2 * Copyright (c) 2004, 2005 Lev Walkin <vlm@lionet.info>. All rights reserved.
3 * Redistribution and modifications are permitted subject to BSD license.
5 #include <asn_application.h>
6 #include <asn_internal.h>
7 #include <xer_support.h> /* XER/XML parsing support */
11 * Decode the XER encoding of a given type.
14 xer_decode(asn_codec_ctx_t *opt_codec_ctx, asn_TYPE_descriptor_t *td,
15 void **struct_ptr, const void *buffer, size_t size) {
16 asn_codec_ctx_t s_codec_ctx;
19 * Stack checker requires that the codec context
20 * must be allocated on the stack.
23 if(opt_codec_ctx->max_stack_size) {
24 s_codec_ctx = *opt_codec_ctx;
25 opt_codec_ctx = &s_codec_ctx;
28 /* If context is not given, be security-conscious anyway */
29 memset(&s_codec_ctx, 0, sizeof(s_codec_ctx));
30 s_codec_ctx.max_stack_size = _ASN_DEFAULT_STACK_MAX;
31 opt_codec_ctx = &s_codec_ctx;
35 * Invoke type-specific decoder.
37 return td->xer_decoder(opt_codec_ctx, td, struct_ptr, 0, buffer, size);
43 pxml_chunk_type_e chunk_type;
45 const void *chunk_buf;
46 int callback_not_invoked;
50 xer__token_cb(pxml_chunk_type_e type, const void *_chunk_data, size_t _chunk_size, void *key) {
51 struct xer__cb_arg *arg = (struct xer__cb_arg *)key;
52 arg->chunk_type = type;
53 arg->chunk_size = _chunk_size;
54 arg->chunk_buf = _chunk_data;
55 arg->callback_not_invoked = 0;
56 return -1; /* Terminate the XML parsing */
60 * Fetch the next token from the XER/XML stream.
63 xer_next_token(int *stateContext, const void *buffer, size_t size, pxer_chunk_type_e *ch_type) {
64 struct xer__cb_arg arg;
65 int new_stateContext = *stateContext;
68 arg.callback_not_invoked = 1;
69 ret = pxml_parse(&new_stateContext, buffer, size, xer__token_cb, &arg);
70 if(ret < 0) return -1;
71 if(arg.callback_not_invoked) {
72 assert(ret == 0); /* No data was consumed */
73 return 0; /* Try again with more data */
75 assert(arg.chunk_size);
76 assert(arg.chunk_buf == buffer);
80 * Translate the XML chunk types into more convenient ones.
82 switch(arg.chunk_type) {
86 case PXML_TAG: return 0; /* Want more */
91 case PXML_COMMENT_END:
92 *ch_type = PXER_COMMENT;
96 *stateContext = new_stateContext;
97 return arg.chunk_size;
100 #define CSLASH 0x2f /* '/' */
101 #define LANGLE 0x3c /* '<' */
102 #define RANGLE 0x3e /* '>' */
105 xer_check_tag(const void *buf_ptr, int size, const char *need_tag) {
106 const char *buf = (const char *)buf_ptr;
108 xer_check_tag_e ct = XCT_OPENING;
110 if(size < 2 || buf[0] != LANGLE || buf[size-1] != RANGLE) {
112 ASN_DEBUG("Broken XML tag: \"%c...%c\"",
113 buf[0], buf[size - 1]);
118 * Determine the tag class.
120 if(buf[1] == CSLASH) {
121 buf += 2; /* advance past "</" */
122 size -= 3; /* strip "</" and ">" */
124 if(size > 0 && buf[size-1] == CSLASH)
125 return XCT_BROKEN; /* </abc/> */
127 buf++; /* advance past "<" */
128 size -= 2; /* strip "<" and ">" */
129 if(size > 0 && buf[size-1] == CSLASH) {
131 size--; /* One more, for "/" */
135 /* Sometimes we don't care about the tag */
136 if(!need_tag || !*need_tag)
137 return (xer_check_tag_e)(XCT__UNK__MASK | ct);
140 * Determine the tag name.
142 for(end = buf + size; buf < end; buf++, need_tag++) {
143 int b = *buf, n = *need_tag;
147 case 0x09: case 0x0a: case 0x0c: case 0x0d:
149 /* "<abc def/>": whitespace is normal */
153 return (xer_check_tag_e)(XCT__UNK__MASK | ct);
156 return XCT_BROKEN; /* Embedded 0 in buf?! */
159 return (xer_check_tag_e)(XCT__UNK__MASK | ct);
166 #define ADVANCE(num_bytes) do { \
167 size_t num = (num_bytes); \
168 buf_ptr = ((const char *)buf_ptr) + num; \
170 consumed_myself += num; \
174 #define RETURN(_code) do { \
176 rval.consumed = consumed_myself; \
177 if(rval.code != RC_OK) \
178 ASN_DEBUG("Failed with %d", rval.code); \
182 #define XER_GOT_BODY(chunk_buf, chunk_size, size) do { \
183 ssize_t converted_size = body_receiver \
184 (struct_key, chunk_buf, chunk_size, \
185 (size_t)chunk_size < size); \
186 if(converted_size == -1) RETURN(RC_FAIL); \
187 if(converted_size == 0 \
188 && size == (size_t)chunk_size) \
190 chunk_size = converted_size; \
192 #define XER_GOT_EMPTY() do { \
193 if(body_receiver(struct_key, 0, 0, size > 0) == -1) \
198 * Generalized function for decoding the primitive values.
201 xer_decode_general(asn_codec_ctx_t *opt_codec_ctx,
202 asn_struct_ctx_t *ctx, /* Type decoder context */
204 const char *xml_tag, /* Expected XML tag */
205 const void *buf_ptr, size_t size,
206 int (*opt_unexpected_tag_decoder)
207 (void *struct_key, const void *chunk_buf, size_t chunk_size),
208 ssize_t (*body_receiver)
209 (void *struct_key, const void *chunk_buf, size_t chunk_size,
214 ssize_t consumed_myself = 0;
219 * Phases of XER/XML processing:
220 * Phase 0: Check that the opening tag matches our expectations.
221 * Phase 1: Processing body and reacting on closing tag.
223 if(ctx->phase > 1) RETURN(RC_FAIL);
225 pxer_chunk_type_e ch_type; /* XER chunk type */
226 ssize_t ch_size; /* Chunk size */
227 xer_check_tag_e tcv; /* Tag check value */
230 * Get the next part of the XML stream.
232 ch_size = xer_next_token(&ctx->context, buf_ptr, size,
235 case -1: RETURN(RC_FAIL);
240 case PXER_COMMENT: /* Got XML comment */
241 ADVANCE(ch_size); /* Skip silently */
244 if(ctx->phase == 0) {
246 * We have to ignore whitespace here,
247 * but in order to be forward compatible
248 * with EXTENDED-XER (EMBED-VALUES, #25)
249 * any text is just ignored here.
252 XER_GOT_BODY(buf_ptr, ch_size, size);
257 break; /* Check the rest down there */
261 assert(ch_type == PXER_TAG && size);
263 tcv = xer_check_tag(buf_ptr, ch_size, xml_tag);
266 * Expecting the opening tag
267 * for the type being processed.
269 * Waiting for the closing XML tag.
273 if(ctx->phase) break;
274 /* Finished decoding of an empty element */
277 ctx->phase = 2; /* Phase out */
280 if(ctx->phase) break;
282 ctx->phase = 1; /* Processing body phase */
285 if(!ctx->phase) break;
287 ctx->phase = 2; /* Phase out */
291 * Certain tags in the body may be expected.
293 if(opt_unexpected_tag_decoder
294 && opt_unexpected_tag_decoder(struct_key,
295 buf_ptr, ch_size) >= 0) {
296 /* Tag's processed fine */
299 /* We are not expecting
300 * the closing tag anymore. */
301 ctx->phase = 2; /* Phase out */
308 break; /* Unexpected tag */
311 ASN_DEBUG("Unexpected XML tag (expected \"%s\")", xml_tag);
312 break; /* Dark and mysterious things have just happened */
320 xer_whitespace_span(const void *chunk_buf, size_t chunk_size) {
321 const char *p = (const char *)chunk_buf;
322 const char *pend = p + chunk_size;
324 for(; p < pend; p++) {
329 * CARRIAGE RETURN (13)
332 case 0x09: case 0x0a: case 0x0d: case 0x20:
339 return (p - (const char *)chunk_buf);
343 * This is a vastly simplified, non-validating XML tree skipper.
346 xer_skip_unknown(xer_check_tag_e tcv, ber_tlv_len_t *depth) {
351 /* These negate each other. */
360 return (tcv == XCT_CLOSING) ? 2 : 1;