diff --git a/ChangeLog b/ChangeLog index a61d7755a0..11594803fe 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,19 @@ +2017-09-02 Paul Eggert + + scratch_buffer: don’t use private glibc API + Suggested by Florian Weimer in: + http://lists.gnu.org/archive/html/bug-gnulib/2017-09/msg00004.html + * lib/scratch_buffer.h: Rename to lib/malloc/scratch_buffer.h. + * lib/scratch_buffer_grow.c: Rename to + lib/malloc/scratch_buffer_grow.c. + * lib/scratch_buffer_grow_preserve.c: Rename to + lib/malloc/scratch_buffer_grow_preserve.c. + * lib/scratch_buffer_set_array_size.c: Rename to + lib/malloc/scratch_buffer_set_array_size.c. + * lib/scratch_buffer.h: New file. + * modules/scratch_buffer (Files, Makefile.am): + Adjust to source-file renaming. + 2017-09-01 Paul Eggert glob: use scratch_buffer instead of extend_alloca diff --git a/lib/malloc/scratch_buffer.h b/lib/malloc/scratch_buffer.h new file mode 100644 index 0000000000..bb04662eb2 --- /dev/null +++ b/lib/malloc/scratch_buffer.h @@ -0,0 +1,135 @@ +/* Variable-sized buffer with on-stack default allocation. + Copyright (C) 2015-2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#ifndef _SCRATCH_BUFFER_H +#define _SCRATCH_BUFFER_H + +/* Scratch buffers with a default stack allocation and fallback to + heap allocation. It is expected that this function is used in this + way: + + struct scratch_buffer tmpbuf; + scratch_buffer_init (&tmpbuf); + + while (!function_that_uses_buffer (tmpbuf.data, tmpbuf.length)) + if (!scratch_buffer_grow (&tmpbuf)) + return -1; + + scratch_buffer_free (&tmpbuf); + return 0; + + The allocation functions (scratch_buffer_grow, + scratch_buffer_grow_preserve, scratch_buffer_set_array_size) make + sure that the heap allocation, if any, is freed, so that the code + above does not have a memory leak. The buffer still remains in a + state that can be deallocated using scratch_buffer_free, so a loop + like this is valid as well: + + struct scratch_buffer tmpbuf; + scratch_buffer_init (&tmpbuf); + + while (!function_that_uses_buffer (tmpbuf.data, tmpbuf.length)) + if (!scratch_buffer_grow (&tmpbuf)) + break; + + scratch_buffer_free (&tmpbuf); + + scratch_buffer_grow and scratch_buffer_grow_preserve are guaranteed + to grow the buffer by at least 512 bytes. This means that when + using the scratch buffer as a backing store for a non-character + array whose element size, in bytes, is 512 or smaller, the scratch + buffer only has to grow once to make room for at least one more + element. +*/ + +#include +#include +#include + +/* Scratch buffer. Must be initialized with scratch_buffer_init + before its use. */ +struct scratch_buffer { + void *data; /* Pointer to the beginning of the scratch area. */ + size_t length; /* Allocated space at the data pointer, in bytes. */ + max_align_t __space[(1023 + sizeof (max_align_t)) / sizeof (max_align_t)]; +}; + +/* Initializes *BUFFER so that BUFFER->data points to BUFFER->__space + and BUFFER->length reflects the available space. */ +static inline void +scratch_buffer_init (struct scratch_buffer *buffer) +{ + buffer->data = buffer->__space; + buffer->length = sizeof (buffer->__space); +} + +/* Deallocates *BUFFER (if it was heap-allocated). */ +static inline void +scratch_buffer_free (struct scratch_buffer *buffer) +{ + if (buffer->data != buffer->__space) + free (buffer->data); +} + +/* Grow *BUFFER by some arbitrary amount. The buffer contents is NOT + preserved. Return true on success, false on allocation failure (in + which case the old buffer is freed). On success, the new buffer is + larger than the previous size. On failure, *BUFFER is deallocated, + but remains in a free-able state, and errno is set. */ +bool __libc_scratch_buffer_grow (struct scratch_buffer *buffer); +libc_hidden_proto (__libc_scratch_buffer_grow) + +/* Alias for __libc_scratch_buffer_grow. */ +static __always_inline bool +scratch_buffer_grow (struct scratch_buffer *buffer) +{ + return __glibc_likely (__libc_scratch_buffer_grow (buffer)); +} + +/* Like __libc_scratch_buffer_grow, but preserve the old buffer + contents on success, as a prefix of the new buffer. */ +bool __libc_scratch_buffer_grow_preserve (struct scratch_buffer *buffer); +libc_hidden_proto (__libc_scratch_buffer_grow_preserve) + +/* Alias for __libc_scratch_buffer_grow_preserve. */ +static __always_inline bool +scratch_buffer_grow_preserve (struct scratch_buffer *buffer) +{ + return __glibc_likely (__libc_scratch_buffer_grow_preserve (buffer)); +} + +/* Grow *BUFFER so that it can store at least NELEM elements of SIZE + bytes. The buffer contents are NOT preserved. Both NELEM and SIZE + can be zero. Return true on success, false on allocation failure + (in which case the old buffer is freed, but *BUFFER remains in a + free-able state, and errno is set). It is unspecified whether this + function can reduce the array size. */ +bool __libc_scratch_buffer_set_array_size (struct scratch_buffer *buffer, + size_t nelem, size_t size); +libc_hidden_proto (__libc_scratch_buffer_set_array_size) + +/* Alias for __libc_scratch_set_array_size. */ +static __always_inline bool +scratch_buffer_set_array_size (struct scratch_buffer *buffer, + size_t nelem, size_t size) +{ + return __glibc_likely (__libc_scratch_buffer_set_array_size + (buffer, nelem, size)); +} + +#endif /* _SCRATCH_BUFFER_H */ diff --git a/lib/scratch_buffer_grow.c b/lib/malloc/scratch_buffer_grow.c similarity index 100% rename from lib/scratch_buffer_grow.c rename to lib/malloc/scratch_buffer_grow.c diff --git a/lib/scratch_buffer_grow_preserve.c b/lib/malloc/scratch_buffer_grow_preserve.c similarity index 100% rename from lib/scratch_buffer_grow_preserve.c rename to lib/malloc/scratch_buffer_grow_preserve.c diff --git a/lib/scratch_buffer_set_array_size.c b/lib/malloc/scratch_buffer_set_array_size.c similarity index 100% rename from lib/scratch_buffer_set_array_size.c rename to lib/malloc/scratch_buffer_set_array_size.c diff --git a/lib/scratch_buffer.h b/lib/scratch_buffer.h index bb04662eb2..52f0ed634a 100644 --- a/lib/scratch_buffer.h +++ b/lib/scratch_buffer.h @@ -1,135 +1,4 @@ -/* Variable-sized buffer with on-stack default allocation. - Copyright (C) 2015-2017 Free Software Foundation, Inc. - This file is part of the GNU C Library. - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Lesser General Public - License as published by the Free Software Foundation; either - version 2.1 of the License, or (at your option) any later version. - - The GNU C Library is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with the GNU C Library; if not, see - . */ - -#ifndef _SCRATCH_BUFFER_H -#define _SCRATCH_BUFFER_H - -/* Scratch buffers with a default stack allocation and fallback to - heap allocation. It is expected that this function is used in this - way: - - struct scratch_buffer tmpbuf; - scratch_buffer_init (&tmpbuf); - - while (!function_that_uses_buffer (tmpbuf.data, tmpbuf.length)) - if (!scratch_buffer_grow (&tmpbuf)) - return -1; - - scratch_buffer_free (&tmpbuf); - return 0; - - The allocation functions (scratch_buffer_grow, - scratch_buffer_grow_preserve, scratch_buffer_set_array_size) make - sure that the heap allocation, if any, is freed, so that the code - above does not have a memory leak. The buffer still remains in a - state that can be deallocated using scratch_buffer_free, so a loop - like this is valid as well: - - struct scratch_buffer tmpbuf; - scratch_buffer_init (&tmpbuf); - - while (!function_that_uses_buffer (tmpbuf.data, tmpbuf.length)) - if (!scratch_buffer_grow (&tmpbuf)) - break; - - scratch_buffer_free (&tmpbuf); - - scratch_buffer_grow and scratch_buffer_grow_preserve are guaranteed - to grow the buffer by at least 512 bytes. This means that when - using the scratch buffer as a backing store for a non-character - array whose element size, in bytes, is 512 or smaller, the scratch - buffer only has to grow once to make room for at least one more - element. -*/ - -#include -#include -#include - -/* Scratch buffer. Must be initialized with scratch_buffer_init - before its use. */ -struct scratch_buffer { - void *data; /* Pointer to the beginning of the scratch area. */ - size_t length; /* Allocated space at the data pointer, in bytes. */ - max_align_t __space[(1023 + sizeof (max_align_t)) / sizeof (max_align_t)]; -}; - -/* Initializes *BUFFER so that BUFFER->data points to BUFFER->__space - and BUFFER->length reflects the available space. */ -static inline void -scratch_buffer_init (struct scratch_buffer *buffer) -{ - buffer->data = buffer->__space; - buffer->length = sizeof (buffer->__space); -} - -/* Deallocates *BUFFER (if it was heap-allocated). */ -static inline void -scratch_buffer_free (struct scratch_buffer *buffer) -{ - if (buffer->data != buffer->__space) - free (buffer->data); -} - -/* Grow *BUFFER by some arbitrary amount. The buffer contents is NOT - preserved. Return true on success, false on allocation failure (in - which case the old buffer is freed). On success, the new buffer is - larger than the previous size. On failure, *BUFFER is deallocated, - but remains in a free-able state, and errno is set. */ -bool __libc_scratch_buffer_grow (struct scratch_buffer *buffer); -libc_hidden_proto (__libc_scratch_buffer_grow) - -/* Alias for __libc_scratch_buffer_grow. */ -static __always_inline bool -scratch_buffer_grow (struct scratch_buffer *buffer) -{ - return __glibc_likely (__libc_scratch_buffer_grow (buffer)); -} - -/* Like __libc_scratch_buffer_grow, but preserve the old buffer - contents on success, as a prefix of the new buffer. */ -bool __libc_scratch_buffer_grow_preserve (struct scratch_buffer *buffer); -libc_hidden_proto (__libc_scratch_buffer_grow_preserve) - -/* Alias for __libc_scratch_buffer_grow_preserve. */ -static __always_inline bool -scratch_buffer_grow_preserve (struct scratch_buffer *buffer) -{ - return __glibc_likely (__libc_scratch_buffer_grow_preserve (buffer)); -} - -/* Grow *BUFFER so that it can store at least NELEM elements of SIZE - bytes. The buffer contents are NOT preserved. Both NELEM and SIZE - can be zero. Return true on success, false on allocation failure - (in which case the old buffer is freed, but *BUFFER remains in a - free-able state, and errno is set). It is unspecified whether this - function can reduce the array size. */ -bool __libc_scratch_buffer_set_array_size (struct scratch_buffer *buffer, - size_t nelem, size_t size); -libc_hidden_proto (__libc_scratch_buffer_set_array_size) - -/* Alias for __libc_scratch_set_array_size. */ -static __always_inline bool -scratch_buffer_set_array_size (struct scratch_buffer *buffer, - size_t nelem, size_t size) -{ - return __glibc_likely (__libc_scratch_buffer_set_array_size - (buffer, nelem, size)); -} - -#endif /* _SCRATCH_BUFFER_H */ +#define __libc_scratch_buffer_grow gl_scratch_buffer_grow +#define __libc_scratch_buffer_grow_preserve gl_scratch_buffer_grow_preserve +#define __libc_scratch_buffer_set_array_size gl_scratch_buffer_set_array_size +#include diff --git a/modules/scratch_buffer b/modules/scratch_buffer index 7502d707db..e59dd62c9d 100644 --- a/modules/scratch_buffer +++ b/modules/scratch_buffer @@ -3,9 +3,10 @@ Variable-sized buffer with on-stack default allocation. Files: lib/scratch_buffer.h -lib/scratch_buffer_grow.c -lib/scratch_buffer_grow_preserve.c -lib/scratch_buffer_set_array_size.c +lib/malloc/scratch_buffer.h +lib/malloc/scratch_buffer_grow.c +lib/malloc/scratch_buffer_grow_preserve.c +lib/malloc/scratch_buffer_set_array_size.c Depends-on: libc-config @@ -13,14 +14,11 @@ stdbool stddef configure.ac: -AC_CHECK_FUNCS_ONCE([__libc_scratch_buffer_grow]) -if test "$ac_cv_func___libc_scratch_buffer_grow" != yes; then - AC_LIBOBJ([scratch_buffer_grow]) - AC_LIBOBJ([scratch_buffer_grow_preserve]) - AC_LIBOBJ([scratch_buffer_set_array_size]) -fi Makefile.am: +lib_SOURCES += malloc/scratch_buffer_grow.c \ + malloc/scratch_buffer_grow_preserve.c \ + malloc/scratch_buffer_set_array_size.c Include: