diff options
Diffstat (limited to 'dev/arduino-terminal/ext/arduino/core/avr-libc/realloc.c')
| -rw-r--r-- | dev/arduino-terminal/ext/arduino/core/avr-libc/realloc.c | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/dev/arduino-terminal/ext/arduino/core/avr-libc/realloc.c b/dev/arduino-terminal/ext/arduino/core/avr-libc/realloc.c new file mode 100644 index 0000000..b76ce56 --- /dev/null +++ b/dev/arduino-terminal/ext/arduino/core/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; +} + |