Backported malloc and realloc from avr-libc 1.8.0 (without test code)

See #857

1 files changed, 150 insertions, 0 deletions

diff --git a/cores/arduino/avr-libc/realloc.c b/cores/arduino/avr-libc/realloc.c
new file mode 100644
index 0000000..b76ce56
--- /dev/null
+++ b/cores/arduino/avr-libc/realloc.c
@@ -0,0 +1,150 @@
+/* Copyright (c) 2004, 2010 Joerg Wunsch
+   All rights reserved.
+
+   Redistribution and use in source and binary forms, with or without
+   modification, are permitted provided that the following conditions are met:
+
+   * Redistributions of source code must retain the above copyright
+     notice, this list of conditions and the following disclaimer.
+
+   * Redistributions in binary form must reproduce the above copyright
+     notice, this list of conditions and the following disclaimer in
+     the documentation and/or other materials provided with the
+     distribution.
+
+   * Neither the name of the copyright holders nor the names of
+     contributors may be used to endorse or promote products derived
+     from this software without specific prior written permission.
+
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+  POSSIBILITY OF SUCH DAMAGE.
+*/
+/* $Id: realloc.c 2127 2010-06-07 14:49:37Z joerg_wunsch $ */
+
+#include <stdlib.h>
+#include <string.h>
+#include "sectionname.h"
+#include "stdlib_private.h"
+
+#include <avr/io.h>
+
+ATTRIBUTE_CLIB_SECTION
+void *
+realloc(void *ptr, size_t len)
+{
+	struct __freelist *fp1, *fp2, *fp3, *ofp3;
+	char *cp, *cp1;
+	void *memp;
+	size_t s, incr;
+
+	/* Trivial case, required by C standard. */
+	if (ptr == 0)
+		return malloc(len);
+
+	cp1 = (char *)ptr;
+	cp1 -= sizeof(size_t);
+	fp1 = (struct __freelist *)cp1;
+
+	cp = (char *)ptr + len; /* new next pointer */
+	if (cp < cp1)
+		/* Pointer wrapped across top of RAM, fail. */
+		return 0;
+
+	/*
+	 * See whether we are growing or shrinking.  When shrinking,
+	 * we split off a chunk for the released portion, and call
+	 * free() on it.  Therefore, we can only shrink if the new
+	 * size is at least sizeof(struct __freelist) smaller than the
+	 * previous size.
+	 */
+	if (len <= fp1->sz) {
+		/* The first test catches a possible unsigned int
+		 * rollover condition. */
+		if (fp1->sz <= sizeof(struct __freelist) ||
+		    len > fp1->sz - sizeof(struct __freelist))
+			return ptr;
+		fp2 = (struct __freelist *)cp;
+		fp2->sz = fp1->sz - len - sizeof(size_t);
+		fp1->sz = len;
+		free(&(fp2->nx));
+		return ptr;
+	}
+
+	/*
+	 * If we get here, we are growing.  First, see whether there
+	 * is space in the free list on top of our current chunk.
+	 */
+	incr = len - fp1->sz;
+	cp = (char *)ptr + fp1->sz;
+	fp2 = (struct __freelist *)cp;
+	for (s = 0, ofp3 = 0, fp3 = __flp;
+	     fp3;
+	     ofp3 = fp3, fp3 = fp3->nx) {
+		if (fp3 == fp2 && fp3->sz + sizeof(size_t) >= incr) {
+			/* found something that fits */
+			if (fp3->sz + sizeof(size_t) - incr > sizeof(struct __freelist)) {
+				/* split off a new freelist entry */
+				cp = (char *)ptr + len;
+				fp2 = (struct __freelist *)cp;
+				fp2->nx = fp3->nx;
+				fp2->sz = fp3->sz - incr;
+				fp1->sz = len;
+			} else {
+				/* it just fits, so use it entirely */
+				fp1->sz += fp3->sz + sizeof(size_t);
+				fp2 = fp3->nx;
+			}
+			if (ofp3)
+				ofp3->nx = fp2;
+			else
+				__flp = fp2;
+			return ptr;
+		}
+		/*
+		 * Find the largest chunk on the freelist while
+		 * walking it.
+		 */
+		if (fp3->sz > s)
+			s = fp3->sz;
+	}
+	/*
+	 * If we are the topmost chunk in memory, and there was no
+	 * large enough chunk on the freelist that could be re-used
+	 * (by a call to malloc() below), quickly extend the
+	 * allocation area if possible, without need to copy the old
+	 * data.
+	 */
+	if (__brkval == (char *)ptr + fp1->sz && len > s) {
+		cp1 = __malloc_heap_end;
+		cp = (char *)ptr + len;
+		if (cp1 == 0)
+			cp1 = STACK_POINTER() - __malloc_margin;
+		if (cp < cp1) {
+			__brkval = cp;
+			fp1->sz = len;
+			return ptr;
+		}
+		/* If that failed, we are out of luck. */
+		return 0;
+	}
+
+	/*
+	 * Call malloc() for a new chunk, then copy over the data, and
+	 * release the old region.
+	 */
+	if ((memp = malloc(len)) == 0)
+		return 0;
+	memcpy(memp, ptr, fp1->sz);
+	free(ptr);
+	return memp;
+}
+