FFmpeg
uuid.c
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1 /*
2  * Copyright (c) 2022 Pierre-Anthony Lemieux <pal@palemieux.com>
3  * Zane van Iperen <zane@zanevaniperen.com>
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
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12  * FFmpeg is distributed in the hope that it will be useful,
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15  * Lesser General Public License for more details.
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19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 /*
23  * Copyright (C) 1996, 1997 Theodore Ts'o.
24  *
25  * Redistribution and use in source and binary forms, with or without
26  * modification, are permitted provided that the following conditions
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50  */
51 
52 /**
53  * @file
54  * UUID parsing and serialization utilities.
55  * The library treat the UUID as an opaque sequence of 16 unsigned bytes,
56  * i.e. ignoring the internal layout of the UUID, which depends on the type
57  * of the UUID.
58  *
59  * @author Pierre-Anthony Lemieux <pal@palemieux.com>
60  * @author Zane van Iperen <zane@zanevaniperen.com>
61  */
62 
63 #include "uuid.h"
64 #include "error.h"
65 #include "avstring.h"
66 
67 int av_uuid_parse(const char *in, AVUUID uu)
68 {
69  if (strlen(in) != 36)
70  return AVERROR(EINVAL);
71 
72  return av_uuid_parse_range(in, in + 36, uu);
73 }
74 
75 static int xdigit_to_int(char c)
76 {
77  c = av_tolower(c);
78 
79  if (c >= 'a' && c <= 'f')
80  return c - 'a' + 10;
81 
82  if (c >= '0' && c <= '9')
83  return c - '0';
84 
85  return -1;
86 }
87 
88 int av_uuid_parse_range(const char *in_start, const char *in_end, AVUUID uu)
89 {
90  int i;
91  const char *cp;
92 
93  if ((in_end - in_start) != 36)
94  return AVERROR(EINVAL);
95 
96  for (i = 0, cp = in_start; i < 16; i++) {
97  int hi;
98  int lo;
99 
100  if (i == 4 || i == 6 || i == 8 || i == 10)
101  cp++;
102 
103  hi = xdigit_to_int(*cp++);
104  lo = xdigit_to_int(*cp++);
105 
106  if (hi == -1 || lo == -1)
107  return AVERROR(EINVAL);
108 
109  uu[i] = (hi << 4) + lo;
110  }
111 
112  return 0;
113 }
114 
115 static const char hexdigits_lower[16] = "0123456789abcdef";
116 
117 void av_uuid_unparse(const AVUUID uuid, char *out)
118 {
119  char *p = out;
120 
121  for (int i = 0; i < 16; i++) {
122  uint8_t tmp;
123 
124  if (i == 4 || i == 6 || i == 8 || i == 10)
125  *p++ = '-';
126 
127  tmp = uuid[i];
128  *p++ = hexdigits_lower[tmp >> 4];
129  *p++ = hexdigits_lower[tmp & 15];
130  }
131 
132  *p = '\0';
133 }
134 
135 int av_uuid_urn_parse(const char *in, AVUUID uu)
136 {
137  if (av_stristr(in, "urn:uuid:") != in)
138  return AVERROR(EINVAL);
139 
140  return av_uuid_parse(in + 9, uu);
141 }
AVERROR
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later. That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another. Frame references ownership and permissions
AVUUID
uint8_t AVUUID[AV_UUID_LEN]
Definition: uuid.h:60
out
FILE * out
Definition: movenc.c:54
av_stristr
char * av_stristr(const char *s1, const char *s2)
Locate the first case-independent occurrence in the string haystack of the string needle.
Definition: avstring.c:59
tmp
static uint8_t tmp[11]
Definition: aes_ctr.c:28
av_uuid_unparse
void av_uuid_unparse(const AVUUID uuid, char *out)
Serializes a AVUUID into a string representation according to IETF RFC 4122.
Definition: uuid.c:117
c
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
Definition: undefined.txt:32
error.h
hexdigits_lower
static const char hexdigits_lower[16]
Definition: uuid.c:115
av_uuid_parse
int av_uuid_parse(const char *in, AVUUID uu)
Parses a string representation of a UUID formatted according to IETF RFC 4122 into an AVUUID.
Definition: uuid.c:67
uuid.h
xdigit_to_int
static int xdigit_to_int(char c)
Definition: uuid.c:75
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:269
av_uuid_parse_range
int av_uuid_parse_range(const char *in_start, const char *in_end, AVUUID uu)
Parses a string representation of a UUID formatted according to IETF RFC 4122 into an AVUUID.
Definition: uuid.c:88
avstring.h
av_tolower
static av_const int av_tolower(int c)
Locale-independent conversion of ASCII characters to lowercase.
Definition: avstring.h:247
av_uuid_urn_parse
int av_uuid_urn_parse(const char *in, AVUUID uu)
Parses a URN representation of a UUID, as specified at IETF RFC 4122, into an AVUUID.
Definition: uuid.c:135