avformat/aviobuf: add ff_read_line_to_bprint and ff_read_line_to_bprint_overwrite functions

To be able to read lines longer than a static buffer size.
Signed-off-by: Marton Balint <cus@passwd.hu>

libavformat/aviobuf.c

@@ -823,6 +823,52 @@ int ff_get_line(AVIOContext *s, char *buf, int maxlen)
     return i;
 }
 
+int64_t ff_read_line_to_bprint(AVIOContext *s, AVBPrint *bp)
+{
+    int len, end;
+    int64_t read = 0;
+    char tmp[1024];
+    char c;
+
+    do {
+        len = 0;
+        do {
+            c = avio_r8(s);
+            end = (c == '\r' || c == '\n' || c == '\0');
+            if (!end)
+                tmp[len++] = c;
+        } while (!end && len < sizeof(tmp));
+        av_bprint_append_data(bp, tmp, len);
+        read += len;
+    } while (!end);
+
+    if (c == '\r' && avio_r8(s) != '\n' && !avio_feof(s))
+        avio_skip(s, -1);
+
+    if (!c && s->error)
+        return s->error;
+
+    if (!c && !read && avio_feof(s))
+        return AVERROR_EOF;
+
+    return read;
+}
+
+int64_t ff_read_line_to_bprint_overwrite(AVIOContext *s, AVBPrint *bp)
+{
+    int64_t ret;
+
+    av_bprint_clear(bp);
+    ret = ff_read_line_to_bprint(s, bp);
+    if (ret < 0)
+        return ret;
+
+    if (!av_bprint_is_complete(bp))
+        return AVERROR(ENOMEM);
+
+    return bp->len;
+}
+
 int avio_get_str(AVIOContext *s, int maxlen, char *buf, int buflen)
 {
     int i;

libavformat/internal.h

@@ -299,6 +299,32 @@ void ff_put_v(AVIOContext *bc, uint64_t val);
  */
 int ff_get_line(AVIOContext *s, char *buf, int maxlen);
 
+/**
+ * Read a whole line of text from AVIOContext to an AVBPrint buffer. Stop
+ * reading after reaching a \\r, a \\n, a \\r\\n, a \\0 or EOF.  The line
+ * ending characters are NOT included in the buffer, but they are skipped on
+ * the input.
+ *
+ * @param s the read-only AVIOContext
+ * @param bp the AVBPrint buffer
+ * @return the length of the read line, not including the line endings,
+ *         negative on error.
+ */
+int64_t ff_read_line_to_bprint(AVIOContext *s, AVBPrint *bp);
+
+/**
+ * Read a whole line of text from AVIOContext to an AVBPrint buffer overwriting
+ * its contents. Stop reading after reaching a \\r, a \\n, a \\r\\n, a \\0 or
+ * EOF. The line ending characters are NOT included in the buffer, but they
+ * are skipped on the input.
+ *
+ * @param s the read-only AVIOContext
+ * @param bp the AVBPrint buffer
+ * @return the length of the read line not including the line endings,
+ *         negative on error, or if the buffer becomes truncated.
+ */
+int64_t ff_read_line_to_bprint_overwrite(AVIOContext *s, AVBPrint *bp);
+
 #define SPACE_CHARS " \t\r\n"
 
 /**