general improvements

diff --git a/utf8.c b/utf8.c
index eb785875042920b84e56abbd235ef9eb7ef22ac4..3b42fadffd7ccb89a5658fdf8d314014f299a769 100644 (file)
--- a/utf8.c
+++ b/utf8.c
@@ -4,6 +4,11 @@
 
 /* This code is originally from http://www.cl.cam.ac.uk/~mgk25/ucs/ */
 
+static const char utf16_be_bom[] = {'\xFE', '\xFF'};
+static const char utf16_le_bom[] = {'\xFF', '\xFE'};
+static const char utf32_be_bom[] = {'\0', '\0', '\xFE', '\xFF'};
+static const char utf32_le_bom[] = {'\xFF', '\xFE', '\0', '\0'};
+
 struct interval {
        ucs_char_t first;
        ucs_char_t last;
@@ -470,16 +475,17 @@ int utf8_fprintf(FILE *stream, const char *format, ...)
 #else
        typedef char * iconv_ibp;
 #endif
-char *reencode_string_iconv(const char *in, size_t insz, iconv_t conv, size_t *outsz_p)
+char *reencode_string_iconv(const char *in, size_t insz, iconv_t conv,
+                           size_t bom_len, size_t *outsz_p)
 {
        size_t outsz, outalloc;
        char *out, *outpos;
        iconv_ibp cp;
 
        outsz = insz;
-       outalloc = st_add(outsz, 1); /* for terminating NUL */
+       outalloc = st_add(outsz, 1 + bom_len); /* for terminating NUL */
        out = xmalloc(outalloc);
-       outpos = out;
+       outpos = out + bom_len;
        cp = (iconv_ibp)in;
 
        while (1) {
@@ -540,10 +546,44 @@ char *reencode_string_len(const char *in, size_t insz,
 {
        iconv_t conv;
        char *out;
+       const char *bom_str = NULL;
+       size_t bom_len = 0;
 
        if (!in_encoding)
                return NULL;
 
+       /* UTF-16LE-BOM is the same as UTF-16 for reading */
+       if (same_utf_encoding("UTF-16LE-BOM", in_encoding))
+               in_encoding = "UTF-16";
+
+       /*
+        * For writing, UTF-16 iconv typically creates "UTF-16BE-BOM"
+        * Some users under Windows want the little endian version
+        *
+        * We handle UTF-16 and UTF-32 ourselves only if the platform does not
+        * provide a BOM (which we require), since we want to match the behavior
+        * of the system tools and libc as much as possible.
+        */
+       if (same_utf_encoding("UTF-16LE-BOM", out_encoding)) {
+               bom_str = utf16_le_bom;
+               bom_len = sizeof(utf16_le_bom);
+               out_encoding = "UTF-16LE";
+       } else if (same_utf_encoding("UTF-16BE-BOM", out_encoding)) {
+               bom_str = utf16_be_bom;
+               bom_len = sizeof(utf16_be_bom);
+               out_encoding = "UTF-16BE";
+#ifdef ICONV_OMITS_BOM
+       } else if (same_utf_encoding("UTF-16", out_encoding)) {
+               bom_str = utf16_be_bom;
+               bom_len = sizeof(utf16_be_bom);
+               out_encoding = "UTF-16BE";
+       } else if (same_utf_encoding("UTF-32", out_encoding)) {
+               bom_str = utf32_be_bom;
+               bom_len = sizeof(utf32_be_bom);
+               out_encoding = "UTF-32BE";
+#endif
+       }
+
        conv = iconv_open(out_encoding, in_encoding);
        if (conv == (iconv_t) -1) {
                in_encoding = fallback_encoding(in_encoding);
@@ -553,9 +593,10 @@ char *reencode_string_len(const char *in, size_t insz,
                if (conv == (iconv_t) -1)
                        return NULL;
        }
-
-       out = reencode_string_iconv(in, insz, conv, outsz);
+       out = reencode_string_iconv(in, insz, conv, bom_len, outsz);
        iconv_close(conv);
+       if (out && bom_str && bom_len)
+               memcpy(out, bom_str, bom_len);
        return out;
 }
 #endif
@@ -566,11 +607,6 @@ static int has_bom_prefix(const char *data, size_t len,
        return data && bom && (len >= bom_len) && !memcmp(data, bom, bom_len);
 }
 
-static const char utf16_be_bom[] = {'\xFE', '\xFF'};
-static const char utf16_le_bom[] = {'\xFF', '\xFE'};
-static const char utf32_be_bom[] = {'\0', '\0', '\xFE', '\xFF'};
-static const char utf32_le_bom[] = {'\xFF', '\xFE', '\0', '\0'};
-
 int has_prohibited_utf_bom(const char *enc, const char *data, size_t len)
 {
        return (