370 lines
8.7 KiB
C
370 lines
8.7 KiB
C
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/*
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* Copyright (c) 2004-2017 Lev Walkin <vlm@lionet.info>. All rights reserved.
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* Redistribution and modifications are permitted subject to BSD license.
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*/
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#include <asn_application.h>
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#include <asn_internal.h>
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#include <xer_support.h> /* XER/XML parsing support */
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/*
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* Decode the XER encoding of a given type.
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*/
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asn_dec_rval_t
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xer_decode(const asn_codec_ctx_t *opt_codec_ctx,
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const asn_TYPE_descriptor_t *td, void **struct_ptr,
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const void *buffer, size_t size) {
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asn_codec_ctx_t s_codec_ctx;
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/*
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* Stack checker requires that the codec context
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* must be allocated on the stack.
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*/
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if(opt_codec_ctx) {
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if(opt_codec_ctx->max_stack_size) {
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s_codec_ctx = *opt_codec_ctx;
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opt_codec_ctx = &s_codec_ctx;
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}
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} else {
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/* If context is not given, be security-conscious anyway */
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memset(&s_codec_ctx, 0, sizeof(s_codec_ctx));
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s_codec_ctx.max_stack_size = ASN__DEFAULT_STACK_MAX;
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opt_codec_ctx = &s_codec_ctx;
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}
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/*
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* Invoke type-specific decoder.
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*/
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return td->op->xer_decoder(opt_codec_ctx, td, struct_ptr, 0, buffer, size);
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}
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struct xer__cb_arg {
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pxml_chunk_type_e chunk_type;
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size_t chunk_size;
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const void *chunk_buf;
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int callback_not_invoked;
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};
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static int
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xer__token_cb(pxml_chunk_type_e type, const void *_chunk_data, size_t _chunk_size, void *key) {
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struct xer__cb_arg *arg = (struct xer__cb_arg *)key;
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arg->chunk_type = type;
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arg->chunk_size = _chunk_size;
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arg->chunk_buf = _chunk_data;
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arg->callback_not_invoked = 0;
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return -1; /* Terminate the XML parsing */
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}
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/*
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* Fetch the next token from the XER/XML stream.
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*/
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ssize_t
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xer_next_token(int *stateContext, const void *buffer, size_t size, pxer_chunk_type_e *ch_type) {
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struct xer__cb_arg arg;
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int new_stateContext = *stateContext;
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ssize_t ret;
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arg.callback_not_invoked = 1;
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ret = pxml_parse(&new_stateContext, buffer, size, xer__token_cb, &arg);
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if(ret < 0) return -1;
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if(arg.callback_not_invoked) {
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assert(ret == 0); /* No data was consumed */
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*ch_type = PXER_WMORE;
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return 0; /* Try again with more data */
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} else {
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assert(arg.chunk_size);
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assert(arg.chunk_buf == buffer);
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}
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/*
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* Translate the XML chunk types into more convenient ones.
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*/
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switch(arg.chunk_type) {
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case PXML_TEXT:
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*ch_type = PXER_TEXT;
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break;
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case PXML_TAG:
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*ch_type = PXER_WMORE;
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return 0; /* Want more */
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case PXML_TAG_END:
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*ch_type = PXER_TAG;
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break;
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case PXML_COMMENT:
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case PXML_COMMENT_END:
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*ch_type = PXER_COMMENT;
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break;
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}
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*stateContext = new_stateContext;
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return arg.chunk_size;
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}
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#define CSLASH 0x2f /* '/' */
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#define LANGLE 0x3c /* '<' */
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#define RANGLE 0x3e /* '>' */
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xer_check_tag_e
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xer_check_tag(const void *buf_ptr, int size, const char *need_tag) {
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const char *buf = (const char *)buf_ptr;
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const char *end;
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xer_check_tag_e ct = XCT_OPENING;
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if(size < 2 || buf[0] != LANGLE || buf[size-1] != RANGLE) {
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if(size >= 2)
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ASN_DEBUG("Broken XML tag: \"%c...%c\"",
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buf[0], buf[size - 1]);
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return XCT_BROKEN;
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}
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/*
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* Determine the tag class.
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*/
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if(buf[1] == CSLASH) {
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buf += 2; /* advance past "</" */
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size -= 3; /* strip "</" and ">" */
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ct = XCT_CLOSING;
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if(size > 0 && buf[size-1] == CSLASH)
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return XCT_BROKEN; /* </abc/> */
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} else {
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buf++; /* advance past "<" */
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size -= 2; /* strip "<" and ">" */
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if(size > 0 && buf[size-1] == CSLASH) {
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ct = XCT_BOTH;
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size--; /* One more, for "/" */
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}
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}
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/* Sometimes we don't care about the tag */
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if(!need_tag || !*need_tag)
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return (xer_check_tag_e)(XCT__UNK__MASK | ct);
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/*
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* Determine the tag name.
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*/
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for(end = buf + size; buf < end; buf++, need_tag++) {
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int b = *buf, n = *need_tag;
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if(b != n) {
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if(n == 0) {
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switch(b) {
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case 0x09: case 0x0a: case 0x0c: case 0x0d:
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case 0x20:
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/* "<abc def/>": whitespace is normal */
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return ct;
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}
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}
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return (xer_check_tag_e)(XCT__UNK__MASK | ct);
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}
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if(b == 0)
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return XCT_BROKEN; /* Embedded 0 in buf?! */
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}
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if(*need_tag)
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return (xer_check_tag_e)(XCT__UNK__MASK | ct);
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return ct;
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}
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#undef ADVANCE
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#define ADVANCE(num_bytes) do { \
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size_t num = (num_bytes); \
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buf_ptr = ((const char *)buf_ptr) + num; \
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size -= num; \
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consumed_myself += num; \
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} while(0)
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#undef RETURN
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#define RETURN(_code) do { \
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rval.code = _code; \
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rval.consumed = consumed_myself; \
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if(rval.code != RC_OK) \
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ASN_DEBUG("Failed with %d", rval.code); \
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return rval; \
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} while(0)
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#define XER_GOT_BODY(chunk_buf, chunk_size, size) do { \
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ssize_t converted_size = body_receiver \
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(struct_key, chunk_buf, chunk_size, \
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(size_t)chunk_size < size); \
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if(converted_size == -1) RETURN(RC_FAIL); \
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if(converted_size == 0 \
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&& size == (size_t)chunk_size) \
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RETURN(RC_WMORE); \
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chunk_size = converted_size; \
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} while(0)
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#define XER_GOT_EMPTY() do { \
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if(body_receiver(struct_key, 0, 0, size > 0) == -1) \
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RETURN(RC_FAIL); \
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} while(0)
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/*
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* Generalized function for decoding the primitive values.
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*/
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asn_dec_rval_t
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xer_decode_general(const asn_codec_ctx_t *opt_codec_ctx,
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asn_struct_ctx_t *ctx, /* Type decoder context */
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void *struct_key,
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const char *xml_tag, /* Expected XML tag */
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const void *buf_ptr, size_t size,
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int (*opt_unexpected_tag_decoder)
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(void *struct_key, const void *chunk_buf, size_t chunk_size),
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ssize_t (*body_receiver)
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(void *struct_key, const void *chunk_buf, size_t chunk_size,
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int have_more)
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) {
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asn_dec_rval_t rval;
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ssize_t consumed_myself = 0;
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(void)opt_codec_ctx;
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/*
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* Phases of XER/XML processing:
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* Phase 0: Check that the opening tag matches our expectations.
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* Phase 1: Processing body and reacting on closing tag.
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*/
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if(ctx->phase > 1) RETURN(RC_FAIL);
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for(;;) {
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pxer_chunk_type_e ch_type; /* XER chunk type */
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ssize_t ch_size; /* Chunk size */
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xer_check_tag_e tcv; /* Tag check value */
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/*
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* Get the next part of the XML stream.
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*/
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ch_size = xer_next_token(&ctx->context, buf_ptr, size,
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&ch_type);
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if(ch_size == -1) {
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RETURN(RC_FAIL);
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} else {
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switch(ch_type) {
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case PXER_WMORE:
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RETURN(RC_WMORE);
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case PXER_COMMENT: /* Got XML comment */
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ADVANCE(ch_size); /* Skip silently */
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continue;
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case PXER_TEXT:
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if(ctx->phase == 0) {
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/*
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* We have to ignore whitespace here,
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* but in order to be forward compatible
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* with EXTENDED-XER (EMBED-VALUES, #25)
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* any text is just ignored here.
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*/
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} else {
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XER_GOT_BODY(buf_ptr, ch_size, size);
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}
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ADVANCE(ch_size);
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continue;
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case PXER_TAG:
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break; /* Check the rest down there */
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}
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}
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assert(ch_type == PXER_TAG && size);
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tcv = xer_check_tag(buf_ptr, ch_size, xml_tag);
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/*
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* Phase 0:
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* Expecting the opening tag
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* for the type being processed.
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* Phase 1:
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* Waiting for the closing XML tag.
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*/
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switch(tcv) {
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case XCT_BOTH:
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if(ctx->phase) break;
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/* Finished decoding of an empty element */
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XER_GOT_EMPTY();
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ADVANCE(ch_size);
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ctx->phase = 2; /* Phase out */
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RETURN(RC_OK);
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case XCT_OPENING:
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if(ctx->phase) break;
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ADVANCE(ch_size);
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ctx->phase = 1; /* Processing body phase */
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continue;
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case XCT_CLOSING:
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if(!ctx->phase) break;
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ADVANCE(ch_size);
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ctx->phase = 2; /* Phase out */
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RETURN(RC_OK);
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case XCT_UNKNOWN_BO:
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/*
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* Certain tags in the body may be expected.
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*/
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if(opt_unexpected_tag_decoder
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&& opt_unexpected_tag_decoder(struct_key,
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buf_ptr, ch_size) >= 0) {
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/* Tag's processed fine */
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ADVANCE(ch_size);
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if(!ctx->phase) {
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/* We are not expecting
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* the closing tag anymore. */
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ctx->phase = 2; /* Phase out */
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RETURN(RC_OK);
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}
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continue;
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}
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/* Fall through */
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default:
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break; /* Unexpected tag */
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}
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ASN_DEBUG("Unexpected XML tag (expected \"%s\")", xml_tag);
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break; /* Dark and mysterious things have just happened */
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}
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RETURN(RC_FAIL);
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}
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size_t
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xer_whitespace_span(const void *chunk_buf, size_t chunk_size) {
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const char *p = (const char *)chunk_buf;
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const char *pend = p + chunk_size;
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for(; p < pend; p++) {
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switch(*p) {
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/* X.693, #8.1.4
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* HORISONTAL TAB (9)
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* LINE FEED (10)
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* CARRIAGE RETURN (13)
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* SPACE (32)
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*/
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case 0x09: case 0x0a: case 0x0d: case 0x20:
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continue;
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default:
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break;
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}
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break;
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}
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return (p - (const char *)chunk_buf);
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}
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/*
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* This is a vastly simplified, non-validating XML tree skipper.
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*/
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int
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xer_skip_unknown(xer_check_tag_e tcv, ber_tlv_len_t *depth) {
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assert(*depth > 0);
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switch(tcv) {
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case XCT_BOTH:
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case XCT_UNKNOWN_BO:
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/* These negate each other. */
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return 0;
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case XCT_OPENING:
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case XCT_UNKNOWN_OP:
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++(*depth);
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return 0;
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case XCT_CLOSING:
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case XCT_UNKNOWN_CL:
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if(--(*depth) == 0)
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return (tcv == XCT_CLOSING) ? 2 : 1;
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return 0;
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default:
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return -1;
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}
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}
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