WebSVN – HelenOS – Diff – /trunk/uspace/lib/libc/generic/string.c

 /*
  * Copyright (c) 2005 Martin Decky
  * Copyright (c) 2008 Jiri Svoboda
  * 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 libc
  * @{
  */
 /** @file
  */
 #include <string.h>
 #include <stdlib.h>
 #include <limits.h>
 #include <ctype.h>
 #include <malloc.h>
+#include <errno.h>
+#include <string.h>
+/** Byte mask consisting of lowest @n bits (out of 8) */
+#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 8) */
+#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 character from a string.
+ *
+ * Decode a single character from a string of size @a size. Decoding starts
+ * at @a offset and this offset is moved to the beginning of the next
+ * character. In case of decoding error, offset generally advances at least
+ * by one. However, offset is never moved beyond size.
+ *
+ * @param str    String (not necessarily NULL-terminated).
+ * @param offset Byte offset in string where to start decoding.
+ * @param size   Size of the string (in bytes).
+ *
+ * @return Value of decoded character, U_SPECIAL on decoding error or
+ *         NULL if attempt to decode beyond @a size.
+ *
+ */
+wchar_t str_decode(const char *str, size_t *offset, size_t size)
+{
+    if (*offset + 1 > size)
+        return 0;
+    /* First byte read from string */
+    uint8_t b0 = (uint8_t) str[(*offset)++];
+    /* Determine code length */
+    unsigned int b0_bits;  /* Data bits in first byte */
+    unsigned int cbytes;   /* Number of continuation bytes */
+    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 U_SPECIAL;
+    }
+    if (*offset + cbytes > size)
+        return U_SPECIAL;
+    wchar_t ch = b0 & LO_MASK_8(b0_bits);
+    /* Decode continuation bytes */
+    while (cbytes > 0) {
+        uint8_t b = (uint8_t) str[(*offset)++];
+        /* Must be 10xxxxxx */
+        if ((b & 0xc0) != 0x80)
+            return U_SPECIAL;
+        /* Shift data bits to ch */
+        ch = (ch << CONT_BITS) | (wchar_t) (b & LO_MASK_8(CONT_BITS));
+        cbytes--;
+    }
+    return ch;
+}
+/** Encode a single character to string representation.
+ *
+ * Encode a single character to string representation (i.e. UTF-8) and store
+ * it into a buffer at @a offset. Encoding starts at @a offset and this offset
+ * is moved to the position where the next character can be written to.
+ *
+ * @param ch     Input character.
+ * @param str    Output buffer.
+ * @param offset Byte offset where to start writing.
+ * @param size   Size of the output buffer (in bytes).
+ *
+ * @return EOK if the character was encoded successfully, EOVERFLOW if there
+ *     was not enough space in the output buffer or EINVAL if the character
+ *     code was invalid.
+ */
+int chr_encode(const wchar_t ch, char *str, size_t *offset, size_t size)
+{
+    if (*offset >= size)
+        return EOVERFLOW;
+    if (!chr_check(ch))
+        return EINVAL;
+    /* Unsigned version of ch (bit operations should only be done
+       on unsigned types). */
+    uint32_t cc = (uint32_t) ch;
+    /* Determine how many continuation bytes are needed */
+    unsigned int b0_bits;  /* Data bits in first byte */
+    unsigned int cbytes;   /* Number of continuation bytes */
+    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 EINVAL;
+    }
+    /* Check for available space in buffer */
+    if (*offset + cbytes >= size)
+        return EOVERFLOW;
+    /* Encode continuation bytes */
+    unsigned int i;
+    for (i = cbytes; i > 0; i--) {
+        str[*offset + i] = 0x80 | (cc & LO_MASK_32(CONT_BITS));
+        cc = cc >> CONT_BITS;
+    }
+    /* Encode first byte */
+    str[*offset] = (cc & LO_MASK_32(b0_bits)) | HI_MASK_8(8 - b0_bits - 1);
+    /* Advance offset */
+    *offset += cbytes + 1;
+    return EOK;
+}
+/** Check whether character is valid
+ *
+ * @return True if character is a valid Unicode code point.
+ *
+ */
+bool chr_check(const wchar_t ch)
+{
+    if ((ch >= 0) && (ch <= 1114111))
+        return true;
+    return false;
+}
 /** Count the number of characters in the string, not including terminating 0.
+ *
  * @param str       String.
  * @return      Number of characters in string.
  */
 size_t strlen(const char *str)
+{
     size_t counter = 0;
     while (str[counter] != 0)
         counter++;
     return counter;
+}
 int strcmp(const char *a, const char *b)
+{
     int c = 0;
     while (a[c] && b[c] && (!(a[c] - b[c])))
         c++;
     return (a[c] - b[c]);
+}
 int strncmp(const char *a, const char *b, size_t n)
+{
     size_t c = 0;
     while (c < n && a[c] && b[c] && (!(a[c] - b[c])))
         c++;
     return ( c < n ? a[c] - b[c] : 0);
+}
 int stricmp(const char *a, const char *b)
+{
     int c = 0;
     while (a[c] && b[c] && (!(tolower(a[c]) - tolower(b[c]))))
         c++;
     return (tolower(a[c]) - tolower(b[c]));
+}
 /** Return pointer to the first occurence of character c in string.
+ *
  * @param str       Scanned string.
  * @param c     Searched character (taken as one byte).
  * @return      Pointer to the matched character or NULL if it is not
  *          found in given string.
  */
 char *strchr(const char *str, int c)
+{
     while (*str != '\0') {
         if (*str == (char) c)
             return (char *) str;
         str++;
+    }
     return NULL;
+}
 /** Return pointer to the last occurence of character c in string.
+ *
  * @param str       Scanned string.
  * @param c     Searched character (taken as one byte).
  * @return      Pointer to the matched character or NULL if it is not
  *          found in given string.
  */
 char *strrchr(const char *str, int c)
+{
     char *retval = NULL;
     while (*str != '\0') {
         if (*str == (char) c)
             retval = (char *) str;
         str++;
+    }
     return (char *) retval;
+}
 /** Convert string to a number.
  * Core of strtol and strtoul functions.
+ *
  * @param nptr      Pointer to string.
  * @param endptr    If not NULL, function stores here pointer to the first
  *          invalid character.
  * @param base      Zero or number between 2 and 36 inclusive.
  * @param sgn       It's set to 1 if minus found.
  * @return      Result of conversion.
  */
 static unsigned long
 _strtoul(const char *nptr, char **endptr, int base, char *sgn)
+{
     unsigned char c;
     unsigned long result = 0;
     unsigned long a, b;
     const char *str = nptr;
     const char *tmpptr;
     while (isspace(*str))
         str++;
     if (*str == '-') {
         *sgn = 1;
         ++str;
     } else if (*str == '+')
         ++str;
     if (base) {
         if ((base == 1) || (base > 36)) {
             /* FIXME: set errno to EINVAL */
             return 0;
+        }
         if ((base == 16) && (*str == '0') && ((str[1] == 'x') ||
             (str[1] == 'X'))) {
             str += 2;
+        }
     } else {
         base = 10;
         if (*str == '0') {
             base = 8;
             if ((str[1] == 'X') || (str[1] == 'x'))  {
                 base = 16;
                 str += 2;
+            }
+        }
+    }
     tmpptr = str;
     while (*str) {
         c = *str;
         c = (c >= 'a' ? c - 'a' + 10 : (c >= 'A' ? c - 'A' + 10 :
             (c <= '9' ? c - '0' : 0xff)));
         if (c > base) {
             break;
+        }
         a = (result & 0xff) * base + c;
         b = (result >> 8) * base + (a >> 8);
         if (b > (ULONG_MAX >> 8)) {
             /* overflow */
             /* FIXME: errno = ERANGE*/
             return ULONG_MAX;
+        }
         result = (b << 8) + (a & 0xff);
         ++str;
+    }
     if (str == tmpptr) {
         /*
          * No number was found => first invalid character is the first
          * character of the string.
          */
         /* FIXME: set errno to EINVAL */
         str = nptr;
         result = 0;
+    }
     if (endptr)
         *endptr = (char *) str;
     if (nptr == str) {
         /*FIXME: errno = EINVAL*/
         return 0;
+    }
     return result;
+}
 /** Convert initial part of string to long int according to given base.
  * The number may begin with an arbitrary number of whitespaces followed by
  * optional sign (`+' or `-'). If the base is 0 or 16, the prefix `0x' may be
  * inserted and the number will be taken as hexadecimal one. If the base is 0
  * and the number begin with a zero, number will be taken as octal one (as with
  * base 8). Otherwise the base 0 is taken as decimal.
+ *
  * @param nptr      Pointer to string.
  * @param endptr    If not NULL, function stores here pointer to the first
  *          invalid character.
  * @param base      Zero or number between 2 and 36 inclusive.
  * @return      Result of conversion.
  */
 long int strtol(const char *nptr, char **endptr, int base)
+{
     char sgn = 0;
     unsigned long number = 0;
     number = _strtoul(nptr, endptr, base, &sgn);
     if (number > LONG_MAX) {
         if ((sgn) && (number == (unsigned long) (LONG_MAX) + 1)) {
             /* FIXME: set 0 to errno */
             return number;
+        }
         /* FIXME: set ERANGE to errno */
         return (sgn ? LONG_MIN : LONG_MAX);
+    }
     return (sgn ? -number : number);
+}
 /** Convert initial part of string to unsigned long according to given base.
  * The number may begin with an arbitrary number of whitespaces followed by
  * optional sign (`+' or `-'). If the base is 0 or 16, the prefix `0x' may be
  * inserted and the number will be taken as hexadecimal one. If the base is 0
  * and the number begin with a zero, number will be taken as octal one (as with
  * base 8). Otherwise the base 0 is taken as decimal.
+ *
  * @param nptr      Pointer to string.
  * @param endptr    If not NULL, function stores here pointer to the first
  *          invalid character
  * @param base      Zero or number between 2 and 36 inclusive.
  * @return      Result of conversion.
  */
 unsigned long strtoul(const char *nptr, char **endptr, int base)
+{
     char sgn = 0;
     unsigned long number = 0;
     number = _strtoul(nptr, endptr, base, &sgn);
     return (sgn ? -number : number);
+}
 char *strcpy(char *dest, const char *src)
+{
     char *orig = dest;
     while ((*(dest++) = *(src++)))
+        ;
     return orig;
+}
 char *strncpy(char *dest, const char *src, size_t n)
+{
     char *orig = dest;
     while ((*(dest++) = *(src++)) && --n)
+        ;
     return orig;
+}
 char *strcat(char *dest, const char *src)
+{
     char *orig = dest;
     while (*dest++)
+        ;
     --dest;
     while ((*dest++ = *src++))
+        ;
     return orig;
+}
 char * strdup(const char *s1)
+{
     size_t len = strlen(s1) + 1;
     void *ret = malloc(len);
     if (ret == NULL)
         return (char *) NULL;
     return (char *) memcpy(ret, s1, len);
+}
 char *strtok(char *s, const char *delim)
+{
     static char *next;
     return strtok_r(s, delim, &next);
+}
 char *strtok_r(char *s, const char *delim, char **next)
+{
     char *start, *end;
     if (s == NULL)
         s = *next;
     /* Skip over leading delimiters. */
     while (*s && (strchr(delim, *s) != NULL)) ++s;
     start = s;
     /* Skip over token characters. */
     while (*s && (strchr(delim, *s) == NULL)) ++s;
     end = s;
     *next = (*s ? s + 1 : s);
     if (start == end) {
         return NULL;    /* No more tokens. */
+    }
     /* Overwrite delimiter with NULL terminator. */
     *end = '\0';
     return start;
+}
 /** @}
  */

Subversion Repositories HelenOS

(root)/trunk/uspace/lib/libc/generic/string.c – Rev 3731 → 4226