API fix: packet_seek should take an index rather than offset
[babeltrace.git] / formats / ctf / ctf.c
index 5911b19d25cdaa5f45735893a0771af1fbf42b6a..17f299c3dece67bb334c769a1516fa9898ba0c60 100644 (file)
@@ -65,12 +65,14 @@ extern int yydebug;
 
 static
 struct trace_descriptor *ctf_open_trace(const char *path, int flags,
-               void (*packet_seek)(struct stream_pos *pos, size_t offset,
-                       int whence), FILE *metadata_fp);
+               void (*packet_seek)(struct stream_pos *pos, size_t index,
+                       int whence),
+               FILE *metadata_fp);
 static
 struct trace_descriptor *ctf_open_mmap_trace(
                struct mmap_stream_list *mmap_list,
-               void (*packet_seek)(struct stream_pos *pos, size_t offset, int whence),
+               void (*packet_seek)(struct stream_pos *pos, size_t index,
+                       int whence),
                FILE *metadata_fp);
 
 static
@@ -436,7 +438,11 @@ void ctf_fini_pos(struct ctf_stream_pos *pos)
        (void) g_array_free(pos->packet_index, TRUE);
 }
 
-void ctf_packet_seek(struct stream_pos *stream_pos, size_t offset, int whence)
+/*
+ * for SEEK_CUR: go to next packet.
+ * for SEEK_POS: go to packet numer (index).
+ */
+void ctf_packet_seek(struct stream_pos *stream_pos, size_t index, int whence)
 {
        struct ctf_stream_pos *pos =
                container_of(stream_pos, struct ctf_stream_pos, parent);
@@ -444,7 +450,7 @@ void ctf_packet_seek(struct stream_pos *stream_pos, size_t offset, int whence)
                container_of(pos, struct ctf_file_stream, pos);
        int ret;
        off_t off;
-       struct packet_index *index;
+       struct packet_index *packet_index;
 
        if (pos->prot == PROT_WRITE && pos->content_size_loc)
                *pos->content_size_loc = pos->offset;
@@ -468,11 +474,10 @@ void ctf_packet_seek(struct stream_pos *stream_pos, size_t offset, int whence)
                switch (whence) {
                case SEEK_CUR:
                        /* The writer will add padding */
-                       assert(pos->offset + offset == pos->packet_size);
                        pos->mmap_offset += WRITE_PACKET_LEN / CHAR_BIT;
                        break;
                case SEEK_SET:
-                       assert(offset == 0);    /* only seek supported for now */
+                       assert(index == 0);     /* only seek supported for now */
                        pos->cur_index = 0;
                        break;
                default:
@@ -495,27 +500,25 @@ void ctf_packet_seek(struct stream_pos *stream_pos, size_t offset, int whence)
                                return;
                        }
                        /* For printing discarded event count */
-                       index = &g_array_index(pos->packet_index,
+                       packet_index = &g_array_index(pos->packet_index,
                                        struct packet_index, pos->cur_index);
-                       events_discarded_diff = index->events_discarded;
+                       events_discarded_diff = packet_index->events_discarded;
                        file_stream->parent.prev_timestamp_end =
-                                               index->timestamp_end;
+                                               packet_index->timestamp_end;
                        if (pos->cur_index > 0) {
-                               index = &g_array_index(pos->packet_index,
+                               packet_index = &g_array_index(pos->packet_index,
                                                struct packet_index,
                                                pos->cur_index - 1);
-                               events_discarded_diff -= index->events_discarded;
+                               events_discarded_diff -= packet_index->events_discarded;
                        }
                        file_stream->parent.events_discarded = events_discarded_diff;
                        file_stream->parent.prev_timestamp = file_stream->parent.timestamp;
                        /* The reader will expect us to skip padding */
-                       assert(pos->offset + offset == pos->content_size);
                        ++pos->cur_index;
                        break;
                }
                case SEEK_SET:
-                       if (offset == 0)
-                               pos->cur_index = 0;
+                       pos->cur_index = index;
                        file_stream->parent.prev_timestamp = 0;
                        file_stream->parent.prev_timestamp_end = 0;
                        break;
@@ -546,20 +549,19 @@ void ctf_packet_seek(struct stream_pos *stream_pos, size_t offset, int whence)
                        pos->offset = EOF;
                        return;
                }
-               index = &g_array_index(pos->packet_index, struct packet_index,
+               packet_index = &g_array_index(pos->packet_index, struct packet_index,
                                       pos->cur_index);
-               pos->mmap_offset = index->offset;
+               pos->mmap_offset = packet_index->offset;
 
                /* Lookup context/packet size in index */
-               file_stream->parent.timestamp = index->timestamp_begin;
-               pos->content_size = index->content_size;
-               pos->packet_size = index->packet_size;
-               if (index->data_offset < index->content_size) {
+               file_stream->parent.timestamp = packet_index->timestamp_begin;
+               pos->content_size = packet_index->content_size;
+               pos->packet_size = packet_index->packet_size;
+               if (packet_index->data_offset < packet_index->content_size) {
                        pos->offset = 0;        /* will read headers */
-               } else if (index->data_offset == index->content_size) {
+               } else if (packet_index->data_offset == packet_index->content_size) {
                        /* empty packet */
-                       pos->offset = index->data_offset;
-                       offset = 0;
+                       pos->offset = packet_index->data_offset;
                        whence = SEEK_CUR;
                        goto read_next_packet;
                } else {
@@ -770,7 +772,7 @@ int ctf_open_trace_metadata_stream_read(struct ctf_trace *td, FILE **fp,
 
 static
 int ctf_open_trace_metadata_read(struct ctf_trace *td,
-               void (*packet_seek)(struct stream_pos *pos, size_t offset,
+               void (*packet_seek)(struct stream_pos *pos, size_t index,
                        int whence), FILE *metadata_fp)
 {
        struct ctf_scanner *scanner;
@@ -1243,7 +1245,7 @@ error:
  */
 static
 int ctf_open_file_stream_read(struct ctf_trace *td, const char *path, int flags,
-               void (*packet_seek)(struct stream_pos *pos, size_t offset,
+               void (*packet_seek)(struct stream_pos *pos, size_t index,
                        int whence))
 {
        int ret;
@@ -1294,7 +1296,7 @@ error:
 static
 int ctf_open_trace_read(struct ctf_trace *td,
                const char *path, int flags,
-               void (*packet_seek)(struct stream_pos *pos, size_t offset,
+               void (*packet_seek)(struct stream_pos *pos, size_t index,
                        int whence), FILE *metadata_fp)
 {
        int ret;
@@ -1378,7 +1380,7 @@ error:
 
 static
 struct trace_descriptor *ctf_open_trace(const char *path, int flags,
-               void (*packet_seek)(struct stream_pos *pos, size_t offset,
+               void (*packet_seek)(struct stream_pos *pos, size_t index,
                        int whence), FILE *metadata_fp)
 {
        struct ctf_trace *td;
@@ -1467,7 +1469,7 @@ end:
 static
 int ctf_open_mmap_stream_read(struct ctf_trace *td,
                struct mmap_stream *mmap_info,
-               void (*packet_seek)(struct stream_pos *pos, size_t offset,
+               void (*packet_seek)(struct stream_pos *pos, size_t index,
                        int whence))
 {
        int ret;
@@ -1502,7 +1504,7 @@ error_def:
 
 int ctf_open_mmap_trace_read(struct ctf_trace *td,
                struct mmap_stream_list *mmap_list,
-               void (*packet_seek)(struct stream_pos *pos, size_t offset,
+               void (*packet_seek)(struct stream_pos *pos, size_t index,
                        int whence),
                FILE *metadata_fp)
 {
@@ -1535,7 +1537,8 @@ error:
 static
 struct trace_descriptor *ctf_open_mmap_trace(
                struct mmap_stream_list *mmap_list,
-               void (*packet_seek)(struct stream_pos *pos, size_t offset, int whence),
+               void (*packet_seek)(struct stream_pos *pos, size_t index,
+                       int whence),
                FILE *metadata_fp)
 {
        struct ctf_trace *td;
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