2 files changed, 86 insertions, 30 deletions

diff --git a/trace-cmd.h b/trace-cmd.h
index be38ef2..0ebed96 100644
--- a/trace-cmd.h
+++ b/trace-cmd.h
@@ -53,6 +53,9 @@ tracecmd_read_data(struct tracecmd_handle *handle, int cpu);
 struct record *
 tracecmd_read_at(struct tracecmd_handle *handle, unsigned long long offset,
                  int *cpu);
+struct record *
+tracecmd_translate_data(struct tracecmd_handle *handle,
+                        void *ptr, int size);
 
 int tracecmd_ftrace_overrides(void);
 
diff --git a/trace-input.c b/trace-input.c
index 38dd53d..6fee129 100644
--- a/trace-input.c
+++ b/trace-input.c
@@ -700,6 +700,82 @@ tracecmd_read_at(struct tracecmd_handle *handle, unsigned long long offset,
                 return find_and_read_event(handle, offset, pcpu);
 }
 
+static unsigned int
+translate_data(void **ptr, unsigned long long *delta, int *length)
+{
+        unsigned long long extend;
+        unsigned int type_len_ts;
+        unsigned int type_len;
+
+        type_len_ts = data2host4(*ptr);
+        *ptr += 4;
+
+        type_len = type_len4host(type_len_ts);
+        *delta = ts4host(type_len_ts);
+
+        switch (type_len) {
+        case RINGBUF_TYPE_PADDING:
+                *length = data2host4(*ptr);
+                *ptr += 4;
+                *length *= 4;
+                *ptr += *length;
+                break;
+
+        case RINGBUF_TYPE_TIME_EXTEND:
+                extend = data2host4(*ptr);
+                *ptr += 4;
+                extend <<= TS_SHIFT;
+                extend += *delta;
+                *delta = extend;
+                break;
+
+        case RINGBUF_TYPE_TIME_STAMP:
+                *ptr += 12;
+                break;
+        case 0:
+                *length = data2host4(*ptr) - 4;
+                *length = (*length + 3) & ~3;
+                *ptr += 4;
+                break;
+        default:
+                *length = type_len * 4;
+                break;
+        }
+
+        return type_len;
+}
+
+struct record *
+tracecmd_translate_data(struct tracecmd_handle *handle,
+                        void *ptr, int size)
+{
+        struct record *data;
+        unsigned int type_len;
+
+        /* minimum record read is 8, (warn?) (TODO: make 8 into macro) */
+        if (size < 8)
+                return NULL;
+
+        data = malloc(sizeof(*data));
+        if (!data)
+                return NULL;
+        memset(data, 0, sizeof(*data));
+
+        data->data = ptr;
+        type_len = translate_data(&data->data, &data->ts, &data->size);
+        switch (type_len) {
+        case RINGBUF_TYPE_PADDING:
+        case RINGBUF_TYPE_TIME_EXTEND:
+        case RINGBUF_TYPE_TIME_STAMP:
+                data->data = NULL;
+                break;
+        default:
+                break;
+        }
+
+        return data;
+}
+
 struct record *
 tracecmd_peek_data(struct tracecmd_handle *handle, int cpu)
 {
@@ -708,10 +784,8 @@ tracecmd_peek_data(struct tracecmd_handle *handle, int cpu)
         int index = handle->cpu_data[cpu].index;
         void *ptr = page + index;
         unsigned long long extend;
-        unsigned int type_len_ts;
         unsigned int type_len;
-        unsigned int delta;
-        unsigned int length;
+        int length;
 
         /* Hack to work around function graph read ahead */
         tracecmd_curr_thread_handle = handle;
@@ -766,46 +840,25 @@ read_again:
                 return data;
         }
 
-        type_len_ts = data2host4(ptr);
-        ptr += 4;
-
-        type_len = type_len4host(type_len_ts);
-        delta = ts4host(type_len_ts);
+        type_len = translate_data(&ptr, &extend, &length);
 
         switch (type_len) {
         case RINGBUF_TYPE_PADDING:
-                if (!delta) {
+                if (!extend) {
                         warning("error, hit unexpected end of page");
                         return NULL;
                 }
-                length = data2host4(ptr);
-                ptr += 4;
-                length *= 4;
-                ptr += length;
-                goto read_again;
-
+                /* fall through */
         case RINGBUF_TYPE_TIME_EXTEND:
-                extend = data2host4(ptr);
-                ptr += 4;
-                extend <<= TS_SHIFT;
-                extend += delta;
                 handle->cpu_data[cpu].timestamp += extend;
-                goto read_again;
-
+                /* fall through */
         case RINGBUF_TYPE_TIME_STAMP:
-                ptr += 12;
-                break;
-        case 0:
-                length = data2host4(ptr) - 4;
-                length = (length + 3) & ~3;
-                ptr += 4;
-                break;
+                goto read_again;
         default:
-                length = type_len * 4;
                 break;
         }
 
-        handle->cpu_data[cpu].timestamp += delta;
+        handle->cpu_data[cpu].timestamp += extend;
 
         data = malloc(sizeof(*data));
         if (!data)