/* ----------------------------------------------------------------------------
* decode_term.c
* ----------------------------------------------------------------------------
* Mastering programmed by YAMASHINA Hio
*
* Copyright 2008 YAMASHINA Hio
* ----------------------------------------------------------------------------
* $Id: decode_term.c 41500 2008-02-18 07:10:55Z hio $
* ------------------------------------------------------------------------- */
/*
usage:
declare_call_handler(proc)
{
const char* str_ptr;
const char* re_ptr;
void* str_xbuf;
void* re_xbuf;
int str_len;
int re_len;
int rx_flags;
DEBUG(printf("decode: str\r\n"));
str_ptr = _decode_string(&buff, buff_end, &str_len, &str_xbuf);
if( str_ptr!=NULL )
{
DEBUG(printf("str = [%.*s] (%d)\r\n", str_len, str_ptr, str_len));
}else
{
return (int)ERL_DRV_ERROR_GENERAL;
}
DEBUG(printf("decode: re\r\n"));
re_ptr = _decode_string(&buff, buff_end, &re_len, &re_xbuf);
if( re_ptr!=NULL )
{
DEBUG(printf("re = [%.*s] (%d)\r\n", re_len, re_ptr, re_len));
}else
{
xbuf_free(str_xbuf);
return (int)ERL_DRV_ERROR_GENERAL;
}
...
xbuf_free(str_xbuf);
xbuf_free(re_xbuf);
}
*/
typedef struct {
unsigned char* wptr;
const unsigned char* end;
int req;
unsigned char data[1];
} xbuff_t;
static int _decode_string_heavy(const unsigned char* in, const unsigned char* in_end, xbuff_t** pxbuff);
/* ----------------------------------------------------------------------------
* _decode_string(&in, end, &len, &xbuff).
* term_to_binary()でpackされた文字列のデコード.
* 外部形式 binary/atom/string/list をサポート.
* inが開始位置, endがデータの終端.
* デコードに成功すると,
* - 復帰値: 文字列へのポインタ(NULL終端なし)
* - len: 文字列の長さ(バイト長)
* - xbuff: alloc情報
* の3つの情報を返す.
* デコードに失敗した場合は NULL を返す.
* 文字列は入力データを直接参照する場合もあるし,
* 別途確保した領域を使うこともある.
* xbuffにその情報を記録している.
* 使い終わったら xbuff_free(xbuff) で解放すること.
* ------------------------------------------------------------------------- */
static const char* _decode_string(const unsigned char** pbuff, const unsigned char* buff_end, int* plen, void** pxbuff)
{
const unsigned char* buff = *pbuff;
if( buff+1<=buff_end )
{
}else
{
*pxbuff = NULL;
return NULL;
}
switch( buff[0] )
{
case BINARY_EXT:
*pxbuff = NULL;
DEBUG(printf(" decode from binary\r\n"));
if( buff+4<=buff_end )
{
const int len = (buff[1]<<24) + (buff[2]<<16) + (buff[3]<<8) + buff[4];
DEBUG(printf(" len = %d\n", len));
DEBUG(printf(" str = [%.*s]\n", len, buff+5));
*plen = len;
*pbuff = buff+5+len;
return (char*)buff+5;
}else
{
return NULL;
}
case ATOM_EXT:
case STRING_EXT:
*pxbuff = NULL;
DEBUG(printf(" decode from string/atom\r\n"));
if( buff+3<=buff_end )
{
const int len = (buff[1]<<8) + buff[2];
DEBUG(printf(" len = %d\n", len));
DEBUG(printf(" str = [%.*s]\n", len, buff+3));
*plen = len;
*pbuff = buff+3+len;
return (char*)buff+3;
}else
{
return NULL;
}
case NIL_EXT:
*pxbuff = NULL;
*plen = 0;
*pbuff = buff+1;
return (char*)buff+1;
case LIST_EXT:
{
const int len = (buff[1]<<24) + (buff[2]<<16) + (buff[3]<<8) + buff[4];
xbuff_t* xbuff = driver_alloc(sizeof(*xbuff)+len-1);
int ret;
xbuff->wptr = &xbuff->data[0];
xbuff->end = xbuff->wptr + len;
xbuff->req = 0;
DEBUG(printf("HEAVY: len=%d\n", len));
ret = _decode_string_heavy(buff, buff_end, &xbuff);
DEBUG(printf("heavy : %d\n", ret));
*pxbuff = xbuff;
if( ret!=-1 )
{
*pbuff = buff+ret;
*plen = xbuff->wptr-xbuff->data;
DEBUG(printf("- [%.*s]\n", *plen, xbuff->data));
return (char*)xbuff->data;
}else
{
return NULL;
}
}
}
return NULL;
}
static void xbuff_expect(xbuff_t** pxbuff, int req)
{
(*pxbuff)->req += req;
return;
}
static xbuff_t* xbuff_extend(xbuff_t** pxbuff)
{
xbuff_t* xbuff = *pxbuff;
unsigned char* old_buf;
xbuff_t* new_xbuff;
int req, siz;
old_buf = (void*)xbuff;
req = xbuff->req!=0 ? xbuff->req : 32;
siz = ((xbuff->end - (unsigned char*)xbuff) + req + 7) & ~7;
new_xbuff = driver_realloc(xbuff, siz);
if( new_xbuff!=NULL )
{
new_xbuff->wptr = new_xbuff->wptr + ((unsigned char*)new_xbuff - old_buf);
new_xbuff->end = (unsigned char*)new_xbuff + siz;
new_xbuff->req = 0;
*pxbuff = new_xbuff;
return new_xbuff;
}else
{
return NULL;
}
}
static int _decode_string_heavy(const unsigned char* in, const unsigned char* in_end, xbuff_t** pxbuff)
{
if( in>=in_end )
{
return -1;
}
switch( *in )
{
case NIL_EXT:
DEBUG(printf("heavy: nil\n"));
return 1;
case SMALL_INTEGER_EXT:
DEBUG(printf("heavy: small_int\n"));
if( in+2<in_end )
{
xbuff_t* xbuff = *pxbuff;
if( xbuff->wptr<xbuff->end ){
*(*pxbuff)->wptr++ = in[1];
}else if( xbuff_extend(pxbuff) ){
*(*pxbuff)->wptr++ = in[1];
}else{
return -1;
}
return 2;
}else
{
return -1;
}
case STRING_EXT:
DEBUG(printf("heavy: string\n"));
if( in+3<in_end )
{
const int len = (in[1]<<8) + in[2];
xbuff_expect(pxbuff, len);
if( (*pxbuff)->wptr+len<(*pxbuff)->end )
{
memcpy((*pxbuff)->wptr, in+3, len);
}else if( xbuff_extend(pxbuff) )
{
memcpy((*pxbuff)->wptr, in+3, len);
}else{
return -1;
}
DEBUG(printf(".. %d\n", len+3));
(*pxbuff)->wptr += len;
return len+3;
}else
{
return -1;
}
case BINARY_EXT:
DEBUG(printf("heavy: binary\n"));
if( in+5<in_end )
{
const int len = (in[1]<<24) + (in[2]<<16) + (in[3]<<8) + in[4];
xbuff_expect(pxbuff, len);
if( (*pxbuff)->wptr+len<(*pxbuff)->end )
{
memcpy((*pxbuff)->wptr, in+5, len);
}else if( xbuff_extend(pxbuff) )
{
memcpy((*pxbuff)->wptr, in+5, len);
}else{
return -1;
}
DEBUG(printf(".. %d\n", len+3));
(*pxbuff)->wptr += len;
return len+5;
}else
{
return -1;
}
case LIST_EXT:
DEBUG(printf("heavy: list\n"));
if( in+5<in_end )
{
const int len = (in[1]<<24) + (in[2]<<16) + (in[3]<<8) + in[4];
int total_step;
int i;
xbuff_expect(pxbuff, len);
total_step = 5;
in += 5;
for( i=0; i<len; ++i )
{
int step = _decode_string_heavy(in, in_end, pxbuff);
if( step==-1 )
{
return -1;
}
in += step;
total_step += step;
}
if( in<in_end && *in==NIL_EXT )
{
return total_step+1;
}
return -1;
}else
{
return -1;
}
default:
DEBUG(printf("heavy: unknown %c (%d)\n", *in, *in));
return -1;
}
}
#define xbuf_free(var) if(var==NULL){}else{driver_free(var);}
/* ----------------------------------------------------------------------------
* End of File.
* ------------------------------------------------------------------------- */