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26 lines
558 B
C
26 lines
558 B
C
#include "fmt.h"
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/* write int in least amount of bytes, return number of bytes */
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/* as used in ASN.1 length */
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size_t fmt_asn1derlength(char* dest,unsigned long long l) {
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/* encoding is either l%128 or (0x80+number of bytes,bytes) */
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size_t needed=(sizeof l),i;
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if (l<128) {
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if (dest) *dest=l&0x7f;
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return 1;
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}
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for (i=1; i<needed; ++i)
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if (!(l>>(i*8)))
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break;
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if (dest) {
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size_t j=i;
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*dest=(char)(0x80+i); ++dest;
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while (j) {
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--j;
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*dest=(char)((l>>(j*8))&0xff);
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++dest;
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}
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}
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return i+1;
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}
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