/**************************************************************************** * libs/libc/string/lib_strtokr.c * * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. The * ASF licenses this file to you 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. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include /**************************************************************************** * Private Data ****************************************************************************/ /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: strtok_r * * Description: * The strtok_r() function is a reentrant version strtok(). * Like strtok(), it parses a string into a sequence of * tokens. On the first call to strtok() the string to be * parsed should be specified in 'str'. In each subsequent * call that should parse the same string, 'str' should be * NULL. * * The 'saveptr' argument is a pointer to a char * * variable that is used internally by strtok_r() in * order to maintain context between successive calls * that parse the same string. * * On the first call to strtok_r(), 'str' should point to the * string to be parsed, and the value of 'saveptr' is * ignored. In subsequent calls, 'str' should be NULL, and * saveptr should be unchanged since the previous call. * * The 'delim' argument specifies a set of characters that * delimit the tokens in the parsed string. The caller * may specify different strings in delim in successive * calls that parse the same string. * * Each call to strtok_r() returns a pointer to a null- * terminated string containing the next token. This * string does not include the delimiting character. If * no more tokens are found, strtok_r() returns NULL. * * A sequence of two or more contiguous delimiter * characters in the parsed string is considered to be a * single delimiter. Delimiter characters at the start or * end of the string are ignored. The tokens returned by * strtok() are always non-empty strings. * * Returned Value: * strtok_r() returns a pointer to the next token, or NULL * if there are no more tokens. * ****************************************************************************/ FAR char *strtok_r(FAR char *str, FAR const char *delim, FAR char **saveptr) { FAR char *pbegin; FAR char *pend = NULL; /* Decide if we are starting a new string or continuing from * the point we left off. */ if (str) { pbegin = str; } else if (saveptr && *saveptr) { pbegin = *saveptr; } else { return NULL; } /* Find the beginning of the next token */ for (; *pbegin && strchr(delim, *pbegin) != NULL; pbegin++); /* If we are at the end of the string with nothing * but delimiters found, then return NULL. */ if (!*pbegin) { return NULL; } /* Find the end of the token */ for (pend = pbegin + 1; *pend && strchr(delim, *pend) == NULL; pend++); /* pend either points to the end of the string or to * the first delimiter after the string. */ if (*pend) { /* Turn the delimiter into a null terminator */ *pend++ = '\0'; } /* Save the pointer where we left off and return the * beginning of the token. */ if (saveptr) { *saveptr = pend; } return pbegin; }