Added the UTF-8, UTF-16 and ISO Lat 1 conversion routines, not yet used, Daniel.
diff --git a/encoding.c b/encoding.c
new file mode 100644
index 0000000..033e45e
--- /dev/null
+++ b/encoding.c
@@ -0,0 +1,175 @@
+/*
+ * encoding.c : implements the encoding conversion functions needed for XML
+ *
+ * Related specs:
+ * rfc2044 (UTF-8 and UTF-16) F. Yergeau Alis Technologies
+ * [ISO-10646] UTF-8 and UTF-16 in Annexes
+ * [ISO-8859-1] ISO Latin-1 characters codes.
+ * [UNICODE] The Unicode Consortium, "The Unicode Standard --
+ * Worldwide Character Encoding -- Version 1.0", Addison-
+ * Wesley, Volume 1, 1991, Volume 2, 1992. UTF-8 is
+ * described in Unicode Technical Report #4.
+ * [US-ASCII] Coded Character Set--7-bit American Standard Code for
+ * Information Interchange, ANSI X3.4-1986.
+ *
+ * Original code from "Martin J. Duerst" <duerst@w3.org>
+ *
+ * See Copyright for the status of this software.
+ *
+ * $Id$
+ *
+ * Daniel.Veillard@w3.org
+ */
+
+#include "encoding.h"
+
+/*
+ * Take a block of ISO Latin 1 chars in and try to convert it to an UTF-8
+ * block of chars out.
+ *
+ * Returns the number of byte written, or -1 by lack of space.
+ */
+int isolat1ToUTF8(unsigned char* out, int outlen, unsigned char* in, int inlen)
+{
+ unsigned char* outstart= out;
+ unsigned char* outend= out+outlen;
+ unsigned char* inend= in+inlen;
+ unsigned char c;
+
+ while (in < inend) {
+ c= *in++;
+ if (c < 0x80) {
+ if (out >= outend) return -1;
+ *out++ = c;
+ }
+ else {
+ if (out >= outend) return -1;
+ *out++ = 0xC0 | (c >> 6);
+ if (out >= outend) return -1;
+ *out++ = 0x80 | (0x3F & c);
+ }
+ }
+ return out-outstart;
+}
+
+
+/*
+ * Take a block of UTF-8 chars in and try to convert it to an ISO Latin 1
+ * block of chars out.
+ *
+ * Returns the number of byte written, or -1 by lack of space, or -2
+ * if the transcoding failed.
+ *
+ * TODO: need a fallback mechanism ...
+ */
+int UTF8Toisolat1(unsigned char* out, int outlen, unsigned char* in, int inlen)
+{
+ unsigned char* outstart= out;
+ unsigned char* outend= out+outlen;
+ unsigned char* inend= in+inlen;
+ unsigned char c, d;
+
+ while (in < inend) {
+ c= *in++;
+ if (c < 0x80) {
+ if (out >= outend) return -1;
+ *out++= c;
+ }
+ else if (((c & 0xFE) == 0xC2) && in<inend) {
+ if (out >= outend) return -1;
+ *out++= ((c & 0x03) << 6) | (*in++ & 0x3F);
+ }
+ else return -2;
+ }
+ return out-outstart;
+}
+
+/*
+ * Take a block of UTF-16 ushorts in and try to convert it to an UTF-8
+ * block of chars out.
+ *
+ * Returns the number of byte written, or -1 by lack of space.
+ */
+int UTF16ToUTF8(unsigned char* out, int outlen, unsigned short* in, int inlen)
+{
+ unsigned char* outstart= out;
+ unsigned char* outend= out+outlen;
+ unsigned short* inend= in+inlen;
+ unsigned int c, d;
+ int bits;
+
+ while (in < inend) {
+ c= *in++;
+ if ((c & 0xFC00) == 0xD800) { /* surrogates */
+ if ((in<inend) && (((d=*in++) & 0xFC00) == 0xDC00)) {
+ c &= 0x03FF;
+ c <<= 10;
+ c |= d & 0x03FF;
+ c += 0x10000;
+ }
+ else return -1;
+ }
+
+ /* assertion: c is a single UTF-4 value */
+
+ if (out >= outend) return -1;
+ if (c < 0x80) { *out++= c; bits= -6; }
+ else if (c < 0x800) { *out++= (c >> 6) | 0xC0; bits= 0; }
+ else if (c < 0x10000) { *out++= (c >> 12) | 0xE0; bits= 6; }
+ else { *out++= (c >> 18) | 0xF0; bits= 12; }
+
+ for ( ; bits < 0; bits-= 6) {
+ if (out >= outend) return -1;
+ *out++= (c >> bits) & 0x3F;
+ }
+ }
+ return out-outstart;
+}
+
+/*
+ * Take a block of UTF-8 chars in and try to convert it to an UTF-16
+ * block of chars out.
+ *
+ * Returns the number of byte written, or -1 by lack of space, or -2
+ * if the transcoding failed.
+ *
+ * TODO: need a fallback mechanism ...
+ */
+int UTF8ToUTF16(unsigned short* out, int outlen, unsigned char* in, int inlen)
+{
+ unsigned short* outstart= out;
+ unsigned short* outend= out+outlen;
+ unsigned char* inend= in+inlen;
+ unsigned int c, d, trailing;
+
+ while (in < inend) {
+ d= *in++;
+ if (d < 0x80) { c= d; trailing= 0; }
+ else if (d < 0xC0) return -2; /* trailing byte in leading position */
+ else if (d < 0xE0) { c= d & 0x1F; trailing= 1; }
+ else if (d < 0xF0) { c= d & 0x0F; trailing= 2; }
+ else if (d < 0xF8) { c= d & 0x07; trailing= 3; }
+ else return -2; /* no chance for this in UTF-16 */
+
+ for ( ; trailing; trailing--) {
+ if ((in >= inend) || (((d= *in++) & 0xC0) != 0x80)) return -1;
+ c <<= 6;
+ c |= d & 0x3F;
+ }
+
+ /* assertion: c is a single UTF-4 value */
+ if (c < 0x10000) {
+ if (out >= outend) return -1;
+ *out++ = c;
+ }
+ else if (c < 0x110000) {
+ if (out+1 >= outend) return -1;
+ c -= 0x10000;
+ *out++ = 0xD800 | (c >> 10);
+ *out++ = 0xDC00 | (c & 0x03FF);
+ }
+ else return -1;
+ }
+ return out-outstart;
+}
+