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* Like symtab but rely on ANSI C features.

This commit is contained in:
bg- 2007-04-25 15:33:29 +00:00
parent 7e540078f1
commit f7908e332f
2 changed files with 162 additions and 0 deletions
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99
core/loader/sym.c Normal file
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/*
* Copyright (c) 2007, Swedish Institute of Computer Science
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)$Id: sym.c,v 1.1 2007/04/25 15:33:54 bg- Exp $
*/
#ifdef __AVR__
#include <avr/pgmspace.h>
#endif
#include "loader/sym.h"
#include <string.h>
static union sym_value
sym_lookup(const char *name, const struct sym_bol *symbols, int nelts)
{
union sym_value ret;
int start, middle, end;
int r;
start = 0;
end = nelts - 1;
while(start <= end) {
/* Check middle, divide */
middle = (start + end) / 2;
#ifdef __AVR__
PGM_P addr = (PGM_P)pgm_read_word(&symbols[middle].name);
r = strcmp_P(name, addr);
#else
r = strcmp(name, symbols[middle].name);
#endif
if(r < 0) {
end = middle - 1;
} else if(r > 0) {
start = middle + 1;
} else {
#ifdef __AVR__
ret.func = (sym_func_t)pgm_read_word(&symbols[middle].value);
return ret;
#else
return symbols[middle].value;
#endif
}
}
ret.obj = NULL;
ret.func = NULL;
return ret;
}
/* Lookup a pointer to an ANSI C object. */
void *
sym_object(const char *name)
{
union sym_value ret;
ret = sym_lookup(name, sym_obj, sym_obj_nelts);
if(ret.obj != NULL)
return ret.obj;
/*
* If the implementation puts constants into the text segment, this
* is where to find them!
*/
ret = sym_lookup(name, sym_func, sym_func_nelts);
return ret.obj;
}
/* Lookup a pointer to an ANSI C function. */
sym_func_t
sym_function(const char *name)
{
return sym_lookup(name, sym_func, sym_func_nelts).func;
}

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core/loader/sym.h Normal file
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/*
* Copyright (c) 2007, Swedish Institute of Computer Science
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)$Id: sym.h,v 1.1 2007/04/25 15:33:29 bg- Exp $
*/
#ifndef SYM_H
#define SYM_H
typedef void (*sym_func_t)();
/*
* Even with an explicit cast, it is invalid to convert a function
* pointer to an object pointer or a pointer to void, or vice-versa.
*/
union sym_value {
void *obj; /* Object pointer */
sym_func_t func; /* or function pointer */
};
struct sym_bol {
const char *name;
union sym_value value;
};
/* Lookup a pointer to an ANSI C object. */
void *sym_object(const char *name);
/* Lookup a pointer to an ANSI C function. */
sym_func_t sym_function(const char *name);
extern const int sym_obj_nelts;
extern const int sym_func_nelts;
extern const struct sym_bol sym_obj[/* sym_obj_nelts */];
extern const struct sym_bol sym_func[/* sym_func__nelts */];
#endif /* SYM_H */