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baff1af72d
The original Scheme implementation is astonishingly slow. Rewriting SHA-2 in C yields around x10000 speed boost for premade strings and bytevectors. For input ports this is alleviated to x100 boost. The implementation is divided into two parts: native computational backend and thin Scheme interface. It is tedious to properly do IO from C, so the Scheme code handles reading data from an input port and the C code performs actual computations on byte buffers (which is also used to handle strings and bytevectors directly). Scheme wrapper reads data in chunked manner with 'read-bytevector'. Currently, the chunk size has insignificant impact on performance as soon as it is bigger than 64. Also, using simply read-bytevector turned out to be 33% faster than preallocating a buffer and filling it with read-bytevector! One tricky part is how to get exact 32-bit integers in C89. We have no <inttypes.h> there, so instead we use <limits.h> to see whether we have a standard type with suitable boundaries. The other one is how to return a properly tagged sha_context from C. Chibi FFI currently cannot handle the case when a procedure returns either a C pointer (which needs to be boxed) or an exception (which should be left as is). To workaround this sexp_start_sha() receives a dummy argument of type sha_context; this makes Chibi FFI to put a proper type tag into 'self', which is then extracted in the C code. This commits adds a new shared library 'crypto$(SO)' with intent to keep there all native code of (chibi crypto) libraries. This allows to simply put any future native implementation of SHA-512 or MD5 in some md5.c and just include those files into crypto.stub.
28 lines
655 B
C
28 lines
655 B
C
#ifndef CHIBI_CRYPTO_INTEGERS_H
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#define CHIBI_CRYPTO_INTEGERS_H
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#if __STDC_VERSION__ >= 199901L /* C99 */
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# include <inttypes.h>
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typedef uint32_t sexp_uint32_t;
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typedef uint8_t sexp_uint8_t;
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#else
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# include <limits.h>
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#
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# if UCHAR_MAX == 255
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typedef unsigned char sexp_uint8_t;
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# else
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# error Could not find 8-bit type
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# endif
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#
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# if UINT_MAX == 4294967295U
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typedef unsigned int sexp_uint32_t;
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# elif ULONG_MAX == 4294967295UL
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typedef unsigned long sexp_uint32_t;
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# elif USHRT_MAX == 4294967295U
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typedef unsigned short sexp_uint32_t;
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# else
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# error Could not find 32-bit type
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# endif
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#endif
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#endif /* CHIBI_CRYPTO_INTEGERS_H */
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