1 files changed, 99 insertions, 0 deletions
diff --git a/mpjpeg.c b/mpjpeg.c
new file mode 100644
index 0000000..dd4b96e
--- /dev/null
+++ b/mpjpeg.c
@@ -0,0 +1,99 @@
+/* Copyright 2016 Luke Shumaker */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "mpjpeg.h"
+#include "util.h"
+
+#define STARTS_WITH(str, prefix) strncmp(str, prefix, sizeof(prefix)-1)
+
+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;
+}
+
+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) {
+		printf("getting frame\n");
+		s->back->len = -1;
+		/* read the frame header (MIME headers) */
+		line_len = getline(&line_buf, &line_cap, stream);
+		if (strcmp(line_buf, boundary) != 0)
+			return;
+		ssize_t framelen = -1;
+		while (strcmp(line_buf, "\r\n") != 0 && line_len >= 0) {
+			line_len = getline(&line_buf, &line_cap, stream);
+			if (STARTS_WITH(line_buf, "Content-Type:") == 0) {
+				printf("line: <%s>\n", line_buf);
+				s->back->len = atoi(&line_buf[strlen("Content-Type:")]);
+			}
+		}
+		if (s->back->len < 0)
+			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(line_buf, framelen, 1, stream) != 1)
+			return;
+
+		printf("got frame on fd %d\n", fd);
+
+		/* swap the frames */
+		pthread_mutex_lock(&s->frontlock);
+		struct frame *tmp = s->front;
+		s->front = s->back;
+		s->back = tmp;
+		pthread_mutex_unlock(&s->frontlock);
+	}
+
+}
+
+void mpjpeg_writer(struct mpjpeg_stream *s, int fd, const char *boundary) {
+	struct frame myframe = { 0 };
+	struct frame *lastframe = NULL;
+	while(1) {
+		/* get the most recent frame (copy front to myframe) */
+		pthread_mutex_lock(&s->frontlock);
+		if (s->front == lastframe) { /* TODO: use a pthread_cond_t instead of a busy loop */
+			pthread_mutex_unlock(&s->frontlock);
+			continue;
+		}
+		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->front;
+		pthread_mutex_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)
+			return;
+		if (write(fd, myframe.data, myframe.len) < myframe.len)
+			return;
+	}
+}
+
+void init_mpjpeg_stream(struct mpjpeg_stream *s) {
+	ZERO(s->a);
+	ZERO(s->b);
+	s->front = &s->a;
+	s->back = &s->b;
+	pthread_mutex_init(&s->frontlock, NULL);
+}