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-rw-r--r--src/utils/utf16.c239
1 files changed, 239 insertions, 0 deletions
diff --git a/src/utils/utf16.c b/src/utils/utf16.c
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+++ b/src/utils/utf16.c
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+/*
+ * This file is part of Hubbub.
+ * Licensed under the MIT License,
+ * http://www.opensource.org/licenses/mit-license.php
+ * Copyright 2007 John-Mark Bell <jmb@netsurf-browser.org>
+ */
+
+/** \file
+ * UTF-16 manipulation functions (implementation).
+ */
+
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "utils/utf16.h"
+
+/**
+ * Convert a UTF-16 sequence into a single UCS4 character
+ *
+ * \param s The sequence to process
+ * \param len Length of sequence
+ * \param ucs4 Pointer to location to receive UCS4 character (host endian)
+ * \param clen Pointer to location to receive byte length of UTF-16 sequence
+ * \return CHARSET_OK on success, appropriate error otherwise
+ */
+inline charset_error _dom_utf16_to_ucs4(const uint8_t *s, size_t len,
+ uint32_t *ucs4, size_t *clen)
+{
+ const uint16_t *ss = (const uint16_t *) (const void *) s;
+
+ if (s == NULL || ucs4 == NULL || clen == NULL)
+ return CHARSET_BADPARM;
+
+ if (len < 2)
+ return CHARSET_NEEDDATA;
+
+ if (*ss < 0xD800 || *ss > 0xDFFF) {
+ *ucs4 = *ss;
+ *clen = 2;
+ } else if (0xD800 <= *ss && *ss <= 0xBFFF) {
+ if (len < 4)
+ return CHARSET_NEEDDATA;
+
+ if (0xDC00 <= ss[1] && ss[1] <= 0xE000) {
+ *ucs4 = (((s[0] >> 6) & 0x1f) + 1) |
+ ((s[0] & 0x3f) | (s[1] & 0x3ff));
+ *clen = 4;
+ } else {
+ return CHARSET_INVALID;
+ }
+ }
+
+ return CHARSET_OK;
+}
+
+/**
+ * Convert a single UCS4 character into a UTF-16 sequence
+ *
+ * \param ucs4 The character to process (0 <= c <= 0x7FFFFFFF) (host endian)
+ * \param s Pointer to 4 byte long output buffer
+ * \param len Pointer to location to receive length of multibyte sequence
+ * \return CHARSET_OK on success, appropriate error otherwise
+ */
+inline charset_error _dom_utf16_from_ucs4(uint32_t ucs4, uint8_t *s,
+ size_t *len)
+{
+ uint16_t *ss = (uint16_t *) (void *) s;
+ uint32_t l = 0;
+
+ if (s == NULL || len == NULL)
+ return CHARSET_BADPARM;
+ else if (ucs4 < 0x10000) {
+ *ss = (uint16_t) ucs4;
+ l = 2;
+ } else if (ucs4 < 0x110000) {
+ ss[0] = 0xD800 | (((ucs4 >> 16) & 0x1f) - 1) | (ucs4 >> 10);
+ ss[1] = 0xDC00 | (ucs4 & 0x3ff);
+ l = 4;
+ } else {
+ return CHARSET_INVALID;
+ }
+
+ *len = l;
+
+ return CHARSET_OK;
+}
+
+/**
+ * Calculate the length (in characters) of a bounded UTF-16 string
+ *
+ * \param s The string
+ * \param max Maximum length
+ * \param len Pointer to location to receive length of string
+ * \return CHARSET_OK on success, appropriate error otherwise
+ */
+inline charset_error _dom_utf16_length(const uint8_t *s, size_t max,
+ size_t *len)
+{
+ const uint16_t *ss = (const uint16_t *) (const void *) s;
+ const uint16_t *end = (const uint16_t *) (const void *) (s + max);
+ int l = 0;
+
+ if (s == NULL || len == NULL)
+ return CHARSET_BADPARM;
+
+ while (ss < end) {
+ if (*ss < 0xD800 || 0xDFFF < *ss)
+ ss++;
+ else
+ ss += 2;
+
+ l++;
+ }
+
+ *len = l;
+
+ return CHARSET_OK;
+}
+
+/**
+ * Calculate the length (in bytes) of a UTF-16 character
+ *
+ * \param s Pointer to start of character
+ * \param len Pointer to location to receive length
+ * \return CHARSET_OK on success, appropriate error otherwise
+ */
+inline charset_error _dom_utf16_char_byte_length(const uint8_t *s,
+ size_t *len)
+{
+ const uint16_t *ss = (const uint16_t *) (const void *) s;
+
+ if (s == NULL || len == NULL)
+ return CHARSET_BADPARM;
+
+ if (*ss < 0xD800 || 0xDFFF < *ss)
+ *len = 2;
+ else
+ *len = 4;
+
+ return CHARSET_OK;
+}
+
+/**
+ * Find previous legal UTF-16 char in string
+ *
+ * \param s The string
+ * \param off Offset in the string to start at
+ * \param prevoff Pointer to location to receive offset of first byte of
+ * previous legal character
+ * \return CHARSET_OK on success, appropriate error otherwise
+ */
+inline charset_error _dom_utf16_prev(const uint8_t *s, uint32_t off,
+ uint32_t *prevoff)
+{
+ const uint16_t *ss = (const uint16_t *) (const void *) s;
+
+ if (s == NULL || prevoff == NULL)
+ return CHARSET_BADPARM;
+
+ if (off < 2)
+ *prevoff = 0;
+ else if (ss[-1] < 0xDC00 || ss[-1] > 0xDFFF)
+ *prevoff = off - 2;
+ else
+ *prevoff = (off < 4) ? 0 : off - 4;
+
+ return CHARSET_OK;
+}
+
+/**
+ * Find next legal UTF-16 char in string
+ *
+ * \param s The string (assumed valid)
+ * \param len Maximum offset in string
+ * \param off Offset in the string to start at
+ * \param nextoff Pointer to location to receive offset of first byte of
+ * next legal character
+ * \return CHARSET_OK on success, appropriate error otherwise
+ */
+inline charset_error _dom_utf16_next(const uint8_t *s, uint32_t len,
+ uint32_t off, uint32_t *nextoff)
+{
+ const uint16_t *ss = (const uint16_t *) (const void *) s;
+
+ if (s == NULL || off >= len || nextoff == NULL)
+ return CHARSET_BADPARM;
+
+ if (len - off < 4)
+ *nextoff = len;
+ else if (ss[1] < 0xD800 || ss[1] > 0xDBFF)
+ *nextoff = off + 2;
+ else
+ *nextoff = (len - off < 6) ? len : off + 4;
+
+ return CHARSET_OK;
+}
+
+/**
+ * Find next legal UTF-16 char in string
+ *
+ * \param s The string (assumed to be of dubious validity)
+ * \param len Maximum offset in string
+ * \param off Offset in the string to start at
+ * \param nextoff Pointer to location to receive offset of first byte of
+ * next legal character
+ * \return CHARSET_OK on success, appropriate error otherwise
+ */
+inline charset_error _dom_utf16_next_paranoid(const uint8_t *s,
+ uint32_t len, uint32_t off, uint32_t *nextoff)
+{
+ const uint16_t *ss = (const uint16_t *) (const void *) s;
+
+ if (s == NULL || off >= len || nextoff == NULL)
+ return CHARSET_BADPARM;
+
+ while (1) {
+ if (len - off < 4) {
+ return CHARSET_NEEDDATA;
+ } else if (ss[1] < 0xD800 || ss[1] > 0xDFFF) {
+ *nextoff = off + 2;
+ break;
+ } else if (ss[1] >= 0xD800 && ss[1] <= 0xDBFF) {
+ if (len - off < 6)
+ return CHARSET_NEEDDATA;
+
+ if (ss[2] >= 0xDC00 && ss[2] <= 0xDFFF) {
+ *nextoff = off + 4;
+ break;
+ } else {
+ ss++;
+ off += 2;
+ }
+ }
+ }
+
+ return CHARSET_OK;
+}
+