Support for charset conversion from any encoding to ASCII.

src/error.h

@@ -36,5 +36,6 @@
 #define ISO_FILE_IS_NOT_DIR				-108
 #define ISO_FILE_IS_NOT_SYMLINK			-109
 
+#define ISO_CHARSET_CONV_ERROR           -150
 
 #endif /*LIBISO_ERROR_H_*/

src/util.c

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2007 Vreixo Formoso
+ * Copyright (c) 2007 Mario Danic
  * 
  * This file is part of the libisofs project; you can redistribute it and/or 
  * modify it under the terms of the GNU General Public License version 2 as 
@@ -7,6 +8,13 @@
  */
 
 #include "util.h"
+#include "error.h"
+
+#include <stdlib.h>
+#include <wchar.h>
+#include <iconv.h>
+#include <string.h>
+#include <errno.h>
 
 int div_up(int n, int div)
 {
@@ -17,3 +25,154 @@ int round_up(int n, int mul)
 {
     return div_up(n, mul) * mul;
 }
+
+/**
+ * Convert a str in a specified codeset to WCHAR_T. 
+ * The result must be free() when no more needed
+ * 
+ * @return
+ *      1 success, < 0 error
+ */
+static 
+int str2wchar(const char *icharset, const char *input, wchar_t **output) 
+{
+    iconv_t conv;
+    size_t inbytes;
+    size_t outbytes;
+    char *ret;
+    char *src;
+    wchar_t *wstr;
+    size_t n;
+    
+    if (icharset == NULL || input == NULL || output == NULL) {
+        return ISO_NULL_POINTER;
+    }
+
+    conv = iconv_open("WCHAR_T", icharset);
+    if (conv == (iconv_t)-1) {
+        return ISO_CHARSET_CONV_ERROR;
+    }
+    
+    inbytes = strlen(input);
+    outbytes = (inbytes + 1) * sizeof(wchar_t);
+
+    /* we are sure that numchars <= inbytes */
+    wstr = malloc(outbytes);
+    if (wstr == NULL) {
+        return ISO_MEM_ERROR;
+    }
+    ret = (char *)wstr;
+    src = (char *)input;
+
+    n = iconv(conv, &src, &inbytes, &ret, &outbytes);
+    while (n == -1) {
+        
+        if( errno != EINVAL ) {
+            /* error, should never occur */
+            iconv_close(conv);
+            free(wstr);
+            return ISO_CHARSET_CONV_ERROR;
+        }
+            
+        /* invalid input string charset, just ignore */
+        /* printf("String %s is not encoded in %s\n", str, codeset); */
+        inbytes--;
+
+        if (!inbytes)
+            break;
+        n = iconv(conv, &src, &inbytes, &ret, &outbytes);
+    }
+    iconv_close(conv);
+    
+    *( (wchar_t *)ret )='\0';
+    *output = wstr;
+    return ISO_SUCCESS;
+}
+
+int str2ascii(const char *icharset, const char *input, char **output)
+{
+    int result;
+    wchar_t *wsrc_;
+    char *ret;
+    char *ret_;
+    char *src;
+    iconv_t conv;
+    size_t numchars;
+    size_t outbytes;
+    size_t inbytes;
+    size_t n;
+    
+    if (icharset == NULL || input == NULL || output == NULL) {
+        return ISO_NULL_POINTER;
+    }
+
+    /* convert the string to a wide character string. Note: outbytes
+     * is in fact the number of characters in the string and doesn't
+     * include the last NULL character.
+     */
+    result = str2wchar(icharset, input, &wsrc_);
+    if (result < 0) {
+        return result;
+    }
+    src = (char *)wsrc_;
+    numchars = wcslen(wsrc_);
+    
+    inbytes = numchars * sizeof(wchar_t);
+
+    ret_ = malloc(numchars + 1);
+    if (ret_ == NULL) {
+        return ISO_MEM_ERROR;
+    }
+    outbytes = numchars;
+    ret = ret_;
+
+    /* initialize iconv */
+    conv = iconv_open("ASCII", "WCHAR_T");
+    if (conv == (iconv_t)-1) {
+        free(wsrc_);
+        free(ret_);
+        return ISO_CHARSET_CONV_ERROR;
+    }
+
+    n = iconv(conv, &src, &inbytes, &ret, &outbytes);
+    while(n == -1) {
+        /* The destination buffer is too small. Stops here. */
+        if (errno == E2BIG)
+            break;
+
+        /* An incomplete multi bytes sequence was found. We 
+         * can't do anything here. That's quite unlikely. */
+        if (errno == EINVAL)
+            break;
+
+        /* The last possible error is an invalid multi bytes
+         * sequence. Just replace the character with a "_". 
+         * Probably the character doesn't exist in ascii like
+         * "é, è, à, ç, ..." in French. */
+        *ret++ = '_';
+        outbytes--;
+
+        if (!outbytes)
+            break;
+
+        /* There was an error with one character but some other remain
+         * to be converted. That's probably a multibyte character.
+         * See above comment. */
+        src += sizeof(wchar_t);
+        inbytes -= sizeof(wchar_t);
+
+        if (!inbytes)
+            break;
+
+        n = iconv(conv, &src, &inbytes, &ret, &outbytes);
+    }
+
+    iconv_close(conv);
+
+    *ret='\0';
+    free(wsrc_);
+    
+    *output = ret_;
+    return ISO_SUCCESS;
+}
+

src/util.h

@@ -13,5 +13,6 @@ extern inline int div_up(int n, int div);
 
 extern inline int round_up(int n, int mul);
 
+int str2ascii(const char *icharset, const char *input, char **output);
 
 #endif /*LIBISO_UTIL_H_*/