Imported libSDF into VOID tree

external/libsdf/libSDF/SDFhdrio.c

@@ -0,0 +1,86 @@
+/* An implementation of getc, using MPMY functions.  */
+
+#include <stddef.h>
+#include <errno.h>
+#include "Msgs.h"
+#include "error.h"
+#include "SDF-private.h"
+#include "stdio.h"
+#include "mpmy_io.h"
+
+#define MYBUFSZ 4096
+
+/* Assumption:  we can only have one header at a time being read.
+   The header is opened, read anc closed, all during the course of SDFopen
+   so we don't have to screw around with multiple open files, etc. */
+
+static MPMYFile *fp;
+static char buf[MYBUFSZ];
+static char *ptr;
+static char *endbuf;
+static int buf_offset;
+
+
+int SDF_Hdropen(const char *name){
+    fp = MPMY_Fopen(name, MPMY_RDONLY|MPMY_SINGL);
+    if( fp == NULL )
+	return -1;
+    endbuf = ptr = buf;
+    buf_offset = 0;
+    Msg("SDF", ("SDFhdropen:  return fp=%p\n", fp));
+    return 0;
+}
+
+void SDF_Hdrclose(void){
+    Msg("SDF", ("SDFhdrclose called\n"));
+    MPMY_Fclose(fp);
+    endbuf = ptr = NULL;
+    fp = NULL;
+    buf_offset = -1;
+}
+
+int SDF_Hdroffset(void){
+    if( ptr == NULL )
+	return -1;
+    return buf_offset + (ptr - buf);
+}
+
+int SDF_Hdrgetc(){
+    int nread;
+
+    if( ptr == NULL ){
+	Msgf(("SDFhdrgetc: Returning EOF, ptr==NULL\n"));
+	return EOF;
+    }
+
+    if( ptr < endbuf ){
+	if( *ptr == '\0' ){
+	    SinglWarning("Returning NULL at char %d in SDFhdrio\n", (int)(ptr-buf));
+	}
+	Msgf(("SDF_hdrgetc:  %c\n", *ptr));
+	return *ptr++;
+    }
+
+    nread = MPMY_Fread(buf, 1, MYBUFSZ, fp);
+    {int i;
+     int sum = 0;
+     for(i=0; i<nread; i++){
+	 sum ^= buf[i];
+     }
+     Msgf(("SDFhdrio Fread(%d), obtained %d, sum=%d\n", MYBUFSZ, nread, sum));
+    }
+    if(nread <= 0 ) {
+	if( nread < 0 ){
+	    SinglWarning("SDFhdrio: MPMY_Fread returns %d, errno=%d\n", nread, errno);
+	}
+	Msgf(("SDFhdrgetc:  Returning EOF, nread=%d, errno=%d\n", nread, errno));
+	return EOF;		/* don't distinguish between error and EOF? */
+    }
+    buf_offset += endbuf - buf;
+    ptr = buf;
+    endbuf = ptr + nread;
+    /* This tail recursion is guaranteed to terminate on the second try
+       because we have guaranteed that endbuf>ptr */
+    return SDF_Hdrgetc();
+}
+