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