z_whatami_to_str(whatami: u8, buf: *mut c_char, len: usize) -> i8 {
+    if buf.is_null() || len == 0 {
+        return -1;
+    }
+    match WhatAmIMatcher::try_from(whatami) {
+        Err(_) => -1,
+        Ok(w) => {
+            let s = w.to_str();
+            let res = s.copy_to_c_array(buf as *mut c_void, len - 1);
+            unsafe {
+                *((buf as usize + res) as *mut c_char) = 0;
+            }
+            (s.len() - res) as i8
+        }
+    }
+}