Introduce thread-safe ufo_decoder_decode_frame function

2 files changed, 70 insertions, 31 deletions

diff --git a/src/ufodecode.c b/src/ufodecode.c
index 5b8b874..0f1d068 100644
--- a/src/ufodecode.c
+++ b/src/ufodecode.c
@@ -86,7 +86,7 @@ void ufo_decoder_set_raw_data(ufo_decoder decoder, uint32_t *raw, size_t num_byt
     decoder->current_pos = 0;
 }
 
-static int ufo_decode_frame(ufo_decoder decoder, uint16_t *pixel_buffer, uint16_t *cmask, uint32_t *raw, size_t num_words, int *offset)
+static int ufo_decode_frame_channels(ufo_decoder decoder, uint16_t *pixel_buffer, uint16_t *cmask, uint32_t *raw, size_t num_words, size_t *offset)
 {
     static int channel_order[IPECAMERA_NUM_CHANNELS] = { 15, 13, 14, 12, 10, 8, 11, 7, 9, 6, 5, 2, 4, 3, 0, 1 };
     static int channel_size = (2 + IPECAMERA_PIXELS_PER_CHANNEL / 3);
@@ -279,46 +279,33 @@ void ufo_deinterlace_weave(const uint16_t *in1, const uint16_t *in2, uint16_t *o
 }
 
 
+
 /**
- * \brief Iterate and decode next frame
+ * \brief Decodes frame
  *
- * This function tries to decode the next frame in the currently set raw data
- * stream. 
+ * This function tries to decode the supplied data
  *
  * \param decoder An ufo_decoder instance
+ * \param raw Raw data stream
+ * \param num_bytes Size of data stream buffer in bytes
  * \param pixels If pointer with NULL content is passed, a new buffer is
  * allocated otherwise, this user-supplied buffer is used.
  * \param frame_number Frame number as reported in the header
  * \param time_stamp Time stamp of the frame as reported in the header
  * \paran cmask Change-mask
  *
- * \return 0 in case of no error, ENOSR if end of stream was reached, ENOMEM if
- * NULL was passed but no memory could be allocated, EILSEQ if data stream is
- * corrupt and EFAULT if pixels is a NULL-pointer.
+ * \return number of decoded bytes or 0 in case of error
  */
-int ufo_decoder_get_next_frame(ufo_decoder decoder, uint16_t **pixels, uint32_t *frame_number, uint32_t *time_stamp, uint16_t *cmask)
+size_t ufo_decoder_decode_frame(ufo_decoder decoder, uint32_t *raw, size_t num_bytes, uint16_t *pixels, uint32_t *frame_number, uint32_t *time_stamp, uint16_t *cmask)
 {
 
-    uint32_t *raw = decoder->raw;
     int err = 0;
-    size_t pos = decoder->current_pos;
-    int advance;
-    const size_t num_words = decoder->num_bytes / 4;
-
-    if (pixels == NULL)
-        return EFAULT;
-
-    if (pos >= num_words)
-        return ENOSR; 
-
-    if (num_words < 16)
-        return EILSEQ;
+    size_t pos = 0;
+    size_t advance;
+    const size_t num_words = num_bytes / 4;
 
-    if (*pixels == NULL) {
-        *pixels = (uint16_t *) malloc(IPECAMERA_WIDTH * decoder->height * sizeof(uint16_t));
-        if (*pixels == NULL)
-            return ENOMEM;
-    }
+    if ((pixels == NULL)||(num_words < 16))
+        return 0;
 
 #ifdef DEBUG
     CHECK_VALUE(raw[pos++], 0x51111111);
@@ -331,17 +318,15 @@ int ufo_decoder_get_next_frame(ufo_decoder decoder, uint16_t **pixels, uint32_t
     *frame_number = raw[pos++] & 0xFFFFFFF;
     CHECK_VALUE(raw[pos] >> 28, 0x5);
     *time_stamp = raw[pos++] & 0xFFFFFFF;
-    if (err)
-        return EILSEQ;
+    if (err) return 0;
 #else
     *frame_number = raw[pos + 6] & 0xFFFFFFF;
     *time_stamp = raw[pos + 7] & 0xFFFFFFF;
     pos += 8;
 #endif
 
-    err = ufo_decode_frame(decoder, *pixels, cmask, raw + pos, num_words - pos - 8, &advance);
-    if (err)
-        return EILSEQ;
+    err = ufo_decode_frame_channels(decoder, pixels, cmask, raw + pos, num_words - pos - 8, &advance);
+    if (err) return 0;
 
     pos += advance;
 
@@ -360,10 +345,63 @@ int ufo_decoder_get_next_frame(ufo_decoder decoder, uint16_t **pixels, uint32_t
     CHECK_VALUE(raw[pos++], 0x0FFFFFFF);
     CHECK_VALUE(raw[pos++], 0x00000000);
     CHECK_VALUE(raw[pos++], 0x01111111);
+
+    if (err) return 0;
 #else
     pos += 8;
 #endif
 
+    return pos;
+}
+
+
+
+/**
+ * \brief Iterate and decode next frame
+ *
+ * This function tries to decode the next frame in the currently set raw data
+ * stream. 
+ *
+ * \param decoder An ufo_decoder instance
+ * \param pixels If pointer with NULL content is passed, a new buffer is
+ * allocated otherwise, this user-supplied buffer is used.
+ * \param frame_number Frame number as reported in the header
+ * \param time_stamp Time stamp of the frame as reported in the header
+ * \paran cmask Change-mask
+ *
+ * \return 0 in case of no error, ENOSR if end of stream was reached, ENOMEM if
+ * NULL was passed but no memory could be allocated, EILSEQ if data stream is
+ * corrupt and EFAULT if pixels is a NULL-pointer.
+ */
+int ufo_decoder_get_next_frame(ufo_decoder decoder, uint16_t **pixels, uint32_t *frame_number, uint32_t *time_stamp, uint16_t *cmask)
+{
+
+    uint32_t *raw = decoder->raw;
+    size_t pos = decoder->current_pos;
+    size_t advance;
+    const size_t num_words = decoder->num_bytes / 4;
+
+    if (pixels == NULL)
+        return 0;
+
+    if (pos >= num_words)
+        return ENOSR; 
+
+    if (num_words < 16)
+        return EILSEQ;
+
+    if (*pixels == NULL) {
+        *pixels = (uint16_t *) malloc(IPECAMERA_WIDTH * decoder->height * sizeof(uint16_t));
+        if (*pixels == NULL)
+            return ENOMEM;
+    }
+    
+    advance = ufo_decoder_decode_frame(decoder, raw + pos * 4, decoder->num_bytes - pos * 4, *pixels, frame_number, time_stamp, cmask);
+    if (!advance) 
+	return EILSEQ;
+
+    pos += advance;
+
     /* if bytes left and we see fill bytes, skip them */
     if (((pos + 2) < num_words) && ((raw[pos] == 0x0) && (raw[pos+1] == 0x1111111))) {
         pos += 2;
diff --git a/src/ufodecode.h b/src/ufodecode.h
index 990607a..3ae7f70 100644
--- a/src/ufodecode.h
+++ b/src/ufodecode.h
@@ -12,6 +12,7 @@ extern "C" {
 
 ufo_decoder ufo_decoder_new(uint32_t height, uint32_t width, uint32_t *raw, size_t num_bytes);
 void ufo_decoder_free(ufo_decoder decoder);
+size_t ufo_decoder_decode_frame(ufo_decoder decoder, uint32_t *raw, size_t num_bytes, uint16_t *pixels, uint32_t *frame_number, uint32_t *time_stamp, uint16_t *cmask);
 void ufo_decoder_set_raw_data(ufo_decoder decoder, uint32_t *raw, size_t num_bytes);
 int ufo_decoder_get_next_frame(ufo_decoder decoder, uint16_t **pixels, uint32_t *frame_number, uint32_t *time_stamp, uint16_t *cmask);