hb-common.c

   1 // C99 port from c++ is protected by a GNU Lesser GPLv3
   2 // Copyright © 2013 Sylvain BERTRAND <sylvain.bertrand@gmail.com>
   3 //                                   <sylware@legeek.net>
   4 #define _GNU_SOURCE
   5 #include <string.h>
   6 #include <stdlib.h>
   7
   8 #include "hb.h"
   9 #include "hb-private.h"
  10 #include "hb-atomic-private.h"
  11
  12 //this is actually hb_language_t type
  13 struct hb_language_impl_t {
  14   const char s[1];
  15 };
  16
  17 static const char canon_map[256] = {
  18    0,   0,   0,   0,   0,   0,   0,   0,    0,   0,   0,   0,   0,   0,   0,   0,
  19    0,   0,   0,   0,   0,   0,   0,   0,    0,   0,   0,   0,   0,   0,   0,   0,
  20    0,   0,   0,   0,   0,   0,   0,   0,    0,   0,   0,   0,   0,  '-',  0,   0,
  21   '0', '1', '2', '3', '4', '5', '6', '7',  '8', '9',  0,   0,   0,   0,   0,   0,
  22   '-', 'a', 'b', 'c', 'd', 'e', 'f', 'g',  'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o',
  23   'p', 'q', 'r', 's', 't', 'u', 'v', 'w',  'x', 'y', 'z',  0,   0,   0,   0,  '-',
  24    0,  'a', 'b', 'c', 'd', 'e', 'f', 'g',  'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o',
  25   'p', 'q', 'r', 's', 't', 'u', 'v', 'w',  'x', 'y', 'z',  0,   0,   0,   0,   0
  26 };
  27
  28 static hb_bool_t
  29 lang_equal(hb_language_t v1,
  30            const void *v2)
  31 {
  32   const unsigned char *p1 = (const unsigned char*)v1;
  33   const unsigned char *p2 = (const unsigned char*)v2;
  34
  35   while (*p1 && *p1 == canon_map[*p2])
  36     p1++, p2++;
  37   return *p1 == canon_map[*p2];
  38 }
  39
  40 struct hb_language_item_t {
  41
  42   struct hb_language_item_t *next;
  43   hb_language_t lang;
  44 };
  45
  46 static hb_language_t
  47 lang_assign(const char *s)
  48 {
  49   hb_language_t lang = (hb_language_t)strdup(s);
  50   for (unsigned char *p = (unsigned char *)lang; *p; p++)
  51     *p = canon_map[*p];
  52   return lang;
  53 }
  54
  55 /* Thread-safe lock-free language list */
  56
  57 static struct hb_language_item_t *lang_items;
  58
  59 static struct hb_language_item_t *
  60 language_item_find_or_insert(const char *key)
  61 {
  62   struct hb_language_item_t *first_lang_item = hb_atomic_ptr_get(&lang_items);
  63
  64   while (1) {
  65     for (struct hb_language_item_t *lang_item = first_lang_item; lang_item;
  66                                                     lang_item = lang_item->next)
  67       if (lang_equal(lang_item->lang, key))
  68         return lang_item;
  69
  70     //Not found; allocate one.
  71     struct hb_language_item_t *lang_item = calloc(1, sizeof(*lang_item));
  72     if (!lang_item)
  73       return NULL;
  74     lang_item->next = first_lang_item;
  75     lang_item->lang = lang_assign(key);
  76
  77     if (hb_atomic_ptr_cmpexch(&lang_items, &first_lang_item, &lang_item))
  78       return lang_item;
  79     free (lang_item);
  80   }
  81 }
  82
  83 hb_language_t
  84 hb_language_from_string(const char *str, int len)
  85 {
  86   if (!str || !len || !*str)
  87     return HB_LANGUAGE_INVALID;
  88
  89   if (len >= 0) {
  90     char strbuf[64];
  91     len = MIN(len, (int)sizeof(strbuf) - 1);
  92     str = (char*)memcpy(strbuf, str, len);
  93     strbuf[len] = '\0';
  94   }
  95
  96   struct hb_language_item_t *item = language_item_find_or_insert(str);
  97
  98   return item ? item->lang : HB_LANGUAGE_INVALID;
  99 }
 100
 101 hb_tag_t
 102 hb_tag_from_string(const char *str, int len)
 103 {
 104   char tag[4];
 105   unsigned i;
 106
 107   if (!str || !len || !*str)
 108     return HB_TAG_NONE;
 109
 110   if (len < 0 || len > 4)
 111     len = 4;
 112   for (i = 0; i < (unsigned)len && str[i]; ++i)
 113     tag[i] = str[i];
 114   for (; i < 4; ++i)
 115     tag[i] = ' ';
 116   return HB_TAG_CHAR4(tag);
 117 }
 118
 119 const char *
 120 hb_language_to_string(hb_language_t language)
 121 {
 122   //This is actually NULL-safe!
 123   return language->s;
 124 }