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scsh-0.6/c/external.c

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/* Copyright (c) 1993-1999 by Richard Kelsey and Jonathan Rees.
See file COPYING. */
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <setjmp.h>
#include <stdarg.h>
#include "c-mods.h"
#include "scheme48.h"
#include "scheme48vm.h"
/*
* The Joy of C
* I don't understand why we need this, but we do.
*/
struct s_jmp_buf {
jmp_buf buf;
};
/*
* Longjump target set up by the most recent call into C.
*/
static struct s_jmp_buf current_return_point;
/*
* The name of the procedure we are currently executing; used for error messages.
*/
static s48_value current_procedure;
/*
* Stack of Scheme stack-block records which represent portions of the process
* stack.
*/
static s48_value current_stack_block = S48_FALSE;
/*
* These need to agree with the record definition in callback.scm.
*/
#define STACK_BLOCK_FREE(stack_block) S48_UNSAFE_RECORD_REF(stack_block, 0)
#define STACK_BLOCK_UNWIND(stack_block) S48_UNSAFE_RECORD_REF(stack_block, 1)
#define STACK_BLOCK_PROC(stack_block) S48_UNSAFE_RECORD_REF(stack_block, 2)
#define STACK_BLOCK_THREAD(stack_block) S48_UNSAFE_RECORD_REF(stack_block, 3)
#define STACK_BLOCK_NEXT(stack_block) S48_UNSAFE_RECORD_REF(stack_block, 4)
/*
* For debugging.
*/
/*
static int callback_depth()
{
int depth = 0;
s48_value stack = current_stack_block;
for(; stack != S48_FALSE; depth++, stack = STACK_BLOCK_NEXT(stack));
return depth;
}
*/
/*
* The value being returned from an external call. The returns may be preceded
* by a longjmp(), so we stash the value here.
*/
static s48_value external_return_value;
/* Exports to Scheme */
static s48_value s48_clear_stack_top(void);
static s48_value s48_trampoline(s48_value proc, s48_value nargs);
/* Imports from Scheme */
static s48_value the_record_type_binding = S48_FALSE;
static s48_value stack_block_type_binding = S48_FALSE;
static s48_value callback_binding = S48_FALSE;
static s48_value delay_callback_return_binding = S48_FALSE;
static s48_value bignum_to_long_binding = S48_FALSE;
static s48_value long_to_bignum_binding = S48_FALSE;
void
s48_initialize_external()
{
S48_GC_PROTECT_GLOBAL(the_record_type_binding);
the_record_type_binding = s48_get_imported_binding("s48-the-record-type");
S48_GC_PROTECT_GLOBAL(stack_block_type_binding);
stack_block_type_binding = s48_get_imported_binding("s48-stack-block-type");
S48_GC_PROTECT_GLOBAL(callback_binding);
callback_binding = s48_get_imported_binding("s48-callback");
S48_GC_PROTECT_GLOBAL(delay_callback_return_binding);
delay_callback_return_binding =
s48_get_imported_binding("s48-delay-callback-return");
S48_GC_PROTECT_GLOBAL(bignum_to_long_binding);
bignum_to_long_binding = s48_get_imported_binding("s48-bignum-to-long");
S48_GC_PROTECT_GLOBAL(long_to_bignum_binding);
long_to_bignum_binding = s48_get_imported_binding("s48-long-to-bignum");
S48_GC_PROTECT_GLOBAL(current_stack_block);
S48_GC_PROTECT_GLOBAL(current_procedure);
S48_EXPORT_FUNCTION(s48_clear_stack_top);
S48_EXPORT_FUNCTION(s48_trampoline);
}
/* The three reasons for an extern-call longjump. */
#define NO_THROW 0
#define EXCEPTION_THROW 1
#define CLEANUP_THROW 2
/*
* Used to call `proc' from Scheme code. `nargs' the number of arguments in
* vector `argv'. If `spread_p' is true the procedure is applied to the
* arguments, otherwise `proc' is just called on `nargs' and `argv'.
*
* We do a setjmp() to get a return point for clearing off this portion of
* the process stack. This is used when `proc' calls back to Scheme and
* then a throw transfers control up past the call to `proc'.
*/
s48_value
s48_external_call(s48_value sch_proc, s48_value proc_name,
long nargs, char *char_argv)
{
volatile char *gc_roots_marker; /* volatile to survive longjumps */
volatile s48_value name = proc_name; /* volatile to survive longjumps */
/* int depth = callback_depth(); */ /* debugging */
long *argv = (long *) char_argv;
s48_value (*proc)() = (s48_value (*)())
*S48_EXTRACT_VALUE_POINTER(sch_proc, long);
int throw_reason;
current_procedure = name;
S48_CHECK_VALUE(sch_proc);
S48_CHECK_STRING(name);
gc_roots_marker = s48_set_gc_roots_baseB();
/* fprintf(stderr, "[external_call at depth %d]\n", depth); */
throw_reason = setjmp(current_return_point.buf);
if (throw_reason == NO_THROW) { /* initial entry */
switch (nargs) {
case 0:
external_return_value = proc();
break;
case 1:
external_return_value = proc(argv[0]);
break;
case 2:
external_return_value = proc(argv[1], argv[0]);
break;
case 3:
external_return_value = proc(argv[2], argv[1], argv[0]);
break;
case 4:
external_return_value = proc(argv[3], argv[2], argv[1], argv[0]);
break;
case 5:
external_return_value = proc(argv[4],
argv[3], argv[2], argv[1], argv[0]);
break;
case 6:
external_return_value = proc(argv[5], argv[4],
argv[3], argv[2], argv[1], argv[0]);
break;
case 7:
external_return_value = proc(argv[6], argv[5], argv[4],
argv[3], argv[2], argv[1], argv[0]);
break;
case 8:
external_return_value = proc(argv[7], argv[6], argv[5], argv[4],
argv[3], argv[2], argv[1], argv[0]);
break;
case 9:
external_return_value = proc(argv[8],
argv[7], argv[6], argv[5], argv[4],
argv[3], argv[2], argv[1], argv[0]);
break;
case 10:
external_return_value = proc(argv[9], argv[8],
argv[7], argv[6], argv[5], argv[4],
argv[3], argv[2], argv[1], argv[0]);
break;
case 11:
external_return_value = proc(argv[10], argv[9], argv[8],
argv[7], argv[6], argv[5], argv[4],
argv[3], argv[2], argv[1], argv[0]);
break;
case 12:
external_return_value = proc(argv[11], argv[10], argv[9], argv[8],
argv[7], argv[6], argv[5], argv[4],
argv[3], argv[2], argv[1], argv[0]);
break;
default:
fprintf(stderr, "external-apply called with too many arguments");
exit(-1); }
/* Raise an exception if the user neglected to pop off some gc roots. */
if (! s48_release_gc_roots_baseB((char *)gc_roots_marker)) {
s48_raise_scheme_exception(S48_EXCEPTION_GC_PROTECTION_MISMATCH, 0);
}
/* Clear any free stack-blocks off of the top of the stack-block stack and
then longjmp past the corresponding portions of the process stack. */
if (current_stack_block != S48_FALSE &&
STACK_BLOCK_FREE(current_stack_block) == S48_TRUE) {
s48_value bottom_free_block;
do {
bottom_free_block = current_stack_block;
current_stack_block = STACK_BLOCK_NEXT(current_stack_block);
}
while (current_stack_block != S48_FALSE &&
STACK_BLOCK_FREE(current_stack_block) == S48_TRUE);
/* fprintf(stderr, "[Freeing stack blocks from %d to %d]\n",
depth,
callback_depth()); */
longjmp(S48_EXTRACT_VALUE_POINTER(STACK_BLOCK_UNWIND(bottom_free_block),
struct s_jmp_buf)->buf,
CLEANUP_THROW);
}
}
else { /* throwing an exception or uwinding the stack */
/* fprintf(stderr, "[external_call throw; was %d and now %d]\n",
depth,
callback_depth());
fprintf(stderr, "[throw unrolling to %ld]\n", gc_roots_marker); */
s48_release_gc_roots_baseB((char *)gc_roots_marker);
}
/* Check to see if a thread is waiting to return to the next block down. */
if (current_stack_block != S48_FALSE &&
STACK_BLOCK_THREAD(current_stack_block) != S48_FALSE) {
/* fprintf(stderr, "[releasing return at %d]\n", callback_depth()); */
if (throw_reason == EXCEPTION_THROW) {
/* We are in the midst of raising an exception, so we need to piggyback
our exception on that one. */
s48_value old_exception
= s48_resetup_external_exception(S48_EXCEPTION_CALLBACK_RETURN_UNCOVERED,
2);
s48_push(old_exception);
s48_push(current_stack_block);
external_return_value = S48_UNSPECIFIC;
}
else {
s48_setup_external_exception(S48_EXCEPTION_CALLBACK_RETURN_UNCOVERED, 2);
s48_push(current_stack_block);
s48_push(external_return_value);
external_return_value = S48_UNSPECIFIC;
}
}
return external_return_value;
}
/*
* Call Scheme function `proc' from C. We push the call-back depth, `proc',
* and the arguments on the Scheme stack and then restart the VM. The restarted
* VM calls the Scheme procedure `callback' which wraps the call to `proc' with
* a dynamic-wind. This prevents downward throws back into the call to `proc',
* which C can't handle, and allows the C stack to be cleaned up if an upward
* throw occurs.
*
* The maximum number of arguments is determined by the amount of space reserved
* on the Scheme stack for exceptions. See the definition of stack-slack in
* scheme/vm/stack.scm.
*/
s48_value
s48_call_scheme(s48_value proc, long nargs, ...)
{
int i;
va_list arguments;
s48_value value;
s48_value unwind, stack_block;
S48_DECLARE_GC_PROTECT(2);
S48_GC_PROTECT_2(unwind, proc);
va_start(arguments, nargs);
S48_SHARED_BINDING_CHECK(callback_binding);
/* It would be nice to push a list of the arguments, but we have no way
of preserving them across a cons. */
if (nargs < 0 || 10 < nargs) { /* DO NOT INCREASE THIS NUMBER */
s48_value sch_nargs = s48_enter_integer(nargs); /* `proc' is protected */
s48_raise_scheme_exception(S48_EXCEPTION_TOO_MANY_ARGUMENTS_IN_CALLBACK,
2, proc, sch_nargs);
}
/* fprintf(stderr, "[s48_call, %ld args, depth %d]\n",
nargs, callback_depth()); */
s48_push(S48_UNSPECIFIC); /* placeholder */
s48_push(proc);
for (i = 0; i < nargs; i++)
s48_push(va_arg(arguments, s48_value));
va_end(arguments);
/* With everything safely on the stack we can do the necessary allocation. */
unwind = S48_MAKE_VALUE(struct s_jmp_buf);
S48_EXTRACT_VALUE(unwind, struct s_jmp_buf) = current_return_point;
stack_block = s48_make_record(stack_block_type_binding);
STACK_BLOCK_UNWIND(stack_block) = unwind;
STACK_BLOCK_PROC(stack_block) = current_procedure;
STACK_BLOCK_NEXT(stack_block) = current_stack_block;
STACK_BLOCK_FREE(stack_block) = S48_FALSE;
STACK_BLOCK_THREAD(stack_block) = S48_FALSE;
S48_GC_UNPROTECT(); /* no more references to `unwind' or `proc'. */
current_stack_block = stack_block;
/* if(s48_stack_ref(nargs + 1) != S48_UNSPECIFIC)
fprintf(stderr, "[stack_block set missed]\n"); */
s48_stack_setB(nargs + 1, stack_block);
/* fprintf(stderr, "[s48_call, %ld args, depth %d, off we go]\n",
nargs, callback_depth()); */
value = s48_restart(S48_UNSAFE_SHARED_BINDING_REF(callback_binding),
nargs + 2);
for (;s48_Scallback_return_stack_blockS != current_stack_block;) {
if (s48_Scallback_return_stack_blockS == S48_FALSE) {
/* fprintf(stderr, "[s48_call returning from VM %ld]\n", callback_depth()); */
exit(value);
}
else {
/* Someone has returned (because of threads) to the wrong section of the
C stack. We call back to a Scheme procedure that will suspend until
out block is at the top of the stack. */
s48_push(s48_Scallback_return_stack_blockS);
s48_push(S48_UNSAFE_SHARED_BINDING_REF(delay_callback_return_binding));
s48_push(s48_Scallback_return_stack_blockS);
s48_push(value);
/* fprintf(stderr, "[Premature return, %ld args, depth %d, back we go]\n",
nargs, callback_depth()); */
s48_disable_interruptsB();
value = s48_restart(S48_UNSAFE_SHARED_BINDING_REF(callback_binding), 4);
}
}
/* Restore the state of the current stack block. */
unwind = STACK_BLOCK_UNWIND(current_stack_block);
current_return_point = S48_EXTRACT_VALUE(unwind, struct s_jmp_buf);
current_procedure = STACK_BLOCK_PROC(current_stack_block);
current_stack_block = STACK_BLOCK_NEXT(current_stack_block);
/* fprintf(stderr, "[s48_call returns from depth %d]\n", callback_depth()); */
return value;
}
/*
* Because the top of the stack is cleared on the return from every external
* call, this doesn't have to do anything but exist.
*/
static s48_value
s48_clear_stack_top()
{
/* fprintf(stderr, "[Clearing stack top]\n"); */
return S48_UNSPECIFIC;
}
/*
* For testing callbacks. This just calls its argument on the specified number
* of values.
*/
static s48_value
s48_trampoline(s48_value proc, s48_value nargs)
{
fprintf(stderr, "[C trampoline, %ld args]\n", S48_UNSAFE_EXTRACT_FIXNUM(nargs));
switch (s48_extract_fixnum(nargs)) {
case -2: {
S48_DECLARE_GC_PROTECT(1);
S48_GC_PROTECT_1(proc);
return S48_FALSE;
}
case -1: {
long n = - s48_extract_integer(proc);
fprintf(stderr, "[extract magnitude is %ld (%lx)]\n", n, n);
return s48_enter_integer(n);
}
case 0: {
s48_value value = s48_call_scheme(proc, 0);
if (value == S48_FALSE)
s48_raise_string_os_error("trampoline bouncing");
return value;
}
case 1:
return s48_call_scheme(proc, 1, s48_enter_fixnum(100));
case 2:
return s48_call_scheme(proc, 2, s48_enter_fixnum(100), s48_enter_fixnum(200));
case 3:
return s48_call_scheme(proc, 3, s48_enter_fixnum(100), s48_enter_fixnum(200),
s48_enter_fixnum(300));
default:
s48_raise_range_error(nargs, s48_enter_fixnum(0), s48_enter_fixnum(3));
return S48_UNDEFINED; /* not that we ever get here */
}
}
/********************************/
/*
* Raising exceptions. We push the arguments on the stack end then throw out
* of the most recent call from Scheme.
*
* The maximum number of arguments is determined by the amount of space reserved
* on the Scheme stack for exceptions. See the definition of stack-slack in
* scheme/vm/stack.scm.
*/
void
s48_raise_scheme_exception(long why, long nargs, ...)
{
int i;
va_list irritants;
va_start(irritants, nargs);
s48_setup_external_exception(why, nargs + 1);
if (10 < nargs) { /* DO NOT INCREASE THIS NUMBER */
fprintf(stderr, "s48_raise_scheme_exception() called with more than 10 arguments, discarding surplus\n");
nargs = 10;
}
s48_push(current_procedure);
for (i = 0; i < nargs; i++)
s48_push(va_arg(irritants, s48_value));
va_end(irritants);
external_return_value = S48_UNSPECIFIC;
longjmp(current_return_point.buf, EXCEPTION_THROW);
}
/* Specific exceptions */
void
s48_raise_argtype_error(s48_value value) {
s48_raise_scheme_exception(S48_EXCEPTION_WRONG_TYPE_ARGUMENT, 1, value);
}
void
s48_raise_argnumber_error(s48_value value, s48_value min, s48_value max) {
s48_raise_scheme_exception(S48_EXCEPTION_WRONG_NUMBER_OF_ARGUMENTS,
3, value, min, max);
}
void
s48_raise_range_error(s48_value value, s48_value min, s48_value max) {
s48_raise_scheme_exception(S48_EXCEPTION_INDEX_OUT_OF_RANGE,
3, value, min, max);
}
void
s48_raise_closed_channel_error() {
s48_raise_scheme_exception(S48_EXCEPTION_CLOSED_CHANNEL, 0);
}
void
s48_raise_os_error(int the_errno) {
s48_raise_scheme_exception(S48_EXCEPTION_OS_ERROR, 2,
s48_enter_fixnum(the_errno),
s48_enter_string(strerror(the_errno)));
}
void
s48_raise_string_os_error(char *reason) {
s48_raise_scheme_exception(S48_EXCEPTION_OS_ERROR, 1,
s48_enter_string(reason));
}
void
s48_raise_out_of_memory_error() {
s48_raise_scheme_exception(S48_EXCEPTION_OUT_OF_MEMORY, 0);
}
/********************************/
/* Support routines for external code */
/*
* Type-safe procedures for checking types and dereferencing and setting slots.
*/
int
s48_stob_has_type(s48_value thing, int type)
{
return S48_STOB_P(thing) && (S48_STOB_TYPE(thing) == type);
}
long
s48_stob_length(s48_value thing, int type)
{
if (!(S48_STOB_P(thing) && (S48_STOB_TYPE(thing) == type)))
s48_raise_argtype_error(thing);
return S48_STOB_DESCRIPTOR_LENGTH(thing);
}
long
s48_stob_byte_length(s48_value thing, int type)
{
if (!(S48_STOB_P(thing) && (S48_STOB_TYPE(thing) == type)))
s48_raise_argtype_error(thing);
if (type == S48_STOBTYPE_STRING)
return S48_STOB_BYTE_LENGTH(thing) - 1;
else
return S48_STOB_BYTE_LENGTH(thing);
}
s48_value
s48_stob_ref(s48_value thing, int type, long offset)
{
long length;
if (!(S48_STOB_P(thing) && (S48_STOB_TYPE(thing) == type)))
s48_raise_argtype_error(thing);
length = S48_STOB_DESCRIPTOR_LENGTH(thing);
if (offset < 0 || length <= offset)
s48_raise_range_error(s48_enter_integer(offset),
S48_UNSAFE_ENTER_FIXNUM(0),
S48_UNSAFE_ENTER_FIXNUM(length - 1));
return S48_STOB_REF(thing, offset);
}
void
s48_stob_set(s48_value thing, int type, long offset, s48_value value)
{
long length;
if (!(S48_STOB_P(thing) &&
(S48_STOB_TYPE(thing) == type) &&
!S48_STOB_IMMUTABLEP(thing)))
s48_raise_argtype_error(thing);
length = S48_STOB_DESCRIPTOR_LENGTH(thing);
if (offset < 0 || length <= offset)
s48_raise_range_error(s48_enter_integer(offset),
S48_UNSAFE_ENTER_FIXNUM(0),
S48_UNSAFE_ENTER_FIXNUM(length - 1));
S48_STOB_SET(thing, offset, value);
}
char
s48_byte_ref(s48_value thing, int type, long offset)
{
long length;
if (!(S48_STOB_P(thing) && (S48_STOB_TYPE(thing) == type)))
s48_raise_argtype_error(thing);
length = (type == S48_STOBTYPE_STRING) ?
S48_STOB_BYTE_LENGTH(thing) - 1 :
S48_STOB_BYTE_LENGTH(thing);
if (offset < 0 || length <= offset)
s48_raise_range_error(s48_enter_integer(offset),
S48_UNSAFE_ENTER_FIXNUM(0),
S48_UNSAFE_ENTER_FIXNUM(length - 1));
return S48_STOB_BYTE_REF(thing, offset);
}
void
s48_byte_set(s48_value thing, int type, long offset, char value)
{
long length;
if (!(S48_STOB_P(thing) && (S48_STOB_TYPE(thing) == type)))
s48_raise_argtype_error(thing);
length = (type == S48_STOBTYPE_STRING) ?
S48_STOB_BYTE_LENGTH(thing) - 1 :
S48_STOB_BYTE_LENGTH(thing);
if (offset < 0 || length <= offset)
s48_raise_range_error(s48_enter_integer(offset),
S48_UNSAFE_ENTER_FIXNUM(0),
S48_UNSAFE_ENTER_FIXNUM(length - 1));
S48_STOB_BYTE_SET(thing, offset, value);
}
void *
s48_value_pointer(s48_value value)
{
S48_CHECK_VALUE(value);
return S48_ADDRESS_AFTER_HEADER(value, void *);
}
/********************************/
/* Numbers, characters, and pointers. */
/*
* These two functions have the same range as the unsafe macros, but they signal
* an error if things go wrong, instead of silently producing garbage. Unlike
* the integer versions they cannot cause a GC.
*/
s48_value
s48_enter_fixnum(long value)
{
if (value < S48_MIN_FIXNUM_VALUE || S48_MAX_FIXNUM_VALUE < value)
s48_raise_argtype_error(s48_enter_integer(value));
return S48_UNSAFE_ENTER_FIXNUM(value);
}
long
s48_extract_fixnum(s48_value value)
{
if (! S48_FIXNUM_P(value))
s48_raise_argtype_error(value);
return S48_UNSAFE_EXTRACT_FIXNUM(value);
}
/*
* If `value' fits in a fixnum we put it there. Larger values are passed to the
* Scheme procedure LONG-TO-BIGNUM as the sign and the two sixteen-bit halves of
* the negative magnitude. Using the negative magnitude avoids problems with
* two's complement's asymmetry.
*/
s48_value
s48_enter_integer(long value)
{
if (S48_MIN_FIXNUM_VALUE <= value && value <= S48_MAX_FIXNUM_VALUE)
return S48_UNSAFE_ENTER_FIXNUM(value);
else {
S48_SHARED_BINDING_CHECK(long_to_bignum_binding);
if (value < 0)
return s48_call_scheme(S48_SHARED_BINDING_REF(long_to_bignum_binding),
3,
S48_FALSE,
S48_UNSAFE_ENTER_FIXNUM(value >> 16),
S48_UNSAFE_ENTER_FIXNUM(value & 0xFFFF));
else
return s48_call_scheme(S48_SHARED_BINDING_REF(long_to_bignum_binding),
3,
S48_TRUE,
S48_UNSAFE_ENTER_FIXNUM((- value) >> 16),
S48_UNSAFE_ENTER_FIXNUM((- value) & 0xFFFF));
}
}
/*
* If we have a fixnum we just extract it. Bignums require a call back into
* Scheme 48. (BIGNUM-TO-LONG n) returns a vector containing the sign and the
* high and low sixteen-bit halves of N. If N is not an integer we get #f back.
* Again, we use negative numbers to stay out of trouble.
*/
long
s48_extract_integer(s48_value value)
{
if (S48_FIXNUM_P(value))
return S48_UNSAFE_EXTRACT_FIXNUM(value);
else {
s48_value stuff;
S48_DECLARE_GC_PROTECT(1);
S48_GC_PROTECT_1(value);
S48_SHARED_BINDING_CHECK(bignum_to_long_binding);
stuff = s48_call_scheme(S48_SHARED_BINDING_REF(bignum_to_long_binding),
1,
value);
S48_GC_UNPROTECT();
if (stuff == S48_FALSE)
s48_raise_argtype_error(value);
/* The first VECTOR_REF does the type checking for the rest. */
{
long low = S48_UNSAFE_EXTRACT_FIXNUM(S48_VECTOR_REF(stuff, 2));
s48_value boxed_high = S48_UNSAFE_VECTOR_REF(stuff, 1);
long high = S48_UNSAFE_EXTRACT_FIXNUM(boxed_high);
int pos_p = S48_EXTRACT_BOOLEAN(S48_UNSAFE_VECTOR_REF(stuff, 0));
if ((! S48_FIXNUM_P(boxed_high)) ||
high > (pos_p ? 0x7FFF : 0x8000))
s48_raise_argtype_error(value);
{
long magnitude = ((- high) << 16) - low;
return pos_p ? - magnitude : magnitude;
}
}
}
}
/*
* Doubles and characters are straightforward.
*/
s48_value
s48_enter_double(double value)
{
s48_value obj;
obj = s48_allocate_stob(S48_STOBTYPE_DOUBLE, sizeof(double));
S48_UNSAFE_EXTRACT_DOUBLE(obj) = value;
return obj;
}
double
s48_extract_double(s48_value s48_double)
{
if (! S48_DOUBLE_P(s48_double))
s48_raise_argtype_error(s48_double);
return S48_UNSAFE_EXTRACT_DOUBLE(s48_double);
}
s48_value
s48_enter_char(unsigned char a_char)
{
if (a_char > 255)
s48_raise_range_error(s48_enter_fixnum(a_char),
s48_enter_fixnum(0),
s48_enter_fixnum(255));
return S48_UNSAFE_ENTER_CHAR(a_char);
}
unsigned char
s48_extract_char(s48_value a_char)
{
if (! S48_CHAR_P(a_char))
s48_raise_argtype_error(a_char);
return S48_UNSAFE_EXTRACT_CHAR(a_char);
}
/********************************/
/* Allocation */
s48_value
s48_enter_pointer(void *pointer)
{
s48_value obj;
obj = s48_allocate_stob(S48_STOBTYPE_BYTE_VECTOR, sizeof(void *));
*(S48_ADDRESS_AFTER_HEADER(obj, void **)) = pointer;
return obj;
}
s48_value
s48_cons(s48_value v1, s48_value v2)
{
s48_value obj;
S48_DECLARE_GC_PROTECT(2);
S48_GC_PROTECT_2(v1, v2);
obj = s48_allocate_stob(S48_STOBTYPE_PAIR, 2 * sizeof(s48_value));
S48_UNSAFE_SET_CAR(obj, v1);
S48_UNSAFE_SET_CDR(obj, v2);
S48_GC_UNPROTECT();
return obj;
}
s48_value
s48_make_weak_pointer(s48_value value)
{
s48_value obj;
S48_DECLARE_GC_PROTECT(1);
S48_GC_PROTECT_1(value);
obj = s48_allocate_stob(S48_STOBTYPE_WEAK_POINTER, sizeof(s48_value));
S48_STOB_SET(obj, 0, value);
S48_GC_UNPROTECT();
return obj;
}
s48_value
s48_enter_substring(char *str, int length)
{
s48_value obj = s48_allocate_stob(S48_STOBTYPE_STRING, length + 1);
strncpy(S48_UNSAFE_EXTRACT_STRING(obj), str, length);
*(S48_UNSAFE_EXTRACT_STRING(obj) + length) = '\0';
return obj;
}
s48_value
s48_enter_string(char *str)
{
return s48_enter_substring(str, strlen(str));
}
char *
s48_extract_string(s48_value string)
{
S48_CHECK_STRING(string);
return S48_UNSAFE_EXTRACT_STRING(string);
}
s48_value
s48_make_string(int length, char init)
{
s48_value obj = s48_allocate_stob(S48_STOBTYPE_STRING, length+1);
memset(S48_UNSAFE_EXTRACT_STRING(obj), init, length);
S48_UNSAFE_EXTRACT_STRING(obj)[length] = '\0';
return obj;
}
s48_value
s48_make_vector(int length, s48_value init)
{
int i;
s48_value obj;
S48_DECLARE_GC_PROTECT(1);
S48_GC_PROTECT_1(init);
obj = s48_allocate_stob(S48_STOBTYPE_VECTOR, length * sizeof(s48_value));
for (i = 0; i < length; ++i)
S48_UNSAFE_VECTOR_SET(obj, i, init);
S48_GC_UNPROTECT();
return obj;
}
s48_value
s48_make_byte_vector(int length)
{
return s48_allocate_stob(S48_STOBTYPE_BYTE_VECTOR, length);
}
s48_value
s48_make_record(s48_value type_shared_binding)
{
int i, number_of_fields;
s48_value record = S48_FALSE;
s48_value record_type = S48_FALSE;
S48_DECLARE_GC_PROTECT(1);
S48_GC_PROTECT_1(record_type);
S48_SHARED_BINDING_CHECK(type_shared_binding);
S48_SHARED_BINDING_CHECK(the_record_type_binding);
record_type = S48_SHARED_BINDING_REF(type_shared_binding);
s48_check_record_type(record_type, the_record_type_binding);
number_of_fields =
S48_UNSAFE_EXTRACT_FIXNUM(S48_RECORD_TYPE_NUMBER_OF_FIELDS(record_type));
record = s48_allocate_stob(S48_STOBTYPE_RECORD,
(number_of_fields + 1) * sizeof(s48_value));
S48_UNSAFE_RECORD_SET(record, -1, record_type);
for (i = 0; i < number_of_fields; ++i)
S48_UNSAFE_RECORD_SET(record, i, S48_UNSPECIFIC);
S48_GC_UNPROTECT();
return record;
}
/*
* Raise an exception if `record' is not a record whose type is the one
* found in `type_binding'.
*/
void
s48_check_record_type(s48_value record, s48_value type_binding)
{
if (! S48_RECORD_P(S48_SHARED_BINDING_REF(type_binding)))
s48_raise_scheme_exception(S48_EXCEPTION_UNBOUND_EXTERNAL_NAME, 1,
S48_SHARED_BINDING_NAME(type_binding));
if ((! S48_RECORD_P(record)) ||
(S48_UNSAFE_SHARED_BINDING_REF(type_binding) !=
S48_UNSAFE_RECORD_REF(record, -1)))
s48_raise_argtype_error(record);
}
long
s48_length(s48_value list)
{
long i = 0;
while (!(S48_EQ(list, S48_NULL)))
{
list = S48_CDR(list);
++i;
}
return S48_UNSAFE_ENTER_FIXNUM(i);
}
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