94 lines
2.5 KiB
C
94 lines
2.5 KiB
C
#include "asn_application.h"
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#include "asn_internal.h"
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#include "per_decoder.h"
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/*
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* Decode a "Production of a complete encoding", X.691#10.1.
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* The complete encoding contains at least one byte, and is an integral
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* multiple of 8 bytes.
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*/
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asn_dec_rval_t
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uper_decode_complete(asn_codec_ctx_t *opt_codec_ctx, asn_TYPE_descriptor_t *td, void **sptr, const void *buffer, size_t size) {
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asn_dec_rval_t rval;
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rval = uper_decode(opt_codec_ctx, td, sptr, buffer, size, 0, 0);
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if(rval.consumed) {
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/*
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* We've always given 8-aligned data,
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* so convert bits to integral bytes.
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*/
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rval.consumed += 7;
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rval.consumed >>= 3;
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} else if(rval.code == RC_OK) {
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if(size) {
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if(((uint8_t *)buffer)[0] == 0) {
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rval.consumed = 1; /* 1 byte */
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} else {
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ASN_DEBUG("Expecting single zeroed byte");
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rval.code = RC_FAIL;
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}
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} else {
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/* Must contain at least 8 bits. */
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rval.code = RC_WMORE;
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}
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}
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return rval;
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}
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asn_dec_rval_t
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uper_decode(asn_codec_ctx_t *opt_codec_ctx, asn_TYPE_descriptor_t *td, void **sptr, const void *buffer, size_t size, int skip_bits, int unused_bits) {
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asn_codec_ctx_t s_codec_ctx;
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asn_dec_rval_t rval;
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asn_per_data_t pd;
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if(skip_bits < 0 || skip_bits > 7
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|| unused_bits < 0 || unused_bits > 7
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|| (unused_bits > 0 && !size))
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_ASN_DECODE_FAILED;
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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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/* Fill in the position indicator */
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memset(&pd, 0, sizeof(pd));
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pd.buffer = (const uint8_t *)buffer;
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pd.nboff = skip_bits;
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pd.nbits = 8 * size - unused_bits; /* 8 is CHAR_BIT from <limits.h> */
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if(pd.nboff > pd.nbits)
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_ASN_DECODE_FAILED;
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/*
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* Invoke type-specific decoder.
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*/
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if(!td->uper_decoder)
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_ASN_DECODE_FAILED; /* PER is not compiled in */
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rval = td->uper_decoder(opt_codec_ctx, td, 0, sptr, &pd);
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if(rval.code == RC_OK) {
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/* Return the number of consumed bits */
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rval.consumed = ((pd.buffer - (const uint8_t *)buffer) << 3)
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+ pd.nboff - skip_bits;
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ASN_DEBUG("PER decoding consumed %d, counted %d",
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rval.consumed, pd.moved);
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assert(rval.consumed == pd.moved);
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} else {
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/* PER codec is not a restartable */
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rval.consumed = 0;
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}
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return rval;
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}
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