lavf: move srtdec:read_chunk() to subtitles utils.

This function can be useful for various other subtitles formats.

1 files changed, 46 insertions, 0 deletions

diff --git a/libavformat/subtitles.c b/libavformat/subtitles.c
index b264ec5e05..4088cf344d 100644
--- a/libavformat/subtitles.c
+++ b/libavformat/subtitles.c
@@ -192,3 +192,49 @@ const char *ff_smil_get_attr_ptr(const char *s, const char *attr)
     }
     return NULL;
 }
+
+static inline int is_eol(char c)
+{
+    return c == '\r' || c == '\n';
+}
+
+void ff_subtitles_read_chunk(AVIOContext *pb, AVBPrint *buf)
+{
+    char eol_buf[5];
+    int n = 0, i = 0, nb_eol = 0;
+
+    av_bprint_clear(buf);
+
+    for (;;) {
+        char c = avio_r8(pb);
+
+        if (!c)
+            break;
+
+        /* ignore all initial line breaks */
+        if (n == 0 && is_eol(c))
+            continue;
+
+        /* line break buffering: we don't want to add the trailing \r\n */
+        if (is_eol(c)) {
+            nb_eol += c == '\n';
+            if (nb_eol == 2)
+                break;
+            eol_buf[i++] = c;
+            if (i == sizeof(eol_buf) - 1)
+                break;
+            continue;
+        }
+
+        /* only one line break followed by data: we flush the line breaks
+         * buffer */
+        if (i) {
+            eol_buf[i] = 0;
+            av_bprintf(buf, "%s", eol_buf);
+            i = nb_eol = 0;
+        }
+
+        av_bprint_chars(buf, c, 1);
+        n++;
+    }
+}