mirror of https://gerrit.osmocom.org/asn1c
decoder template
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/*
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* This is a generic BER decoder template for any ASN.1 type.
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*
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* To compile, please redefine the asn_DEF as shown:
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*
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* cc -Dasn_DEF=asn_DEF_MyCustomType -o myTypeDecoder.o -c decoder-template.c
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*/
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif
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#include <stdio.h>
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#include <sys/types.h>
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#include <unistd.h> /* for getopt */
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#include <string.h> /* for strerror(3) */
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#include <errno.h> /* for errno */
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#include <assert.h> /* for assert(3) */
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#include <sysexits.h> /* for EX_* exit codes */
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#include <constr_TYPE.h>
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extern asn_TYPE_descriptor_t asn_DEF; /* ASN.1 type to be decoded */
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/*
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* Open file and parse its BER contens.
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*/
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static void *data_decode_from_file(const char *fname, ssize_t suggested_bufsize);
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int opt_debug; /* -d */
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static int opt_check; /* -c */
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static int opt_print; /* -p */
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static int opt_stack; /* -s */
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static int opt_toxml; /* -x */
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#define DEBUG(fmt, args...) do { \
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if(!opt_debug) break; \
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fprintf(stderr, fmt, ##args); \
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fprintf(stderr, "\n"); \
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} while(0)
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int
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main(int ac, char **av) {
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ssize_t suggested_bufsize = 8192; /* close or equal to stdio buffer */
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int number_of_iterations = 1;
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int num;
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int ch;
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/*
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* Pocess the command-line argments.
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*/
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while((ch = getopt(ac, av, "b:cdn:hps:x")) != -1)
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switch(ch) {
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case 'b':
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suggested_bufsize = atoi(optarg);
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if(suggested_bufsize < 1
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|| suggested_bufsize > 16 * 1024 * 1024) {
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fprintf(stderr,
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"-b %s: Improper buffer size (1..16M)\n",
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optarg);
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exit(EX_UNAVAILABLE);
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}
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break;
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case 'c':
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opt_check = 1;
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break;
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case 'd':
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opt_debug++; /* Double -dd means ASN.1 debug */
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break;
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case 'n':
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number_of_iterations = atoi(optarg);
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if(number_of_iterations < 1) {
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fprintf(stderr,
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"-n %s: Improper iterations count\n", optarg);
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exit(EX_UNAVAILABLE);
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}
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break;
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case 'p':
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opt_print++;
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break;
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case 's':
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opt_stack = atoi(optarg);
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if(opt_stack <= 0) {
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fprintf(stderr,
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"-s %s: Value greater than 0 expected\n",
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optarg);
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exit(EX_UNAVAILABLE);
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}
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break;
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case 'x':
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opt_toxml++;
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break;
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case 'h':
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default:
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fprintf(stderr,
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"Usage: %s [options] <data.ber> ...\n"
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"Where options are:\n"
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" -b <size> Set the i/o buffer size (default is %ld)\n"
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" -c Check ASN.1 constraints after decoding\n"
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" -d Enable debugging (-dd is even better)\n"
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" -n <num> Process files <num> times\n"
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" -s <size> Set the stack usage limit\n"
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" -p Print out the decoded contents\n"
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" -x Print out as XML\n"
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, av[0], (long)suggested_bufsize);
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exit(EX_USAGE);
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}
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ac -= optind;
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av += optind;
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if(ac < 1) {
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fprintf(stderr, "Error: missing filename\n");
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exit(EX_USAGE);
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}
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setvbuf(stdout, 0, _IOLBF, 0);
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for(num = 0; num < number_of_iterations; num++) {
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int ac_i;
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/*
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* Process all files in turn.
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*/
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for(ac_i = 0; ac_i < ac; ac_i++) {
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char *fname = av[ac_i];
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void *structure;
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/*
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* Decode the encoded structure from file.
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*/
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structure = data_decode_from_file(fname, suggested_bufsize);
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if(!structure) {
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/* Error message is already printed */
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exit(EX_DATAERR);
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}
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fprintf(stderr, "%s: decoded successfully\n", fname);
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if(opt_print) asn_fprint(stdout, &asn_DEF, structure);
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if(opt_toxml
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&& xer_fprint(stdout, &asn_DEF, structure)) {
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fprintf(stderr, "%s: Cannot convert into XML\n", fname);
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exit(EX_UNAVAILABLE);
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}
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/* Check ASN.1 constraints */
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if(opt_check) {
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char errbuf[128];
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size_t errlen = sizeof(errbuf);
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if(asn_check_constraints(&asn_DEF, structure,
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errbuf, &errlen)) {
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fprintf(stderr, "%s: ASN.1 constraint "
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"check failed: %s\n", fname, errbuf);
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exit(EX_DATAERR);
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}
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}
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asn_DEF.free_struct(&asn_DEF, structure, 0);
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}
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}
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return 0;
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}
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static char *buffer;
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static size_t buf_offset; /* Offset from the start */
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static size_t buf_len; /* Length of meaningful contents */
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static size_t buf_size; /* Allocated memory */
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static off_t buf_shifted; /* Number of bytes ever shifted */
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#define bufptr (buffer + buf_offset)
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#define bufend (buffer + buf_offset + buf_len)
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/*
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* Ensure that the buffer contains at least this amoount of free space.
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*/
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static void buf_extend(size_t bySize) {
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DEBUG("buf_extend(%ld) { o=%ld l=%ld s=%ld }",
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(long)bySize, (long)buf_offset, (long)buf_len, (long)buf_size);
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if(buf_size >= (buf_offset + buf_len + bySize)) {
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return; /* Nothing to do */
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} else if(bySize <= buf_offset) {
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DEBUG("\tContents shifted by %ld", (long)buf_offset);
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/* Shift the buffer contents */
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memmove(buffer, buffer + buf_offset, buf_len);
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buf_shifted += buf_offset;
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buf_offset = 0;
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} else {
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size_t newsize = (buf_size << 2) + bySize;
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void *p = realloc(buffer, newsize);
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if(p) {
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buffer = p;
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buf_size = newsize;
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DEBUG("\tBuffer reallocated to %ld", (long)newsize);
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} else {
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perror("realloc()");
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exit(EX_OSERR);
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}
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}
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}
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static void *data_decode_from_file(const char *fname, ssize_t suggested_bufsize) {
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static char *fbuf;
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static ssize_t fbuf_size;
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static asn_codec_ctx_t s_codec_ctx;
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asn_codec_ctx_t *opt_codec_ctx = 0;
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void *structure = 0;
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size_t rd;
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FILE *fp;
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if(opt_stack) {
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s_codec_ctx.max_stack_size = opt_stack;
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opt_codec_ctx = &s_codec_ctx;
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}
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DEBUG("Processing file %s", fname);
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fp = fopen(fname, "r");
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if(!fp) {
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fprintf(stderr, "%s: %s\n", fname, strerror(errno));
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return 0;
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}
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/* prepare the file buffer */
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if(fbuf_size != suggested_bufsize) {
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fbuf = realloc(fbuf, suggested_bufsize);
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if(!fbuf) {
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perror("realloc()");
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exit(EX_OSERR);
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}
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fbuf_size = suggested_bufsize;
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}
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buf_shifted = 0;
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buf_offset = 0;
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buf_len = 0;
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while((rd = fread(fbuf, 1, fbuf_size, fp)) || !feof(fp)) {
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asn_dec_rval_t rval;
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int using_local_buf;
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/*
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* Copy the data over, or use the original buffer.
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*/
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if(buf_len) {
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/* Append the new data into the intermediate buffer */
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buf_extend(rd);
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memcpy(bufend, fbuf, rd);
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buf_len += rd;
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rval = ber_decode(opt_codec_ctx, &asn_DEF,
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(void **)&structure, bufptr, buf_len);
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DEBUG("ber_decode(%ld) consumed %ld, code %d",
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(long)buf_len, (long)rval.consumed, rval.code);
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/*
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* Adjust position inside the source buffer.
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*/
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assert(rval.consumed <= buf_len);
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buf_offset += rval.consumed;
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buf_len -= rval.consumed;
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} else {
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using_local_buf = 1;
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/* Feed the chunk of data into a BER decoder routine */
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rval = ber_decode(opt_codec_ctx, &asn_DEF,
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(void **)&structure, fbuf, rd);
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DEBUG("ber_decode(%ld) consumed %ld, code %d",
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(long)rd, (long)rval.consumed, rval.code);
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/*
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* Switch the remainder into the intermediate buffer.
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*/
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if(rval.code != RC_FAIL && rval.consumed < rd) {
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buf_extend(rd - rval.consumed);
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memcpy(bufend,
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fbuf + rval.consumed,
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rd - rval.consumed);
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buf_len = rd - rval.consumed;
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}
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}
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switch(rval.code) {
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case RC_OK:
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DEBUG("RC_OK, finishing up");
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fclose(fp);
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return structure;
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case RC_WMORE:
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DEBUG("RC_WMORE, continuing...");
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continue;
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case RC_FAIL:
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break;
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}
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break;
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}
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fclose(fp);
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/* Clean up partially decoded structure */
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asn_DEF.free_struct(&asn_DEF, structure, 0);
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fprintf(stderr, "%s: "
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"BER failure past %lld byte\n",
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fname, (long long)(buf_shifted + buf_offset));
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return 0;
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}
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@ -41,11 +41,11 @@ constr_SEQUENCE_OF.h constr_SEQUENCE_OF.c asn_SEQUENCE_OF.h constr_SET_OF.h
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constr_SET.h constr_SET.c
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constr_SET_OF.h constr_SET_OF.c asn_SET_OF.h
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COMMON-FILES: # This is a special section
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asn_application.h
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asn_internal.h
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asn_codecs.h
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COMMON-FILES: # THIS IS A SPECIAL SECTION
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asn_application.h # Applications should include this file
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asn_system.h # Platform-dependent types
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asn_codecs.h # Return types of encoders and decoders
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asn_internal.h # Internal stuff
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OCTET_STRING.h OCTET_STRING.c # This one is used too widely
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BIT_STRING.h BIT_STRING.c # This one is necessary for the above one
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asn_codecs_prim.c asn_codecs_prim.h # enc/decoders for primitive types
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@ -58,3 +58,4 @@ constraints.h constraints.c # Subtype constraints support
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xer_support.h xer_support.c # XML parsing
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xer_decoder.h xer_decoder.c # XER decoding support
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xer_encoder.h xer_encoder.c # XER encoding support
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#asn-decoder-template.c # Template for quick decoder creation
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