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-rw-r--r--src/common/utf8.c235
1 files changed, 235 insertions, 0 deletions
diff --git a/src/common/utf8.c b/src/common/utf8.c
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--- /dev/null
+++ b/src/common/utf8.c
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+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+/*
+ * Ceph - scalable distributed file system
+ *
+ * Copyright (C) 2011 New Dream Network
+ *
+ * This is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License version 2.1, as published by the Free Software
+ * Foundation. See file COPYING.
+ *
+ */
+#include "common/utf8.h"
+
+#include <string.h>
+
+/*
+ * http://www.unicode.org/versions/Unicode6.0.0/ch03.pdf - page 94
+ *
+ * Table 3-7. Well-Formed UTF-8 Byte Sequences
+ *
+ * +--------------------+------------+-------------+------------+-------------+
+ * | Code Points | First Byte | Second Byte | Third Byte | Fourth Byte |
+ * +--------------------+------------+-------------+------------+-------------+
+ * | U+0000..U+007F | 00..7F | | | |
+ * +--------------------+------------+-------------+------------+-------------+
+ * | U+0080..U+07FF | C2..DF | 80..BF | | |
+ * +--------------------+------------+-------------+------------+-------------+
+ * | U+0800..U+0FFF | E0 | A0..BF | 80..BF | |
+ * +--------------------+------------+-------------+------------+-------------+
+ * | U+1000..U+CFFF | E1..EC | 80..BF | 80..BF | |
+ * +--------------------+------------+-------------+------------+-------------+
+ * | U+D000..U+D7FF | ED | 80..9F | 80..BF | |
+ * +--------------------+------------+-------------+------------+-------------+
+ * | U+E000..U+FFFF | EE..EF | 80..BF | 80..BF | |
+ * +--------------------+------------+-------------+------------+-------------+
+ * | U+10000..U+3FFFF | F0 | 90..BF | 80..BF | 80..BF |
+ * +--------------------+------------+-------------+------------+-------------+
+ * | U+40000..U+FFFFF | F1..F3 | 80..BF | 80..BF | 80..BF |
+ * +--------------------+------------+-------------+------------+-------------+
+ * | U+100000..U+10FFFF | F4 | 80..8F | 80..BF | 80..BF |
+ * +--------------------+------------+-------------+------------+-------------+
+ */
+
+static int high_bits_set(int c)
+{
+ int ret = 0;
+ while (1) {
+ if ((c & 0x80) != 0x080)
+ break;
+ c <<= 1;
+ ++ret;
+ }
+ return ret;
+}
+
+/* Encode a 31-bit UTF8 code point to 'buf'.
+ * Assumes buf is of size MAX_UTF8_SZ
+ * Returns -1 on failure; number of bytes in the encoded value otherwise.
+ */
+int encode_utf8(unsigned long u, unsigned char *buf)
+{
+ /* Unroll loop for common code points */
+ if (u <= 0x0000007F) {
+ buf[0] = u;
+ return 1;
+ } else if (u <= 0x000007FF) {
+ buf[0] = 0xC0 | (u >> 6);
+ buf[1] = 0x80 | (u & 0x3F);
+ return 2;
+ } else if (u <= 0x0000FFFF) {
+ buf[0] = 0xE0 | (u >> 12);
+ buf[1] = 0x80 | ((u >> 6) & 0x3F);
+ buf[2] = 0x80 | (u & 0x3F);
+ return 3;
+ } else if (u <= 0x001FFFFF) {
+ buf[0] = 0xF0 | (u >> 18);
+ buf[1] = 0x80 | ((u >> 12) & 0x3F);
+ buf[2] = 0x80 | ((u >> 6) & 0x3F);
+ buf[3] = 0x80 | (u & 0x3F);
+ return 4;
+ } else {
+ /* Rare/illegal code points */
+ if (u <= 0x03FFFFFF) {
+ for (int i = 4; i >= 1; --i) {
+ buf[i] = 0x80 | (u & 0x3F);
+ u >>= 6;
+ }
+ buf[0] = 0xF8 | u;
+ return 5;
+ } else if (u <= 0x7FFFFFFF) {
+ for (int i = 5; i >= 1; --i) {
+ buf[i] = 0x80 | (u & 0x3F);
+ u >>= 6;
+ }
+ buf[0] = 0xFC | u;
+ return 6;
+ }
+ return -1;
+ }
+}
+
+/*
+ * Decode a UTF8 character from an array of bytes. Return character code.
+ * Upon error, return INVALID_UTF8_CHAR.
+ */
+unsigned long decode_utf8(unsigned char *buf, int nbytes)
+{
+ unsigned long code;
+ int i, j;
+
+ if (nbytes <= 0)
+ return INVALID_UTF8_CHAR;
+
+ if (nbytes == 1) {
+ if (buf[0] >= 0x80)
+ return INVALID_UTF8_CHAR;
+ return buf[0];
+ }
+
+ i = high_bits_set(buf[0]);
+ if (i != nbytes)
+ return INVALID_UTF8_CHAR;
+ code = buf[0] & (0xff >> i);
+ for (j = 1; j < nbytes; ++j) {
+ if ((buf[j] & 0xc0) != 0x80)
+ return INVALID_UTF8_CHAR;
+ code = (code << 6) | (buf[j] & 0x3f);
+ }
+
+ // Check for invalid code points
+ if (code == 0xFFFE)
+ return INVALID_UTF8_CHAR;
+ if (code == 0xFFFF)
+ return INVALID_UTF8_CHAR;
+ if (code >= 0xD800 && code <= 0xDFFF)
+ return INVALID_UTF8_CHAR;
+
+ return code;
+}
+
+int check_utf8(const char *buf, int len)
+{
+ /*
+ * "char" is "signed" on x86 but "unsigned" on aarch64 by default.
+ * Below code depends on signed/unsigned comparisons, define an
+ * unsigned buffer explicitly to fix the gap.
+ */
+ const unsigned char *bufu = (const unsigned char *)buf;
+ int err_pos = 1;
+
+ while (len) {
+ int nbytes;
+ unsigned char byte1 = bufu[0];
+
+ /* 00..7F */
+ if (byte1 <= 0x7F) {
+ nbytes = 1;
+ /* C2..DF, 80..BF */
+ } else if (len >= 2 && byte1 >= 0xC2 && byte1 <= 0xDF &&
+ (signed char)bufu[1] <= (signed char)0xBF) {
+ nbytes = 2;
+ } else if (len >= 3) {
+ unsigned char byte2 = bufu[1];
+
+ /* Is byte2, byte3 between 0x80 ~ 0xBF */
+ int byte2_ok = (signed char)byte2 <= (signed char)0xBF;
+ int byte3_ok = (signed char)bufu[2] <= (signed char)0xBF;
+
+ if (byte2_ok && byte3_ok &&
+ /* E0, A0..BF, 80..BF */
+ ((byte1 == 0xE0 && byte2 >= 0xA0) ||
+ /* E1..EC, 80..BF, 80..BF */
+ (byte1 >= 0xE1 && byte1 <= 0xEC) ||
+ /* ED, 80..9F, 80..BF */
+ (byte1 == 0xED && byte2 <= 0x9F) ||
+ /* EE..EF, 80..BF, 80..BF */
+ (byte1 >= 0xEE && byte1 <= 0xEF))) {
+ nbytes = 3;
+ } else if (len >= 4) {
+ /* Is byte4 between 0x80 ~ 0xBF */
+ int byte4_ok = (signed char)bufu[3] <= (signed char)0xBF;
+
+ if (byte2_ok && byte3_ok && byte4_ok &&
+ /* F0, 90..BF, 80..BF, 80..BF */
+ ((byte1 == 0xF0 && byte2 >= 0x90) ||
+ /* F1..F3, 80..BF, 80..BF, 80..BF */
+ (byte1 >= 0xF1 && byte1 <= 0xF3) ||
+ /* F4, 80..8F, 80..BF, 80..BF */
+ (byte1 == 0xF4 && byte2 <= 0x8F))) {
+ nbytes = 4;
+ } else {
+ return err_pos;
+ }
+ } else {
+ return err_pos;
+ }
+ } else {
+ return err_pos;
+ }
+
+ len -= nbytes;
+ err_pos += nbytes;
+ bufu += nbytes;
+ }
+
+ return 0;
+}
+
+int check_utf8_cstr(const char *buf)
+{
+ return check_utf8(buf, strlen(buf));
+}
+
+int is_control_character(int c)
+{
+ return (((c != 0) && (c < 0x20)) || (c == 0x7f));
+}
+
+int check_for_control_characters(const char *buf, int len)
+{
+ int i;
+ for (i = 0; i < len; ++i) {
+ if (is_control_character((int)(unsigned char)buf[i])) {
+ return i + 1;
+ }
+ }
+ return 0;
+}
+
+int check_for_control_characters_cstr(const char *buf)
+{
+ return check_for_control_characters(buf, strlen(buf));
+}
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