/* * Copyright (c) 2001-2004 Jakub Jermar * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * - Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * - Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * - The name of the author may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ /** @addtogroup generic * @{ */ /** * @file * @brief Miscellaneous functions. */ #include #include #include #include #include #include char invalch = '?'; /** Byte mask consisting of lowest @n bits (out of eight). */ #define LO_MASK_8(n) ((uint8_t)((1 << (n)) - 1)) /** Byte mask consisting of lowest @n bits (out of 32). */ #define LO_MASK_32(n) ((uint32_t)((1 << (n)) - 1)) /** Byte mask consisting of highest @n bits (out of eight). */ #define HI_MASK_8(n) (~LO_MASK_8(8 - (n))) /** Number of data bits in a UTF-8 continuation byte. */ #define CONT_BITS 6 /** Decode a single UTF-8 character from a NULL-terminated string. * * Decode a single UTF-8 character from a plain char NULL-terminated * string. Decoding starts at @index and this index is moved to the * beginning of the next character. In case of decoding error, * index advances. However, index is never moved beyond (str+limit). * * @param str Plain character NULL-terminated string. * @param index Index (counted in plain characters) where to start * the decoding. * @param limit Maximal allowed value of index. * * @return Decoded character in UTF-32 or '?' if the encoding is wrong. * */ wchar_t utf8_decode(const char *str, index_t *index, index_t limit) { uint8_t b0, b; /* Bytes read from str. */ wchar_t ch; int b0_bits; /* Data bits in first byte. */ int cbytes; /* Number of continuation bytes. */ if (*index + 1 > limit) return invalch; b0 = (uint8_t) str[(*index)++]; /* Determine code length. */ if ((b0 & 0x80) == 0) { /* 0xxxxxxx (Plain ASCII) */ b0_bits = 7; cbytes = 0; } else if ((b0 & 0xe0) == 0xc0) { /* 110xxxxx 10xxxxxx */ b0_bits = 5; cbytes = 1; } else if ((b0 & 0xf0) == 0xe0) { /* 1110xxxx 10xxxxxx 10xxxxxx */ b0_bits = 4; cbytes = 2; } else if ((b0 & 0xf8) == 0xf0) { /* 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx */ b0_bits = 3; cbytes = 3; } else { /* 10xxxxxx -- unexpected continuation byte. */ return invalch; } if (*index + cbytes > limit) { return invalch; } ch = b0 & LO_MASK_8(b0_bits); /* Decode continuation bytes. */ while (cbytes > 0) { b = (uint8_t) str[(*index)++]; /* Must be 10xxxxxx. */ if ((b & 0xc0) != 0x80) { return invalch; } /* Shift data bits to ch. */ ch = (ch << CONT_BITS) | (wchar_t) (b & LO_MASK_8(CONT_BITS)); --cbytes; } return ch; } /** Encode a single UTF-32 character as UTF-8 * * Encode a single UTF-32 character as UTF-8 and store it into * the given buffer at @index. Encoding starts at @index and * this index is moved at the position where the next character * can be written to. * * @param ch Input UTF-32 character. * @param str Output buffer. * @param index Index (counted in plain characters) where to start * the encoding * @param limit Maximal allowed value of index. * * @return True if the character was encoded or false if there is not * enought space in the output buffer or the character is invalid * Unicode code point. * */ bool utf8_encode(const wchar_t ch, char *str, index_t *index, index_t limit) { uint32_t cc; /* Unsigned version of ch. */ int cbytes; /* Number of continuation bytes. */ int b0_bits; /* Number of data bits in first byte. */ int i; if (*index >= limit) return false; if (ch < 0) return false; /* Bit operations should only be done on unsigned numbers. */ cc = (uint32_t) ch; /* Determine how many continuation bytes are needed. */ if ((cc & ~LO_MASK_32(7)) == 0) { b0_bits = 7; cbytes = 0; } else if ((cc & ~LO_MASK_32(11)) == 0) { b0_bits = 5; cbytes = 1; } else if ((cc & ~LO_MASK_32(16)) == 0) { b0_bits = 4; cbytes = 2; } else if ((cc & ~LO_MASK_32(21)) == 0) { b0_bits = 3; cbytes = 3; } else { /* Codes longer than 21 bits are not supported. */ return false; } /* Check for available space in buffer. */ if (*index + cbytes >= limit) return false; /* Encode continuation bytes. */ for (i = cbytes; i > 0; --i) { str[*index + i] = 0x80 | (cc & LO_MASK_32(CONT_BITS)); cc = cc >> CONT_BITS; } /* Encode first byte. */ str[*index] = (cc & LO_MASK_32(b0_bits)) | HI_MASK_8(8 - b0_bits - 1); /* Advance index. */ *index += (1 + cbytes); return true; } /** Get bytes used by UTF-8 characters. * * Get the number of bytes (count of plain characters) which * are used by a given count of UTF-8 characters in a string. * As UTF-8 encoding is multibyte, there is no constant * correspondence between number of characters and used bytes. * * @param str UTF-8 string to consider. * @param count Number of UTF-8 characters to count. * * @return Number of bytes used by the characters. * */ size_t utf8_count_bytes(const char *str, count_t count) { size_t size = 0; index_t index = 0; index_t iprev; wchar_t ch; while (true) { iprev = index; if (size >= count) break; ch = utf8_decode(str, &index, UTF8_NO_LIMIT); if (ch == '\0') break; size++; } return iprev; } /** Check whether character is plain ASCII. * * @return True if character is plain ASCII. * */ bool ascii_check(const wchar_t ch) { if ((ch >= 0) && (ch <= 127)) return true; return false; } /** Check whether character is Unicode. * * @return True if character is valid Unicode code point. * */ bool unicode_check(const wchar_t ch) { if ((ch >= 0) && (ch <= 1114111)) return true; return false; } /** Return number of plain characters in a string. * * @param str NULL-terminated string. * * @return Number of characters in str. * */ size_t strlen(const char *str) { size_t size; for (size = 0; str[size]; size++); return size; } /** Return number of UTF-8 characters in a string. * * @param str NULL-terminated UTF-8 string. * * @return Number of UTF-8 characters in str. * */ size_t strlen_utf8(const char *str) { size_t size = 0; index_t index = 0; while (utf8_decode(str, &index, UTF8_NO_LIMIT) != 0) { size++; } return size; } /** Return number of UTF-32 characters in a string. * * @param str NULL-terminated UTF-32 string. * * @return Number of UTF-32 characters in str. * */ size_t strlen_utf32(const wchar_t *str) { size_t size; for (size = 0; str[size]; size++); return size; } /** Compare two NULL terminated strings * * Do a char-by-char comparison of two NULL terminated strings. * The strings are considered equal iff they consist of the same * characters on the minimum of their lengths. * * @param src First string to compare. * @param dst Second string to compare. * * @return 0 if the strings are equal, -1 if first is smaller, 1 if second smaller. * */ int strcmp(const char *src, const char *dst) { for (; *src && *dst; src++, dst++) { if (*src < *dst) return -1; if (*src > *dst) return 1; } if (*src == *dst) return 0; if (!*src) return -1; return 1; } /** Compare two NULL terminated strings * * Do a char-by-char comparison of two NULL terminated strings. * The strings are considered equal iff they consist of the same * characters on the minimum of their lengths and specified maximal * length. * * @param src First string to compare. * @param dst Second string to compare. * @param len Maximal length for comparison. * * @return 0 if the strings are equal, -1 if first is smaller, 1 if second smaller. * */ int strncmp(const char *src, const char *dst, size_t len) { unsigned int i; for (i = 0; (*src) && (*dst) && (i < len); src++, dst++, i++) { if (*src < *dst) return -1; if (*src > *dst) return 1; } if (i == len || *src == *dst) return 0; if (!*src) return -1; return 1; } /** Copy NULL terminated string. * * Copy at most 'len' characters from string 'src' to 'dest'. * If 'src' is shorter than 'len', '\0' is inserted behind the * last copied character. * * @param src Source string. * @param dest Destination buffer. * @param len Size of destination buffer. * */ void strncpy(char *dest, const char *src, size_t len) { unsigned int i; for (i = 0; i < len; i++) { if (!(dest[i] = src[i])) return; } dest[i - 1] = '\0'; } /** Find first occurence of character in string. * * @param s String to search. * @param i Character to look for. * * @return Pointer to character in @a s or NULL if not found. */ extern char *strchr(const char *s, int i) { while (*s != '\0') { if (*s == i) return (char *) s; ++s; } return NULL; } /** @} */