[FFmpeg-devel] [PATCH 1/7] avutil/uuid: add utility library for manipulating UUIDs as specified in RFC 4122
Pierre-Anthony Lemieux
pal at sandflow.com
Mon Feb 28 05:22:06 EET 2022
On Tue, Feb 22, 2022 at 6:21 AM James Almer <jamrial at gmail.com> wrote:
>
>
>
> On 2/22/2022 10:01 AM, Zane van Iperen wrote:
> > Loosely based on libuuid
> >
> > Co-authored-by: Pierre-Anthony Lemieux <pal at palemieux.com>
> > Signed-off-by: Pierre-Anthony Lemieux <pal at palemieux.com>
> > Signed-off-by: Zane van Iperen <zane at zanevaniperen.com>
> > ---
> > libavutil/Makefile | 2 +
> > libavutil/uuid.c | 156 ++++++++++++++++++++++++++++++++++++++++++
> > libavutil/uuid.h | 167 +++++++++++++++++++++++++++++++++++++++++++++
> > 3 files changed, 325 insertions(+)
> > create mode 100644 libavutil/uuid.c
> > create mode 100644 libavutil/uuid.h
> >
> > diff --git a/libavutil/Makefile b/libavutil/Makefile
> > index d17876df1a..e0f40412d0 100644
> > --- a/libavutil/Makefile
> > +++ b/libavutil/Makefile
> > @@ -80,6 +80,7 @@ HEADERS = adler32.h \
> > timestamp.h \
> > tree.h \
> > twofish.h \
> > + uuid.h \
> > version.h \
> > video_enc_params.h \
> > xtea.h \
> > @@ -172,6 +173,7 @@ OBJS = adler32.o \
> > tx_float.o \
> > tx_double.o \
> > tx_int32.o \
> > + uuid.o \
> > video_enc_params.o \
> > film_grain_params.o \
> >
> > diff --git a/libavutil/uuid.c b/libavutil/uuid.c
> > new file mode 100644
> > index 0000000000..7bcbbe487f
> > --- /dev/null
> > +++ b/libavutil/uuid.c
> > @@ -0,0 +1,156 @@
> > +/*
> > + * Copyright (c) 2022 Pierre-Anthony Lemieux <pal at palemieux.com>
> > + * Zane van Iperen <zane at zanevaniperen.com>
> > + *
> > + * This file is part of FFmpeg.
> > + *
> > + * FFmpeg 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.
> > + *
> > + * FFmpeg 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 FFmpeg; if not, write to the Free Software
> > + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
> > + */
> > +
> > +/*
> > + * Copyright (C) 1996, 1997 Theodore Ts'o.
> > + *
> > + * Redistribution and use in source and binary forms, with or without
> > + * modification, are permitted provided that the following conditions
> > + * are met:
> > + * 1. Redistributions of source code must retain the above copyright
> > + * notice, and the entire permission notice in its entirety,
> > + * including the disclaimer of warranties.
> > + * 2. Redistributions in binary form must reproduce the above copyright
> > + * notice, this list of conditions and the following disclaimer in the
> > + * documentation and/or other materials provided with the distribution.
> > + * 3. The name of the author may not be used to endorse or promote
> > + * products derived from this software without specific prior
> > + * written permission.
> > + *
> > + * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
> > + * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
> > + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF
> > + * WHICH ARE HEREBY DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE
> > + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
> > + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
> > + * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
> > + * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
> > + * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
> > + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
> > + * USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH
> > + * DAMAGE.
> > + */
> > +
> > +/**
> > + * @file
> > + * UUID parsing and serialization utilities.
> > + * The library treat the UUID as an opaque sequence of 16 unsigned bytes,
> > + * i.e. ignoring the internal layout of the UUID, which depends on the type
> > + * of the UUID.
> > + *
> > + * @author Pierre-Anthony Lemieux <pal at palemieux.com>
> > + * @author Zane van Iperen <zane at zanevaniperen.com>
> > + */
> > +
> > +#include "uuid.h"
> > +#include "error.h"
> > +#include "avstring.h"
> > +#include <stdlib.h>
> > +#include <string.h>
> > +
> > +int av_uuid_parse(const char *in, AVUUID uu)
> > +{
> > + size_t len = strlen(in);
> > + if (len != 36)
> > + return -1;
> > +
> > + return av_uuid_parse_range(in, in + len, uu);
> > +}
> > +
> > +int av_uuid_parse_range(const char *in_start, const char *in_end, AVUUID uu)
> > +{
> > + int i;
> > + const char *cp;
> > + char buf[3];
> > +
> > + if ((in_end - in_start) != 36)
> > + return -1;
> > +
> > + for (i = 0, cp = in_start; i < 36; i++, cp++) {
> > +
> > + if (i == 8 || i == 13 || i == 18 || i == 23) {
> > + if (*cp == '-')
> > + continue;
> > + return AVERROR(EINVAL);
> > + }
> > +
> > + if (!av_isxdigit(*cp))
> > + return AVERROR(EINVAL);
> > + }
> > +
> > + buf[2] = '\0';
> > + for (i = 0, cp = in_start; i < 16; i++) {
> > +
> > + if (i == 4 || i == 6 || i == 8 || i == 10)
> > + cp++;
> > +
> > + buf[0] = *cp++;
> > + buf[1] = *cp++;
> > +
> > + errno = 0;
> > + uu[i] = strtoul(buf, NULL, 16);
> > + if (errno)
> > + return AVERROR(errno);
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +void av_uuid_unparse(const AVUUID uuid, char *out)
> > +{
> > + static char const hexdigits_lower[16] = "0123456789abcdef";
> > +
> > + char *p = out;
> > +
> > + for (int i = 0; i < 16; i++) {
> > + size_t tmp;
> > +
> > + if (i == 4 || i == 6 || i == 8 || i == 10) {
> > + *p++ = '-';
> > + }
> > +
> > + tmp = uuid[i];
> > + *p++ = hexdigits_lower[tmp >> 4];
> > + *p++ = hexdigits_lower[tmp & 15];
> > + }
> > +
> > + *p = '\0';
> > +}
> > +
> > +int av_uuid_urn_parse(const char *in, AVUUID uu)
> > +{
> > + return av_uuid_parse(in + 9, uu);
> > +}
> > +
> > +int av_uuid_equal(const AVUUID uu1, const AVUUID uu2)
> > +{
> > + return memcmp(uu1, uu2, AV_UUID_LEN) == 0;
> > +}
> > +
> > +void av_uuid_copy(AVUUID dest, const AVUUID src)
> > +{
> > + memcpy(dest, src, AV_UUID_LEN);
> > +}
> > +
> > +void av_uuid_nil_set(AVUUID uu)
> > +{
> > + memset(uu, 0, AV_UUID_LEN);
>
> These three seem unnecessary. We don't need new public symbols for this
> when we can just state in the doxy that you can copy, compare or zero by
> assignment or zeroing or any such standard method.
I think explicit calls like `av_uuid_nil_set(uu)` are preferable over
`memset(uu, 0, 16)`:
- it makes it easier for folks that are not familiar with UUIDs to
correctly use the library in particular and UUIDs in general
- it makes it easier to find/refactor UUID-related processing across
the codebase
- it is testable (in contrast to documentation)
- it makes the code easier to read IMHO
>
> > +}
> > diff --git a/libavutil/uuid.h b/libavutil/uuid.h
> > new file mode 100644
> > index 0000000000..b5d8166898
> > --- /dev/null
> > +++ b/libavutil/uuid.h
> > @@ -0,0 +1,167 @@
> > +/*
> > + * Copyright (c) 2022 Pierre-Anthony Lemieux <pal at palemieux.com>
> > + * Zane van Iperen <zane at zanevaniperen.com>
> > + *
> > + * This file is part of FFmpeg.
> > + *
> > + * FFmpeg 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.
> > + *
> > + * FFmpeg 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 FFmpeg; if not, write to the Free Software
> > + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
> > + */
> > +
> > +/*
> > + * Copyright (C) 1996, 1997 Theodore Ts'o.
> > + *
> > + * Redistribution and use in source and binary forms, with or without
> > + * modification, are permitted provided that the following conditions
> > + * are met:
> > + * 1. Redistributions of source code must retain the above copyright
> > + * notice, and the entire permission notice in its entirety,
> > + * including the disclaimer of warranties.
> > + * 2. Redistributions in binary form must reproduce the above copyright
> > + * notice, this list of conditions and the following disclaimer in the
> > + * documentation and/or other materials provided with the distribution.
> > + * 3. The name of the author may not be used to endorse or promote
> > + * products derived from this software without specific prior
> > + * written permission.
> > + *
> > + * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
> > + * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
> > + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF
> > + * WHICH ARE HEREBY DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE
> > + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
> > + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
> > + * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
> > + * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
> > + * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
> > + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
> > + * USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH
> > + * DAMAGE.
> > + */
> > +
> > +/**
> > + * @file
> > + * UUID parsing and serialization utilities.
> > + * The library treat the UUID as an opaque sequence of 16 unsigned bytes,
> > + * i.e. ignoring the internal layout of the UUID, which depends on the type
> > + * of the UUID.
> > + *
> > + * @author Pierre-Anthony Lemieux <pal at palemieux.com>
> > + * @author Zane van Iperen <zane at zanevaniperen.com>
> > + */
> > +
> > +#ifndef AVUTIL_UUID_H
> > +#define AVUTIL_UUID_H
> > +
> > +#include <stdint.h>
> > +
> > +#define AV_PRI_UUID \
> > + "%02hhx%02hhx%02hhx%02hhx-%02hhx%02hhx-" \
> > + "%02hhx%02hhx-%02hhx%02hhx-%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx"
> > +
> > +#define AV_PRI_URN_UUID \
> > + "urn:uuid:%02hhx%02hhx%02hhx%02hhx-%02hhx%02hhx-" \
> > + "%02hhx%02hhx-%02hhx%02hhx-%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx"
> > +
> > +/* AV_UUID_ARG() is used together with AV_PRI_UUID() or AV_PRI_URN_UUID
> > + * to print UUIDs, e.g.
> > + * av_log(NULL, AV_LOG_DEBUG, "UUID: " AV_PRI_UUID, AV_UUID_ARG(uuid));
> > + */
> > +#define AV_UUID_ARG(x) \
> > + (x)[0], (x)[1], (x)[2], (x)[3], \
> > + (x)[4], (x)[5], (x)[6], (x)[7], \
> > + (x)[8], (x)[9], (x)[10], (x)[11], \
> > + (x)[12], (x)[13], (x)[14], (x)[15]
> > +
> > +#define AV_UUID_LEN 16
> > +
> > +/* Binary representation of a UUID */
> > +typedef uint8_t AVUUID[AV_UUID_LEN];
> > +
> > +/**
> > + * Parses a string representation of a UUID formatted according to IETF RFC 4122
> > + * into an AVUUID. The parsing is case-insensitive. The string must be 37
> > + * characters long, including the terminating NULL character.
> > + *
> > + * Example string representation: "2fceebd0-7017-433d-bafb-d073a7116696"
> > + *
> > + * @param[in] in String representation of a UUID,
> > + * e.g. 2fceebd0-7017-433d-bafb-d073a7116696
> > + * @param[out] uu AVUUID
> > + * @return A non-zero value in case of an error.
> > + */
> > +int av_uuid_parse(const char *in, AVUUID uu);
> > +
> > +/**
> > + * Parses a URN representation of a UUID, as specified at IETF RFC 4122,
> > + * into an AVUUID. The parsing is case-insensitive. The string must be 46
> > + * characters long, including the terminating NULL character.
> > + *
> > + * Example string representation: "urn:uuid:2fceebd0-7017-433d-bafb-d073a7116696"
> > + *
> > + * @param[in] in URN UUID
> > + * @param[out] uu AVUUID
> > + * @return A non-zero value in case of an error.
> > + */
> > +int av_uuid_urn_parse(const char *in, AVUUID uu);
> > +
> > +/**
> > + * Parses a string representation of a UUID formatted according to IETF RFC 4122
> > + * into an AVUUID. The parsing is case-insensitive. The string must consist of
> > + * 36 characters, i.e. `in_end - in_start == 36`
> > + *
> > + * @param[in] in_start Pointer to the first character of the string representation
> > + * @param[in] in_end Pointer to the character after the last character of the
> > + * string representation. That memory location is never
> > + * accessed
> > + * @param[out] uu AVUUID
> > + * @return A non-zero value in case of an error.
> > + */
> > +int av_uuid_parse_range(const char *in_start, const char *in_end, AVUUID uu);
> > +
> > +/**
> > + * Serializes a AVUUID into a string representation according to IETF RFC 4122.
> > + * The string is lowercase and always 37 characters long, including the
> > + * terminating NULL character.
> > + *
> > + * @param[in] uu AVUUID
> > + * @param[out] out Pointer to a array of no less than 37 characters.
> > + * @return A non-zero value in case of an error.
> > + */
> > +void av_uuid_unparse(const AVUUID uu, char *out);
> > +
> > +/**
> > + * Compares two UUIDs for equality.
> > + *
> > + * @param[in] uu1 AVUUID
> > + * @param[in] uu2 AVUUID
> > + * @return Nonzero if uu1 and uu2 are identical, 0 otherwise
> > + */
> > +int av_uuid_equal(const AVUUID uu1, const AVUUID uu2);
> > +
> > +/**
> > + * Copies the bytes of src into dest.
> > + *
> > + * @param[out] dest AVUUID
> > + * @param[in] src AVUUID
> > + */
> > +void av_uuid_copy(AVUUID dest, const AVUUID src);
> > +
> > +/**
> > + * Sets a UUID to nil
> > + *
> > + * @param[in,out] uu UUID to be set to nil
> > + */
> > +void av_uuid_nil_set(AVUUID uu);
> > +
> > +#endif /* AVUTIL_UUID_H */
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