comparison tools/swab.c @ 0:5242703e91d3 tip

Initial checkin for AIM92 aimR8.2 (last updated May 1997).

+/*
+    swab.c      swap bytes
+    ------
+
+  Read and write binary shorts (2-bytes).
+  With no filename arguments, data is expected on the stdin, and the
+  result is written on the stdout. Otherwise each given filename is
+  processed in turn. When the `output' option is "off" output overwrites the
+  respective input file. (The respective output for the stdin is the stdout).
+  Otherwise all results are written to the one given output file
+  (which is the stdout by default).
+
+*/
+
+#include <stdio.h>
+#include <math.h>
+#include "options.h"
+
+
+char applic[]     = "Swap byte order of binary 2-byte data." ;
+
+static char *helpstr,   *outstr,  *sizestr  ;
+
+static Options option[] = {
+    {   "help"      ,   "off"       ,  &helpstr     ,   "help"                                      , DEBUG   },
+    {   "output"    ,   "stdout"    ,  &outstr      ,   "output filename (off = overwrite input)"   , VAL     },
+    {   "SIZE"      ,   "262144"    ,  &sizestr     ,   "buffer size in bytes"                      , SVAL    },
+   ( char * ) 0 } ;
+
+
+int    SIZE        ;    /* size of temp buffer for stdin data      */
+
+main(argc, argv)
+int   argc ;
+char *argv[] ;
+{
+    FILE *ifp, *ofp ;
+    int   i, j, n, doOpen, doCreate  ;
+    char *data, *Y ;
+
+    i = getopts( option, argc, argv ) ;
+    if ( !isoff( helpstr ) )
+	helpopts( helpstr, argv[0], applic, option ) ;
+
+    SIZE  = atoi( sizestr ) ;
+
+    doOpen = doCreate = 0 ;
+
+    if ( i == 0 ) ifp = stdin ;
+    else doOpen++ ;
+
+    if ( isoff( outstr ) ) {
+	if ( i == 0 )   ofp = stdout ;  /* o/p = i/p which is stdin   */
+	else            doCreate++ ;    /* o/p = i/p for current file */
+    }
+    else if ( isstr( outstr, "stdout") ) ofp = stdout ;
+    else if ( ( ofp = fopen( outstr, "w" ) ) == (FILE *)0 ) {
+	fprintf( stderr,"swab: can't create %s\n", outstr ) ;
+	exit( 1 ) ;
+    }
+
+    Y = (char *)malloc( sizeof( short ) ) ;
+    if ( ( data = (char *)malloc( SIZE ) ) == NULL ) {
+	fprintf( stderr, "malloc out of space\n" ) ;
+	exit( 1 ) ;
+    }
+
+    do {
+
+	if ( doOpen   && ( ifp = fopen( argv[argc-i], "r" ) ) == (FILE *)0 ) {
+	    fprintf( stderr,"swab: can't open %s\n", argv[argc-i] ) ;
+	    exit( 1 ) ;
+	}
+
+	for ( n = 0 ; n < SIZE && fread( &data[n], sizeof(short), 1, ifp ) ; n += 2 )
+	    ;
+	if ( n == SIZE ) fprintf( stderr, "warning: buffer out of space, increase SIZE\n" ) ;
+
+	if ( doOpen   ) fclose( ifp ) ;
+
+	if ( doCreate && ( ofp = fopen( argv[argc-i], "w" ) ) == (FILE *)0 ) {
+	    fprintf( stderr,"swab: can't create %s\n", argv[argc-i] ) ;
+	    exit( 1 ) ;
+	}
+
+	for ( j = 0 ; j < n ; j += 2 ) {
+	    *Y     = data[j+1] ;
+	    *(Y+1) = data[j]   ;
+	    fwrite( Y, sizeof(short), 1, ofp );
+	}
+
+	if ( doCreate ) fclose( ofp ) ;
+
+    } while ( --i > 0 ) ;
+
+}
+