From 64b9e1fa7b645daa36ca0018dc168d4f871fd538 Mon Sep 17 00:00:00 2001 From: Thomas Martitz Date: Thu, 21 Nov 2013 11:40:04 +0100 Subject: buflib: Add buflib_context_relocate(). This function relocates a buflib back buffer, updating pointers in struct buflib_context. It does not move any data by itself. The intended use-case is buflib-on-buflib, where a buflib back buffer is allocated with buflib and attempted to be moved. The move_callback() can call this and return BUFLIB_CB_OK on success. No move_callback() is called for the subordinate buflib buffer, therefore it must not contain non-movable allocations. The caller is generally responsible moving the data and all its implications. Change-Id: I869219f9cff786a172c9e917a5f34470073892e6 --- firmware/buflib.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) (limited to 'firmware/buflib.c') diff --git a/firmware/buflib.c b/firmware/buflib.c index 4233bf9a61..d7a24b8722 100644 --- a/firmware/buflib.c +++ b/firmware/buflib.c @@ -117,6 +117,32 @@ buflib_init(struct buflib_context *ctx, void *buf, size_t size) (unsigned long)size / 1024, ((unsigned long)size%1000)/10); } +bool buflib_context_relocate(struct buflib_context *ctx, void *buf) +{ + union buflib_data *handle, *bd_buf = buf; + ptrdiff_t diff = bd_buf - ctx->buf_start; + + /* cannot continue if the buffer is not aligned, since we would need + * to reduce the size of the buffer for aligning */ + if ((uintptr_t)buf & 0x3) + return false; + + /* relocate the handle table entries */ + for (handle = ctx->last_handle; handle < ctx->handle_table; handle++) + { + if (handle->alloc) + handle->alloc += diff * sizeof(union buflib_data); + } + /* relocate the pointers in the context */ + ctx->handle_table += diff; + ctx->last_handle += diff; + ctx->first_free_handle += diff; + ctx->buf_start += diff; + ctx->alloc_end += diff; + + return true; +} + /* Allocate a new handle, returning 0 on failure */ static inline union buflib_data* handle_alloc(struct buflib_context *ctx) -- cgit v1.2.3