[Mesa-dev] [PATCH] util: implement strndup for WIN32

[Neil Roberts]

I think this implementation will have problems if the string being
copied is not null terminated. It's not clear from the man pages whether
that is an allowed way to use the function but a quick Google shows up a
few similar patches where they have later been fixed by using strnlen.
It looks like strnlen is available in MinGW so I think it would be worth
doing.

I notice that ralloc_strndup has a similar problem so maybe it would be
worth fixing both of them in a separate patch.

I don't understand the reasoning for using calloc instead of malloc.
Won't that just add redundant overhead?

Sorry this review was too late to get in before the patch landed.

Regards,
- Neil

Samuel Iglesias Gonsalvez <siglesias at igalia.com> writes:

> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92124
> Cc: Jose Fonseca <jfonseca at vmware.com>
> ---
>
> I tested it on MSVC but not MinGW. I hope I did not something wrong.
>
>  src/mesa/main/shader_query.cpp |  1 +
>  src/util/Makefile.sources      |  1 +
>  src/util/strndup.c             | 47 ++++++++++++++++++++++++++++++++++++++++++
>  src/util/strndup.h             | 28 +++++++++++++++++++++++++
>  4 files changed, 77 insertions(+)
>  create mode 100644 src/util/strndup.c
>  create mode 100644 src/util/strndup.h
>
> diff --git a/src/mesa/main/shader_query.cpp b/src/mesa/main/shader_query.cpp
> index e020dce..0cada50 100644
> --- a/src/mesa/main/shader_query.cpp
> +++ b/src/mesa/main/shader_query.cpp
> @@ -37,6 +37,7 @@
>  #include "../glsl/program.h"
>  #include "uniforms.h"
>  #include "main/enums.h"
> +#include "util/strndup.h"
>  
>  extern "C" {
>  #include "shaderapi.h"
> diff --git a/src/util/Makefile.sources b/src/util/Makefile.sources
> index afdd0cb..10f2c02 100644
> --- a/src/util/Makefile.sources
> +++ b/src/util/Makefile.sources
> @@ -17,6 +17,7 @@ MESA_UTIL_FILES :=	\
>  	set.c \
>  	set.h \
>  	simple_list.h \
> +	strndup.c \
>  	strtod.c \
>  	strtod.h \
>  	texcompress_rgtc_tmp.h \
> diff --git a/src/util/strndup.c b/src/util/strndup.c
> new file mode 100644
> index 0000000..6e5bb22
> --- /dev/null
> +++ b/src/util/strndup.c
> @@ -0,0 +1,47 @@
> +/*
> + * Copyright (c) 2015 Intel Corporation
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the next
> + * paragraph) shall be included in all copies or substantial portions of the
> + * Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
> + * IN THE SOFTWARE.
> + */
> +
> +#if defined(_WIN32)
> +#include <stdlib.h>
> +#include "strndup.h"
> +
> +char *
> +strndup(const char *str, size_t max)
> +{
> +   size_t n;
> +   char *ptr;
> +
> +   if (str == NULL)
> +      return NULL;
> +
> +   n = strlen(str);
> +   if (n > max)
> +      n = max;
> +
> +   ptr = (char *) malloc((n + 1) * sizeof(char));
> +   memcpy(ptr, str, n);
> +   ptr[n] = '\0';
> +   return ptr;
> +}
> +
> +#endif
> diff --git a/src/util/strndup.h b/src/util/strndup.h
> new file mode 100644
> index 0000000..dc8cdd2
> --- /dev/null
> +++ b/src/util/strndup.h
> @@ -0,0 +1,28 @@
> +/*
> + * Copyright (c) 2015 Intel Corporation
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the next
> + * paragraph) shall be included in all copies or substantial portions of the
> + * Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
> + * IN THE SOFTWARE.
> + */
> +
> +#if defined(_WIN32)
> +
> +extern char *strndup(const char *str, size_t max);
> +
> +#endif
> -- 
> 2.1.4
>
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