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Lib: added a generic CBOR parser framework
This commit is contained in:
Maria Matejka
parent
850bbf02c1
commit
8d5fcfc6e8
@ -1,4 +1,4 @@
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src := bitmap.c bitops.c blake2s.c blake2b.c cbor.c cbor_parse_tools.c cbor_shortcuts.c checksum.c defer.c event.c flowspec.c idm.c ip.c lists.c lockfree.c mac.c md5.c mempool.c net.c netindex.c patmatch.c printf.c rcu.c resource.c runtime.c sha1.c sha256.c sha512.c slab.c slists.c strtoul.c tbf.c timer.c xmalloc.c
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src := bitmap.c bitops.c blake2s.c blake2b.c cbor.c cbor-parser.c cbor_parse_tools.c cbor_shortcuts.c checksum.c defer.c event.c flowspec.c idm.c ip.c lists.c lockfree.c mac.c md5.c mempool.c net.c netindex.c patmatch.c printf.c rcu.c resource.c runtime.c sha1.c sha256.c sha512.c slab.c slists.c strtoul.c tbf.c timer.c xmalloc.c
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obj := $(src-o-files)
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$(all-lib)
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180
lib/cbor-parser.c
Normal file
180
lib/cbor-parser.c
Normal file
@ -0,0 +1,180 @@
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/*
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* BIRD CBOR parser
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*
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* (c) 2024 Maria Matejka <mq@jmq.cz>
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*
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* Can be freely distributed and used under the terms of the GNU GPL.
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*/
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#include "lib/birdlib.h"
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#include "lib/cbor.h"
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struct cbor_parser_context *
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cbor_parser_new(pool *p, uint stack_max_depth)
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{
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linpool *lp = lp_new(p);
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struct cbor_parser_context *ctx = lp_allocz(
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lp, sizeof *ctx + (stack_max_depth + 1) * sizeof ctx->stack_countdown[0]);
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ctx->lp = lp;
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ctx->flush = lp_save(lp);
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ctx->type = 0xff;
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ctx->stack_countdown[0] = 1;
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ctx->stack_max = stack_max_depth;
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return ctx;
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}
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void cbor_parser_reset(struct cbor_parser_context *ctx)
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{
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lp_restore(ctx->lp, ctx->flush);
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ctx->flush = lp_save(ctx->lp);
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ctx->type = 0xff;
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ctx->target_buf = NULL;
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ctx->target_len = 0;
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ctx->error = NULL;
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ctx->partial_state = CPE_TYPE;
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ctx->partial_countdown = 0;
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ctx->stack_pos = 0;
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ctx->stack_countdown[0] = 1;
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}
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#define CBOR_PARSER_ERROR(...) do { \
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ctx->error = lp_sprintf(ctx->lp, __VA_ARGS__);\
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return CPR_ERROR; \
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} while (0)
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enum cbor_parse_result
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cbor_parse_byte(struct cbor_parser_context *ctx, const byte bp)
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{
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ctx->tflags = 0;
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switch (ctx->partial_state)
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{
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case CPE_EXIT:
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CBOR_PARSER_ERROR("Trailing byte %02x", bp);
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case CPE_ITEM_DONE:
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bug("You have to check cbor_parse_block_end() before running cbor_parse_byte()");
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case CPE_TYPE:
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/* Split the byte to type and value */
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ctx->type = bp >> 5;
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ctx->value = bp & 0x1f;
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if (ctx->type == 7)
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{
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if (ctx->value < 20)
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CBOR_PARSER_ERROR("Unknown simple value %u", ctx->value);
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else if (ctx->value < 24)
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; /* false, true, null, undefined */
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else if (ctx->value < 28)
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{
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/* Need more data */
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ctx->partial_state = CPE_READ_INT;
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ctx->partial_countdown = (1 << (ctx->value - 24));
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ctx->value = 0;
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break;
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}
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else if (ctx->value == 31)
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; /* break-stop */
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else
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CBOR_PARSER_ERROR("Unknown simple value %u", ctx->value);
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}
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else
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{
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if (ctx->value < 24)
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; /* Immediate value, fall through */
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else if (ctx->value < 28)
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{
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/* Need more data */
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ctx->partial_state = CPE_READ_INT;
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ctx->partial_countdown = (1 << (ctx->value - 24));
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ctx->value = 0;
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break;
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}
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else if ((ctx->value == 31) && (ctx->type >= 2) && (ctx->type <= 5))
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/* Indefinite length, fall through */
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ctx->tflags |= CPT_VARLEN;
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else
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CBOR_PARSER_ERROR("Garbled additional value %u for type %u", ctx->value, ctx->type);
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}
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/* fall through */
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case CPE_READ_INT:
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if (ctx->partial_state == CPE_READ_INT)
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{
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/* Reading a network order integer */
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ctx->value <<= 8;
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ctx->value |= bp;
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if (--ctx->partial_countdown)
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break;
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}
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/* fall through */
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case CPE_COMPLETE_INT:
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/* Some types are completely parsed, some not yet */
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switch (ctx->type)
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{
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case 0:
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case 1:
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case 7:
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ctx->partial_state = CPE_ITEM_DONE;
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break;
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case 2:
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case 3:
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ctx->partial_state = CPE_READ_BYTE;
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ctx->partial_countdown = ctx->value;
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break;
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case 4:
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case 5:
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if (++ctx->stack_pos >= ctx->stack_max)
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CBOR_PARSER_ERROR("Stack too deep");
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/* set array/map size;
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* once for arrays, twice for maps;
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* ~0 for indefinite, plus one for the array/map head itself */
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ctx->stack_countdown[ctx->stack_pos] = (ctx->tflags & CPT_VARLEN) ? ~0ULL :
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(ctx->value * (ctx->type - 3)) ;
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ctx->partial_state = CPE_TYPE;
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break;
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}
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/* Process the value */
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return CPR_MAJOR;
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case CPE_READ_BYTE:
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*ctx->target_buf = bp;
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ctx->target_buf++;
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if (--ctx->target_len)
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break;
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ctx->target_buf = NULL;
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ctx->partial_state = CPE_ITEM_DONE;
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return CPR_STR_END;
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}
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return CPR_MORE;
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}
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bool
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cbor_parse_block_end(struct cbor_parser_context *ctx)
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{
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if (ctx->partial_state != CPE_ITEM_DONE)
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return false;
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if (--ctx->stack_countdown[ctx->stack_pos])
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{
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ctx->partial_state = CPE_TYPE;
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return false;
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}
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if (!ctx->stack_pos--)
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ctx->partial_state = CPE_EXIT;
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return true;
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}
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18
lib/cbor.c
18
lib/cbor.c
@ -3,6 +3,24 @@
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#include "lib/cbor.h"
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static const char *cbor_type_str_a[] = {
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"POSINT",
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"NEGINT",
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"BYTES",
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"TEXT",
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"ARRAY",
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"MAP",
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"TAG",
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"SPECIAL",
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};
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const char *
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cbor_type_str(enum cbor_basic_type t)
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{
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return (t < ARRAY_SIZE(cbor_type_str_a)) ?
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cbor_type_str_a[t] :
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tmp_sprintf("(unknown: %u)", t);
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}
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void write_item(struct cbor_writer *writer, uint8_t major, uint64_t num);
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void check_memory(struct cbor_writer *writer, int add_size);
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76
lib/cbor.h
76
lib/cbor.h
@ -3,6 +3,18 @@
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#include "nest/bird.h"
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enum cbor_basic_type {
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CBOR_POSINT = 0,
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CBOR_NEGINT = 1,
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CBOR_BYTES = 2,
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CBOR_TEXT = 3,
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CBOR_ARRAY = 4,
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CBOR_MAP = 5,
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CBOR_TAG = 6,
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CBOR_SPECIAL = 7,
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};
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const char *cbor_type_str(enum cbor_basic_type);
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struct cbor_writer {
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int pt; // where will next byte go
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@ -55,4 +67,68 @@ void cbor_write_item_with_constant_val_length_4(struct cbor_writer *writer, uint
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void rewrite_4bytes_int(struct cbor_writer *writer, int pt, int num);
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/*
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* Parser bits
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*/
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struct cbor_parser_context {
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/* Public part */
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linpool *lp; /* Linpool for in-parser allocations */
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byte type; /* Last parsed type */
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enum {
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CPT_VARLEN = 1,
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} tflags; /* Additional flags for the type / value pair */
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u64 value; /* Last parsed (integer) value */
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byte *target_buf; /* Target buf for CBOR_BYTES or CBOR_TEXT */
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uint target_len; /* Set how many bytes to store */
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const char *error; /* Error message */
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/* Private part */
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lp_state *flush; /* Linpool reset pointer */
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enum { /* Multi-byte reader */
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CPE_TYPE = 0,
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CPE_READ_INT,
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CPE_COMPLETE_INT,
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CPE_READ_BYTE,
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CPE_ITEM_DONE,
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CPE_EXIT,
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} partial_state;
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u64 partial_countdown; /* How many items remaining in CBOR_ARRAY / CBOR_MAP */
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uint stack_pos, stack_max; /* Nesting of CBOR_ARRAY / CBOR_MAP */
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u64 stack_countdown[0];
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};
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struct cbor_parser_context *cbor_parser_new(pool *, uint stack_max_depth);
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static inline void cbor_parser_free(struct cbor_parser_context *ctx)
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{ rfree(ctx->lp); }
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void cbor_parser_reset(struct cbor_parser_context *ctx);
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enum cbor_parse_result {
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CPR_ERROR = 0,
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CPR_MORE = 1,
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CPR_MAJOR = 2,
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CPR_STR_END = 3,
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} cbor_parse_byte(struct cbor_parser_context *, const byte);
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bool cbor_parse_block_end(struct cbor_parser_context *);
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#define CBOR_PARSE_IF(_ctx, _type, _target) if (((_ctx)->type == CBOR_##_type) && CBOR_STORE_##_type((_ctx), _target))
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#define CBOR_PARSE_ONLY(_ctx, _type, _target) CBOR_PARSE_IF(_ctx, _type, _target) {} else CBOR_PARSER_ERROR("Expected %s for %s, got %s", #_type, #_target, cbor_type_str((_ctx)->type))
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#define CBOR_STORE_POSINT(_ctx, _target) ((_target = (_ctx)->value), 1)
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#define CBOR_STORE_NEGINT(_ctx, _target) ((_target = -1LL-(_ctx)->value), 1)
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#define CBOR_STORE_BYTES(_ctx, _target) ({ \
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if ((_ctx)->tflags & CPT_VARLEN) CBOR_PARSER_ERROR("Variable length string not supported yet"); \
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if ((_target)) CBOR_PARSER_ERROR("Duplicate argument %s", #_target); \
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ASSERT_DIE(!(_ctx)->target_buf); \
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_target = (_ctx)->target_buf = lp_alloc((_ctx)->lp, ((_ctx)->target_len = (_ctx)->value) + 1); \
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1; })
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#define CBOR_STORE_TEXT CBOR_STORE_BYTES
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#endif
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