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decoder.c
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decoder.c
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#include "ruby.h"
#include <string.h>
#define ERL_VERSION 131
#define ERL_SMALL_INT 97
#define ERL_INT 98
#define ERL_SMALL_BIGNUM 110
#define ERL_LARGE_BIGNUM 111
#define ERL_FLOAT 99
#define ERL_ATOM 100
#define ERL_REF 101
#define ERL_NEW_REF 114
#define ERL_PORT 102
#define ERL_PID 103
#define ERL_SMALL_TUPLE 104
#define ERL_LARGE_TUPLE 105
#define ERL_NIL 106
#define ERL_STRING 107
#define ERL_LIST 108
#define ERL_BIN 109
#define ERL_FUN 117
#define ERL_NEW_FUN 112
static VALUE mErlectricity;
static VALUE cDecoder;
void Init_decoder();
VALUE method_read_any_from(VALUE klass, VALUE rString);
VALUE read_any_raw(unsigned char **pData);
// checkers
void check_int(int num) {
char buf[17];
sprintf(buf, "%u", num);
rb_raise(rb_eStandardError, buf);
}
void check_str(char *str) {
rb_raise(rb_eStandardError, str);
}
// string peekers/readers
unsigned int peek_1(unsigned char **pData) {
return (unsigned int) **pData;
}
unsigned int peek_2(unsigned char **pData) {
return (unsigned int) ((**pData << 8) + *(*pData + 1));
}
unsigned int peek_4(unsigned char **pData) {
return (unsigned int) ((**pData << 24) + (*(*pData + 1) << 16) + (*(*pData + 2) << 8) + *(*pData + 3));
}
unsigned int read_1(unsigned char **pData) {
unsigned int val = peek_1(pData);
*pData += 1;
return val;
}
unsigned int read_2(unsigned char **pData) {
unsigned int val = peek_2(pData);
*pData += 2;
return val;
}
unsigned int read_4(unsigned char **pData) {
unsigned int val = peek_4(pData);
*pData += 4;
return val;
}
// tuples, lists
VALUE read_small_tuple(unsigned char **pData) {
if(read_1(pData) != ERL_SMALL_TUPLE) {
rb_raise(rb_eStandardError, "Invalid Type, not a small tuple");
}
int arity = read_1(pData);
VALUE array = rb_ary_new2(arity);
int i;
for(i = 0; i < arity; ++i) {
rb_ary_store(array, i, read_any_raw(pData));
}
return array;
}
VALUE read_large_tuple(unsigned char **pData) {
if(read_1(pData) != ERL_LARGE_TUPLE) {
rb_raise(rb_eStandardError, "Invalid Type, not a large tuple");
}
int arity = read_4(pData);
VALUE array = rb_ary_new2(arity);
int i;
for(i = 0; i < arity; ++i) {
rb_ary_store(array, i, read_any_raw(pData));
}
return array;
}
VALUE read_list(unsigned char **pData) {
if(read_1(pData) != ERL_LIST) {
rb_raise(rb_eStandardError, "Invalid Type, not an erlang list");
}
int size = read_4(pData);
VALUE array = rb_ary_new2(size);
int i;
for(i = 0; i < size; ++i) {
rb_ary_store(array, i, read_any_raw(pData));
}
read_1(pData);
return array;
}
// primitives
void read_string_raw(unsigned char *dest, unsigned char **pData, int length) {
memcpy((char *) dest, (char *) *pData, length);
*(dest + length) = (unsigned char) 0;
*pData += length;
}
VALUE read_bin(unsigned char **pData) {
if(read_1(pData) != ERL_BIN) {
rb_raise(rb_eStandardError, "Invalid Type, not an erlang binary");
}
int length = read_4(pData);
unsigned char buf[length + 1];
read_string_raw(buf, pData, length);
return rb_str_new2((char *) buf);
}
VALUE read_string(unsigned char **pData) {
if(read_1(pData) != ERL_STRING) {
rb_raise(rb_eStandardError, "Invalid Type, not an erlang string");
}
int length = read_2(pData);
unsigned char buf[length + 1];
read_string_raw(buf, pData, length);
VALUE array = rb_ary_new2(length);
int i = 0;
for(i; i < length; ++i) {
rb_ary_store(array, i, INT2NUM(*(buf + i)));
}
return array;
}
VALUE read_atom(unsigned char **pData) {
if(read_1(pData) != ERL_ATOM) {
rb_raise(rb_eStandardError, "Invalid Type, not an atom");
}
int length = read_2(pData);
unsigned char buf[length + 1];
read_string_raw(buf, pData, length);
return ID2SYM(rb_intern((char *) buf));
}
VALUE read_small_int(unsigned char **pData) {
if(read_1(pData) != ERL_SMALL_INT) {
rb_raise(rb_eStandardError, "Invalid Type, not a small int");
}
int value = read_1(pData);
return INT2FIX(value);
}
VALUE read_int(unsigned char **pData) {
if(read_1(pData) != ERL_INT) {
rb_raise(rb_eStandardError, "Invalid Type, not an int");
}
long long value = read_4(pData);
long long negative = ((value >> 31) & 0x1 == 1);
if(negative) {
value = (value - ((long long) 1 << 32));
}
return INT2FIX(value);
}
VALUE read_small_bignum(unsigned char **pData) {
if(read_1(pData) != ERL_SMALL_BIGNUM) {
rb_raise(rb_eStandardError, "Invalid Type, not a small bignum");
}
unsigned int size = read_1(pData);
unsigned int sign = read_1(pData);
VALUE num = INT2NUM(0);
VALUE tmp;
unsigned char buf[size + 1];
read_string_raw(buf, pData, size);
int i;
for(i = 0; i < size; ++i) {
tmp = INT2FIX(*(buf + i));
tmp = rb_funcall(tmp, rb_intern("<<"), 1, INT2NUM(i * 8));
num = rb_funcall(num, rb_intern("+"), 1, tmp);
}
if(sign) {
num = rb_funcall(num, rb_intern("*"), 1, INT2NUM(-1));
}
return num;
}
VALUE read_large_bignum(unsigned char **pData) {
if(read_1(pData) != ERL_LARGE_BIGNUM) {
rb_raise(rb_eStandardError, "Invalid Type, not a small bignum");
}
unsigned int size = read_4(pData);
unsigned int sign = read_1(pData);
VALUE num = INT2NUM(0);
VALUE tmp;
unsigned char buf[size + 1];
read_string_raw(buf, pData, size);
int i;
for(i = 0; i < size; ++i) {
tmp = INT2FIX(*(buf + i));
tmp = rb_funcall(tmp, rb_intern("<<"), 1, INT2NUM(i * 8));
num = rb_funcall(num, rb_intern("+"), 1, tmp);
}
if(sign) {
num = rb_funcall(num, rb_intern("*"), 1, INT2NUM(-1));
}
return num;
}
VALUE read_float(unsigned char **pData) {
if(read_1(pData) != ERL_FLOAT) {
rb_raise(rb_eStandardError, "Invalid Type, not a float");
}
unsigned char buf[32];
read_string_raw(buf, pData, 31);
VALUE rString = rb_str_new2((char *) buf);
return rb_funcall(rString, rb_intern("to_f"), 0);
}
VALUE read_nil(unsigned char **pData) {
if(read_1(pData) != ERL_NIL) {
rb_raise(rb_eStandardError, "Invalid Type, not a nil list");
}
return rb_ary_new2(0);
}
// specials
VALUE read_pid(unsigned char **pData) {
if(read_1(pData) != ERL_PID) {
rb_raise(rb_eStandardError, "Invalid Type, not a pid");
}
VALUE node = read_atom(pData);
VALUE id = INT2NUM(read_4(pData));
VALUE serial = INT2NUM(read_4(pData));
VALUE creation = INT2FIX(read_1(pData));
VALUE pid_class = rb_const_get(mErlectricity, rb_intern("Pid"));
return rb_funcall(pid_class, rb_intern("new"), 4, node, id, serial, creation);
}
VALUE read_new_reference(unsigned char **pData) {
if(read_1(pData) != ERL_NEW_REF) {
rb_raise(rb_eStandardError, "Invalid Type, not a new-style reference");
}
int size = read_2(pData);
VALUE node = read_atom(pData);
VALUE creation = INT2FIX(read_1(pData));
VALUE id = rb_ary_new2(size);
int i;
for(i = 0; i < size; ++i) {
rb_ary_store(id, i, INT2NUM(read_4(pData)));
}
VALUE newref_class = rb_const_get(mErlectricity, rb_intern("NewReference"));
return rb_funcall(newref_class, rb_intern("new"), 3, node, creation, id);
}
// read_any_raw
VALUE read_any_raw(unsigned char **pData) {
switch(peek_1(pData)) {
case ERL_SMALL_INT:
return read_small_int(pData);
break;
case ERL_INT:
return read_int(pData);
break;
case ERL_FLOAT:
return read_float(pData);
break;
case ERL_ATOM:
return read_atom(pData);
break;
case ERL_PID:
return read_pid(pData);
break;
case ERL_SMALL_TUPLE:
return read_small_tuple(pData);
break;
case ERL_LARGE_TUPLE:
return read_large_tuple(pData);
break;
case ERL_NIL:
return read_nil(pData);
break;
case ERL_STRING:
return read_string(pData);
break;
case ERL_LIST:
return read_list(pData);
break;
case ERL_BIN:
return read_bin(pData);
break;
case ERL_SMALL_BIGNUM:
return read_small_bignum(pData);
break;
case ERL_LARGE_BIGNUM:
return read_large_bignum(pData);
break;
case ERL_NEW_REF:
return read_new_reference(pData);
break;
}
return Qnil;
}
VALUE method_read_any_from(VALUE klass, VALUE rString) {
unsigned char *data = (unsigned char *) StringValuePtr(rString);
unsigned char **pData = &data;
// check protocol version
if(read_1(pData) != ERL_VERSION) {
rb_raise(rb_eStandardError, "Bad Magic");
}
return read_any_raw(pData);
}
void Init_decoder() {
mErlectricity = rb_const_get(rb_cObject, rb_intern("Erlectricity"));
cDecoder = rb_define_class_under(mErlectricity, "Decoder", rb_cObject);
rb_define_singleton_method(cDecoder, "read_any_from", method_read_any_from, 1);
}