36 lines
868 B
C
36 lines
868 B
C
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/*
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** Write a 64-bit variable-length integer to memory starting at p[0].
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** The length of data write will be between 1 and 9 bytes. The number
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** of bytes written is returned.
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**
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** A variable-length integer consists of the lower 7 bits of each byte
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** for all bytes that have the 8th bit set and one byte with the 8th
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** bit clear. Except, if we get to the 9th byte, it stores the full
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** 8 bits and is the last byte.
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*/
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SQLITE_PRIVATE int sqlite3PutVarint(unsigned char *p, u64 v){
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int i, j, n;
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u8 buf[10];
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if( v & (((u64)0xff000000)<<32) ){
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p[8] = v;
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v >>= 8;
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for(i=7; i>=0; i--){
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p[i] = (v & 0x7f) | 0x80;
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v >>= 7;
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}
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return 9;
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}
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n = 0;
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do{
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buf[n++] = (v & 0x7f) | 0x80;
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v >>= 7;
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}while( v!=0 );
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buf[0] &= 0x7f;
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assert( n<=9 );
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for(i=0, j=n-1; j>=0; j--, i++){
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p[i] = buf[j];
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}
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return n;
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}
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