scsh-0.5/cig/libcig1.c

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/* Generic routines for Scheme48/C interfacing -- mostly for converting
** strings and null-terminated vectors back and forth.
** Copyright (c) 1993 by Olin Shivers.
*/
#include "libcig.h"
#include <errno.h>
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#include <string.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#define Malloc(type,n) ((type *) malloc(sizeof(type)*(n)))
#define Free(p) (free((char *)(p)))
/* (c2scheme_strcpy dest_scheme_string source_C_string)
** Copies C string's chars into Scheme string. Return #t.
** If C string is NULL, do nothing and return #f.
*/
int c2scheme_strcpy(scheme_value sstr, const char *cstr)
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{
if( cstr ) {
strncpy( (char*) StobData(sstr), cstr, STRING_LENGTH(sstr) );
return 1;
}
else return 0;
}
/* Same as above, but free the C string when we are done. */
int c2scheme_strcpy_free(scheme_value sstr, const char *cstr)
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{
if( cstr ) {
strncpy( (char*) StobData(sstr), cstr, STRING_LENGTH(sstr) );
Free(cstr);
return 1;
}
else return 0;
}
char *scheme2c_strcpy(scheme_value sstr)
{
char *result;
int slen;
slen = STRING_LENGTH(sstr);
result = Malloc(char, slen+1);
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if( result == NULL ) {
fprintf(stderr,
"Fatal error: C stub tried to copy Scheme string,\n"
"but malloc failed on arg 0x%x, errno %d.\n",
sstr, errno);
exit(-1);
}
memcpy(result, cig_string_body(sstr), slen);
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result[slen] = '\000';
return result;
}
/* One arg, a zero-terminated C word vec. Returns length.
** The terminating null is not counted. Returns #f on NULL.
*/
scheme_value c_veclen(const long *vec)
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{
const long *vptr = vec;
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if( !vptr ) return SCHFALSE;
while( *vptr ) vptr++;
return ENTER_FIXNUM(vptr - vec);
}
/* Copy string from into string to. If to is NULL, malloc a fresh string
** (if the malloc loses, return NULL).
** If from is NULL, then
** - if to is NULL, do nothing and return NULL.
** - Otherwise, deposit a single nul byte.
** Under normal conditions, this routine returns the destination string.
**
** The little boundary cases of this procedure are a study in obfuscation
** because C doesn't have a reasonable string data type. Give me a break.
*/
char *copystring(char *to, const char *from)
{
if( from ) {
int slen = strlen(from)+1;
if( !to && !(to = Malloc(char, slen)) ) return NULL;
else return memcpy(to, from, slen);
}
else
return to ? *to = '\000', to : NULL;
}
/* As in copystring, but if malloc loses, print out an error msg and croak. */
char *copystring_or_die(const char *str ) /* Note: NULL -> NULL. */
{
if( str ) {
int len = strlen(str)+1;
char *new_str = Malloc(char, len);
if( ! new_str ) {
fprintf(stderr, "copystring: Malloc failed.\n");
exit(-1);
}
return memcpy(new_str, str, len);
}
else return NULL;
}
int cstring_nullp( const char *s ) { return ! s; }
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scheme_value strlen_or_false(const char *s)
{ return s ? ENTER_FIXNUM(strlen(s)) : SCHFALSE; }
/* svec is a Scheme vector of C string carriers. Scan over the C strings
** in cvec, and initialise the corresponding string carriers in svec.
*/
void set_strvec_carriers(scheme_value svec, char const * const * cvec)
{
int svec_len = VECTOR_LENGTH(svec);
char const * const * cv = cvec;
scheme_value *sv = &VECTOR_REF(svec,0);
for(; svec_len > 0; cv++, sv++, svec_len-- ) {
/* *sv is a (cons (make-alien <c-string>) <string-length>). */
scheme_value carrier = *sv;
scheme_value alien = CAR(carrier);
CDR(carrier) = ENTER_FIXNUM(strlen(*cv));
AlienVal(alien) = (long) *cv;
}
}
/* Helper function for arg checking. Why bother, actually? */
void cig_check_nargs(int arity, int nargs, const char *fn)
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{
if( arity != nargs ) {
fprintf(stderr,
"Cig fatal error (%s) -- C stub expected %d arg%s, "
"but got %d.\n",
fn, arity, (arity == 1) ? "" : "s", nargs);
exit(-1);
}
}