/*
* Copyright (c) 2004, 2005 Lev Walkin <vlm@lionet.info>. All rights reserved.
* Redistribution and modifications are permitted subject to BSD license.
*/
#include <asn_application.h>
#include <asn_internal.h>
#include <xer_support.h> /* XER/XML parsing support */
/*
* Decode the XER encoding of a given type.
*/
asn_dec_rval_t
xer_decode(asn_codec_ctx_t *opt_codec_ctx, asn_TYPE_descriptor_t *td,
void **struct_ptr, const void *buffer, size_t size) {
asn_codec_ctx_t s_codec_ctx;
/*
* Stack checker requires that the codec context
* must be allocated on the stack.
*/
if(opt_codec_ctx) {
if(opt_codec_ctx->max_stack_size) {
s_codec_ctx = *opt_codec_ctx;
opt_codec_ctx = &s_codec_ctx;
}
} else {
/* If context is not given, be security-conscious anyway */
memset(&s_codec_ctx, 0, sizeof(s_codec_ctx));
s_codec_ctx.max_stack_size = _ASN_DEFAULT_STACK_MAX;
opt_codec_ctx = &s_codec_ctx;
}
/*
* Invoke type-specific decoder.
*/
return td->xer_decoder(opt_codec_ctx, td, struct_ptr, 0, buffer, size);
}
struct xer__cb_arg {
pxml_chunk_type_e chunk_type;
size_t chunk_size;
const void *chunk_buf;
int callback_not_invoked;
};
static int
xer__token_cb(pxml_chunk_type_e type, const void *_chunk_data, size_t _chunk_size, void *key) {
struct xer__cb_arg *arg = (struct xer__cb_arg *)key;
arg->chunk_type = type;
arg->chunk_size = _chunk_size;
arg->chunk_buf = _chunk_data;
arg->callback_not_invoked = 0;
return -1; /* Terminate the XML parsing */
}
/*
* Fetch the next token from the XER/XML stream.
*/
ssize_t
xer_next_token(int *stateContext, const void *buffer, size_t size, pxer_chunk_type_e *ch_type) {
struct xer__cb_arg arg;
int new_stateContext = *stateContext;
ssize_t ret;
arg.callback_not_invoked = 1;
ret = pxml_parse(&new_stateContext, buffer, size, xer__token_cb, &arg);
if(ret < 0) return -1;
if(arg.callback_not_invoked) {
assert(ret == 0); /* No data was consumed */
return 0; /* Try again with more data */
} else {
assert(arg.chunk_size);
assert(arg.chunk_buf == buffer);
}
/*
* Translate the XML chunk types into more convenient ones.
*/
switch(arg.chunk_type) {
case PXML_TEXT:
*ch_type = PXER_TEXT;
break;
case PXML_TAG: return 0; /* Want more */
case PXML_TAG_END:
*ch_type = PXER_TAG;
break;
case PXML_COMMENT:
case PXML_COMMENT_END:
*ch_type = PXER_COMMENT;
break;
}
*stateContext = new_stateContext;
return arg.chunk_size;
}
#define CSLASH 0x2f /* '/' */
#define LANGLE 0x3c /* '<' */
#define RANGLE 0x3e /* '>' */
xer_check_tag_e
xer_check_tag(const void *buf_ptr, int size, const char *need_tag) {
const char *buf = (const char *)buf_ptr;
const char *end;
xer_check_tag_e ct = XCT_OPENING;
if(size < 2 || buf[0] != LANGLE || buf[size-1] != RANGLE) {
if(size >= 2)
ASN_DEBUG("Broken XML tag: \"%c...%c\"",
buf[0], buf[size - 1]);
return XCT_BROKEN;
}
/*
* Determine the tag class.
*/
if(buf[1] == CSLASH) {
buf += 2; /* advance past "</" */
size -= 3; /* strip "</" and ">" */
ct = XCT_CLOSING;
if(size > 0 && buf[size-1] == CSLASH)
return XCT_BROKEN; /* </abc/> */
} else {
buf++; /* advance past "<" */
size -= 2; /* strip "<" and ">" */
if(size > 0 && buf[size-1] == CSLASH) {
ct = XCT_BOTH;
size--; /* One more, for "/" */
}
}
/* Sometimes we don't care about the tag */
if(!need_tag || !*need_tag)
return (xer_check_tag_e)(XCT__UNK__MASK | ct);
/*
* Determine the tag name.
*/
for(end = buf + size; buf < end; buf++, need_tag++) {
int b = *buf, n = *need_tag;
if(b != n) {
if(n == 0) {
switch(b) {
case 0x09: case 0x0a: case 0x0c: case 0x0d:
case 0x20:
/* "<abc def/>": whitespace is normal */
return ct;
}
}
return (xer_check_tag_e)(XCT__UNK__MASK | ct);
}
if(b == 0)
return XCT_BROKEN; /* Embedded 0 in buf?! */
}
if(*need_tag)
return (xer_check_tag_e)(XCT__UNK__MASK | ct);
return ct;
}
#undef ADVANCE
#define ADVANCE(num_bytes) do { \
size_t num = (num_bytes); \
buf_ptr = ((const char *)buf_ptr) + num; \
size -= num; \
consumed_myself += num; \
} while(0)
#undef RETURN
#define RETURN(_code) do { \
rval.code = _code; \
rval.consumed = consumed_myself; \
if(rval.code != RC_OK) \
ASN_DEBUG("Failed with %d", rval.code); \
return rval; \
} while(0)
#define XER_GOT_BODY(chunk_buf, chunk_size, size) do { \
ssize_t converted_size = body_receiver \
(struct_key, chunk_buf, chunk_size, \
(size_t)chunk_size < size); \
if(converted_size == -1) RETURN(RC_FAIL); \
if(converted_size == 0 \
&& size == (size_t)chunk_size) \
RETURN(RC_WMORE); \
chunk_size = converted_size; \
} while(0)
#define XER_GOT_EMPTY() do { \
if(body_receiver(struct_key, 0, 0, size > 0) == -1) \
RETURN(RC_FAIL); \
} while(0)
/*
* Generalized function for decoding the primitive values.
*/
asn_dec_rval_t
xer_decode_general(asn_codec_ctx_t *opt_codec_ctx,
asn_struct_ctx_t *ctx, /* Type decoder context */
void *struct_key,
const char *xml_tag, /* Expected XML tag */
const void *buf_ptr, size_t size,
int (*opt_unexpected_tag_decoder)
(void *struct_key, const void *chunk_buf, size_t chunk_size),
ssize_t (*body_receiver)
(void *struct_key, const void *chunk_buf, size_t chunk_size,
int have_more)
) {
asn_dec_rval_t rval;
ssize_t consumed_myself = 0;
(void)opt_codec_ctx;
/*
* Phases of XER/XML processing:
* Phase 0: Check that the opening tag matches our expectations.
* Phase 1: Processing body and reacting on closing tag.
*/
if(ctx->phase > 1) RETURN(RC_FAIL);
for(;;) {
pxer_chunk_type_e ch_type; /* XER chunk type */
ssize_t ch_size; /* Chunk size */
xer_check_tag_e tcv; /* Tag check value */
/*
* Get the next part of the XML stream.
*/
ch_size = xer_next_token(&ctx->context, buf_ptr, size,
&ch_type);
switch(ch_size) {
case -1: RETURN(RC_FAIL);
case 0:
RETURN(RC_WMORE);
default:
switch(ch_type) {
case PXER_COMMENT: /* Got XML comment */
ADVANCE(ch_size); /* Skip silently */
continue;
case PXER_TEXT:
if(ctx->phase == 0) {
/*
* We have to ignore whitespace here,
* but in order to be forward compatible
* with EXTENDED-XER (EMBED-VALUES, #25)
* any text is just ignored here.
*/
} else {
XER_GOT_BODY(buf_ptr, ch_size, size);
}
ADVANCE(ch_size);
continue;
case PXER_TAG:
break; /* Check the rest down there */
}
}
assert(ch_type == PXER_TAG && size);
tcv = xer_check_tag(buf_ptr, ch_size, xml_tag);
/*
* Phase 0:
* Expecting the opening tag
* for the type being processed.
* Phase 1:
* Waiting for the closing XML tag.
*/
switch(tcv) {
case XCT_BOTH:
if(ctx->phase) break;
/* Finished decoding of an empty element */
XER_GOT_EMPTY();
ADVANCE(ch_size);
ctx->phase = 2; /* Phase out */
RETURN(RC_OK);
case XCT_OPENING:
if(ctx->phase) break;
ADVANCE(ch_size);
ctx->phase = 1; /* Processing body phase */
continue;
case XCT_CLOSING:
if(!ctx->phase) break;
ADVANCE(ch_size);
ctx->phase = 2; /* Phase out */
RETURN(RC_OK);
case XCT_UNKNOWN_BO:
/*
* Certain tags in the body may be expected.
*/
if(opt_unexpected_tag_decoder
&& opt_unexpected_tag_decoder(struct_key,
buf_ptr, ch_size) >= 0) {
/* Tag's processed fine */
ADVANCE(ch_size);
if(!ctx->phase) {
/* We are not expecting
* the closing tag anymore. */
ctx->phase = 2; /* Phase out */
RETURN(RC_OK);
}
continue;
}
/* Fall through */
default:
break; /* Unexpected tag */
}
ASN_DEBUG("Unexpected XML tag (expected \"%s\")", xml_tag);
break; /* Dark and mysterious things have just happened */
}
RETURN(RC_FAIL);
}
size_t
xer_whitespace_span(const void *chunk_buf, size_t chunk_size) {
const char *p = (const char *)chunk_buf;
const char *pend = p + chunk_size;
for(; p < pend; p++) {
switch(*p) {
/* X.693, #8.1.4
* HORISONTAL TAB (9)
* LINE FEED (10)
* CARRIAGE RETURN (13)
* SPACE (32)
*/
case 0x09: case 0x0a: case 0x0d: case 0x20:
continue;
default:
break;
}
break;
}
return (p - (const char *)chunk_buf);
}
/*
* This is a vastly simplified, non-validating XML tree skipper.
*/
int
xer_skip_unknown(xer_check_tag_e tcv, ber_tlv_len_t *depth) {
assert(*depth > 0);
switch(tcv) {
case XCT_BOTH:
case XCT_UNKNOWN_BO:
/* These negate each other. */
return 0;
case XCT_OPENING:
case XCT_UNKNOWN_OP:
++(*depth);
return 0;
case XCT_CLOSING:
case XCT_UNKNOWN_CL:
if(--(*depth) == 0)
return (tcv == XCT_CLOSING) ? 2 : 1;
return 0;
default:
return -1;
}
}