| /* string.c - common string routines */ |
| |
| /* |
| * Copyright (c) 2014 Wind River Systems, Inc. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include <string.h> |
| |
| /** |
| * |
| * @brief Copy a string |
| * |
| * @return pointer to destination buffer <d> |
| */ |
| |
| char *strcpy(char *_Restrict d, const char *_Restrict s) |
| { |
| char *dest = d; |
| |
| while (*s != '\0') { |
| *d = *s; |
| d++; |
| s++; |
| } |
| |
| *d = '\0'; |
| |
| return dest; |
| } |
| |
| /** |
| * |
| * @brief Copy part of a string |
| * |
| * @return pointer to destination buffer <d> |
| */ |
| |
| char *strncpy(char *_Restrict d, const char *_Restrict s, size_t n) |
| { |
| char *dest = d; |
| |
| while ((n > 0) && *s != '\0') { |
| *d = *s; |
| s++; |
| d++; |
| n--; |
| } |
| |
| while (n > 0) { |
| *d = '\0'; |
| d++; |
| n--; |
| } |
| |
| return dest; |
| } |
| |
| /** |
| * |
| * @brief String scanning operation |
| * |
| * @return pointer to 1st instance of found byte, or NULL if not found |
| */ |
| |
| char *strchr(const char *s, int c) |
| { |
| char tmp = (char) c; |
| |
| while ((*s != tmp) && (*s != '\0')) |
| s++; |
| |
| return (*s == tmp) ? (char *) s : NULL; |
| } |
| |
| /** |
| * |
| * @brief Get string length |
| * |
| * @return number of bytes in string <s> |
| */ |
| |
| size_t strlen(const char *s) |
| { |
| size_t n = 0; |
| |
| while (*s != '\0') { |
| s++; |
| n++; |
| } |
| |
| return n; |
| } |
| |
| /** |
| * |
| * @brief Compare two strings |
| * |
| * @return negative # if <s1> < <s2>, 0 if <s1> == <s2>, else positive # |
| */ |
| |
| int strcmp(const char *s1, const char *s2) |
| { |
| while ((*s1 == *s2) && (*s1 != '\0')) { |
| s1++; |
| s2++; |
| } |
| |
| return *s1 - *s2; |
| } |
| |
| /** |
| * |
| * @brief Compare part of two strings |
| * |
| * @return negative # if <s1> < <s2>, 0 if <s1> == <s2>, else positive # |
| */ |
| |
| int strncmp(const char *s1, const char *s2, size_t n) |
| { |
| while ((n > 0) && (*s1 == *s2) && (*s1 != '\0')) { |
| s1++; |
| s2++; |
| n--; |
| } |
| |
| return (n == 0) ? 0 : (*s1 - *s2); |
| } |
| |
| char *strcat(char *_Restrict dest, const char *_Restrict src) |
| { |
| strcpy(dest + strlen(dest), src); |
| return dest; |
| } |
| |
| char *strncat(char *_Restrict dest, const char *_Restrict src, size_t n) |
| { |
| char *orig_dest = dest; |
| size_t len = strlen(dest); |
| |
| dest += len; |
| while ((n-- > 0) && (*src != '\0')) { |
| *dest++ = *src++; |
| } |
| *dest = '\0'; |
| |
| return orig_dest; |
| } |
| |
| /** |
| * |
| * @brief Compare two memory areas |
| * |
| * @return negative # if <m1> < <m2>, 0 if <m1> == <m2>, else positive # |
| */ |
| int memcmp(const void *m1, const void *m2, size_t n) |
| { |
| const char *c1 = m1; |
| const char *c2 = m2; |
| |
| if (!n) |
| return 0; |
| |
| while ((--n > 0) && (*c1 == *c2)) { |
| c1++; |
| c2++; |
| } |
| |
| return *c1 - *c2; |
| } |
| |
| /** |
| * |
| * @brief Copy bytes in memory with overlapping areas |
| * |
| * @return pointer to destination buffer <d> |
| */ |
| |
| void *memmove(void *d, const void *s, size_t n) |
| { |
| char *dest = d; |
| const char *src = s; |
| |
| if ((size_t) (d - s) < n) { |
| /* |
| * The <src> buffer overlaps with the start of the <dest> buffer. |
| * Copy backwards to prevent the premature corruption of <src>. |
| */ |
| |
| while (n > 0) { |
| n--; |
| dest[n] = src[n]; |
| } |
| } else { |
| /* It is safe to perform a forward-copy */ |
| while (n > 0) { |
| *dest = *src; |
| dest++; |
| src++; |
| n--; |
| } |
| } |
| |
| return d; |
| } |
| |
| /** |
| * |
| * @brief Copy bytes in memory |
| * |
| * @return pointer to start of destination buffer |
| */ |
| |
| void *memcpy(void *_Restrict d, const void *_Restrict s, size_t n) |
| { |
| /* attempt word-sized copying only if buffers have identical alignment */ |
| |
| unsigned char *d_byte = (unsigned char *)d; |
| const unsigned char *s_byte = (const unsigned char *)s; |
| |
| if ((((unsigned int)d ^ (unsigned int)s_byte) & 0x3) == 0) { |
| |
| /* do byte-sized copying until word-aligned or finished */ |
| |
| while (((unsigned int)d_byte) & 0x3) { |
| if (n == 0) { |
| return d; |
| } |
| *(d_byte++) = *(s_byte++); |
| n--; |
| }; |
| |
| /* do word-sized copying as long as possible */ |
| |
| unsigned int *d_word = (unsigned int *)d_byte; |
| const unsigned int *s_word = (const unsigned int *)s_byte; |
| |
| while (n >= sizeof(unsigned int)) { |
| *(d_word++) = *(s_word++); |
| n -= sizeof(unsigned int); |
| } |
| |
| d_byte = (unsigned char *)d_word; |
| s_byte = (unsigned char *)s_word; |
| } |
| |
| /* do byte-sized copying until finished */ |
| |
| while (n > 0) { |
| *(d_byte++) = *(s_byte++); |
| n--; |
| } |
| |
| return d; |
| } |
| |
| /** |
| * |
| * @brief Set bytes in memory |
| * |
| * @return pointer to start of buffer |
| */ |
| |
| void *memset(void *buf, int c, size_t n) |
| { |
| /* do byte-sized initialization until word-aligned or finished */ |
| |
| unsigned char *d_byte = (unsigned char *)buf; |
| unsigned char c_byte = (unsigned char)c; |
| |
| while (((unsigned int)d_byte) & 0x3) { |
| if (n == 0) { |
| return buf; |
| } |
| *(d_byte++) = c_byte; |
| n--; |
| }; |
| |
| /* do word-sized initialization as long as possible */ |
| |
| unsigned int *d_word = (unsigned int *)d_byte; |
| unsigned int c_word = (unsigned int)(unsigned char)c; |
| |
| c_word |= c_word << 8; |
| c_word |= c_word << 16; |
| |
| while (n >= sizeof(unsigned int)) { |
| *(d_word++) = c_word; |
| n -= sizeof(unsigned int); |
| } |
| |
| /* do byte-sized initialization until finished */ |
| |
| d_byte = (unsigned char *)d_word; |
| |
| while (n > 0) { |
| *(d_byte++) = c_byte; |
| n--; |
| } |
| |
| return buf; |
| } |
| |
| /** |
| * |
| * @brief Scan byte in memory |
| * |
| * @return pointer to start of found byte |
| */ |
| |
| void *memchr(const void *s, unsigned char c, size_t n) |
| { |
| if (n != 0) { |
| const unsigned char *p = s; |
| |
| do { |
| if (*p++ == c) { |
| return ((void *)(p - 1)); |
| } |
| |
| } while (--n != 0); |
| } |
| |
| return NULL; |
| } |