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https://github.com/Michaelangel007/apple2_prodos_utils.git
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50 lines
1.6 KiB
C
50 lines
1.6 KiB
C
/**
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@param {uint64_t} x - Number to convert to comma delimited string
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@param {char*} [output_] - Optional buffer to copy output to
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@return {char*} Returns pointer to comma delimited NULL terminated string
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@notes Does NOT NULL terminate the output_ string (to allow for string concatenation)
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@history
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version 9 - Renamed p,e to dst, end
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Version 8 - Cleanup notes
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Version 7 - cleanup 'x > 9' to 'x > 0'
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Version 6 - Add jsdoc
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Verison 5 - add optional output, does NOT null terminate output
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Version 4 - document hard-coded max string length 32
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Version 3 - cleanup '>= 10' to '> 9'
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Verison 2 - add 4 buffers
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Version 1 - initial implementation
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*/
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const char*
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itoa_comma( uint64_t x, char *output_ = NULL )
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{
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const int MAX_CHARS = 31; // 2^32 - 1 = 4,294,967,295 = 13 chars
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const int NUM_BUFFERS = 4; // 2^64 - 1 = 18,446,744,073,709,551,615 = 26 chars
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static char aString[ NUM_BUFFERS ][ MAX_CHARS+1 ];
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static uint8_t iString = 0;
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char *dst = &aString[ iString ][ MAX_CHARS ];
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char *end = dst; // save copy of end pointer
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*dst-- = 0;
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while( x > 999 )
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{
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*dst-- = '0' + (x % 10); x /= 10;
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*dst-- = '0' + (x % 10); x /= 10;
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*dst-- = '0' + (x % 10); x /= 10;
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*dst-- = ',';
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}
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/* */ { *dst-- = '0' + (x % 10); x /= 10; }
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if (x > 0) { *dst-- = '0' + (x % 10); x /= 10; }
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if (x > 0) { *dst-- = '0' + (x % 10); x /= 10; }
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iString++;
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iString &= (NUM_BUFFERS-1);
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if( output_ )
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memcpy( output_, dst+1, end-dst-1 ); // -1 to NOT include NULL terminator
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return ++dst;
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}
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