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

 /** @file
  */
 #include <string.h>
 #include <stdlib.h>
+#include <assert.h>
 #include <limits.h>
 #include <ctype.h>
 #include <malloc.h>
+#include <errno.h>
+#include <align.h>
+#include <mem.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.
+ *
-/** Count the number of characters in the string, not including terminating 0.
+ * 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.
+ *
- * @param str       String.
- * @return      Number of characters in string.
  */
-size_t strlen(const char *str)
+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;
-    size_t counter = 0;
+        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;
+}
+/** Get size of string.
+ *
+ * Get the number of bytes which are used by the string @a str (excluding the
+ * NULL-terminator).
+ *
+ * @param str String to consider.
+ *
+ * @return Number of bytes used by the string
+ *
+ */
+size_t str_size(const char *str)
+{
+    size_t size = 0;
-    while (str[counter] != 0)
+    while (*str++ != 0)
-        counter++;
+        size++;
+    return size;
+}
+/** Get size of wide string.
+ *
+ * Get the number of bytes which are used by the wide string @a str (excluding the
-    return counter;
+ * NULL-terminator).
+ *
+ * @param str Wide string to consider.
+ *
+ * @return Number of bytes used by the wide string
+ *
+ */
+size_t wstr_size(const wchar_t *str)
+{
+    return (wstr_length(str) * sizeof(wchar_t));
+}
+/** Get size of string with length limit.
+ *
+ * Get the number of bytes which are used by up to @a max_len first
+ * characters in the string @a str. If @a max_len is greater than
+ * the length of @a str, the entire string is measured (excluding the
+ * NULL-terminator).
+ *
+ * @param str     String to consider.
+ * @param max_len Maximum number of characters to measure.
+ *
+ * @return Number of bytes used by the characters.
+ *
+ */
-int strcmp(const char *a, const char *b)
+size_t str_lsize(const char *str, count_t max_len)
+{
-    int c = 0;
+    count_t len = 0;
+    size_t offset = 0;
-    while (a[c] && b[c] && (!(a[c] - b[c])))
+    while (len < max_len) {
+        if (str_decode(str, &offset, STR_NO_LIMIT) == 0)
+            break;
-        c++;
+        len++;
+    }
-    return (a[c] - b[c]);
+    return offset;
+}
+/** Get size of wide string with length limit.
+ *
+ * Get the number of bytes which are used by up to @a max_len first
+ * wide characters in the wide string @a str. If @a max_len is greater than
+ * the length of @a str, the entire wide string is measured (excluding the
+ * NULL-terminator).
+ *
+ * @param str     Wide string to consider.
+ * @param max_len Maximum number of wide characters to measure.
+ *
+ * @return Number of bytes used by the wide characters.
+ *
+ */
-int strncmp(const char *a, const char *b, size_t n)
+size_t wstr_lsize(const wchar_t *str, count_t max_len)
+{
-    size_t c = 0;
+    return (wstr_nlength(str, max_len * sizeof(wchar_t)) * sizeof(wchar_t));
+}
-    while (c < n && a[c] && b[c] && (!(a[c] - b[c])))
+/** Get number of characters in a string.
+ *
+ * @param str NULL-terminated string.
+ *
+ * @return Number of characters in string.
+ *
-        c++;
+ */
+count_t str_length(const char *str)
+{
+    count_t len = 0;
+    size_t offset = 0;
-    return ( c < n ? a[c] - b[c] : 0);
+    while (str_decode(str, &offset, STR_NO_LIMIT) != 0)
+        len++;
+    return len;
+}
+/** Get number of characters in a wide string.
+ *
+ * @param str NULL-terminated wide string.
+ *
+ * @return Number of characters in @a str.
+ *
+ */
-int stricmp(const char *a, const char *b)
+count_t wstr_length(const wchar_t *wstr)
+{
-    int c = 0;
+    count_t len = 0;
-    while (a[c] && b[c] && (!(tolower(a[c]) - tolower(b[c]))))
+    while (*wstr++ != 0)
-        c++;
+        len++;
-    return (tolower(a[c]) - tolower(b[c]));
+    return len;
+}
-/** Return pointer to the first occurence of character c in string.
+/** Get number of characters in a string with size limit.
+ *
- * @param str       Scanned string.
+ * @param str  NULL-terminated string.
- * @param c     Searched character (taken as one byte).
+ * @param size Maximum number of bytes to consider.
+ *
- * @return      Pointer to the matched character or NULL if it is not
+ * @return Number of characters in string.
+ *
+ */
+count_t str_nlength(const char *str, size_t size)
+{
+    count_t len = 0;
+    size_t offset = 0;
+    while (str_decode(str, &offset, size) != 0)
+        len++;
+    return len;
+}
+/** Get number of characters in a string with size limit.
+ *
- *          found in given string.
+ * @param str  NULL-terminated string.
+ * @param size Maximum number of bytes to consider.
+ *
+ * @return Number of characters in string.
+ *
  */
-char *strchr(const char *str, int c)
+count_t wstr_nlength(const wchar_t *str, size_t size)
 {
-    while (*str != '\0') {
+    count_t len = 0;
-        if (*str == (char) c)
+    count_t limit = ALIGN_DOWN(size, sizeof(wchar_t));
-            return (char *) str;
+    count_t offset = 0;
+    while ((offset < limit) && (*str++ != 0)) {
-        str++;
+        len++;
+        offset += sizeof(wchar_t);
+    }
+    return len;
+}
+/** Check whether character is plain ASCII.
+ *
+ * @return True if character is plain ASCII.
+ *
+ */
+bool ascii_check(wchar_t ch)
+{
+    if ((ch >= 0) && (ch <= 127))
+        return true;
-    return NULL;
+    return false;
+}
+/** Check whether character is valid
+ *
-/** Return pointer to the last occurence of character c in string.
+ * @return True if character is a valid Unicode code point.
+ *
- * @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)
+bool chr_check(wchar_t ch)
+{
+    if ((ch >= 0) && (ch <= 1114111))
+        return true;
-    char *retval = NULL;
+    return false;
+}
+/** 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 s1 First string to compare.
+ * @param s2 Second string to compare.
+ *
+ * @return 0 if the strings are equal, -1 if first is smaller,
+ *         1 if second smaller.
+ *
+ */
+int str_cmp(const char *s1, const char *s2)
+{
+    wchar_t c1 = 0;
+    wchar_t c2 = 0;
+    size_t off1 = 0;
+    size_t off2 = 0;
+    while (true) {
+        c1 = str_decode(s1, &off1, STR_NO_LIMIT);
+        c2 = str_decode(s2, &off2, STR_NO_LIMIT);
+        if (c1 < c2)
+            return -1;
+        if (c1 > c2)
+            return 1;
+        if (c1 == 0 || c2 == 0)
+            break;
+    }
+    return 0;
+}
+/** Compare two NULL terminated strings with length limit.
+ *
+ * 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 the length limit.
+ *
+ * @param s1      First string to compare.
+ * @param s2      Second string to compare.
+ * @param max_len Maximum number of characters to consider.
+ *
+ * @return 0 if the strings are equal, -1 if first is smaller,
+ *         1 if second smaller.
+ *
+ */
+int str_lcmp(const char *s1, const char *s2, count_t max_len)
+{
+    wchar_t c1 = 0;
+    wchar_t c2 = 0;
+    size_t off1 = 0;
+    size_t off2 = 0;
+    count_t len = 0;
-    while (*str != '\0') {
+    while (true) {
+        if (len >= max_len)
+            break;
+        c1 = str_decode(s1, &off1, STR_NO_LIMIT);
+        c2 = str_decode(s2, &off2, STR_NO_LIMIT);
+        if (c1 < c2)
+            return -1;
+        if (c1 > c2)
+            return 1;
-        if (*str == (char) c)
+        if (c1 == 0 || c2 == 0)
+            break;
+        ++len;
+    }
+    return 0;
+}
+/** Copy string.
+ *
+ * Copy source string @a src to destination buffer @a dest.
+ * No more than @a size bytes are written. If the size of the output buffer
+ * is at least one byte, the output string will always be well-formed, i.e.
+ * null-terminated and containing only complete characters.
+ *
+ * @param dst   Destination buffer.
+ * @param count Size of the destination buffer (must be > 0).
+ * @param src   Source string.
+ */
+void str_cpy(char *dest, size_t size, const char *src)
+{
+    wchar_t ch;
+    size_t src_off;
+    size_t dest_off;
+    /* There must be space for a null terminator in the buffer. */
+    assert(size > 0);
+    src_off = 0;
+    dest_off = 0;
+    while ((ch = str_decode(src, &src_off, STR_NO_LIMIT)) != 0) {
+        if (chr_encode(ch, dest, &dest_off, size - 1) != EOK)
+            break;
+    }
+    dest[dest_off] = '\0';
+}
+/** Copy size-limited substring.
+ *
+ * Copy prefix of string @a src of max. size @a size to destination buffer
+ * @a dest. No more than @a size bytes are written. The output string will
+ * always be well-formed, i.e. null-terminated and containing only complete
+ * characters.
+ *
+ * No more than @a n bytes are read from the input string, so it does not
+ * have to be null-terminated.
+ *
+ * @param dst   Destination buffer.
+ * @param count Size of the destination buffer (must be > 0).
+ * @param src   Source string.
+ * @param n Maximum number of bytes to read from @a src.
+ */
+void str_ncpy(char *dest, size_t size, const char *src, size_t n)
+{
+    wchar_t ch;
+    size_t src_off;
+    size_t dest_off;
+    /* There must be space for a null terminator in the buffer. */
+    assert(size > 0);
+    src_off = 0;
+    dest_off = 0;
+    while ((ch = str_decode(src, &src_off, n)) != 0) {
+        if (chr_encode(ch, dest, &dest_off, size - 1) != EOK)
+            break;
+    }
+    dest[dest_off] = '\0';
+}
+/** Append one string to another.
+ *
+ * Append source string @a src to string in destination buffer @a dest.
+ * Size of the destination buffer is @a dest. If the size of the output buffer
+ * is at least one byte, the output string will always be well-formed, i.e.
+ * null-terminated and containing only complete characters.
+ *
+ * @param dst   Destination buffer.
+ * @param count Size of the destination buffer.
+ * @param src   Source string.
+ */
+void str_append(char *dest, size_t size, const char *src)
+{
+    size_t dstr_size;
-            retval = (char *) str;
+    dstr_size = str_size(dest);
+    str_cpy(dest + dstr_size, size - dstr_size, src);
+}
+/** Copy NULL-terminated wide string to string
+ *
+ * Copy source wide string @a src to destination buffer @a dst.
+ * No more than @a size bytes are written. NULL-terminator is always
+ * written after the last succesfully copied character (i.e. if the
+ * destination buffer is has at least 1 byte, it will be always
+ * NULL-terminated).
+ *
+ * @param src   Source wide string.
+ * @param dst   Destination buffer.
+ * @param count Size of the destination buffer.
+ *
+ */
+void wstr_nstr(char *dst, const wchar_t *src, size_t size)
+{
+    /* No space for the NULL-terminator in the buffer */
+    if (size == 0)
+        return;
+    wchar_t ch;
+    count_t src_idx = 0;
+    size_t dst_off = 0;
+    while ((ch = src[src_idx++]) != 0) {
+        if (chr_encode(ch, dst, &dst_off, size) != EOK)
-        str++;
+            break;
+    }
+    if (dst_off >= size)
+        dst[size - 1] = 0;
+    else
+        dst[dst_off] = 0;
+}
+/** Find first occurence of character in string.
+ *
+ * @param str String to search.
+ * @param ch  Character to look for.
+ *
+ * @return Pointer to character in @a str or NULL if not found.
+ */
+const char *str_chr(const char *str, wchar_t ch)
+{
+    wchar_t acc;
+    size_t off = 0;
+    while ((acc = str_decode(str, &off, STR_NO_LIMIT)) != 0) {
+        if (acc == ch)
+            return (str + off);
+    }
+    return NULL;
+}
+/** Find last occurence of character in string.
+ *
+ * @param str String to search.
+ * @param ch  Character to look for.
+ *
+ * @return Pointer to character in @a str or NULL if not found.
+ */
+const char *str_rchr(const char *str, wchar_t ch)
+{
+    wchar_t acc;
+    size_t off = 0;
+    char *res;
+    res = NULL;
+    while ((acc = str_decode(str, &off, STR_NO_LIMIT)) != 0) {
+        if (acc == ch)
+            res = (str + off);
+    }
+    return res;
+}
+/** Insert a wide character into a wide string.
+ *
+ * Insert a wide character into a wide string at position
+ * @a pos. The characters after the position are shifted.
+ *
+ * @param str     String to insert to.
+ * @param ch      Character to insert to.
+ * @param pos     Character index where to insert.
+ @ @param max_pos Characters in the buffer.
+ *
+ * @return True if the insertion was sucessful, false if the position
+ *         is out of bounds.
+ *
+ */
+bool wstr_linsert(wchar_t *str, wchar_t ch, count_t pos, count_t max_pos)
+{
+    count_t len = wstr_length(str);
+    if ((pos > len) || (pos + 1 > max_pos))
+        return false;
+    count_t i;
+    for (i = len; i + 1 > pos; i--)
+        str[i + 1] = str[i];
+    str[pos] = ch;
+    return true;
+}
+/** Remove a wide character from a wide string.
+ *
+ * Remove a wide character from a wide string at position
+ * @a pos. The characters after the position are shifted.
+ *
+ * @param str String to remove from.
+ * @param pos Character index to remove.
+ *
+ * @return True if the removal was sucessful, false if the position
+ *         is out of bounds.
+ *
+ */
+bool wstr_remove(wchar_t *str, count_t pos)
+{
+    count_t len = wstr_length(str);
+    if (pos >= len)
+        return false;
+    count_t i;
+    for (i = pos + 1; i <= len; i++)
+        str[i - 1] = str[i];
-    return (char *) retval;
+    return true;
+}
+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]));
+}
 /** Convert string to a number.
  * Core of strtol and strtoul functions.
+ *
     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)
+char *str_dup(const char *src)
+{
-    size_t len = strlen(s1) + 1;
+    size_t size = str_size(src);
-    void *ret = malloc(len);
+    void *dest = malloc(size + 1);
-    if (ret == NULL)
+    if (dest == NULL)
         return (char *) NULL;
-    return (char *) memcpy(ret, s1, len);
+    return (char *) memcpy(dest, src, size + 1);
+}
 char *strtok(char *s, const char *delim)
+{
     static char *next;
     if (s == NULL)
         s = *next;
     /* Skip over leading delimiters. */
-    while (*s && (strchr(delim, *s) != NULL)) ++s;
+    while (*s && (str_chr(delim, *s) != NULL)) ++s;
     start = s;
     /* Skip over token characters. */
-    while (*s && (strchr(delim, *s) == NULL)) ++s;
+    while (*s && (str_chr(delim, *s) == NULL)) ++s;
     end = s;
     *next = (*s ? s + 1 : s);
     if (start == end) {
         return NULL;    /* No more tokens. */

Subversion Repositories HelenOS

(root)//branches/dd/uspace/lib/libc/generic/string.c – Rev 4055 → 4296