From 4aca87515a5083ae0e31ce3177189fd43b6d05ac Mon Sep 17 00:00:00 2001 From: Andreas Baumann Date: Sat, 3 Jan 2015 13:58:15 +0100 Subject: patch to Vanilla Tomato 1.28 --- release/src/router/busybox/libbb/xrealloc_vector.c | 45 ++++++++++++++++++++++ 1 file changed, 45 insertions(+) create mode 100644 release/src/router/busybox/libbb/xrealloc_vector.c (limited to 'release/src/router/busybox/libbb/xrealloc_vector.c') diff --git a/release/src/router/busybox/libbb/xrealloc_vector.c b/release/src/router/busybox/libbb/xrealloc_vector.c new file mode 100644 index 00000000..bbd5ab8a --- /dev/null +++ b/release/src/router/busybox/libbb/xrealloc_vector.c @@ -0,0 +1,45 @@ +/* vi: set sw=4 ts=4: */ +/* + * Utility routines. + * + * Copyright (C) 2008 Denys Vlasenko + * + * Licensed under GPLv2, see file LICENSE in this tarball for details. + */ + +#include "libbb.h" + +/* Resize (grow) malloced vector. + * + * #define magic packed two parameters into one: + * sizeof = sizeof_and_shift >> 8 + * shift = (sizeof_and_shift) & 0xff + * + * Lets say shift = 4. 1 << 4 == 0x10. + * If idx == 0, 0x10, 0x20 etc, vector[] is resized to next higher + * idx step, plus one: if idx == 0x20, vector[] is resized to 0x31, + * thus last usable element is vector[0x30]. + * + * In other words: after xrealloc_vector(v, 4, idx) it's ok to use + * at least v[idx] and v[idx+1], for all idx values. + * + * New elements are zeroed out, but only if realloc was done + * (not on every call). You can depend on v[idx] and v[idx+1] being + * zeroed out if you use it like this: + * v = xrealloc_vector(v, 4, idx); + * v[idx].some_fields = ...; - the rest stays 0/NULL + * idx++; + * If you do not advance idx like above, you should be more careful. + * Next call to xrealloc_vector(v, 4, idx) may or may not zero out v[idx]. + */ +void* FAST_FUNC xrealloc_vector_helper(void *vector, unsigned sizeof_and_shift, int idx) +{ + int mask = 1 << (uint8_t)sizeof_and_shift; + + if (!(idx & (mask - 1))) { + sizeof_and_shift >>= 8; /* sizeof(vector[0]) */ + vector = xrealloc(vector, sizeof_and_shift * (idx + mask + 1)); + memset((char*)vector + (sizeof_and_shift * idx), 0, sizeof_and_shift * (mask + 1)); + } + return vector; +} -- cgit v1.2.3-54-g00ecf