Add function "string_decode_base64" in plugin API

ChangeLog

@@ -1,7 +1,7 @@
 WeeChat ChangeLog
 =================
 FlashCode <flashcode@flashtux.org>
-v0.3.2-dev, 2010-02-15
+v0.3.2-dev, 2010-02-16
 
 
 Version 0.3.2 (under dev!)
@@ -20,7 +20,8 @@ Version 0.3.2 (under dev!)
   input (bug #28754)
 * api: add "version_number" for function info_get to get WeeChat version as
   number
-* api: add function "string_encode_base64", fix bug with base64 encoding
+* api: add functions "string_encode_base64" and "string_decode_base64",, fix
+  bug with base64 encoding
 * api: add missing infos in functions buffer_get_integer / buffer_get_string
   and in buffer infolist
 * api: add description of arguments for functions hook_info and hook_infolist

doc/en/weechat_plugin_api.en.txt

@@ -1124,7 +1124,8 @@ Arguments:
 
 * 'from': string to encode
 * 'length': length of string to encode (for example `strlen(from)`)
-* 'to': pointer to string to store result (must be long enough)
+* 'to': pointer to string to store result (must be long enough, result is
+  longer than initial string)
 
 Example:
 
@@ -1135,6 +1136,38 @@ weechat_string_encode_base64 (string, strlen (string), result);
 /* result == "YWJjZGVmZ2g=" */
 ----------------------------------------
 
+weechat_string_decode_base64
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Decode a base64 string.
+
+Prototype:
+
+[source,C]
+----------------------------------------
+int weechat_string_decode_base64 (const char *from, char *to);
+----------------------------------------
+
+Arguments:
+
+* 'from': string to decode
+* 'to': pointer to string to store result (must be long enough, result is
+  shorter than initial string)
+
+Return value:
+
+* length of string stored in *to (does not count final '\0')
+
+Example:
+
+[source,C]
+----------------------------------------
+char *string = "YWJjZGVmZ2g=", result[128];
+int length;
+length = weechat_string_decode_base64 (string, result);
+/* length == 8, result == "abcdefgh" */
+----------------------------------------
+
 [[utf-8]]
 UTF-8
 ~~~~~

doc/fr/weechat_plugin_api.fr.txt

@@ -1139,7 +1139,7 @@ Paramètres :
 * 'from': chaîne à encoder
 * 'length': longueur de chaîne à encoder (par exemple `strlen(from)`)
 * 'to': pointeur vers la chaîne pour stocker le résultat (doit être suffisamment
-  long)
+  long, le résultat est plus long que la chaîne initiale)
 
 Exemple :
 
@@ -1150,6 +1150,38 @@ weechat_string_encode_base64 (string, strlen (string), result);
 /* result == "YWJjZGVmZ2g=" */
 ----------------------------------------
 
+weechat_string_decode_base64
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Décode une chaîne base64.
+
+Prototype :
+
+[source,C]
+----------------------------------------
+int weechat_string_decode_base64 (const char *from, char *to);
+----------------------------------------
+
+Paramètres :
+
+* 'from': chaîne à décoder
+* 'to': pointeur vers la chaîne pour stocker le résultat (doit être suffisamment
+  long, le résultat est plus court que la chaîne initiale)
+
+Valeur de retour :
+
+* longueur de la chaîne stockée dans *to (ne compte pas le '\0' final)
+
+Example:
+
+[source,C]
+----------------------------------------
+char *string = "YWJjZGVmZ2g=", result[128];
+int length;
+length = weechat_string_decode_base64 (string, result);
+/* length == 8, result == "abcdefgh" */
+----------------------------------------
+
 [[utf-8]]
 UTF-8
 ~~~~~

src/core/wee-string.c

@@ -1333,3 +1333,80 @@ string_encode_base64 (const char *from, int length, char *to)
     else
         ptr_to[0] = '\0';
 }
+
+/*
+ * string_convbase64_6x4_to_8x3 : convert 4 bytes of 6 bits to 3 bytes of 8 bits
+ */
+
+void
+string_convbase64_6x4_to_8x3 (const unsigned char *from, unsigned char *to)
+{
+    to[0] = from[0] << 2 | from[1] >> 4;
+    to[1] = from[1] << 4 | from[2] >> 2;
+    to[2] = ((from[2] << 6) & 0xc0) | from[3];
+}
+
+/*
+ * string_decode_base64: decode a base64 string
+ *                       return length of string in *to
+ *                       (does not count final \0)
+ */
+
+int
+string_decode_base64 (const char *from, char *to)
+{
+    const char *ptr_from;
+    int length, to_length, i;
+    char *ptr_to;
+    unsigned char c, in[4], out[3];
+    unsigned char base64_table[]="|$$$}rstuvwxyz{$$$$$$$>?"
+        "@ABCDEFGHIJKLMNOPQRSTUVW$$$$$$XYZ[\\]^_`abcdefghijklmnopq";
+    
+    ptr_from = from;
+    ptr_to = to;
+    
+    ptr_to[0] = '\0';
+    to_length = 0;
+    
+    while (ptr_from && ptr_from[0])
+    {
+        length = 0;
+        for (i = 0; i < 4; i++)
+        {
+            c = 0;
+            while (ptr_from[0] && (c == 0))
+            {
+                c = (unsigned char) ptr_from[0];
+                ptr_from++;
+                c = ((c < 43) || (c > 122)) ? 0 : base64_table[c - 43];
+                if (c)
+                    c = (c == '$') ? 0 : c - 61;
+            }
+            if (ptr_from[0])
+            {
+                length++;
+                if (c)
+                    in[i] = c - 1;
+            }
+            else
+            {
+                in[i] = '\0';
+                break;
+            }
+        }
+        if (length)
+        {
+            string_convbase64_6x4_to_8x3 (in, out);
+            for (i = 0; i < length - 1; i++)
+            {
+                ptr_to[0] = out[i];
+                ptr_to++;
+                to_length++;
+            }
+        }
+    }
+    
+    ptr_to[0] = '\0';
+    
+    return to_length;
+}

src/core/wee-string.h

@@ -57,5 +57,6 @@ extern char *string_iconv_from_internal (const char *charset,
 extern void string_iconv_fprintf (FILE *file, const char *data, ...);
 extern char *string_format_size (unsigned long size);
 extern void string_encode_base64 (const char *from, int length, char *to);
+extern int string_decode_base64 (const char *from, char *to);
 
 #endif /* wee-string.h */

src/plugins/plugin.c

@@ -385,6 +385,7 @@ plugin_load (const char *filename)
         new_plugin->string_format_size = &string_format_size;
         new_plugin->string_remove_color = &gui_color_decode;
         new_plugin->string_encode_base64 = &string_encode_base64;
+        new_plugin->string_decode_base64 = &string_decode_base64;
         
         new_plugin->utf8_has_8bits = &utf8_has_8bits;
         new_plugin->utf8_is_valid = &utf8_is_valid;

src/plugins/weechat-plugin.h

@@ -34,7 +34,7 @@ struct t_weelist;
 struct timeval;
 
 /* API version (used to check that plugin has same API and can be loaded) */
-#define WEECHAT_PLUGIN_API_VERSION "20100215-01"
+#define WEECHAT_PLUGIN_API_VERSION "20100216-01"
 
 /* macros for defining plugin infos */
 #define WEECHAT_PLUGIN_NAME(__name)                                     \
@@ -171,6 +171,7 @@ struct t_weechat_plugin
     char *(*string_format_size) (unsigned long size);
     char *(*string_remove_color) (const char *string, const char *replacement);
     void (*string_encode_base64) (const char *from, int length, char *to);
+    int (*string_decode_base64) (const char *from, char *to);
     
     /* UTF-8 strings */
     int (*utf8_has_8bits) (const char *string);
@@ -720,6 +721,8 @@ extern int weechat_plugin_end (struct t_weechat_plugin *plugin);
     weechat_plugin->string_remove_color(__string, __replacement)
 #define weechat_string_encode_base64(__from, __length, __to)            \
     weechat_plugin->string_encode_base64(__from, __length, __to)
+#define weechat_string_decode_base64(__from, __to)                      \
+    weechat_plugin->string_decode_base64(__from, __to)
 
 /* UTF-8 strings */
 #define weechat_utf8_has_8bits(__string)                                \