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symbols.cc
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symbols.cc
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#include <stdint.h>
#include <string>
#include <list>
#include <tr1/unordered_map>
using namespace std;
/* returns 0 when not found */
extern "C" uint32_t get_symbol(const char *name, int len);
extern "C" void set_symbol(const char *name, int len, uint32_t val);
extern "C" int find_symbol(const char *name, int len, uint32_t *slot, uint32_t *frame);
extern "C" void add_symbol(const char *name, int len, uint32_t *slot, uint32_t *frame);
extern "C" void add_symbol_table();
extern "C" void delete_symbol_table();
extern "C" uint32_t latest_table_size();
tr1::unordered_map<string,uint32_t> table;
string sym_name(const char* name, int len) {
string str;
str.assign(name, len);
return str;
}
uint32_t get_symbol(const char *name, int len) {
string str = sym_name(name, len);
if (table.find(str) != table.end())
return table[str];
else return 0;
}
void set_symbol(const char *name, int len, uint32_t val) {
table[sym_name(name, len)] = val;
}
struct symbol_table {
uint32_t next;
tr1::unordered_map<string, uint32_t> table;
};
list<symbol_table> tables;
void add_symbol_table() {
symbol_table st;
st.next = 1;
tables.push_front(st);
}
void delete_symbol_table() {
tables.pop_front();
}
int find_symbol(const char *name, int len, uint32_t *slot, uint32_t *frame) {
string str = sym_name(name, len);
int pos = 0;
for (list<symbol_table>::iterator it = tables.begin();
it != tables.end(); ++it, ++pos) {
if (it->table.find(str) != it->table.end()) {
*slot = it->table[str];
*frame = pos;
return 1;
}
}
return 0;
}
void add_symbol(const char *name, int len, uint32_t *slot, uint32_t *frame) {
string str = sym_name(name, len);
symbol_table& st = tables.front();
*slot = st.next;
*frame = 0;
st.table[str] = st.next++;
}
uint32_t latest_table_size() {
return tables.front().next;
}