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Add a variant of `locale_charset' that returns its result based solely on |
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information from the environment. See |
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http://lists.gnu.org/archive/html/guile-devel/2011-11/msg00040.html for the |
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rationale. |
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@@ -544,3 +544,120 @@ locale_charset (void) |
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return codeset; |
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} |
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+ |
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+/* A variant of the above, without calls to `setlocale', `nl_langinfo', |
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+ etc. */ |
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+const char * |
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+environ_locale_charset (void) |
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+{ |
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+ static char buf[2 + 10 + 1]; |
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+ const char *codeset, *aliases; |
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+ const char *locale = NULL; |
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+ |
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+ locale = getenv ("LC_ALL"); |
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+ if (locale == NULL || locale[0] == '\0') |
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+ { |
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+ locale = getenv ("LC_CTYPE"); |
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+ if (locale == NULL || locale[0] == '\0') |
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+ locale = getenv ("LANG"); |
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+ } |
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+ |
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+ if (locale != NULL && locale[0] != '\0') |
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+ { |
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+ /* If the locale name contains an encoding after the dot, return it. */ |
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+ const char *dot = strchr (locale, '.'); |
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+ |
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+ if (dot != NULL) |
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+ { |
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+ const char *modifier; |
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+ |
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+ dot++; |
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+ /* Look for the possible @... trailer and remove it, if any. */ |
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+ modifier = strchr (dot, '@'); |
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+ if (modifier == NULL) |
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+ return dot; |
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+ if (modifier - dot < sizeof (buf)) |
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+ { |
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+ memcpy (buf, dot, modifier - dot); |
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+ buf [modifier - dot] = '\0'; |
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+ return buf; |
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+ } |
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+ } |
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+ else if (strcmp (locale, "C") == 0) |
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+ { |
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+ strcpy (buf, "ASCII"); |
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+ return buf; |
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+ } |
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+ else |
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+ codeset = ""; |
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+ } |
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+ else |
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+ codeset = ""; |
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+ |
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+ /* Resolve alias. */ |
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+ { |
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+# ifdef alias_table_defined |
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+ /* On some platforms, UTF-8 locales are the most frequently used ones. |
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+ Speed up the common case and slow down the less common cases by |
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+ testing for this case first. */ |
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+# if defined __OpenBSD__ || (defined __APPLE__ && defined __MACH__) || defined __sun || defined __CYGWIN__ |
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+ if (strcmp (codeset, "UTF-8") == 0) |
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+ goto done_table_lookup; |
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+ else |
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+# endif |
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+ { |
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+ const struct table_entry * const table = alias_table; |
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+ size_t const table_size = |
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+ sizeof (alias_table) / sizeof (struct table_entry); |
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+ /* The table is sorted. Perform a binary search. */ |
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+ size_t hi = table_size; |
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+ size_t lo = 0; |
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+ while (lo < hi) |
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+ { |
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+ /* Invariant: |
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+ for i < lo, strcmp (table[i].alias, codeset) < 0, |
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+ for i >= hi, strcmp (table[i].alias, codeset) > 0. */ |
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+ size_t mid = (hi + lo) >> 1; /* >= lo, < hi */ |
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+ int cmp = strcmp (table[mid].alias, codeset); |
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+ if (cmp < 0) |
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+ lo = mid + 1; |
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+ else if (cmp > 0) |
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+ hi = mid; |
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+ else |
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+ { |
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+ /* Found an i with |
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+ strcmp (table[i].alias, codeset) == 0. */ |
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+ codeset = table[mid].canonical; |
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+ goto done_table_lookup; |
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+ } |
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+ } |
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+ } |
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+ if (0) |
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+ done_table_lookup: ; |
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+ else |
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+# endif |
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+ { |
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+ /* Did not find it in the table. */ |
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+ /* On Mac OS X, all modern locales use the UTF-8 encoding. |
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+ BeOS and Haiku have a single locale, and it has UTF-8 encoding. */ |
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+# if (defined __APPLE__ && defined __MACH__) || defined __BEOS__ || defined __HAIKU__ |
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+ codeset = "UTF-8"; |
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+# else |
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+ /* Don't return an empty string. GNU libc and GNU libiconv interpret |
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+ the empty string as denoting "the locale's character encoding", |
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+ thus GNU libiconv would call this function a second time. */ |
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+ if (codeset[0] == '\0') |
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+ codeset = "ASCII"; |
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+# endif |
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+ } |
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+ } |
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+ |
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+ /* Don't return an empty string. GNU libc and GNU libiconv interpret |
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+ the empty string as denoting "the locale's character encoding", |
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+ thus GNU libiconv would call this function a second time. */ |
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+ if (codeset[0] == '\0') |
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+ /* Default to Latin-1, for backward compatibility with Guile 1.8. */ |
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+ codeset = "ISO-8859-1"; |
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+ |
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+ return codeset; |
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+} |
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