diff --git a/include/lib/libc/string.h b/include/lib/libc/string.h index ee6eeac..de20f61 100644 --- a/include/lib/libc/string.h +++ b/include/lib/libc/string.h @@ -4,7 +4,7 @@ * SPDX-License-Identifier: BSD-3-Clause */ /* - * Portions copyright (c) 2018, ARM Limited and Contributors. + * Portions copyright (c) 2018-2019, ARM Limited and Contributors. * All rights reserved. */ @@ -23,6 +23,7 @@ int strcmp(const char *s1, const char *s2); int strncmp(const char *s1, const char *s2, size_t n); void *memchr(const void *src, int c, size_t len); +void *memrchr(const void *src, int c, size_t len); char *strchr(const char *s, int c); void *memset(void *dst, int val, size_t count); size_t strlen(const char *s); diff --git a/lib/libc/libc.mk b/lib/libc/libc.mk index e1b5560..93d30d0 100644 --- a/lib/libc/libc.mk +++ b/lib/libc/libc.mk @@ -12,6 +12,7 @@ memcmp.c \ memcpy.c \ memmove.c \ + memrchr.c \ memset.c \ printf.c \ putchar.c \ diff --git a/lib/libc/memrchr.c b/lib/libc/memrchr.c new file mode 100644 index 0000000..01caef3 --- /dev/null +++ b/lib/libc/memrchr.c @@ -0,0 +1,24 @@ +/* + * Copyright (c) 2019, Arm Limited. All rights reserved. + * + * SPDX-License-Identifier: BSD-3-Clause + */ + +#include + +#undef memrchr + +void *memrchr(const void *src, int c, size_t len) +{ + const unsigned char *s = src + (len - 1); + + while (len--) { + if (*s == (unsigned char)c) { + return (void*) s; + } + + s--; + } + + return NULL; +}