/* GStreamer EBML I/O
* (c) 2003 Ronald Bultje <rbultje@ronald.bitfreak.net>
*
* ebml-read.c: read EBML data from file/stream
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <string.h>
#include "ebml-read.h"
#include "ebml-ids.h"
#include <gst/math-compat.h>
GST_DEBUG_CATEGORY (ebmlread_debug);
#define GST_CAT_DEFAULT ebmlread_debug
/* Peeks following element id and element length in datastream provided
* by @peek with @ctx as user data.
* Returns GST_FLOW_EOS if not enough data to read id and length.
* Otherwise, @needed provides the prefix length (id + length), and
* @length provides element length.
*
* @object and @offset are provided for informative messaging/debug purposes.
*/
GstFlowReturn
gst_ebml_peek_id_length (guint32 * _id, guint64 * _length, guint * _needed,
GstPeekData peek, gpointer * ctx, GstElement * el, guint64 offset)
{
guint needed;
const guint8 *buf;
gint len_mask = 0x80, read = 1, n = 1, num_ffs = 0;
guint64 total;
guint8 b;
GstFlowReturn ret;
g_return_val_if_fail (_id != NULL, GST_FLOW_ERROR);
g_return_val_if_fail (_length != NULL, GST_FLOW_ERROR);
g_return_val_if_fail (_needed != NULL, GST_FLOW_ERROR);
/* well ... */
*_id = (guint32) GST_EBML_SIZE_UNKNOWN;
*_length = GST_EBML_SIZE_UNKNOWN;
/* read element id */
needed = 2;
ret = peek (ctx, needed, &buf);
if (ret != GST_FLOW_OK)
goto peek_error;
b = GST_READ_UINT8 (buf);
total = (guint64) b;
while (read <= 4 && !(total & len_mask)) {
read++;
len_mask >>= 1;
}
if (G_UNLIKELY (read > 4))
goto invalid_id;
/* need id and at least something for subsequent length */
needed = read + 1;
ret = peek (ctx, needed, &buf);
if (ret != GST_FLOW_OK)
goto peek_error;
while (n < read) {
b = GST_READ_UINT8 (buf + n);
total = (total << 8) | b;
++n;
}
*_id = (guint32) total;
/* read element length */
b = GST_READ_UINT8 (buf + n);
total = (guint64) b;
len_mask = 0x80;
read = 1;
while (read <= 8 && !(total & len_mask)) {
read++;
len_mask >>= 1;
}
if (G_UNLIKELY (read > 8))
goto invalid_length;
if ((total &= (len_mask - 1)) == len_mask - 1)
num_ffs++;
needed += read - 1;
ret = peek (ctx, needed, &buf);
if (ret != GST_FLOW_OK)
goto peek_error;
buf += (needed - read);
n = 1;
while (n < read) {
guint8 b = GST_READ_UINT8 (buf + n);
if (G_UNLIKELY (b == 0xff))
num_ffs++;
total = (total << 8) | b;
++n;
}
if (G_UNLIKELY (read == num_ffs))
*_length = G_MAXUINT64;
else
*_length = total;
*_needed = needed;
return GST_FLOW_OK;
/* ERRORS */
peek_error:
{
if (ret != GST_FLOW_FLUSHING && ret != GST_FLOW_EOS)
GST_WARNING_OBJECT (el, "peek failed, ret = %s", gst_flow_get_name (ret));
else
GST_DEBUG_OBJECT (el, "peek failed, ret = %s", gst_flow_get_name (ret));
*_needed = needed;
return ret;
}
invalid_id:
{
GST_ERROR_OBJECT (el,
"Invalid EBML ID size tag (0x%x) at position %" G_GUINT64_FORMAT " (0x%"
G_GINT64_MODIFIER "x)", (guint) b, offset, offset);
return GST_FLOW_ERROR;
}
invalid_length:
{
GST_ERROR_OBJECT (el,
"Invalid EBML length size tag (0x%x) at position %" G_GUINT64_FORMAT
" (0x%" G_GINT64_MODIFIER "x)", (guint) b, offset, offset);
return GST_FLOW_ERROR;
}
}
/* setup for parsing @buf at position @offset on behalf of @el.
* Takes ownership of @buf. */
void
gst_ebml_read_init (GstEbmlRead * ebml, GstElement * el, GstBuffer * buf,
guint64 offset)
{
GstEbmlMaster m;
g_return_if_fail (el);
g_return_if_fail (buf);
ebml->el = el;
ebml->offset = offset;
ebml->buf = buf;
gst_buffer_map (buf, &ebml->map, GST_MAP_READ);
ebml->readers = g_array_sized_new (FALSE, FALSE, sizeof (GstEbmlMaster), 10);
m.offset = ebml->offset;
gst_byte_reader_init (&m.br, ebml->map.data, ebml->map.size);
g_array_append_val (ebml->readers, m);
}
void
gst_ebml_read_clear (GstEbmlRead * ebml)
{
if (ebml->readers)
g_array_free (ebml->readers, TRUE);
ebml->readers = NULL;
if (ebml->buf) {
gst_buffer_unmap (ebml->buf, &ebml->map);
gst_buffer_unref (ebml->buf);
}
ebml->buf = NULL;
ebml->el = NULL;
}
static GstFlowReturn
gst_ebml_read_peek (GstByteReader * br, guint peek, const guint8 ** data)
{
if (G_LIKELY (gst_byte_reader_peek_data (br, peek, data)))
return GST_FLOW_OK;
else
return GST_FLOW_EOS;
}
static GstFlowReturn
gst_ebml_peek_id_full (GstEbmlRead * ebml, guint32 * id, guint64 * length,
guint * prefix)
{
GstFlowReturn ret;
ret = gst_ebml_peek_id_length (id, length, prefix,
(GstPeekData) gst_ebml_read_peek, (gpointer) gst_ebml_read_br (ebml),
ebml->el, gst_ebml_read_get_pos (ebml));
if (ret != GST_FLOW_OK)
return ret;
GST_LOG_OBJECT (ebml->el, "id 0x%x at offset 0x%" G_GINT64_MODIFIER "x"
" of length %" G_GUINT64_FORMAT ", prefix %d", *id,
gst_ebml_read_get_pos (ebml), *length, *prefix);
#ifndef GST_DISABLE_GST_DEBUG
if (ebmlread_debug->threshold >= GST_LEVEL_LOG) {
const guint8 *data = NULL;
GstByteReader *br = gst_ebml_read_br (ebml);
guint size = gst_byte_reader_get_remaining (br);
if (gst_byte_reader_peek_data (br, size, &data)) {
GST_LOG_OBJECT (ebml->el, "current br %p; remaining %d", br, size);
if (data)
GST_MEMDUMP_OBJECT (ebml->el, "element", data, MIN (size, *length));
}
}
#endif
return ret;
}
GstFlowReturn
gst_ebml_peek_id (GstEbmlRead * ebml, guint32 * id)
{
guint64 length;
guint needed;
return gst_ebml_peek_id_full (ebml, id, &length, &needed);
}
/*
* Read the next element, the contents are supposed to be sub-elements which
* can be read separately. A new bytereader is setup for doing so.
*/
GstFlowReturn
gst_ebml_read_master (GstEbmlRead * ebml, guint32 * id)
{
guint64 length;
guint prefix;
const guint8 *data = NULL;
GstFlowReturn ret;
GstEbmlMaster m;
ret = gst_ebml_peek_id_full (ebml, id, &length, &prefix);
if (ret != GST_FLOW_OK)
return ret;
/* we just at least peeked the id */
if (!gst_byte_reader_skip (gst_ebml_read_br (ebml), prefix))
return GST_FLOW_ERROR; /* FIXME: do proper error handling */
m.offset = gst_ebml_read_get_pos (ebml);
if (!gst_byte_reader_get_data (gst_ebml_read_br (ebml), length, &data))
return GST_FLOW_PARSE;
GST_LOG_OBJECT (ebml->el, "pushing level %d at offset %" G_GUINT64_FORMAT,
ebml->readers->len, m.offset);
gst_byte_reader_init (&m.br, data, length);
g_array_append_val (ebml->readers, m);
return GST_FLOW_OK;
}
/* explicitly pop a bytereader from stack. Usually invoked automagically. */
GstFlowReturn
gst_ebml_read_pop_master (GstEbmlRead * ebml)
{
g_return_val_if_fail (ebml->readers, GST_FLOW_ERROR);
/* never remove initial bytereader */
if (ebml->readers->len > 1) {
GST_LOG_OBJECT (ebml->el, "popping level %d", ebml->readers->len - 1);
g_array_remove_index (ebml->readers, ebml->readers->len - 1);
}
return GST_FLOW_OK;
}
/*
* Skip the next element.
*/
GstFlowReturn
gst_ebml_read_skip (GstEbmlRead * ebml)
{
guint64 length;
guint32 id;
guint prefix;
GstFlowReturn ret;
ret = gst_ebml_peek_id_full (ebml, &id, &length, &prefix);
if (ret != GST_FLOW_OK)
return ret;
if (!gst_byte_reader_skip (gst_ebml_read_br (ebml), length + prefix))
return GST_FLOW_PARSE;
return ret;
}
/*
* Read the next element as a GstBuffer (binary).
*/
GstFlowReturn
gst_ebml_read_buffer (GstEbmlRead * ebml, guint32 * id, GstBuffer ** buf)
{
guint64 length;
guint prefix;
GstFlowReturn ret;
ret = gst_ebml_peek_id_full (ebml, id, &length, &prefix);
if (ret != GST_FLOW_OK)
return ret;
/* we just at least peeked the id */
if (!gst_byte_reader_skip (gst_ebml_read_br (ebml), prefix))
return GST_FLOW_ERROR; /* FIXME: do proper error handling */
if (G_LIKELY (length > 0)) {
guint offset;
offset = gst_ebml_read_get_pos (ebml) - ebml->offset;
if (G_LIKELY (gst_byte_reader_skip (gst_ebml_read_br (ebml), length))) {
*buf = gst_buffer_copy_region (ebml->buf, GST_BUFFER_COPY_ALL,
offset, length);
} else {
*buf = NULL;
return GST_FLOW_PARSE;
}
} else {
*buf = gst_buffer_new ();
}
return ret;
}
/*
* Read the next element, return a pointer to it and its size.
*/
static GstFlowReturn
gst_ebml_read_bytes (GstEbmlRead * ebml, guint32 * id, const guint8 ** data,
guint * size)
{
guint64 length;
guint prefix;
GstFlowReturn ret;
*size = 0;
ret = gst_ebml_peek_id_full (ebml, id, &length, &prefix);
if (ret != GST_FLOW_OK)
return ret;
/* we just at least peeked the id */
if (!gst_byte_reader_skip (gst_ebml_read_br (ebml), prefix))
return GST_FLOW_ERROR; /* FIXME: do proper error handling */
*data = NULL;
if (G_LIKELY (length > 0)) {
if (!gst_byte_reader_get_data (gst_ebml_read_br (ebml), length, data))
return GST_FLOW_PARSE;
}
*size = length;
return ret;
}
/*
* Read the next element as an unsigned int.
*/
GstFlowReturn
gst_ebml_read_uint (GstEbmlRead * ebml, guint32 * id, guint64 * num)
{
const guint8 *data;
guint size;
GstFlowReturn ret;
ret = gst_ebml_read_bytes (ebml, id, &data, &size);
if (ret != GST_FLOW_OK)
return ret;
if (size > 8) {
GST_ERROR_OBJECT (ebml->el,
"Invalid integer element size %d at position %" G_GUINT64_FORMAT " (0x%"
G_GINT64_MODIFIER "x)", size, gst_ebml_read_get_pos (ebml) - size,
gst_ebml_read_get_pos (ebml) - size);
return GST_FLOW_ERROR;
}
if (size == 0) {
*num = 0;
return ret;
}
*num = 0;
while (size > 0) {
*num = (*num << 8) | *data;
size--;
data++;
}
return ret;
}
/*
* Read the next element as a signed int.
*/
GstFlowReturn
gst_ebml_read_sint (GstEbmlRead * ebml, guint32 * id, gint64 * num)
{
const guint8 *data;
guint size;
gboolean negative = 0;
GstFlowReturn ret;
ret = gst_ebml_read_bytes (ebml, id, &data, &size);
if (ret != GST_FLOW_OK)
return ret;
if (size > 8) {
GST_ERROR_OBJECT (ebml->el,
"Invalid integer element size %d at position %" G_GUINT64_FORMAT " (0x%"
G_GINT64_MODIFIER "x)", size, gst_ebml_read_get_pos (ebml) - size,
gst_ebml_read_get_pos (ebml) - size);
return GST_FLOW_ERROR;
}
if (size == 0) {
*num = 0;
return ret;
}
*num = 0;
if (*data & 0x80) {
negative = 1;
*num = *data & ~0x80;
size--;
data++;
}
while (size > 0) {
*num = (*num << 8) | *data;
size--;
data++;
}
/* make signed */
if (negative) {
*num = 0 - *num;
}
return ret;
}
/* Convert 80 bit extended precision float in big endian format to double.
* Code taken from libavutil/intfloat_readwrite.c from ffmpeg,
* licensed under LGPL */
struct _ext_float
{
guint8 exponent[2];
guint8 mantissa[8];
};
static gdouble
_ext2dbl (const guint8 * data)
{
struct _ext_float ext;
guint64 m = 0;
gint e, i;
memcpy (&ext.exponent, data, 2);
memcpy (&ext.mantissa, data + 2, 8);
for (i = 0; i < 8; i++)
m = (m << 8) + ext.mantissa[i];
e = (((gint) ext.exponent[0] & 0x7f) << 8) | ext.exponent[1];
if (e == 0x7fff && m)
return NAN;
e -= 16383 + 63; /* In IEEE 80 bits, the whole (i.e. 1.xxxx)
* mantissa bit is written as opposed to the
* single and double precision formats */
if (ext.exponent[0] & 0x80)
m = -m;
return ldexp (m, e);
}
/*
* Read the next element as a float.
*/
GstFlowReturn
gst_ebml_read_float (GstEbmlRead * ebml, guint32 * id, gdouble * num)
{
const guint8 *data;
guint size;
GstFlowReturn ret;
ret = gst_ebml_read_bytes (ebml, id, &data, &size);
if (ret != GST_FLOW_OK)
return ret;
if (size != 0 && size != 4 && size != 8 && size != 10) {
GST_ERROR_OBJECT (ebml->el,
"Invalid float element size %d at position %" G_GUINT64_FORMAT " (0x%"
G_GINT64_MODIFIER "x)", size, gst_ebml_read_get_pos (ebml) - size,
gst_ebml_read_get_pos (ebml) - size);
return GST_FLOW_ERROR;
}
if (size == 4) {
gfloat f;
memcpy (&f, data, 4);
f = GFLOAT_FROM_BE (f);
*num = f;
} else if (size == 8) {
gdouble d;
memcpy (&d, data, 8);
d = GDOUBLE_FROM_BE (d);
*num = d;
} else if (size == 10) {
*num = _ext2dbl (data);
} else {
/* size == 0 means a value of 0.0 */
*num = 0.0;
}
return ret;
}
/*
* Read the next element as a C string.
*/
static GstFlowReturn
gst_ebml_read_string (GstEbmlRead * ebml, guint32 * id, gchar ** str)
{
const guint8 *data;
guint size;
GstFlowReturn ret;
ret = gst_ebml_read_bytes (ebml, id, &data, &size);
if (ret != GST_FLOW_OK)
return ret;
*str = g_malloc (size + 1);
memcpy (*str, data, size);
(*str)[size] = '\0';
return ret;
}
/*
* Read the next element as an ASCII string.
*/
GstFlowReturn
gst_ebml_read_ascii (GstEbmlRead * ebml, guint32 * id, gchar ** str_out)
{
GstFlowReturn ret;
gchar *str;
gchar *iter;
#ifndef GST_DISABLE_GST_DEBUG
guint64 oldoff = ebml->offset;
#endif
ret = gst_ebml_read_string (ebml, id, &str);
if (ret != GST_FLOW_OK)
return ret;
for (iter = str; *iter != '\0'; iter++) {
if (G_UNLIKELY (*iter & 0x80)) {
GST_ERROR_OBJECT (ebml,
"Invalid ASCII string at offset %" G_GUINT64_FORMAT, oldoff);
g_free (str);
return GST_FLOW_ERROR;
}
}
*str_out = str;
return ret;
}
/*
* Read the next element as a UTF-8 string.
*/
GstFlowReturn
gst_ebml_read_utf8 (GstEbmlRead * ebml, guint32 * id, gchar ** str)
{
GstFlowReturn ret;
#ifndef GST_DISABLE_GST_DEBUG
guint64 oldoff = gst_ebml_read_get_pos (ebml);
#endif
ret = gst_ebml_read_string (ebml, id, str);
if (ret != GST_FLOW_OK)
return ret;
if (str != NULL && *str != NULL && **str != '\0' &&
!g_utf8_validate (*str, -1, NULL)) {
GST_WARNING_OBJECT (ebml->el,
"Invalid UTF-8 string at offset %" G_GUINT64_FORMAT, oldoff);
}
return ret;
}
/*
* Read the next element as a date.
* Returns the seconds since the unix epoch.
*/
GstFlowReturn
gst_ebml_read_date (GstEbmlRead * ebml, guint32 * id, gint64 * date)
{
gint64 ebml_date;
GstFlowReturn ret;
ret = gst_ebml_read_sint (ebml, id, &ebml_date);
if (ret != GST_FLOW_OK)
return ret;
*date = (ebml_date / GST_SECOND) + GST_EBML_DATE_OFFSET;
return ret;
}
/*
* Read the next element as binary data.
*/
GstFlowReturn
gst_ebml_read_binary (GstEbmlRead * ebml,
guint32 * id, guint8 ** binary, guint64 * length)
{
const guint8 *data;
guint size;
GstFlowReturn ret;
ret = gst_ebml_read_bytes (ebml, id, &data, &size);
if (ret != GST_FLOW_OK)
return ret;
*length = size;
*binary = g_memdup (data, size);
return GST_FLOW_OK;
}