fmt: added utf8 encode/decode functions

include/re_fmt.h

@@ -139,3 +139,8 @@ typedef void (fmt_param_h)(const struct pl *name, const struct pl *val,
 bool fmt_param_exists(const struct pl *pl, const char *pname);
 bool fmt_param_get(const struct pl *pl, const char *pname, struct pl *val);
 void fmt_param_apply(const struct pl *pl, fmt_param_h *ph, void *arg);
+
+
+/* unicode */
+int utf8_encode(struct re_printf *pf, const char *str);
+int utf8_decode(struct re_printf *pf, const struct pl *pl);

src/fmt/mod.mk

@@ -13,3 +13,4 @@ SRCS	+= fmt/regex.c
 SRCS	+= fmt/str.c
 SRCS	+= fmt/str_error.c
 SRCS	+= fmt/time.c
+SRCS	+= fmt/unicode.c

src/fmt/unicode.c

@@ -0,0 +1,168 @@
+/**
+ * @file utf8.c  Unicode character coding
+ *
+ * Copyright (C) 2010 Creytiv.com
+ */
+#include <ctype.h>
+#include <re_types.h>
+#include <re_fmt.h>
+
+
+static const char *hex_chars = "0123456789ABCDEF";
+
+
+/**
+ * UTF-8 encode
+ *
+ * @param pf  Print function for output
+ * @param str Input string to encode
+ *
+ * @return 0 if success, otherwise errorcode
+ */
+int utf8_encode(struct re_printf *pf, const char *str)
+{
+	char ubuf[6] = "\\u00", ebuf[2] = "\\";
+
+	if (!pf)
+		return EINVAL;
+
+	if (!str)
+		return 0;
+
+	while (*str) {
+		const uint8_t c = *str++;  /* NOTE: must be unsigned 8-bit */
+		bool unicode = false;
+		char ec = 0;
+		int err;
+
+		switch (c) {
+
+		case '"':  ec = '"'; break;
+		case '\\': ec = '\\'; break;
+		case '/':  ec = '/'; break;
+		case '\b': ec = 'b'; break;
+		case '\f': ec = 'f'; break;
+		case '\n': ec = 'n'; break;
+		case '\r': ec = 'r'; break;
+		case '\t': ec = 't'; break;
+		default:
+			if (c < ' ') {
+				unicode = true;
+			}
+			/* chars in range 0x80-0xff are not escaped */
+			break;
+		}
+
+		if (unicode) {
+			ubuf[4] = hex_chars[(c>>4) & 0xf];
+			ubuf[5] = hex_chars[c & 0xf];
+
+			err = pf->vph(ubuf, sizeof(ubuf), pf->arg);
+		}
+		else if (ec) {
+			ebuf[1] = ec;
+
+			err = pf->vph(ebuf, sizeof(ebuf), pf->arg);
+		}
+		else {
+			err = pf->vph((char *)&c, 1, pf->arg);
+		}
+
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+
+/**
+ * UTF-8 decode
+ *
+ * @param pf Print function for output
+ * @param pl Input buffer to decode
+ *
+ * @return 0 if success, otherwise errorcode
+ */
+int utf8_decode(struct re_printf *pf, const struct pl *pl)
+{
+	size_t i;
+
+	if (!pf)
+		return EINVAL;
+
+	if (!pl)
+		return 0;
+
+	for (i=0; i<pl->l; i++) {
+
+		char ch = pl->p[i];
+		int err;
+
+		if (ch == '\\') {
+
+			uint16_t u = 0;
+
+			++i;
+
+			if (i >= pl->l)
+				return EBADMSG;
+
+			ch = pl->p[i];
+
+			switch (ch) {
+
+			case 'b':
+				ch = '\b';
+				break;
+
+			case 'f':
+				ch = '\f';
+				break;
+
+			case 'n':
+				ch = '\n';
+				break;
+
+			case 'r':
+				ch = '\r';
+				break;
+
+			case 't':
+				ch = '\t';
+				break;
+
+			case 'u':
+				if (i+4 >= pl->l)
+					return EBADMSG;
+
+				if (!isxdigit(pl->p[i+1]) ||
+				    !isxdigit(pl->p[i+2]) ||
+				    !isxdigit(pl->p[i+3]) ||
+				    !isxdigit(pl->p[i+4]))
+					return EBADMSG;
+
+				u |= ((uint16_t)ch_hex(pl->p[++i])) << 12;
+				u |= ((uint16_t)ch_hex(pl->p[++i])) << 8;
+				u |= ((uint16_t)ch_hex(pl->p[++i])) << 4;
+				u |= ((uint16_t)ch_hex(pl->p[++i])) << 0;
+
+				if (u > 255) {
+					ch  = u>>8;
+					err = pf->vph(&ch, 1, pf->arg);
+					if (err)
+						return err;
+				}
+
+				ch = u & 0xff;
+				break;
+			}
+		}
+
+		err = pf->vph(&ch, 1, pf->arg);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}