goto end;
}
+ assert(buffer->capacity >= buffer->size);
if (buffer->capacity < (len + buffer->size)) {
ret = lttng_dynamic_buffer_set_capacity(buffer,
buffer->capacity +
}
if (new_size > buffer->capacity) {
+ size_t original_size = buffer->size;
+ size_t original_capacity = buffer->capacity;
+
ret = lttng_dynamic_buffer_set_capacity(buffer, new_size);
if (ret) {
goto end;
}
+
+ /*
+ * Zero-initialize the space that was left in the buffer at the
+ * before we increased its capacity (original capacity - original size).
+ * The newly acquired capacity (new capacity - original capacity)
+ * is zeroed by lttng_dynamic_buffer_set_capacity().
+ */
+ memset(buffer->data + original_size, 0,
+ original_capacity - original_size);
} else if (new_size > buffer->size) {
memset(buffer->data + buffer->size, 0, new_size - buffer->size);
} else {
}
int lttng_dynamic_buffer_set_capacity(struct lttng_dynamic_buffer *buffer,
- size_t new_capacity)
+ size_t demanded_capacity)
{
int ret = 0;
- size_t rounded_capacity = round_to_power_of_2(new_capacity);
+ void *new_buf;
+ size_t new_capacity = round_to_power_of_2(demanded_capacity);
- if (!buffer || new_capacity < buffer->size) {
+ if (!buffer || demanded_capacity < buffer->size) {
+ /*
+ * Shrinking a buffer's size by changing its capacity is
+ * unsupported.
+ */
ret = -1;
goto end;
}
- if (rounded_capacity == buffer->capacity) {
+ if (new_capacity == buffer->capacity) {
goto end;
}
- if (!buffer->data) {
- buffer->data = zmalloc(rounded_capacity);
- if (!buffer->data) {
- ret = -1;
- goto end;
- }
- } else {
- void *new_buf;
-
- new_buf = realloc(buffer->data, rounded_capacity);
- if (new_buf) {
- if (rounded_capacity > buffer->capacity) {
- memset(new_buf + buffer->capacity, 0,
- rounded_capacity - buffer->capacity);
- }
- } else {
- /* Realloc failed, try to acquire a new block. */
- new_buf = zmalloc(rounded_capacity);
- if (!new_buf) {
- ret = -1;
- goto end;
- }
- memcpy(new_buf, buffer->data, buffer->size);
- free(buffer->data);
- }
- buffer->data = new_buf;
+ /* Memory is initialized by the size increases. */
+ new_buf = realloc(buffer->data, new_capacity);
+ if (!new_buf) {
+ ret = -1;
+ goto end;
}
- buffer->capacity = rounded_capacity;
+ buffer->data = new_buf;
+ buffer->capacity = new_capacity;
end:
return ret;
}