52 lines
1.4 KiB
Markdown
52 lines
1.4 KiB
Markdown
LEB128 or Little Endian Base 128 is a variable-length code compression used to store arbitrarily large integers in a small number of bytes.
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(**integer->leb128** value)
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*value* must be exact integer. Returns the integer as leb128
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bytevector.
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(**leb128->integer** bv . start-index)
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*bv* must be bytevector. Reading of leb128 values start at index 0, unless
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*start-index* is given. *start-index* must be exact integer. Returns exact
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integer of leb128 value.
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(**leb128->integer-and-length** bv . start-index)
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Sams as leb128->integer but returns a pair with integer as car and leb128
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bytevector length, as in how many bytes long the leb128 was, as cdr.
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(**integer->uleb128** value)
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*value* must be exact positive integer or 0. Returns the integer as leb128
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bytevector.
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(**uleb128->integer** bv)
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*bv* must be bytevector. Reading of uleb128 values start at index 0, unless
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*start-index* is given. *start-index* must be exact integer. Returns exact
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positive integer or 0 of uleb128 value.
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(**uleb128->integer-and-length** bv)
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Sams as uleb128->integer but returns a pair with integer as car and uleb128
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bytevector length, as in how many bytes long the leb128 was, as cdr.
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Resources used:
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https://en.wikipedia.org/wiki/LEB128
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- Mostly turning pseudocode from here to Scheme
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https://github.com/mohanson/leb128
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- Code for leb128 to integer handling as we dont know integer size like in C
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