Tested SER file writing, added timestamps at end of SER file; reading should also work

ChangeLog

@@ -1,5 +1,6 @@
 2022-11-09:
-- added preliminary SER file implemenations, not yet tested
+- added preliminary SER file implementations, writing seems to work also
+  with timestamps; reading not yet tested
 - adding save of videodump files for debugging purposes
 - adding make target checkdumpfile to test and gain some basic information
   on videodumpfiles

ser.cc

@@ -29,18 +29,62 @@ SER::SER() {
   header.DateTime = 0;
   header.DateTimeUTC = 0;
 
-  fd = NULL;
+  FileDesc = NULL;
   Frame = NULL;
+  FramePointer = 0;
+  Reading = 1;
+  NumberOfTimeStamps = 0;
+  TimeStamps = NULL;
 }
 
 /*
   Class destructor.  Free resources.
 */
 SER::~SER() {
+
+  if(FileDesc) {
+
+    /* Update header if necessary */
+    if(!Reading) {
+
+      int err;
+      long offset = (long)&header.FrameCount - (long)&header;
+      header.FrameCount = FramePointer;
+      
+      /* goto file beginning */
+      if((err = fseek(FileDesc, offset, SEEK_SET)) == -1) {
+	fprintf(stderr, "Error: failed seek SER file FrameCount (%d, %s)\n", err, strerror(errno));
+      }
+      else {
+	/* write framecount in header data */
+	if((err = fwrite(&header.FrameCount, sizeof(header.FrameCount), 1, FileDesc)) != 1) {
+	  fprintf(stderr, "Error: failed writing SER file FrameCount (%d, %s)\n",
+		  err, strerror(errno));
+	}
+      }
+
+      /* goto file end */
+      if((err = fseek(FileDesc, 0, SEEK_END)) == -1) {
+	fprintf(stderr, "Error: failed seek SER file end (%d, %s)\n", err, strerror(errno));
+      }
+      else {
+	/* write timestamp data */
+	if((err = fwrite(TimeStamps, sizeof(header.DateTime), FramePointer, FileDesc)) != FramePointer) {
+	  fprintf(stderr, "Error: failed writing SER file TimeStamps (%d, %s)\n",
+		  err, strerror(errno));
+	}
+      }
+    }
+
     /* Close file if necessary */
-  if(fd) {
+    fclose(FileDesc);
-    fclose(fd);
   }
+
+  /* Free timestamps */
+  if(TimeStamps) {
+    free(TimeStamps);
+  }
+  
   /* Free frame memory if necessary */
   if(Frame) {
     free(Frame);
@@ -79,6 +123,7 @@ int SER::setTelescope(char *name) {
   for reading, otherwise we try to create the file.
 */
 int SER::setFile(char *name) {
+
   FILE *file;
 
   /* try opening file for reading */
@@ -93,13 +138,15 @@ int SER::setFile(char *name) {
     }
     else {
       fprintf(stdout, "Debug: created file '%s' for writing SER file\n", name);
-      fd = file;
+      FileDesc = file;
+      Reading = 0;
       return 0;
     }
   }
 
   fprintf(stdout, "Debug: opened file '%s' for reading SER file\n", name);
-  fd = file;
+  FileDesc = file;
+  Reading = 1;
   return 0;
 }
 
@@ -113,22 +160,64 @@ int SER::writeHeader(void) {
   /* adjust time stamps for header */
   setDateTime();
 
-  if(fd == NULL) {
+  if(FileDesc == NULL) {
     fprintf(stderr, "Error: writing header, SER file not yet specified\n");
     return -1;
   }
   
   /* goto file beginning */
-  if((err = fseek(fd, 0, SEEK_SET)) == -1) {
+  if((err = fseek(FileDesc, 0, SEEK_SET)) == -1) {
     fprintf(stderr, "Error: failed seek SER file beginning (%d, %s)\n", err, strerror(errno));
     return -1;
   }
 
   /* write header data */
-  if((err = fwrite(&header, sizeof(header), 1, fd)) != 1) {
+  if((err = fwrite(&header, sizeof(header), 1, FileDesc)) != 1) {
     fprintf(stderr, "Error: failed writing SER header (%d, %s)\n", err, strerror(errno));
     return -1;
   }
+
+  /* reset space for timestamps */
+  NumberOfTimeStamps = 16;
+  if(TimeStamps) {
+    free(TimeStamps);
+  }
+  /* allocate some memory for the upcoming timestamps */
+  if((TimeStamps = (int64_t *)malloc(sizeof(header.DateTime) * NumberOfTimeStamps)) == NULL) {
+    fprintf(stderr, "Error: failed to allocate %d bytes for timestamps\n",
+	    sizeof(header.DateTime) * NumberOfTimeStamps);
+    return -1;
+  }
+
+  FramePointer = 0;
+  return 0;
+}
+
+/*
+  The function reads the file header of the SER file.
+ */
+int SER::readHeader(void) {
+
+  int err;
+
+  if(FileDesc == NULL) {
+    fprintf(stderr, "Error: reading header, SER file not yet specified\n");
+    return -1;
+  }
+  
+  /* goto file beginning */
+  if((err = fseek(FileDesc, 0, SEEK_SET)) == -1) {
+    fprintf(stderr, "Error: failed seek SER file beginning (%d, %s)\n", err, strerror(errno));
+    return -1;
+  }
+
+  /* read header data */
+  if((err = fread(&header, sizeof(header), 1, FileDesc)) != 1) {
+    fprintf(stderr, "Error: failed reading SER header (%d, %s)\n", err, strerror(errno));
+    return -1;
+  }
+
+  FramePointer = 0;
   return 0;
 }
 
@@ -138,17 +227,29 @@ int SER::writeHeader(void) {
  */
 int SER::appendFrame(void *data) {
 
-  if(fd == NULL) {
+  if(FileDesc == NULL) {
     fprintf(stderr, "Error: appending frame, SER file not yet specified\n");
     return -1;
   }
   
   /* write frame data */
-  if(fwrite(data, FrameSize, 1, fd) != 1) {
+  if(fwrite(data, FrameSize, 1, FileDesc) != 1) {
     fprintf(stderr, "Error: failed write SER frame (%s)\n", strerror(errno));
     return -1;
   }
 
+  /* ensure we have enough memory allocated for timestamps */
+  if(FramePointer >= NumberOfTimeStamps) {
+    NumberOfTimeStamps *= 2;
+    if((TimeStamps = (int64_t *)realloc(TimeStamps, sizeof(header.DateTime) * NumberOfTimeStamps)) == NULL) { 
+      fprintf(stderr, "Error: failed to re-allocate %d bytes for timestamps\n",
+	      sizeof(header.DateTime) * NumberOfTimeStamps);
+      return -1;
+    }
+  }
+  
+  /* save timestamp for this frame */
+  TimeStamps[FramePointer++] = currentDateTime();
   return 0;
 }
 
@@ -254,12 +355,56 @@ void * SER::allocFrame(void) {
  */
 int SER::readFrame(void *data) {
 
+  int err;
+
   /* read frame data */
-  if(fread(data, FrameSize, 1, fd) != FrameSize) {
+  if((err = fread(data, FrameSize, 1, FileDesc)) != 1) {
-    fprintf(stderr, "Error: failed reading SER frame (%s)\n", strerror(errno));
+    fprintf(stderr, "Error: failed reading SER frame (%d, %s)\n", err, strerror(errno));
+    return -1;
+  }
+
+  /* goto next frame */
+  FramePointer++;
+
+  /* reached end of file? */
+  if(FramePointer >= getNumberOfFrames()) {
+
+    /* goto first frame beginning */
+    if((err = fseek(FileDesc, sizeof(header), SEEK_SET)) == -1) {
+      fprintf(stderr, "Error: failed seeking SER file frame #%d (%d, %s)\n",
+	      0, err, strerror(errno));
       return -1;
     }
 
+    /* start over at beginning */
+    FramePointer = 0;
+  }
+  
+  return 0;
+}
+
+/*
+  The function reads a single frame at the given file position.
+  Frame size is determined by internal header data.
+ */
+int SER::readFrame(void *data, int frame) {
+
+  int err;
+
+  /* goto frame beginning */
+  if((err = fseek(FileDesc, sizeof(header) + frame * FrameSize, SEEK_SET)) == -1) {
+    fprintf(stderr, "Error: failed seeking SER file frame #%d (%d, %s)\n",
+	    frame, err, strerror(errno));
+    return -1;
+  }
+
+  /* read frame data */
+  if((err = fread(data, FrameSize, 1, FileDesc)) != 1) {
+    fprintf(stderr, "Error: failed reading SER frame (%d, %s)\n", err, strerror(errno));
+    return -1;
+  }
+
+  FramePointer = frame + 1;
   return 0;
 }
 
@@ -277,6 +422,18 @@ int32_t SER::getNumberOfFrames(void) {
   return header.FrameCount;
 }
 
+/*
+  Sets the current timestamps in the header.
+ */
+int64_t SER::setDateTime(void) {
+
+  int64_t hundred_nano_seconds = currentDateTime();
+
+  header.DateTime = hundred_nano_seconds;
+  header.DateTimeUTC = hundred_nano_seconds + differenceLocalUTC();
+  return header.DateTime;
+}
+
 /*
   Timestamps in SER
   -----------------
@@ -288,18 +445,17 @@ int32_t SER::getNumberOfFrames(void) {
   maximum value represents 100 nanoseconds before the beginning of
   January 1 of the year 10000.
 */
-int64_t SER::setDateTime() {
+int64_t SER::currentDateTime(void) {
 
   int64_t hundred_nano_seconds;
   struct timeval current_time;
+  struct timezone current_zone;
 
   /* get time since 01.01.1970 00:00 */
-  gettimeofday(&current_time, NULL);
+  gettimeofday (&current_time, &current_zone);
-  hundred_nano_seconds = (62135769600L + current_time.tv_sec) * 10000000L +
+  hundred_nano_seconds = (62135596800L + current_time.tv_sec) * 10000000L +
     current_time.tv_usec * 10L;
-  header.DateTime = hundred_nano_seconds;
+  return hundred_nano_seconds;
-  header.DateTimeUTC = hundred_nano_seconds + differenceLocalUTC();
-  return header.DateTime;
 }
 
 /*
@@ -325,5 +481,7 @@ int64_t SER::differenceLocalUTC(void) {
   /* Unfortunately, GMT still has summer time. Get rid of it:*/
   if (gmt_time_info.tm_isdst == 1) gmt_ts -= 3600;
 
-  return (loc_ts-gmt_ts) * 10000000L;
+  fprintf(stdout, "Debug: difference between local time and UTC is %ld hours\n",
+	  (loc_ts - gmt_ts) / 3600);
+  return ((int64_t)gmt_ts - (int64_t)loc_ts) * 10000000L;
 }

ser.h

@@ -11,6 +11,9 @@
   ser->setColorID(SER_COLORID_RGB);
   ser->setPixelDepth(8);
   ser->setFile((char *)"test.ser");
+  ser->setObserver((char *)"Steffen Pohle");
+  ser->setTelescope((char *)"Sky-Watcher EVOSTAR 102");
+  ser->setInstrument((char *)"Svbony SV305");
   ser->setNumberOfFrames(1);
   ser->writeHeader();
   uint8_t * data = (uint8_t *) ser->allocFrame();
@@ -72,13 +75,18 @@ class SER {
   struct SER_Header header;
 
   /* internal data */
-  FILE *fd;
+  FILE * FileDesc;
   int NumberOfPlanes;
   int BytesPerPixel;
   size_t FrameSize;
   void * Frame;
+  int FramePointer;
+  int Reading;
+  int64_t * TimeStamps;
+  int NumberOfTimeStamps;
   
   void updateHeaderData(void);
+  int64_t differenceLocalUTC(void);
   
  public:
   SER();
@@ -97,13 +105,15 @@ class SER {
   int32_t getNumberOfFrames(void);
   void setNumberOfFrames(int32_t);
   int64_t setDateTime(void);
-  int64_t differenceLocalUTC(void);
+  int64_t currentDateTime(void);
   size_t getFrameSize(void);
   
   int setFile(char *);
   int writeHeader(void);
+  int readHeader(void);
   int appendFrame(void *);
   int readFrame(void *);
+  int readFrame(void *, int);
   void * allocFrame(void);
 };