Refactor: nal.c/.h full cleanup.

- Move constant from the signature of calc_checksum into a macro.

src/encoder.c

@@ -448,7 +448,7 @@ void read_one_frame(FILE* file, encoder_control* encoder)
  */
 static void add_checksum(encoder_control* encoder)
 {
-  unsigned char checksum[3][16];
+  unsigned char checksum[3][SEI_HASH_MAX_LENGTH];
   uint32_t checksum_val;
   unsigned int i;
 

src/nal.c

@@ -13,89 +13,84 @@
 
 #include <stdlib.h>
 #include <string.h>
+#include <assert.h>
 
 #include "config.h"
 #include "bitstream.h"
 #include "cabac.h"
 #include "encoder.h"
 
-
-void nal_write(FILE* output, uint8_t* buffer, uint32_t buffer_len, uint8_t nal_ref, uint8_t nal_type, uint8_t temporal_id)
+/**
+ * \brief Write a Network Abstraction Layer (NAL) packet to the output.
+ */
+void nal_write(FILE *output, uint8_t *buffer, uint32_t buffer_len, uint8_t nal_ref, uint8_t nal_type, uint8_t temporal_id)
 {
   uint8_t byte;
   uint32_t i;
-  uint8_t zerocount=0;
+  uint8_t zerocount = 0;
 
-  /* Some useful constants */
+  // Some useful constants
   const uint8_t emulation_prevention_three_byte = 0x03;
   const uint8_t start_code_prefix_one_3bytes = 0x01;
   const uint8_t zero = 0x00;
 
-  /*start_code_prefix_one_3bytes */  
-  
-  /*
-  if(temporal_id == 0)
-  {
-    fwrite(&zero, 1, 1, output);
-  }
-  */  
+  // start_code_prefix_one_3bytes
   fwrite(&zero, 1, 1, output);
   fwrite(&zero, 1, 1, output);
   fwrite(&start_code_prefix_one_3bytes, 1, 1, output);
 
-  /* Handle header bits with full bytes instead of using bitstream */
-  /* forbidden_zero_flag(1) + nal_unit_type(6) + 1bit of nuh_layer_id*/
-  byte = nal_type<<1;
+  // Handle header bits with full bytes instead of using bitstream
+  // forbidden_zero_flag(1) + nal_unit_type(6) + 1bit of nuh_layer_id
+  byte = nal_type << 1;
   fwrite(&byte, 1, 1, output);
 
-  /* 5bits of nuh_layer_id + nuh_temporal_id_plus1(3) */
-  byte = (temporal_id+1)&7;
+  // 5bits of nuh_layer_id + nuh_temporal_id_plus1(3)
+  byte = (temporal_id + 1) & 7;
   fwrite(&byte, 1, 1, output);
 
-  /* Write out bytes and add emulation_prevention_three_byte when needed */
-  for(i = 0; i < buffer_len; i++)
-  {
-    if(zerocount == 2 && buffer[i] < 4) /* Prevent 0x0000 + 00/01/02/03 */
-    {
-      /* Inserting 0x03 */
+  // Write out bytes and add emulation_prevention_three_byte when needed
+  for (i = 0; i < buffer_len; ++i) {
+    // Prevent 0x0000 + 00/01/02 byte sequences from occurring by prefixing
+    // the last byte with 0x03. Do the same for 0x03.
+    if (zerocount == 2 && buffer[i] < 4) {
       fwrite(&emulation_prevention_three_byte, 1, 1, output);
       zerocount = 0;
     }
-    if(buffer[i] == 0)
-    {
+    if(buffer[i] == 0) {
       zerocount++;
-    }
-    else
-    {
+    } else {
       zerocount = 0;
     }
 
-    /* Write the actual data */
+    // Write the actual data
     fwrite(&buffer[i], 1, 1, output);
   }
 
-  /* If last byte was 0, add emulation_prevention_three_byte */
-  if(buffer[buffer_len-1] == 0)
-  {
+  // If last byte was 0, add emulation_prevention_three_byte
+  if (buffer[buffer_len - 1] == 0) {
     fwrite(&emulation_prevention_three_byte, 1, 1, output);
   }
-
 }
 
 
-/*!
- \brief Calculate checksum for one color of the picture.
- \param data Beginning of the pixel data for the picture.
- \param height Height of the picture.
- \param width Width of the picture.
- \param stride Width of one row in the pixel array.
- \returns Void
-*/
-static void array_checksum(const uint8_t* data, const int height, const int width, const int stride, unsigned char checksum_out[])
+/**
+ * \brief Calculate checksum for one color of the picture.
+ * \param data Beginning of the pixel data for the picture.
+ * \param height Height of the picture.
+ * \param width Width of the picture.
+ * \param stride Width of one row in the pixel array.
+ */
+static void array_checksum(const uint8_t* data, 
+                           const int height, const int width,
+                           const int stride, 
+                           unsigned char checksum_out[SEI_HASH_MAX_LENGTH])
 {
 	unsigned char mask;
 	unsigned int checksum = 0;
 	int y, x;
+
+  assert(SEI_HASH_MAX_LENGTH >= 4);
+
 	for (y = 0; y < height; ++y) {
 		for (x = 0; x < width; ++x) {
 			mask = (x & 0xff) ^ (y & 0xff) ^ (x >> 8) ^ (y >> 8);
@@ -104,7 +99,7 @@ static void array_checksum(const uint8_t* data, const int height, const int widt
 		}
 	}
 
-  /* Unpack uint into byte-array.*/
+  // Unpack uint into byte-array.
 	checksum_out[0] = (checksum >> 24) & 0xff;
 	checksum_out[1] = (checksum >> 16) & 0xff;
 	checksum_out[2] = (checksum >> 8) & 0xff;
@@ -118,7 +113,7 @@ static void array_checksum(const uint8_t* data, const int height, const int widt
  \param checksum_out Result of the calculation.
  \returns Void
 */
-void picture_checksum(const picture* pic, unsigned char checksum_out[][16])
+void picture_checksum(const picture* pic, unsigned char checksum_out[][SEI_HASH_MAX_LENGTH])
 {
 	int stride = pic->width; /* TODO: != width, if there is a luma margin. */
 	array_checksum(pic->y_recdata, pic->height, pic->width, pic->width, checksum_out[0]);

src/nal.h

@@ -19,8 +19,11 @@
 #include "picture.h"
 
 
-/*!
- * \brief NAL unit type codes
+//////////////////////////////////////////////////////////////////////////
+// TYPES
+
+/**
+ * \brief NAL unit type codes.
  * 
  * These are the nal_unit_type codes from Table 7-1 ITU-T H.265 v1.0.
  * The type codes have been prefixed with "NAL_".
@@ -73,7 +76,15 @@ enum {
   // Unspecified UNSPEC 48-63
 };
 
-void nal_write(FILE* output, uint8_t* buffer, uint32_t buffer_len, uint8_t nal_ref, uint8_t nal_type, uint8_t temporal_id);
-void picture_checksum(const picture* pic, unsigned char checksum_out[][16]);
+#define SEI_HASH_MAX_LENGTH 4
+
+//////////////////////////////////////////////////////////////////////////
+// FUNCTIONS
+void nal_write(FILE *output, uint8_t *buffer, uint32_t buffer_len,
+               uint8_t nal_ref, uint8_t nal_type, uint8_t temporal_id);
+void picture_checksum(const picture *pic,
+                      unsigned char checksum_out[][SEI_HASH_MAX_LENGTH]);
+
+
 
 #endif