From 9bff7c133e73ecfb200614d7a7d386a164a1a61f Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Sat, 25 Aug 2012 23:15:13 -0400 Subject: [PATCH] implement "low hanging fruit" from C11 based on Gregor's patch sent to the list. includes: - stdalign.h - removing gets in C11 mode - adding aligned_alloc and adjusting other functions to use it - adding 'x' flag to fopen for exclusive mode --- include/stdalign.h | 15 +++++++++++ include/stdio.h | 2 ++ include/stdlib.h | 1 + src/malloc/aligned_alloc.c | 51 +++++++++++++++++++++++++++++++++++++ src/malloc/memalign.c | 8 +----- src/malloc/posix_memalign.c | 43 +++---------------------------- src/stdio/fopen.c | 4 +-- 7 files changed, 75 insertions(+), 49 deletions(-) create mode 100644 include/stdalign.h create mode 100644 src/malloc/aligned_alloc.c diff --git a/include/stdalign.h b/include/stdalign.h new file mode 100644 index 00000000..b6e50aeb --- /dev/null +++ b/include/stdalign.h @@ -0,0 +1,15 @@ +#ifndef _STDALIGN_H +#define _STDALIGN_H + +/* this whole header only works in C11 or with compiler extensions */ +#if __STDC_VERSION__ < 201112L && defined( __GNUC__) +#define _Alignas(t) __attribute__((__aligned__(t))) +#define _Alignof(t) __alignof__(t) +#endif + +#define alignas _Alignas +#define alignof _Alignof +#define __alignas_is_defined 1 +#define __alignof_is_defined 1 + +#endif diff --git a/include/stdio.h b/include/stdio.h index 19ab8bcd..9aa2f782 100644 --- a/include/stdio.h +++ b/include/stdio.h @@ -90,7 +90,9 @@ int putc(int, FILE *); int putchar(int); char *fgets(char *, int, FILE *); +#if __STDC_VERSION__ < 201112L char *gets(char *); +#endif int fputs(const char *, FILE *); int puts(const char *); diff --git a/include/stdlib.h b/include/stdlib.h index c1d93e71..1749cb3b 100644 --- a/include/stdlib.h +++ b/include/stdlib.h @@ -38,6 +38,7 @@ void *malloc (size_t); void *calloc (size_t, size_t); void *realloc (void *, size_t); void free (void *); +void *aligned_alloc(size_t alignment, size_t size); void abort (void); int atexit (void (*) (void)); diff --git a/src/malloc/aligned_alloc.c b/src/malloc/aligned_alloc.c new file mode 100644 index 00000000..d623420b --- /dev/null +++ b/src/malloc/aligned_alloc.c @@ -0,0 +1,51 @@ +#include +#include +#include + +/* This function should work with most dlmalloc-like chunk bookkeeping + * systems, but it's only guaranteed to work with the native implementation + * used in this library. */ + +void *aligned_alloc(size_t align, size_t len) +{ + unsigned char *mem, *new, *end; + size_t header, footer; + + if ((align & -align & -sizeof(void *)) != align) { + errno = EINVAL; + return NULL; + } + + if (len > SIZE_MAX - align) { + errno = ENOMEM; + return NULL; + } + + if (align <= 4*sizeof(size_t)) { + if (!(mem = malloc(len))) + return NULL; + return mem; + } + + if (!(mem = malloc(len + align-1))) + return NULL; + + header = ((size_t *)mem)[-1]; + end = mem + (header & -8); + footer = ((size_t *)end)[-2]; + new = (void *)((uintptr_t)mem + align-1 & -align); + + if (!(header & 7)) { + ((size_t *)new)[-2] = ((size_t *)mem)[-2] + (new-mem); + ((size_t *)new)[-1] = ((size_t *)mem)[-1] - (new-mem); + return new; + } + + ((size_t *)mem)[-1] = header&7 | new-mem; + ((size_t *)new)[-2] = footer&7 | new-mem; + ((size_t *)new)[-1] = header&7 | end-new; + ((size_t *)end)[-2] = footer&7 | end-new; + + if (new != mem) free(mem); + return new; +} diff --git a/src/malloc/memalign.c b/src/malloc/memalign.c index 61f456e4..a594c636 100644 --- a/src/malloc/memalign.c +++ b/src/malloc/memalign.c @@ -3,11 +3,5 @@ void *memalign(size_t align, size_t len) { - void *mem; - int ret; - if ((ret = posix_memalign(&mem, align, len))) { - errno = ret; - return 0; - } - return mem; + return aligned_alloc(align, len); } diff --git a/src/malloc/posix_memalign.c b/src/malloc/posix_memalign.c index 2ae928c8..42cf2740 100644 --- a/src/malloc/posix_memalign.c +++ b/src/malloc/posix_memalign.c @@ -1,47 +1,10 @@ #include -#include #include -/* This function should work with most dlmalloc-like chunk bookkeeping - * systems, but it's only guaranteed to work with the native implementation - * used in this library. */ - int posix_memalign(void **res, size_t align, size_t len) { - unsigned char *mem, *new, *end; - size_t header, footer; - - if ((align & -align & -sizeof(void *)) != align) return EINVAL; - if (len > SIZE_MAX - align) return ENOMEM; - - if (align <= 4*sizeof(size_t)) { - if (!(mem = malloc(len))) - return errno; - *res = mem; - return 0; - } - - if (!(mem = malloc(len + align-1))) - return errno; - - header = ((size_t *)mem)[-1]; - end = mem + (header & -8); - footer = ((size_t *)end)[-2]; - new = (void *)((uintptr_t)mem + align-1 & -align); - - if (!(header & 7)) { - ((size_t *)new)[-2] = ((size_t *)mem)[-2] + (new-mem); - ((size_t *)new)[-1] = ((size_t *)mem)[-1] - (new-mem); - *res = new; - return 0; - } - - ((size_t *)mem)[-1] = header&7 | new-mem; - ((size_t *)new)[-2] = footer&7 | new-mem; - ((size_t *)new)[-1] = header&7 | end-new; - ((size_t *)end)[-2] = footer&7 | end-new; - - if (new != mem) free(mem); - *res = new; + void *mem = aligned_alloc(align, len); + if (!mem) return errno; + *res = mem; return 0; } diff --git a/src/stdio/fopen.c b/src/stdio/fopen.c index 084cc73c..0d5b1af2 100644 --- a/src/stdio/fopen.c +++ b/src/stdio/fopen.c @@ -5,7 +5,6 @@ FILE *fopen(const char *filename, const char *mode) FILE *f; int fd; int flags; - int plus = !!strchr(mode, '+'); /* Check for valid initial mode character */ if (!strchr("rwa", *mode)) { @@ -14,9 +13,10 @@ FILE *fopen(const char *filename, const char *mode) } /* Compute the flags to pass to open() */ - if (plus) flags = O_RDWR; + if (strchr(mode, '+')) flags = O_RDWR; else if (*mode == 'r') flags = O_RDONLY; else flags = O_WRONLY; + if (strchr(mode, 'x')) flags |= O_EXCL; if (*mode != 'r') flags |= O_CREAT; if (*mode == 'w') flags |= O_TRUNC; if (*mode == 'a') flags |= O_APPEND; -- 2.20.1