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40 lines
1.1 KiB
C
40 lines
1.1 KiB
C
#include "scan.h"
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size_t scan_varint(const char* in,size_t len, unsigned long long* n) {
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size_t i;
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unsigned long long l;
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if (len==0) return 0;
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for (l=0, i=0; i<len; ++i) {
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if (i*7+7>sizeof(l)*8) // value too large to fit in destination integer!
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return 0;
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l+=(unsigned long long)(in[i]&0x7f) << (i*7);
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if (!(in[i]&0x80)) {
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if (in[i]==0) return 0; // libowfat extension: reject non-minimal encoding
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*n=l;
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return i+1;
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}
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}
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return 0;
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}
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#ifdef __ELF__
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size_t scan_pb_type0_int(const char* dest,size_t len,unsigned long long* l) __attribute__((alias("scan_varint")));
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#else
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size_t scan_pb_type0_int(const char* dest,size_t len,unsigned long long* l) {
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return scan_varint(dest,len,l);
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}
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#endif
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#ifdef UNITTEST
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#include <assert.h>
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int main() {
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unsigned long long n;
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assert(scan_varint("\x05",1,&n)==1 && n==5);
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assert(scan_varint("\x80\x00",2,&n)==0); // non-minimal encoding
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assert(scan_varint("\x80\x80",2,&n)==0); // truncated (last byte in sequence has high bit 0)
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assert(scan_varint("\x80\x80\x80\x80\x80\x80\x80\x80\x80\x01",10,&n)==0); // value too large
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return 0;
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}
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#endif
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