serial_recv.c

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/*
 * This file is part of the Fun programming language.
 * https://fun-lang.xyz/
 *
 * Copyright 2025 Johannes Findeisen <you@hanez.org>
 * Licensed under the terms of the Apache-2.0 license.
 * https://opensource.org/license/apache-2-0
 */


#ifdef __unix__
#include <unistd.h>
#endif

case OP_SERIAL_RECV: {
 /* Pops maxlen (int), fd (int); returns data (string) */
 Value maxv = pop_value(vm);
 Value fdv = pop_value(vm);
 char *out = NULL;
#ifdef __unix__
 if (fdv.type != VAL_INT || maxv.type != VAL_INT) {
 fprintf(stderr, "Runtime type error: serial_recv expects (int fd, int maxlen)\n");
 } else {
 int fd = (int)fdv.i;
 int maxlen = (int)maxv.i;
 if (maxlen <= 0) maxlen = 4096;
 if (maxlen > 1 << 20) maxlen = 1 << 20; /* cap at 1MB */
 out = (char *)malloc((size_t)maxlen + 1);
 if (out) {
 ssize_t n = read(fd, out, (size_t)maxlen);
 if (n <= 0) {
 free(out);
 out = NULL;
 } else {
 out[n] = '\0';
 }
 }
 }
#endif
 free_value(maxv);
 free_value(fdv);
 Value s = make_string(out ? out : "");
 if (out) free(out);
 push_value(vm, s);
 break;
}