[FFmpeg-devel] [PATCH v2 2/6] avformat/srtdec: UTF-16 support
wm4
nfxjfg at googlemail.com
Thu Sep 4 22:40:23 CEST 2014
---
ff_subtitles_read_line() now returns an error if a 0 byte is
encountered. This is faster and could be considered more correct.
It also handles UTF recode errors better.
---
libavformat/srtdec.c | 25 +++++++++++++-----------
libavformat/subtitles.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++--
libavformat/subtitles.h | 36 +++++++++++++++++++++++++++++++---
3 files changed, 96 insertions(+), 16 deletions(-)
diff --git a/libavformat/srtdec.c b/libavformat/srtdec.c
index 53182cd..b63d344 100644
--- a/libavformat/srtdec.c
+++ b/libavformat/srtdec.c
@@ -31,20 +31,21 @@ typedef struct {
static int srt_probe(AVProbeData *p)
{
- const unsigned char *ptr = p->buf;
int i, v, num = 0;
+ FFTextReader tr;
- if (AV_RB24(ptr) == 0xEFBBBF)
- ptr += 3; /* skip UTF-8 BOM */
+ ff_text_init_buf(&tr, p->buf, p->buf_size);
- while (*ptr == '\r' || *ptr == '\n')
- ptr++;
+ while (ff_text_peek_r8(&tr) == '\r' || ff_text_peek_r8(&tr) == '\n')
+ ff_text_r8(&tr);
for (i=0; i<2; i++) {
+ char buf[128];
+ if (ff_subtitles_read_line(&tr, buf, sizeof(buf)) < 0)
+ break;
if ((num == i || num + 1 == i)
- && sscanf(ptr, "%*d:%*2d:%*2d%*1[,.]%*3d --> %*d:%*2d:%*2d%*1[,.]%3d", &v) == 1)
+ && sscanf(buf, "%*d:%*2d:%*2d%*1[,.]%*3d --> %*d:%*2d:%*2d%*1[,.]%3d", &v) == 1)
return AVPROBE_SCORE_MAX;
- num = atoi(ptr);
- ptr += ff_subtitles_next_line(ptr);
+ num = atoi(buf);
}
return 0;
}
@@ -79,6 +80,8 @@ static int srt_read_header(AVFormatContext *s)
AVBPrint buf;
AVStream *st = avformat_new_stream(s, NULL);
int res = 0;
+ FFTextReader tr;
+ ff_text_init_avio(&tr, s->pb);
if (!st)
return AVERROR(ENOMEM);
@@ -88,11 +91,11 @@ static int srt_read_header(AVFormatContext *s)
av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
- while (!avio_feof(s->pb)) {
- ff_subtitles_read_chunk(s->pb, &buf);
+ while (!ff_text_eof(&tr)) {
+ ff_subtitles_read_text_chunk(&tr, &buf);
if (buf.len) {
- int64_t pos = avio_tell(s->pb);
+ int64_t pos = ff_text_pos(&tr);
int64_t pts;
int duration;
const char *ptr = buf.str;
diff --git a/libavformat/subtitles.c b/libavformat/subtitles.c
index cebd453..05d52c3 100644
--- a/libavformat/subtitles.c
+++ b/libavformat/subtitles.c
@@ -86,6 +86,23 @@ void ff_text_read(FFTextReader *r, char *buf, size_t size)
*buf++ = ff_text_r8(r);
}
+int ff_text_eof(FFTextReader *r)
+{
+ return r->buf_pos >= r->buf_len && (!r->pb || avio_feof(r->pb));
+}
+
+int ff_text_peek_r8(FFTextReader *r)
+{
+ int c;
+ if (r->buf_pos < r->buf_len)
+ return r->buf[r->buf_pos];
+ c = ff_text_r8(r);
+ r->buf_pos = 0;
+ r->buf_len = 1;
+ r->buf[0] = c;
+ return c;
+}
+
AVPacket *ff_subtitles_queue_insert(FFDemuxSubtitlesQueue *q,
const uint8_t *event, int len, int merge)
{
@@ -303,7 +320,7 @@ static inline int is_eol(char c)
return c == '\r' || c == '\n';
}
-void ff_subtitles_read_chunk(AVIOContext *pb, AVBPrint *buf)
+void ff_subtitles_read_text_chunk(FFTextReader *tr, AVBPrint *buf)
{
char eol_buf[5], last_was_cr = 0;
int n = 0, i = 0, nb_eol = 0;
@@ -311,7 +328,7 @@ void ff_subtitles_read_chunk(AVIOContext *pb, AVBPrint *buf)
av_bprint_clear(buf);
for (;;) {
- char c = avio_r8(pb);
+ char c = ff_text_r8(tr);
if (!c)
break;
@@ -344,3 +361,33 @@ void ff_subtitles_read_chunk(AVIOContext *pb, AVBPrint *buf)
n++;
}
}
+
+void ff_subtitles_read_chunk(AVIOContext *pb, AVBPrint *buf)
+{
+ FFTextReader tr;
+ tr.buf_pos = tr.buf_len = 0;
+ tr.type = 0;
+ tr.pb = pb;
+ ff_subtitles_read_text_chunk(&tr, buf);
+}
+
+ptrdiff_t ff_subtitles_read_line(FFTextReader *tr, char *buf, size_t size)
+{
+ size_t cur = 0;
+ if (!size)
+ return 0;
+ while (cur + 1 < size) {
+ unsigned char c = ff_text_r8(tr);
+ if (!c)
+ return AVERROR_INVALIDDATA;
+ if (c == '\r' || c == '\n')
+ break;
+ buf[cur++] = c;
+ buf[cur] = '\0';
+ }
+ if (ff_text_peek_r8(tr) == '\r')
+ ff_text_r8(tr);
+ if (ff_text_peek_r8(tr) == '\n')
+ ff_text_r8(tr);
+ return cur;
+}
diff --git a/libavformat/subtitles.h b/libavformat/subtitles.h
index 317e40a..d70c9ef 100644
--- a/libavformat/subtitles.h
+++ b/libavformat/subtitles.h
@@ -22,6 +22,7 @@
#define AVFORMAT_SUBTITLES_H
#include <stdint.h>
+#include <stddef.h>
#include "avformat.h"
#include "libavutil/bprint.h"
@@ -82,6 +83,18 @@ int64_t ff_text_pos(FFTextReader *r);
int ff_text_r8(FFTextReader *r);
/**
+ * Return non-zero if EOF was reached.
+ */
+int ff_text_eof(FFTextReader *r);
+
+/**
+ * Like ff_text_r8(), but don't remove the byte from the buffer.
+ *
+ * @note ff_text_eof might incorrectly return true after calling this
+ */
+int ff_text_peek_r8(FFTextReader *r);
+
+/**
* Read the given number of bytes (in UTF-8). On error or EOF, \0 bytes are
* written.
*/
@@ -145,19 +158,24 @@ int ff_smil_extract_next_chunk(AVIOContext *pb, AVBPrint *buf, char *c);
const char *ff_smil_get_attr_ptr(const char *s, const char *attr);
/**
- * @brief Read a subtitles chunk.
+ * @brief Same as ff_subtitles_read_text_chunk(), but read from an AVIOContext.
+ */
+void ff_subtitles_read_chunk(AVIOContext *pb, AVBPrint *buf);
+
+/**
+ * @brief Read a subtitles chunk from FFTextReader.
*
* A chunk is defined by a multiline "event", ending with a second line break.
* The trailing line breaks are trimmed. CRLF are supported.
* Example: "foo\r\nbar\r\n\r\nnext" will print "foo\r\nbar" into buf, and pb
* will focus on the 'n' of the "next" string.
*
- * @param pb I/O context
+ * @param tr I/O context
* @param buf an initialized buf where the chunk is written
*
* @note buf is cleared before writing into it.
*/
-void ff_subtitles_read_chunk(AVIOContext *pb, AVBPrint *buf);
+void ff_subtitles_read_text_chunk(FFTextReader *tr, AVBPrint *buf);
/**
* Get the number of characters to increment to jump to the next line, or to
@@ -178,4 +196,16 @@ static av_always_inline int ff_subtitles_next_line(const char *ptr)
return n;
}
+/**
+ * Read a line of text. Discards line ending characters.
+ * The function handles the following line breaks schemes:
+ * LF, CRLF (MS), or standalone CR (old MacOS).
+ *
+ * Returns the number of bytes written to buf. Always writes a terminating 0,
+ * similar as with snprintf.
+ *
+ * @note returns a negative error code if a \0 byte is found
+ */
+ptrdiff_t ff_subtitles_read_line(FFTextReader *tr, char *buf, size_t size);
+
#endif /* AVFORMAT_SUBTITLES_H */
--
2.1.0
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