Changeset 21059 for trunk/Ohana/src/libfits/header/F_H_field.c

Timestamp:

Dec 30, 2008, 10:01:42 AM (18 years ago)

Author:

eugene

Message:

add ability to read HIERARCH keywords if basic keyword is not found

File:

• trunk/Ohana/src/libfits/header/F_H_field.c (modified) (1 diff)

trunk/Ohana/src/libfits/header/F_H_field.c

@@ -60 +60 @@
 }
 
+// find the given field among the HIERARCH keywords
+// these have the form: HIERARCH KEYWORD = value
+// returns a pointer to the start of the field
+char *gfits_header_hierarch_field (Header *header, char *field, int N) {
+
+  char *buf, *ptr;
+  int i, Nwant, Nfound, Nfield;
+
+  Nfield = strlen (field);
+  if (Nfield >= 71) return NULL;
+
+  buf = header[0].buffer;
+
+  /* find the Nth entry */
+  if (N > 0) {
+    Nfound = 0;
+    for (i = 0; i < header[0].size; i+= FT_LINE_LENGTH, buf += FT_LINE_LENGTH) {
+      // have we found a HIERARCH entry?
+      if (strncmp ("HIERARCH", buf, 8)) continue;
+      ptr = buf + 9; // start of following keyword
+      if (strncmp (field, ptr, Nfield)) continue;
+      Nfound ++;
+      if (Nfound == N) return (ptr);
+    }
+  }
+
+  /* find the Ntotal - Nth entry */
+  if (N < 0) {
+    /* count the entries */
+    Nfound = 0;
+    for (i = 0; i < header[0].size; i+= FT_LINE_LENGTH, buf += FT_LINE_LENGTH) {
+      if (strncmp ("HIERARCH", buf, 8)) continue;
+      ptr = buf + 9; // start of following keyword
+      if (strncmp (field, ptr, Nfield)) continue;
+      Nfound ++;
+    }
+
+    Nwant = Nfound + N + 1;
+    buf = header[0].buffer;
+
+    /* find the Nwant entry */
+    Nfound = 0;
+    for (i = 0; i < header[0].size; i+= FT_LINE_LENGTH, buf += FT_LINE_LENGTH) {
+      if (strncmp ("HIERARCH", buf, 8)) continue;
+      ptr = buf + 9; // start of following keyword
+      if (strncmp (field, ptr, Nfield)) continue;
+      Nfound ++;
+      if (Nwant == Nfound) return (ptr);
+    }
+  }
+
+  return ((char *) NULL);
+
+/* 
+
+   find the Nth entry of this keyword.
+   if N < 0, find the last - N - 1 word (ie, -1 = last)
+
+*/
+}
+
 /*********************** fits header field ****************************/
 char *gfits_header_lineno (Header *header, int N) {