| /* |
| * Copyright (c) 2017 Lev Walkin <vlm@lionet.info>. All rights reserved. |
| * Redistribution and modifications are permitted subject to BSD license. |
| */ |
| #include <asn_internal.h> |
| |
| /* |
| * The OER decoder of any type. |
| */ |
| asn_dec_rval_t |
| oer_decode(asn_codec_ctx_t *opt_codec_ctx, |
| asn_TYPE_descriptor_t *type_descriptor, |
| void **struct_ptr, const void *ptr, 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 type_descriptor->oer_decoder(opt_codec_ctx, type_descriptor, 0, |
| struct_ptr, /* Pointer to the destination structure */ |
| ptr, size /* Buffer and its size */ |
| ); |
| } |
| |
| /* |
| * Open Type is encoded as a length (#8.6) followed by that number of bytes. |
| * Since we're just skipping, reading the length would be enough. |
| */ |
| ssize_t |
| oer_open_type_skip(const void *bufptr, size_t size) { |
| size_t len = 0; |
| return oer_fetch_length(bufptr, size, &len); |
| } |
| |
| /* |
| * Read the Open Type (X.696 (08/2015), #30). |
| * RETURN VALUES: |
| * 0: More data expected than bufptr contains. |
| * -1: Fatal error deciphering length. |
| * >0: Number of bytes used from bufptr. |
| */ |
| ssize_t |
| oer_open_type_get(asn_codec_ctx_t *opt_codec_ctx, |
| struct asn_TYPE_descriptor_s *td, |
| asn_oer_constraints_t *constraints, void **struct_ptr, |
| const void *bufptr, size_t size) { |
| |
| asn_dec_rval_t dr; |
| size_t container_len = 0; |
| ssize_t len_len; |
| |
| /* Get the size of a length determinant */ |
| len_len = oer_fetch_length(bufptr, size, &container_len); |
| if(len_len <= 0) { |
| return len_len; /* Error or more data expected */ |
| } |
| |
| /* |
| * len_len can't be bigger than size, but size without len_len |
| * should be bigger or equal to container length |
| */ |
| if(size - len_len < container_len) { |
| /* More data is expected */ |
| return 0; |
| } |
| |
| dr = td->oer_decoder(opt_codec_ctx, td, constraints, struct_ptr, |
| (const uint8_t *)bufptr + len_len, container_len); |
| if(dr.code == RC_OK) { |
| return len_len + container_len; |
| } else { |
| /* Even if RC_WMORE, we can't get more data into a closed container. */ |
| ASN_STRUCT_FREE(*td, *struct_ptr); |
| *struct_ptr = 0; |
| return -1; |
| } |
| } |
| |