*DECK XERPRN
SUBROUTINE XERPRN (PREFIX, NPREF, MESSG, NWRAP)
C***BEGIN PROLOGUE XERPRN
C***SUBSIDIARY
C***PURPOSE Print error messages processed by XERMSG.
C***LIBRARY SLATEC (XERROR)
C***CATEGORY R3C
C***TYPE ALL (XERPRN-A)
C***KEYWORDS ERROR MESSAGES, PRINTING, XERROR
C***AUTHOR Fong, Kirby, (NMFECC at LLNL)
C***DESCRIPTION
C
C This routine sends one or more lines to each of the (up to five)
C logical units to which error messages are to be sent. This routine
C is called several times by XERMSG, sometimes with a single line to
C print and sometimes with a (potentially very long) message that may
C wrap around into multiple lines.
C
C PREFIX Input argument of type CHARACTER. This argument contains
C characters to be put at the beginning of each line before
C the body of the message. No more than 16 characters of
C PREFIX will be used.
C
C NPREF Input argument of type INTEGER. This argument is the number
C of characters to use from PREFIX. If it is negative, the
C intrinsic function LEN is used to determine its length. If
C it is zero, PREFIX is not used. If it exceeds 16 or if
C LEN(PREFIX) exceeds 16, only the first 16 characters will be
C used. If NPREF is positive and the length of PREFIX is less
C than NPREF, a copy of PREFIX extended with blanks to length
C NPREF will be used.
C
C MESSG Input argument of type CHARACTER. This is the text of a
C message to be printed. If it is a long message, it will be
C broken into pieces for printing on multiple lines. Each line
C will start with the appropriate prefix and be followed by a
C piece of the message. NWRAP is the number of characters per
C piece; that is, after each NWRAP characters, we break and
C start a new line. In addition the characters '$$' embedded
C in MESSG are a sentinel for a new line. The counting of
C characters up to NWRAP starts over for each new line. The
C value of NWRAP typically used by XERMSG is 72 since many
C older error messages in the SLATEC Library are laid out to
C rely on wrap-around every 72 characters.
C
C NWRAP Input argument of type INTEGER. This gives the maximum size
C piece into which to break MESSG for printing on multiple
C lines. An embedded '$$' ends a line, and the count restarts
C at the following character. If a line break does not occur
C on a blank (it would split a word) that word is moved to the
C next line. Values of NWRAP less than 16 will be treated as
C 16. Values of NWRAP greater than 132 will be treated as 132.
C The actual line length will be NPREF + NWRAP after NPREF has
C been adjusted to fall between 0 and 16 and NWRAP has been
C adjusted to fall between 16 and 132.
C
C***REFERENCES R. E. Jones and D. K. Kahaner, XERROR, the SLATEC
C Error-handling Package, SAND82-0800, Sandia
C Laboratories, 1982.
C***ROUTINES CALLED I1MACH, XGETUA
C***REVISION HISTORY (YYMMDD)
C 880621 DATE WRITTEN
C 880708 REVISED AFTER THE SLATEC CML SUBCOMMITTEE MEETING OF
C JUNE 29 AND 30 TO CHANGE THE NAME TO XERPRN AND TO REWORK
C THE HANDLING OF THE NEW LINE SENTINEL TO BEHAVE LIKE THE
C SLASH CHARACTER IN FORMAT STATEMENTS.
C 890706 REVISED WITH THE HELP OF FRED FRITSCH AND REG CLEMENS TO
C STREAMLINE THE CODING AND FIX A BUG THAT CAUSED EXTRA BLANK
C LINES TO BE PRINTED.
C 890721 REVISED TO ADD A NEW FEATURE. A NEGATIVE VALUE OF NPREF
C CAUSES LEN(PREFIX) TO BE USED AS THE LENGTH.
C 891013 REVISED TO CORRECT ERROR IN CALCULATING PREFIX LENGTH.
C 891214 Prologue converted to Version 4.0 format. (WRB)
C 900510 Added code to break messages between words. (RWC)
C 920501 Reformatted the REFERENCES section. (WRB)
C***END PROLOGUE XERPRN
CHARACTER*(*) PREFIX, MESSG
INTEGER NPREF, NWRAP
CHARACTER*148 CBUFF
INTEGER IU(5), NUNIT
CHARACTER*2 NEWLIN
PARAMETER (NEWLIN = '$$')
C***FIRST EXECUTABLE STATEMENT XERPRN
CALL XGETUA(IU,NUNIT)
C
C A ZERO VALUE FOR A LOGICAL UNIT NUMBER MEANS TO USE THE STANDARD
C ERROR MESSAGE UNIT INSTEAD. I1MACH(4) RETRIEVES THE STANDARD
C ERROR MESSAGE UNIT.
C
N = I1MACH(4)
DO 10 I=1,NUNIT
IF (IU(I) .EQ. 0) IU(I) = N
10 CONTINUE
C
C LPREF IS THE LENGTH OF THE PREFIX. THE PREFIX IS PLACED AT THE
C BEGINNING OF CBUFF, THE CHARACTER BUFFER, AND KEPT THERE DURING
C THE REST OF THIS ROUTINE.
C
IF ( NPREF .LT. 0 ) THEN
LPREF = LEN(PREFIX)
ELSE
LPREF = NPREF
ENDIF
LPREF = MIN(16, LPREF)
IF (LPREF .NE. 0) CBUFF(1:LPREF) = PREFIX
C
C LWRAP IS THE MAXIMUM NUMBER OF CHARACTERS WE WANT TO TAKE AT ONE
C TIME FROM MESSG TO PRINT ON ONE LINE.
C
LWRAP = MAX(16, MIN(132, NWRAP))
C
C SET LENMSG TO THE LENGTH OF MESSG, IGNORE ANY TRAILING BLANKS.
C
LENMSG = LEN(MESSG)
N = LENMSG
DO 20 I=1,N
IF (MESSG(LENMSG:LENMSG) .NE. ' ') GO TO 30
LENMSG = LENMSG - 1
20 CONTINUE
30 CONTINUE
C
C IF THE MESSAGE IS ALL BLANKS, THEN PRINT ONE BLANK LINE.
C
IF (LENMSG .EQ. 0) THEN
CBUFF(LPREF+1:LPREF+1) = ' '
DO 40 I=1,NUNIT
WRITE(IU(I), '(A)') CBUFF(1:LPREF+1)
40 CONTINUE
RETURN
ENDIF
C
C SET NEXTC TO THE POSITION IN MESSG WHERE THE NEXT SUBSTRING
C STARTS. FROM THIS POSITION WE SCAN FOR THE NEW LINE SENTINEL.
C WHEN NEXTC EXCEEDS LENMSG, THERE IS NO MORE TO PRINT.
C WE LOOP BACK TO LABEL 50 UNTIL ALL PIECES HAVE BEEN PRINTED.
C
C WE LOOK FOR THE NEXT OCCURRENCE OF THE NEW LINE SENTINEL. THE
C INDEX INTRINSIC FUNCTION RETURNS ZERO IF THERE IS NO OCCURRENCE
C OR IF THE LENGTH OF THE FIRST ARGUMENT IS LESS THAN THE LENGTH
C OF THE SECOND ARGUMENT.
C
C THERE ARE SEVERAL CASES WHICH SHOULD BE CHECKED FOR IN THE
C FOLLOWING ORDER. WE ARE ATTEMPTING TO SET LPIECE TO THE NUMBER
C OF CHARACTERS THAT SHOULD BE TAKEN FROM MESSG STARTING AT
C POSITION NEXTC.
C
C LPIECE .EQ. 0 THE NEW LINE SENTINEL DOES NOT OCCUR IN THE
C REMAINDER OF THE CHARACTER STRING. LPIECE
C SHOULD BE SET TO LWRAP OR LENMSG+1-NEXTC,
C WHICHEVER IS LESS.
C
C LPIECE .EQ. 1 THE NEW LINE SENTINEL STARTS AT MESSG(NEXTC:
C NEXTC). LPIECE IS EFFECTIVELY ZERO, AND WE
C PRINT NOTHING TO AVOID PRODUCING UNNECESSARY
C BLANK LINES. THIS TAKES CARE OF THE SITUATION
C WHERE THE LIBRARY ROUTINE HAS A MESSAGE OF
C EXACTLY 72 CHARACTERS FOLLOWED BY A NEW LINE
C SENTINEL FOLLOWED BY MORE CHARACTERS. NEXTC
C SHOULD BE INCREMENTED BY 2.
C
C LPIECE .GT. LWRAP+1 REDUCE LPIECE TO LWRAP.
C
C ELSE THIS LAST CASE MEANS 2 .LE. LPIECE .LE. LWRAP+1
C RESET LPIECE = LPIECE-1. NOTE THAT THIS
C PROPERLY HANDLES THE END CASE WHERE LPIECE .EQ.
C LWRAP+1. THAT IS, THE SENTINEL FALLS EXACTLY
C AT THE END OF A LINE.
C
NEXTC = 1
50 LPIECE = INDEX(MESSG(NEXTC:LENMSG), NEWLIN)
IF (LPIECE .EQ. 0) THEN
C
C THERE WAS NO NEW LINE SENTINEL FOUND.
C
IDELTA = 0
LPIECE = MIN(LWRAP, LENMSG+1-NEXTC)
IF (LPIECE .LT. LENMSG+1-NEXTC) THEN
DO 52 I=LPIECE+1,2,-1
IF (MESSG(NEXTC+I-1:NEXTC+I-1) .EQ. ' ') THEN
LPIECE = I-1
IDELTA = 1
GOTO 54
ENDIF
52 CONTINUE
ENDIF
54 CBUFF(LPREF+1:LPREF+LPIECE) = MESSG(NEXTC:NEXTC+LPIECE-1)
NEXTC = NEXTC + LPIECE + IDELTA
ELSEIF (LPIECE .EQ. 1) THEN
C
C WE HAVE A NEW LINE SENTINEL AT MESSG(NEXTC:NEXTC+1).
C DON'T PRINT A BLANK LINE.
C
NEXTC = NEXTC + 2
GO TO 50
ELSEIF (LPIECE .GT. LWRAP+1) THEN
C
C LPIECE SHOULD BE SET DOWN TO LWRAP.
C
IDELTA = 0
LPIECE = LWRAP
DO 56 I=LPIECE+1,2,-1
IF (MESSG(NEXTC+I-1:NEXTC+I-1) .EQ. ' ') THEN
LPIECE = I-1
IDELTA = 1
GOTO 58
ENDIF
56 CONTINUE
58 CBUFF(LPREF+1:LPREF+LPIECE) = MESSG(NEXTC:NEXTC+LPIECE-1)
NEXTC = NEXTC + LPIECE + IDELTA
ELSE
C
C IF WE ARRIVE HERE, IT MEANS 2 .LE. LPIECE .LE. LWRAP+1.
C WE SHOULD DECREMENT LPIECE BY ONE.
C
LPIECE = LPIECE - 1
CBUFF(LPREF+1:LPREF+LPIECE) = MESSG(NEXTC:NEXTC+LPIECE-1)
NEXTC = NEXTC + LPIECE + 2
ENDIF
C
C PRINT
C
DO 60 I=1,NUNIT
WRITE(IU(I), '(A)') CBUFF(1:LPREF+LPIECE)
60 CONTINUE
C
IF (NEXTC .LE. LENMSG) GO TO 50
RETURN
END