diff options
Diffstat (limited to '')
-rw-r--r-- | grub-core/lib/adler32.c | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/grub-core/lib/adler32.c b/grub-core/lib/adler32.c new file mode 100644 index 0000000..43b68af --- /dev/null +++ b/grub-core/lib/adler32.c @@ -0,0 +1,102 @@ +/* + * GRUB -- GRand Unified Bootloader + * Copyright (C) 2012 Free Software Foundation, Inc. + * + * GRUB is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * GRUB is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with GRUB. If not, see <http://www.gnu.org/licenses/>. + */ + + +#include <grub/dl.h> +#include <grub/crypto.h> + +GRUB_MOD_LICENSE ("GPLv3+"); + +struct adler32_context +{ + grub_uint16_t a, b; + grub_uint32_t c; +}; + +static void +adler32_init (void *context) +{ + struct adler32_context *ctx = context; + + ctx->a = 1; + ctx->b = 0; +} + +#define MOD 65521 + +static grub_uint16_t +mod_add (grub_uint16_t a, grub_uint16_t b) +{ + if ((grub_uint32_t) a + (grub_uint32_t) b >= MOD) + return a + b - MOD; + return a + b; +} + +static void +adler32_write (void *context, const void *inbuf, grub_size_t inlen) +{ + struct adler32_context *ctx = context; + const grub_uint8_t *ptr = inbuf; + + while (inlen) + { + ctx->a = mod_add (ctx->a, *ptr); + ctx->b = mod_add (ctx->a, ctx->b); + inlen--; + ptr++; + } +} + +static void +adler32_final (void *context __attribute__ ((unused))) +{ +} + +static grub_uint8_t * +adler32_read (void *context) +{ + struct adler32_context *ctx = context; + if (ctx->a > MOD) + ctx->a -= MOD; + if (ctx->b > MOD) + ctx->b -= MOD; + ctx->c = grub_cpu_to_be32 (ctx->a | (ctx->b << 16)); + return (grub_uint8_t *) &ctx->c; +} + +static gcry_md_spec_t spec_adler32 = + { + "ADLER32", 0, 0, 0, 4, + adler32_init, adler32_write, adler32_final, adler32_read, + sizeof (struct adler32_context), +#ifdef GRUB_UTIL + .modname = "adler32", +#endif + .blocksize = 64 + }; + + +GRUB_MOD_INIT(adler32) +{ + grub_md_register (&spec_adler32); +} + +GRUB_MOD_FINI(adler32) +{ + grub_md_unregister (&spec_adler32); +} |