[PATCH] Implement av_samples_fill_arrays().

[Stefano Sabatini]

---
 libavcore/samplefmt.c |   33 +++++++++++++++++++++++++++++++++
 libavcore/samplefmt.h |   29 +++++++++++++++++++++++++++++
 2 files changed, 62 insertions(+), 0 deletions(-)

diff --git a/libavcore/samplefmt.c b/libavcore/samplefmt.c
index 532acd9..d2a7c4f 100644
--- a/libavcore/samplefmt.c
+++ b/libavcore/samplefmt.c
@@ -68,3 +68,36 @@ int av_get_bits_per_sample_fmt(enum AVSampleFormat sample_fmt)
     return sample_fmt < 0 || sample_fmt >= AV_SAMPLE_FMT_NB ?
         0 : sample_fmt_info[sample_fmt].bits;
 }
+
+int av_samples_fill_arrays(uint8_t *pointers[8], int linesizes[8],
+                           uint8_t *buf, int buf_size,
+                           enum AVSampleFormat sample_fmt, int planar,
+                           int nb_channels)
+{
+    int i, step_size = 0;
+    int sample_size = av_get_bits_per_sample_fmt(sample_fmt) >>3;
+    int per_channel_size;
+
+    per_channel_size = buf_size / nb_channels;
+    if (pointers) {
+        pointers[0] = buf;
+        if (planar) {
+            for (i = 1; i < nb_channels; i++) {
+                step_size += per_channel_size;
+                pointers[i] = buf + step_size;
+            }
+        } else { /* packed */
+            for (i = 1; i < nb_channels; i++)
+                pointers[i] = buf;
+        }
+        memset(&pointers[nb_channels], 0, (8-nb_channels) * sizeof(pointers[0]));
+    }
+
+    if (linesizes) {
+        for (i = 0; i < nb_channels; i++)
+            linesizes[i] = planar ? sample_size : nb_channels * sample_size;
+        memset(&linesizes[nb_channels], 0, (8-nb_channels) * sizeof(linesizes[0]));
+    }
+
+    return per_channel_size / sample_size;
+}
diff --git a/libavcore/samplefmt.h b/libavcore/samplefmt.h
index 9701efe..b1abe3d 100644
--- a/libavcore/samplefmt.h
+++ b/libavcore/samplefmt.h
@@ -69,4 +69,33 @@ char *av_get_sample_fmt_string(char *buf, int buf_size, enum AVSampleFormat samp
  */
 int av_get_bits_per_sample_fmt(enum AVSampleFormat sample_fmt);
 
+/**
+ * Fill channel data pointers and linesizes for samples with sample
+ * format sample_fmt.
+ *
+ * The data array is filled with the pointers to the samples data:
+ * for planar, set the start point of each channel's data within the buffer,
+ * for packed, set the start point of the entire buffer only.
+ *
+ * The linesize for each channel specifies the number of bytes to
+ * traverse to reach the next sample of a particular channel:
+ * for planar, it is set to the sample size,
+ * for packed, it is set to number of channels * sample_size.
+ *
+ * @param data array to be filled with the pointer for each channel, may be NULL
+ * @param linesizes array to be filled with the linesize for each channel, may be NULL
+ * @param buf the pointer to a buffer containing the samples, must
+ * contain an integer number of samples
+ * @param buf_size the size of buf in bytes
+ * @param planar >0 if the samples layout is planar, 0 if it is packed
+ * @param nb_channels the number of channels
+ * @return the number of samples in buf, a negative error code in case
+ * of failure
+ * @see av_samples_fill_pointers() and av_samples_fill_linesizes()
+ */
+int av_samples_fill_arrays(uint8_t *data[8], int linesizes[8],
+                           uint8_t *buf, int buf_size,
+                           enum AVSampleFormat sample_fmt, int planar,
+                           int nb_channels);
+
 #endif /* AVCORE_SAMPLEFMT_H */
-- 
1.7.2.3


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