kc3-lang/libxkbcommon/test/.gitignore
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Hash : 36f55c49
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Date : 2013-03-11T12:53:39
keymap: add xkb_keymap_new_from_buffer() The current API doesn't allow the caller to create keymaps from mmap()'ed files. The problem is, xkb_keymap_new_from_string() requires a terminating 0 byte. However, there is no way to guarantee that when using mmap() so a user currently has to copy the whole file just to get the terminating zero byte (assuming they cannot use xkb_keymap_new_from_file()). This adds a new entry xkb_keymap_new_from_buffer() which takes a memory location and the buffer size in bytes. Internally, we depend on yy_scan_{string,byte}() helpers. According to flex documentation these already copy the input string because they are wrappers around yy_scan_buffer(). yy_scan_buffer() on the other hand has some insane requirements. The buffer must be writeable and the last two bytes must be ASCII-NUL. But the buffer may contain other 0 bytes just fine. Because we don't want these constraints in our public API, xkb_keymap_new_from_buffer() needs to create a copy of the input memory. But it then calls yy_scan_buffer() directly. Hence, we have the same number of buffer-copies as with *_from_string() but without the terminating 0 requirement. The explicit yy_scan_buffer() call is preferred over yy_scan_byte() so the buffer-copy operation is not hidden somewhere in flex. Maybe some day we no longer depend on flex and can have a zero-copy API. A user could mmap() a file and it would get parsed right from this buffer. But until then, we shouldn't expose this limitation in the API but instead provide an API that some day can work with zero-copy. Signed-off-by: David Herrmann <dh.herrmann@gmail.com> [ran: rebased on top of my branch] Conflicts: Makefile.am src/xkbcomp/xkbcomp.c
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test/.gitignore