2 * Copyright (c) 2003, 2004 Lev Walkin <vlm@lionet.info>. All rights reserved.
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3 * Redistribution and modifications are permitted subject to BSD license.
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5 #include <asn_internal.h>
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6 #include <ber_tlv_tag.h>
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10 ber_fetch_tag(const void *ptr, size_t size, ber_tlv_tag_t *tag_r) {
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12 ber_tlv_tag_t tclass;
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18 val = *(const uint8_t *)ptr;
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19 tclass = (val >> 6);
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20 if((val &= 0x1F) != 0x1F) {
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22 * Simple form: everything encoded in a single octet.
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23 * Tag Class is encoded using two least significant bits.
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25 *tag_r = (val << 2) | tclass;
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30 * Each octet contains 7 bits of useful information.
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31 * The MSB is 0 if it is the last octet of the tag.
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33 for(val = 0, ptr = ((const char *)ptr) + 1, skipped = 2;
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35 ptr = ((const char *)ptr) + 1, skipped++) {
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36 unsigned int oct = *(const uint8_t *)ptr;
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38 val = (val << 7) | (oct & 0x7F);
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40 * Make sure there are at least 9 bits spare
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41 * at the MS side of a value.
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43 if(val >> ((8 * sizeof(val)) - 9)) {
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45 * We would not be able to accomodate
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46 * any more tag bits.
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51 val = (val << 7) | oct;
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52 *tag_r = (val << 2) | tclass;
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57 return 0; /* Want more */
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62 ber_tlv_tag_fwrite(ber_tlv_tag_t tag, FILE *f) {
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63 char buf[sizeof("[APPLICATION ]") + 32];
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66 ret = ber_tlv_tag_snprint(tag, buf, sizeof(buf));
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67 if(ret >= (ssize_t)sizeof(buf) || ret < 2) {
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72 return fwrite(buf, 1, ret, f);
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76 ber_tlv_tag_snprint(ber_tlv_tag_t tag, char *buf, size_t size) {
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77 const char *type = 0;
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81 case ASN_TAG_CLASS_UNIVERSAL: type = "UNIVERSAL "; break;
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82 case ASN_TAG_CLASS_APPLICATION: type = "APPLICATION "; break;
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83 case ASN_TAG_CLASS_CONTEXT: type = ""; break;
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84 case ASN_TAG_CLASS_PRIVATE: type = "PRIVATE "; break;
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87 ret = snprintf(buf, size, "[%s%u]", type, ((unsigned)tag) >> 2);
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88 if(ret <= 0 && size) buf[0] = '\0'; /* against broken libc's */
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94 ber_tlv_tag_string(ber_tlv_tag_t tag) {
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95 static char buf[sizeof("[APPLICATION ]") + 32];
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97 (void)ber_tlv_tag_snprint(tag, buf, sizeof(buf));
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104 ber_tlv_tag_serialize(ber_tlv_tag_t tag, void *bufp, size_t size) {
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105 int tclass = BER_TAG_CLASS(tag);
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106 ber_tlv_tag_t tval = BER_TAG_VALUE(tag);
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107 uint8_t *buf = (uint8_t *)bufp;
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109 size_t required_size;
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113 /* Encoded in 1 octet */
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114 if(size) buf[0] = (tclass << 6) | tval;
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117 *buf++ = (tclass << 6) | 0x1F;
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122 * Compute the size of the subsequent bytes.
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124 for(required_size = 1, i = 7; i < 8 * sizeof(tval); i += 7) {
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131 if(size < required_size)
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132 return required_size + 1;
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135 * Fill in the buffer, space permitting.
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137 end = buf + required_size - 1;
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138 for(i -= 7; buf < end; i -= 7, buf++)
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139 *buf = 0x80 | ((tval >> i) & 0x7F);
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140 *buf = (tval & 0x7F); /* Last octet without high bit */
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142 return required_size + 1;
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