Mercurial > dropbear
view libtomcrypt/src/misc/adler32.c @ 1853:2be3115a8762
debugging test runner authorized_keys perms
author | Matt Johnston <matt@ucc.asn.au> |
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date | Tue, 19 Oct 2021 13:45:59 +0800 |
parents | 6dba84798cd5 |
children |
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/* LibTomCrypt, modular cryptographic library -- Tom St Denis * * LibTomCrypt is a library that provides various cryptographic * algorithms in a highly modular and flexible manner. * * The library is free for all purposes without any express * guarantee it works. */ #include "tomcrypt.h" /** @file adler32.c Adler-32 checksum algorithm Written and placed in the public domain by Wei Dai Adapted for libtomcrypt by Steffen Jaeckel */ #ifdef LTC_ADLER32 static const unsigned long _adler32_base = 65521; void adler32_init(adler32_state *ctx) { LTC_ARGCHKVD(ctx != NULL); ctx->s[0] = 1; ctx->s[1] = 0; } void adler32_update(adler32_state *ctx, const unsigned char *input, unsigned long length) { unsigned long s1, s2; LTC_ARGCHKVD(ctx != NULL); LTC_ARGCHKVD(input != NULL); s1 = ctx->s[0]; s2 = ctx->s[1]; if (length % 8 != 0) { do { s1 += *input++; s2 += s1; length--; } while (length % 8 != 0); if (s1 >= _adler32_base) s1 -= _adler32_base; s2 %= _adler32_base; } while (length > 0) { s1 += input[0]; s2 += s1; s1 += input[1]; s2 += s1; s1 += input[2]; s2 += s1; s1 += input[3]; s2 += s1; s1 += input[4]; s2 += s1; s1 += input[5]; s2 += s1; s1 += input[6]; s2 += s1; s1 += input[7]; s2 += s1; length -= 8; input += 8; if (s1 >= _adler32_base) s1 -= _adler32_base; s2 %= _adler32_base; } LTC_ARGCHKVD(s1 < _adler32_base); LTC_ARGCHKVD(s2 < _adler32_base); ctx->s[0] = (unsigned short)s1; ctx->s[1] = (unsigned short)s2; } void adler32_finish(adler32_state *ctx, void *hash, unsigned long size) { unsigned char* h; LTC_ARGCHKVD(ctx != NULL); LTC_ARGCHKVD(hash != NULL); h = hash; switch (size) { default: h[3] = ctx->s[0] & 0x0ff; /* FALLTHROUGH */ case 3: h[2] = (ctx->s[0] >> 8) & 0x0ff; /* FALLTHROUGH */ case 2: h[1] = ctx->s[1] & 0x0ff; /* FALLTHROUGH */ case 1: h[0] = (ctx->s[1] >> 8) & 0x0ff; /* FALLTHROUGH */ case 0: ; } } int adler32_test(void) { #ifndef LTC_TEST return CRYPT_NOP; #else const void* in = "libtomcrypt"; const unsigned char adler32[] = { 0x1b, 0xe8, 0x04, 0xba }; unsigned char out[4]; adler32_state ctx; adler32_init(&ctx); adler32_update(&ctx, in, strlen(in)); adler32_finish(&ctx, out, 4); if (compare_testvector(adler32, 4, out, 4, "adler32", 0)) { return CRYPT_FAIL_TESTVECTOR; } return CRYPT_OK; #endif } #endif /* ref: $Format:%D$ */ /* git commit: $Format:%H$ */ /* commit time: $Format:%ai$ */