From 206414f92edb4a2149b504f9c296f687a9572ffe Mon Sep 17 00:00:00 2001 From: Jason Ekstrand Date: Thu, 3 Mar 2016 08:17:36 -0800 Subject: [PATCH] anv/util: Fix vector resizing It wasn't properly handling the fact that wrap-around in the source may not translate to wrap-around in the destination. This really needs unit tests. --- src/intel/vulkan/anv_util.c | 31 +++++++++++++++++++------------ 1 file changed, 19 insertions(+), 12 deletions(-) diff --git a/src/intel/vulkan/anv_util.c b/src/intel/vulkan/anv_util.c index 22fd01c9495..62f47051ec7 100644 --- a/src/intel/vulkan/anv_util.c +++ b/src/intel/vulkan/anv_util.c @@ -144,7 +144,7 @@ anv_vector_init(struct anv_vector *vector, uint32_t element_size, uint32_t size) void * anv_vector_add(struct anv_vector *vector) { - uint32_t offset, size, split, tail; + uint32_t offset, size, split, src_tail, dst_tail; void *data; if (vector->head - vector->tail == vector->size) { @@ -152,18 +152,25 @@ anv_vector_add(struct anv_vector *vector) data = malloc(size); if (data == NULL) return NULL; - split = align_u32(vector->tail, vector->size); - tail = vector->tail & (vector->size - 1); - if (vector->head - split < vector->size) { - memcpy(data + tail, - vector->data + tail, - split - vector->tail); - memcpy(data + vector->size, - vector->data, vector->head - split); + src_tail = vector->tail & (vector->size - 1); + dst_tail = vector->tail & (size - 1); + if (src_tail == 0) { + /* Since we know that the vector is full, this means that it's + * linear from start to end so we can do one copy. + */ + memcpy(data + dst_tail, vector->data, vector->size); } else { - memcpy(data + tail, - vector->data + tail, - vector->head - vector->tail); + /* In this case, the vector is split into two pieces and we have + * to do two copies. We have to be careful to make sure each + * piece goes to the right locations. Thanks to the change in + * size, it may or may not still wrap around. + */ + split = align_u32(vector->tail, vector->size); + assert(vector->tail <= split && split < vector->head); + memcpy(data + dst_tail, vector->data + src_tail, + split - vector->tail); + memcpy(data + (split & (size - 1)), vector->data, + vector->head - split); } free(vector->data); vector->data = data; -- 2.30.2