objc-typeencoding.mm [plain text]
/*
* Copyright (c) 1999-2007 Apple Inc. All Rights Reserved.
*
* @APPLE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this
* file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_LICENSE_HEADER_END@
*/
/***********************************************************************
* objc-typeencoding.m
* Parsing of old-style type strings.
**********************************************************************/
#include "objc-private.h"
/***********************************************************************
* SubtypeUntil.
*
* Delegation.
**********************************************************************/
static int SubtypeUntil (const char * type,
char end)
{
int level = 0;
const char * head = type;
//
while (*type)
{
if (!*type || (!level && (*type == end)))
return (int)(type - head);
switch (*type)
{
case ']': case '}': case ')': level--; break;
case '[': case '{': case '(': level += 1; break;
}
type += 1;
}
_objc_fatal ("Object: SubtypeUntil: end of type encountered prematurely\n");
return 0;
}
/***********************************************************************
* SkipFirstType.
**********************************************************************/
static const char * SkipFirstType (const char * type)
{
while (1)
{
switch (*type++)
{
case 'O': /* bycopy */
case 'n': /* in */
case 'o': /* out */
case 'N': /* inout */
case 'r': /* const */
case 'V': /* oneway */
case '^': /* pointers */
break;
case '@': /* objects */
if (type[0] == '?') type++; /* Blocks */
return type;
/* arrays */
case '[':
while ((*type >= '0') && (*type <= '9'))
type += 1;
return type + SubtypeUntil (type, ']') + 1;
/* structures */
case '{':
return type + SubtypeUntil (type, '}') + 1;
/* unions */
case '(':
return type + SubtypeUntil (type, ')') + 1;
/* basic types */
default:
return type;
}
}
}
/***********************************************************************
* encoding_getNumberOfArguments.
**********************************************************************/
unsigned int
encoding_getNumberOfArguments(const char *typedesc)
{
unsigned nargs;
// First, skip the return type
typedesc = SkipFirstType (typedesc);
// Next, skip stack size
while ((*typedesc >= '0') && (*typedesc <= '9'))
typedesc += 1;
// Now, we have the arguments - count how many
nargs = 0;
while (*typedesc)
{
// Traverse argument type
typedesc = SkipFirstType (typedesc);
// Skip GNU runtime's register parameter hint
if (*typedesc == '+') typedesc++;
// Traverse (possibly negative) argument offset
if (*typedesc == '-')
typedesc += 1;
while ((*typedesc >= '0') && (*typedesc <= '9'))
typedesc += 1;
// Made it past an argument
nargs += 1;
}
return nargs;
}
/***********************************************************************
* encoding_getSizeOfArguments.
**********************************************************************/
unsigned
encoding_getSizeOfArguments(const char *typedesc)
{
unsigned stack_size;
// Get our starting points
stack_size = 0;
// Skip the return type
typedesc = SkipFirstType (typedesc);
// Convert ASCII number string to integer
while ((*typedesc >= '0') && (*typedesc <= '9'))
stack_size = (stack_size * 10) + (*typedesc++ - '0');
return stack_size;
}
/***********************************************************************
* encoding_getArgumentInfo.
**********************************************************************/
unsigned int
encoding_getArgumentInfo(const char *typedesc, unsigned int arg,
const char **type, int *offset)
{
unsigned nargs = 0;
int self_offset = 0;
bool offset_is_negative = NO;
// First, skip the return type
typedesc = SkipFirstType (typedesc);
// Next, skip stack size
while ((*typedesc >= '0') && (*typedesc <= '9'))
typedesc += 1;
// Now, we have the arguments - position typedesc to the appropriate argument
while (*typedesc && nargs != arg)
{
// Skip argument type
typedesc = SkipFirstType (typedesc);
if (nargs == 0)
{
// Skip GNU runtime's register parameter hint
if (*typedesc == '+') typedesc++;
// Skip negative sign in offset
if (*typedesc == '-')
{
offset_is_negative = YES;
typedesc += 1;
}
else
offset_is_negative = NO;
while ((*typedesc >= '0') && (*typedesc <= '9'))
self_offset = self_offset * 10 + (*typedesc++ - '0');
if (offset_is_negative)
self_offset = -(self_offset);
}
else
{
// Skip GNU runtime's register parameter hint
if (*typedesc == '+') typedesc++;
// Skip (possibly negative) argument offset
if (*typedesc == '-')
typedesc += 1;
while ((*typedesc >= '0') && (*typedesc <= '9'))
typedesc += 1;
}
nargs += 1;
}
if (*typedesc)
{
int arg_offset = 0;
*type = typedesc;
typedesc = SkipFirstType (typedesc);
if (arg == 0)
{
*offset = 0;
}
else
{
// Skip GNU register parameter hint
if (*typedesc == '+') typedesc++;
// Pick up (possibly negative) argument offset
if (*typedesc == '-')
{
offset_is_negative = YES;
typedesc += 1;
}
else
offset_is_negative = NO;
while ((*typedesc >= '0') && (*typedesc <= '9'))
arg_offset = arg_offset * 10 + (*typedesc++ - '0');
if (offset_is_negative)
arg_offset = - arg_offset;
*offset = arg_offset - self_offset;
}
}
else
{
*type = 0;
*offset = 0;
}
return nargs;
}
void
encoding_getReturnType(const char *t, char *dst, size_t dst_len)
{
size_t len;
const char *end;
if (!dst) return;
if (!t) {
strncpy(dst, "", dst_len);
return;
}
end = SkipFirstType(t);
len = end - t;
strncpy(dst, t, MIN(len, dst_len));
if (len < dst_len) memset(dst+len, 0, dst_len - len);
}
/***********************************************************************
* encoding_copyReturnType. Returns the method's return type string
* on the heap.
**********************************************************************/
char *
encoding_copyReturnType(const char *t)
{
size_t len;
const char *end;
char *result;
if (!t) return NULL;
end = SkipFirstType(t);
len = end - t;
result = (char *)malloc(len + 1);
strncpy(result, t, len);
result[len] = '\0';
return result;
}
void
encoding_getArgumentType(const char *t, unsigned int index,
char *dst, size_t dst_len)
{
size_t len;
const char *end;
int offset;
if (!dst) return;
if (!t) {
strncpy(dst, "", dst_len);
return;
}
encoding_getArgumentInfo(t, index, &t, &offset);
if (!t) {
strncpy(dst, "", dst_len);
return;
}
end = SkipFirstType(t);
len = end - t;
strncpy(dst, t, MIN(len, dst_len));
if (len < dst_len) memset(dst+len, 0, dst_len - len);
}
/***********************************************************************
* encoding_copyArgumentType. Returns a single argument's type string
* on the heap. Argument 0 is `self`; argument 1 is `_cmd`.
**********************************************************************/
char *
encoding_copyArgumentType(const char *t, unsigned int index)
{
size_t len;
const char *end;
char *result;
int offset;
if (!t) return NULL;
encoding_getArgumentInfo(t, index, &t, &offset);
if (!t) return NULL;
end = SkipFirstType(t);
len = end - t;
result = (char *)malloc(len + 1);
strncpy(result, t, len);
result[len] = '\0';
return result;
}