1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
|
/* Copyright 2016 Luke Shumaker */
#include <errno.h>
#include <error.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "mpjpeg.h"
#include "util.h"
static
char *boundary_line(const char *old) {
size_t len = strlen(old);
char *new = xrealloc(NULL, len+5);
new[0] = '-';
new[1] = '-';
strcpy(&new[2], old);
new[2+len+0] = '\r';
new[2+len+1] = '\n';
new[2+len+2] = '\0';
return new;
}
static
ssize_t safe_atoi(char *str) {
while (*str == ' ')
str++;
size_t len = 0;
while ('0' <= str[len] && str[len] <= '9')
len++;
size_t i = len;
while (str[i] == ' ')
i++;
if (len < 1 || strcmp(&str[i], "\r\n") != 0)
return -1;
return atoi(str);
}
void mpjpeg_reader(struct mpjpeg_stream *s, int fd, const char *boundary) {
FILE *stream = fdopen(fd, "r");
boundary = boundary_line(boundary);
char *line_buf = NULL;
size_t line_cap = 0;
ssize_t line_len = 0;
while (1) {
s->back->len = -1;
/* scan for the first non-empty line */
do {
line_len = getline(&line_buf, &line_cap, stream);
} while (line_len >= 0 && strcmp(line_buf, "\r\n") == 0);
/* make sure it matches the boundary separator */
if (strcmp(line_buf, boundary) != 0) {
error(0, 0, "line does not match boundary: \"%s\"", line_buf);
return;
}
/* read the frame header (MIME headers) */
while (strcmp(line_buf, "\r\n") != 0 && line_len >= 0) {
line_len = getline(&line_buf, &line_cap, stream);
if (strncasecmp(line_buf, "Content-length:", strlen("Content-length:")) == 0) {
s->back->len = safe_atoi(&line_buf[strlen("Content-length:")]);
}
}
if (s->back->len < 0) {
error(0, 0, "did not get frame length");
return;
}
/* read the frame contents (JPEG) */
if (s->back->cap < (size_t)s->back->len)
s->back->data = xrealloc(s->back->data, s->back->cap = s->back->len);
if (fread(s->back->data, s->back->len, 1, stream) != 1) {
error(0, ferror(stream), "fread(%zd)", s->back->len);
return;
}
/* swap the frames */
pthread_rwlock_wrlock(&s->frontlock);
struct frame *tmp = s->front;
s->front = s->back;
s->back = tmp;
s->framecount++;
pthread_rwlock_unlock(&s->frontlock);
}
}
void mpjpeg_writer(struct mpjpeg_stream *s, int fd, const char *boundary) {
struct frame myframe = { 0 };
long lastframe = 0;
pthread_rwlock_rdlock(&s->frontlock);
while(1) {
/* get the most recent frame (copy front to myframe) */
if (myframe.cap < (size_t)s->front->len)
myframe.data = xrealloc(myframe.data, myframe.cap = s->front->len);
memcpy(myframe.data, s->front->data, myframe.len = s->front->len);
lastframe = s->framecount;
pthread_rwlock_unlock(&s->frontlock);
/* send the frame to the client */
if (dprintf(fd, "--%s\r\nContent-Type: image/jpeg\r\nContent-Length: %zd\r\n\r\n", boundary, myframe.len) < 0) {
error(0, errno, "dprintf");
return;
}
if (write(fd, myframe.data, myframe.len) < myframe.len) {
error(0, errno, "write");
return;
}
/* poll until there's a new frame */
pthread_rwlock_rdlock(&s->frontlock);
while (s->framecount == lastframe) {
pthread_rwlock_unlock(&s->frontlock);
usleep(30000); /* a bit over 30 FPS */
pthread_rwlock_rdlock(&s->frontlock);
}
}
}
void init_mpjpeg_stream(struct mpjpeg_stream *s) {
ZERO(s->a);
ZERO(s->b);
s->front = &s->a;
s->back = &s->b;
pthread_rwlock_init(&s->frontlock, NULL);
}
|
