Extend NCodec interface with truncate() method.

Signed-off-by: Rule Timothy (VM/EMT3) <[email protected]>
boschglobal · Feb 2, 2024 · 4ebf80e · 4ebf80e
1 parent 6caad29
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diff --git a/doc/content/apis/ncodec/examples/ncodec_api.c b/doc/content/apis/ncodec/examples/ncodec_api.c
@@ -1,62 +1,62 @@
-// Copyright 2023 Robert Bosch GmbH
-//
-// SPDX-License-Identifier: Apache-2.0
-
-#include <stddef.h>
-#include <stdio.h>
-#include <string.h>
-#include <errno.h>
-#include <dse/ncodec/codec.h>
-
-
-#define MIMETYPE "application/x-codec-example"
-
-
-extern NCodecStreamVTable example_stream;
-extern int                stream_seek(NCODEC* nc, size_t pos, int op);
-
-
-int main(int argc, char* argv[])
-{
-    int                rc;
-    static const char* greeting = "Hello World";
-
-    if (argc > 1) {
-        rc = ncodec_load(argv[1], NULL);
-        if (rc) {
-            printf("Load failed (rc %d)\n", rc);
-            return rc;
-        }
-    }
-
-    NCODEC* nc = ncodec_open(MIMETYPE, (void*)&example_stream);
-    if (nc == NULL) {
-        printf("Open failed (errno %d)\n", errno);
-        return errno;
-    }
-    ncodec_config(nc, (struct NCodecConfigItem){
-                          .name = "name", .value = "simple network codec" });
-
-    /* Write a message to the Network Codec. */
-    ncodec_write(nc, &(struct NCodecMessage){ .frame_id = 42,
-                         .buffer = (uint8_t*)greeting,
-                         .len = strlen(greeting) });
-    ncodec_flush(nc);
-
-    /* Reposition to start of stream. */
-    stream_seek(nc, 0, NCODEC_SEEK_SET);
-
-    /* Read the response from the Network Codec. */
-    NCodecMessage msg = {};
-    rc = ncodec_read(nc, &msg);
-    if (rc > 0) {
-        printf("Message is: %s\n", (char*)msg.buffer);
-    } else {
-        printf("There was no message! (reason %d)\n", rc);
-    }
-
-    /* Close the Network Codec. */
-    ncodec_close(nc);
-
-    return 0;
-}
+// Copyright 2023 Robert Bosch GmbH
+//
+// SPDX-License-Identifier: Apache-2.0
+
+#include <stddef.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <dse/ncodec/codec.h>
+
+
+#define MIMETYPE "application/x-codec-example"
+
+
+extern NCodecStreamVTable example_stream;
+extern int                stream_seek(NCODEC* nc, size_t pos, int op);
+
+
+int main(int argc, char* argv[])
+{
+    int                rc;
+    static const char* greeting = "Hello World";
+
+    if (argc > 1) {
+        rc = ncodec_load(argv[1], NULL);
+        if (rc) {
+            printf("Load failed (rc %d)\n", rc);
+            return rc;
+        }
+    }
+
+    NCODEC* nc = ncodec_open(MIMETYPE, (void*)&example_stream);
+    if (nc == NULL) {
+        printf("Open failed (errno %d)\n", errno);
+        return errno;
+    }
+    ncodec_config(nc, (struct NCodecConfigItem){
+                          .name = "name", .value = "simple network codec" });
+
+    /* Write a message to the Network Codec. */
+    ncodec_write(nc, &(struct NCodecMessage){ .frame_id = 42,
+                         .buffer = (uint8_t*)greeting,
+                         .len = strlen(greeting) });
+    ncodec_flush(nc);
+
+    /* Reposition to start of stream. */
+    stream_seek(nc, 0, NCODEC_SEEK_SET);
+
+    /* Read the response from the Network Codec. */
+    NCodecMessage msg = {};
+    rc = ncodec_read(nc, &msg);
+    if (rc > 0) {
+        printf("Message is: %s\n", (char*)msg.buffer);
+    } else {
+        printf("There was no message! (reason %d)\n", rc);
+    }
+
+    /* Close the Network Codec. */
+    ncodec_close(nc);
+
+    return 0;
+}
diff --git a/doc/content/apis/ncodec/index.md b/doc/content/apis/ncodec/index.md
@@ -77,18 +77,18 @@ center footer Dynamic Simulation Environment
 
 ```c
 typedef struct NCodecConfigItem {
-    const char * name;
-    const char * value;
+    const char* name;
+    const char* value;
 }
 ```
 
 ### NCodecInstance
 
 ```c
 typedef struct NCodecInstance {
-    const char * mime_type;
+    const char* mime_type;
     NCodecVTable codec;
-    NCodecStreamVTable * stream;
+    NCodecStreamVTable* stream;
 }
 ```
 
@@ -97,7 +97,7 @@ typedef struct NCodecInstance {
 ```c
 typedef struct NCodecMessage {
     uint32_t frame_id;
-    uint8_t * buffer;
+    uint8_t* buffer;
     size_t len;
 }
 ```
@@ -124,6 +124,7 @@ typedef struct NCodecVTable {
     NCodecWrite write;
     NCodecRead read;
     NCodecFlush flush;
+    NCodecTruncate truncate;
     NCodecClose close;
 }
 ```
@@ -212,7 +213,8 @@ hint (const char*)
 : The Network Codec library way successfully loaded.
 
 -1
-: The Network Codec library could not be loaded. Inspect `errno` for more details.
+: The Network Codec library could not be loaded. Inspect `errno` for more
+  details.
 
 
 
@@ -270,8 +272,8 @@ nc (NCODEC*)
 : Network Codec object.
 
 msg (NCodecMessage*)
-: (out) The message representation to write to the Network Codec. Caller owns the
-  message buffer/memory.
+: (out) The message representation to write to the Network Codec. Caller owns
+  the message buffer/memory.
 
 #### Returns
 
@@ -314,6 +316,26 @@ NetworkConfigItem
 
 
 
+### ncodec_truncate
+
+#### Parameters
+
+nc (NCODEC*)
+: Network Codec object.
+
+#### Returns
+
+0
+: The Network Codec internal buffers were truncated.
+
+-ENOSTR
+: The object represented by `nc` does not represent a valid stream.
+
+-ENOSR
+: No stream resource has been configured.
+
+
+
 ### ncodec_write
 
 Write the provided message to the Network Codec object.

diff --git a/dse/ncodec/codec.c b/dse/ncodec/codec.c
@@ -2,7 +2,7 @@
 //
 // SPDX-License-Identifier: Apache-2.0
 
-#include "codec.h" // NOLINT
+#include "codec.h"  // NOLINT
 
 
 /**
@@ -25,7 +25,8 @@ Returns
 : The Network Codec library way successfully loaded.
 
 -1
-: The Network Codec library could not be loaded. Inspect `errno` for more details.
+: The Network Codec library could not be loaded. Inspect `errno` for more
+  details.
 */
 extern int ncodec_load(const char* filename, const char* hint);
 
@@ -209,8 +210,8 @@ nc (NCODEC*)
 : Network Codec object.
 
 msg (NCodecMessage*)
-: (out) The message representation to write to the Network Codec. Caller owns the
-  message buffer/memory.
+: (out) The message representation to write to the Network Codec. Caller owns
+  the message buffer/memory.
 
 Returns
 -------
@@ -275,6 +276,37 @@ inline int ncodec_flush(NCODEC* nc)
 }
 
 
+/**
+ncodec_truncate
+===============
+
+Parameters
+----------
+nc (NCODEC*)
+: Network Codec object.
+
+Returns
+-------
+0
+: The Network Codec internal buffers were truncated.
+
+-ENOSTR
+: The object represented by `nc` does not represent a valid stream.
+
+-ENOSR
+: No stream resource has been configured.
+*/
+inline int ncodec_truncate(NCODEC* nc)
+{
+    NCodecInstance* _nc = (NCodecInstance*)nc;
+    if (_nc && _nc->codec.truncate) {
+        return _nc->codec.truncate(nc);
+    } else {
+        return -ENOSTR;
+    }
+}
+
+
 /**
 ncodec_close
 ============