Re: [igt-dev] [PATCH i-g-t 1/3] lib/vec: Add igt_vec

Chris Wilson
2020-01-30T15:31:45Z

Quoting Ville Syrjala (2020-01-30 15:12:27)
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> Add a small std::vector lookalike which grows as needed.
>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
> lib/Makefile.sources | 2 ++
> lib/igt_vec.c | 86 ++++++++++++++++++++++++++++++++++++++++++++
> lib/igt_vec.h | 40 +++++++++++++++++++++
> lib/meson.build | 1 +
> 4 files changed, 129 insertions(+)
> create mode 100644 lib/igt_vec.c
> create mode 100644 lib/igt_vec.h
>
> diff --git a/lib/Makefile.sources b/lib/Makefile.sources
> index 631d6714e5ce..3e573f267e15 100644
> --- a/lib/Makefile.sources
> +++ b/lib/Makefile.sources
> @@ -62,6 +62,8 @@ lib_source_list = \
> igt_sysrq.h \
> igt_x86.h \
> igt_x86.c \
> + igt_vec.c \
> + igt_vec.h \
> igt_vgem.c \
> igt_vgem.h \
> instdone.c \
> diff --git a/lib/igt_vec.c b/lib/igt_vec.c
> new file mode 100644
> index 000000000000..dc4a6172fc8d
> --- /dev/null
> +++ b/lib/igt_vec.c
> @@ -0,0 +1,86 @@
> +/*
> + * Copyright © 2020 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.
> + */
> +
> +#include <stdlib.h>
> +#include <string.h>
> +
> +#include "igt_core.h"
> +#include "igt_vec.h"
> +
> +void igt_vec_init(struct igt_vec *vec, int elem_size)
> +{
> + memset(vec, 0, sizeof(*vec));
> + vec->elem_size = elem_size;
> +}
> +
> +void igt_vec_fini(struct igt_vec *vec)
> +{
> + free(vec->elems);
> + memset(vec, 0, sizeof(*vec));
> +}
> +
> +void *igt_vec_elem(const struct igt_vec *vec, int idx)
> +{
> + igt_assert(idx < vec->len);
> +
> + return vec->elems + idx * vec->elem_size;
> +}
> +
> +void igt_vec_push(struct igt_vec *vec, void *elem)
> +{
> + if (vec->len >= vec->size) {
> + vec->size = vec->size ? vec->size * 2 : 8;
> + vec->elems = realloc(vec->elems, vec->size * vec->elem_size);
> + igt_assert(vec->elems);
> + }
> +
> + vec->len++;
> + memcpy(igt_vec_elem(vec, vec->len - 1), elem, vec->elem_size);

I would have split this into

void *igt_vec_grow(struct igt_vec *vec)
{
if (vec->len++ >= vec->size) {
vec->size = vec->size ? vec->size * 2 : 8;
vec->elems = realloc(vec->elems, vec->size * vec->elem_size);
igt_assert(vec->elems);
}

return igt_vec_elem(vec, vec->len - 1);
}

igt_vec_push(vec, elem)
{
memcpy(igt_vec_grow(vec), elem, vec->size);
}

since we are happy to throw assertions and not worry too much about
error propagation.

> +
> + vec->len++;
> +}
> +
> +int igt_vec_length(const struct igt_vec *vec)
> +{
> + return vec->len;
> +}
> +
> +int igt_vec_index(const struct igt_vec *vec, void *elem)
> +{
> + for (int i = 0; i < vec->len; i++) {
> + if (!memcmp(igt_vec_elem(vec, i), elem, vec->elem_size))
> + return i;
> + }
> +
> + return -1;
> +}
> +
> +void igt_vec_remove(struct igt_vec *vec, int idx)
> +{
> + igt_assert(idx < vec->len);
> +
> + if (idx < vec->len - 1)
> + memmove(igt_vec_elem(vec, idx),
> + igt_vec_elem(vec, idx + 1),
> + (vec->len - 1 - idx) * vec->elem_size);

memmove of 0 not to your liking?

> +
> + vec->len--;
> +}
> diff --git a/lib/igt_vec.h b/lib/igt_vec.h
> new file mode 100644
> index 000000000000..de2549a45841
> --- /dev/null
> +++ b/lib/igt_vec.h
> @@ -0,0 +1,40 @@
> +/*
> + * Copyright © 2020 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.
> + */
> +
> +#ifndef __IGT_VEC_H__
> +#define __IGT_VEC_H__
> +
> +struct igt_vec {
> + void *elems;
> + int elem_size, size, len;

I would have used char[0] and casting just to have a variable length
struct :)

I might have also used longs throughout instead of ints, or in this day
and age, size_t.

Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
-Chris