Ruby 1.9.2p136(2010-12-25revision30365)

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# ext/digest/bubblebabble/bubblebabble.c

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    00001 /************************************************
    00002
    00003   bubblebabble.c - BubbleBabble encoding support
    00004
    00005   $Author: knu $
    00006   created at: Fri Oct 13 18:31:42 JST 2006
    00007
    00008   Copyright (C) 2006 Akinori MUSHA
    00009
    00010   $Id: bubblebabble.c 28341 2010-06-16 09:38:14Z knu $
    00011
    00012 ************************************************/
    00013
    00014 #include "ruby.h"
    00015 #include "../digest.h"
    00016
    00017 static ID id_digest;
    00018
    00019 static VALUE
    00020 bubblebabble_str_new(VALUE str_digest)
    00021 {
    00022     char *digest;
    00023     size_t digest_len;
    00024     VALUE str;
    00025     char *p;
    00026     size_t i, j, seed = 1;
    00027     static const char vowels[] = {
    00028         'a', 'e', 'i', 'o', 'u', 'y'
    00029     };
    00030     static const char consonants[] = {
    00031         'b', 'c', 'd', 'f', 'g', 'h', 'k', 'l', 'm', 'n',
    00032         'p', 'r', 's', 't', 'v', 'z', 'x'
    00033     };
    00034
    00035     StringValue(str_digest);
    00036     digest = RSTRING_PTR(str_digest);
    00037     digest_len = RSTRING_LEN(str_digest);
    00038
    00039     if ((LONG_MAX - 2) / 3 < (digest_len | 1)) {
    00040         rb_raise(rb_eRuntimeError, "digest string too long");
    00041     }
    00042
    00043     str = rb_str_new(0, (digest_len | 1) * 3 + 2);
    00044     p = RSTRING_PTR(str);
    00045
    00046     i = j = 0;
    00047     p[j++] = 'x';
    00048
    00049     for (;;) {
    00050         unsigned char byte1, byte2;
    00051
    00052         if (i >= digest_len) {
    00053             p[j++] = vowels[seed % 6];
    00054             p[j++] = consonants[16];
    00055             p[j++] = vowels[seed / 6];
    00056             break;
    00057         }
    00058
    00059         byte1 = digest[i++];
    00060         p[j++] = vowels[(((byte1 >> 6) & 3) + seed) % 6];
    00061         p[j++] = consonants[(byte1 >> 2) & 15];
    00062         p[j++] = vowels[((byte1 & 3) + (seed / 6)) % 6];
    00063
    00064         if (i >= digest_len) {
    00065             break;
    00066         }
    00067
    00068         byte2 = digest[i++];
    00069         p[j++] = consonants[(byte2 >> 4) & 15];
    00070         p[j++] = '-';
    00071         p[j++] = consonants[byte2 & 15];
    00072
    00073         seed = (seed * 5 + byte1 * 7 + byte2) % 36;
    00074     }
    00075
    00076     p[j] = 'x';
    00077
    00078     return str;
    00079 }
    00080
    00081 /*
    00082  * call-seq:
    00083  *     Digest.bubblebabble(string) -> bubblebabble_string
    00084  *
    00085  * Returns a BubbleBabble encoded version of a given _string_.
    00086  */
    00087 static VALUE
    00088 rb_digest_s_bubblebabble(VALUE klass, VALUE str)
    00089 {
    00090     return bubblebabble_str_new(str);
    00091 }
    00092
    00093 /*
    00094  * call-seq:
    00095  *     Digest::Class.bubblebabble(string, ...) -> hash_string
    00096  *
    00097  * Returns the BubbleBabble encoded hash value of a given _string_.
    00098  */
    00099 static VALUE
    00100 rb_digest_class_s_bubblebabble(int argc, VALUE *argv, VALUE klass)
    00101 {
    00102     return bubblebabble_str_new(rb_funcall2(klass, id_digest, argc, argv));
    00103 }
    00104
    00105 /*
    00106  * call-seq:
    00107  *     digest_obj.bubblebabble -> hash_string
    00108  *
    00109  * Returns the resulting hash value in a Bubblebabble encoded form.
    00110  */
    00111 static VALUE
    00112 rb_digest_instance_bubblebabble(VALUE self)
    00113 {
    00114     return bubblebabble_str_new(rb_funcall(self, id_digest, 0));
    00115 }
    00116
    00117 /*
    00118  * This module adds some methods to Digest classes to perform
    00119  * BubbleBabble encoding.
    00120  */
    00121 void
    00122 Init_bubblebabble(void)
    00123 {
    00124     VALUE mDigest, mDigest_Instance, cDigest_Class;
    00125
    00126     rb_require("digest");
    00127
    00128     mDigest = rb_path2class("Digest");
    00129     mDigest_Instance = rb_path2class("Digest::Instance");
    00130     cDigest_Class = rb_path2class("Digest::Class");
    00131
    00132     /* Digest::bubblebabble() */
    00133     rb_define_module_function(mDigest, "bubblebabble", rb_digest_s_bubblebabble, 1);
    00134
    00135     /* Digest::Class::bubblebabble() */
    00136     rb_define_singleton_method(cDigest_Class, "bubblebabble", rb_digest_class_s_bubblebabble, -1);
    00137
    00138     /* Digest::Instance#bubblebabble() */
    00139     rb_define_method(mDigest_Instance, "bubblebabble", rb_digest_instance_bubblebabble, 0);
    00140
    00141     id_digest = rb_intern("digest");
    00142 }
    00143