/*- * Copyright (c) 2001-2014 Devin Teske <dteske@FreeBSD.org> * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. 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. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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. */ #include <ctype.h> #include <errno.h> #include <stdint.h> #include <stdlib.h> #include <string.h> #include "string_m.h" /* * Counts the number of occurrences of one string that appear in the source * string. Return value is the total count. * * An example use would be if you need to know how large a block of memory * needs to be for a replaceall() series. */ unsigned int strcount(const char *source, const char *find) { const char *p = source; size_t flen; unsigned int n = 0; /* Both parameters are required */ if (source == NULL || find == NULL) return (0); /* Cache the length of find element */ flen = strlen(find); if (strlen(source) == 0 || flen == 0) return (0); /* Loop until the end of the string */ while (*p != '\0') { if (strncmp(p, find, flen) == 0) { /* found an instance */ p += flen; n++; } else p++; } return (n); } /* * Replaces all occurrences of `find' in `source' with `replace'. * * You should not pass a string constant as the first parameter, it needs to be * a pointer to an allocated block of memory. The block of memory that source * points to should be large enough to hold the result. If the length of the * replacement string is greater than the length of the find string, the result * will be larger than the original source string. To allocate enough space for * the result, use the function strcount() declared above to determine the * number of occurrences and how much larger the block size needs to be. * * If source is not large enough, the application will crash. The return value * is the length (in bytes) of the result. * * When an error occurs, -1 is returned and the global variable errno is set * accordingly. Returns zero on success. */ int replaceall(char *source, const char *find, const char *replace) { char *p; char *t; char *temp; size_t flen; size_t rlen; size_t slen; uint32_t n = 0; errno = 0; /* reset global error number */ /* Check that we have non-null parameters */ if (source == NULL) return (0); if (find == NULL) return (strlen(source)); /* Cache the length of the strings */ slen = strlen(source); flen = strlen(find); rlen = replace ? strlen(replace) : 0; /* Cases where no replacements need to be made */ if (slen == 0 || flen == 0 || slen < flen) return (slen); /* If replace is longer than find, we'll need to create a temp copy */ if (rlen > flen) { temp = malloc(slen + 1); if (temp == NULL) /* could not allocate memory */ return (-1); memcpy(temp, source, slen + 1); } else temp = source; /* Reconstruct the string with the replacements */ p = source; t = temp; /* position elements */ while (*t != '\0') { if (strncmp(t, find, flen) == 0) { /* found an occurrence */ for (n = 0; replace && replace[n]; n++) *p++ = replace[n]; t += flen; } else *p++ = *t++; /* copy character and increment */ } /* Terminate the string */ *p = '\0'; /* Free the temporary allocated memory */ if (temp != source) free(temp); /* Return the length of the completed string */ return (strlen(source)); } /* * Expands escape sequences in a buffer pointed to by `source'. This function * steps through each character, and converts escape sequences such as "\n", * "\r", "\t" and others into their respective meanings. * * You should not pass a string constant or literal to this function or the * program will likely segmentation fault when it tries to modify the data. * * The string length will either shorten or stay the same depending on whether * any escape sequences were converted but the amount of memory allocated does * not change. * * Interpreted sequences are: * * \0NNN character with octal value NNN (0 to 3 digits) * \N character with octal value N (0 thru 7) * \a alert (BEL) * \b backslash * \f form feed * \n new line * \r carriage return * \t horizontal tab * \v vertical tab * \xNN byte with hexadecimal value NN (1 to 2 digits) * * All other sequences are unescaped (ie. '\"' and '\#'). */ void strexpand(char *source) { uint8_t c; char *chr; char *pos; char d[4]; /* Initialize position elements */ pos = chr = source; /* Loop until we hit the end of the string */ while (*pos != '\0') { if (*chr != '\\') { *pos = *chr; /* copy character to current offset */ pos++; chr++; continue; } /* Replace the backslash with the correct character */ switch (*++chr) { case 'a': *pos = '\a'; break; /* bell/alert (BEL) */ case 'b': *pos = '\b'; break; /* backspace */ case 'f': *pos = '\f'; break; /* form feed */ case 'n': *pos = '\n'; break; /* new line */ case 'r': *pos = '\r'; break; /* carriage return */ case 't': *pos = '\t'; break; /* horizontal tab */ case 'v': *pos = '\v'; break; /* vertical tab */ case 'x': /* hex value (1 to 2 digits)(\xNN) */ d[2] = '\0'; /* pre-terminate the string */ /* verify next two characters are hex */ d[0] = isxdigit(*(chr+1)) ? *++chr : '\0'; if (d[0] != '\0') d[1] = isxdigit(*(chr+1)) ? *++chr : '\0'; /* convert the characters to decimal */ c = (uint8_t)strtoul(d, 0, 16); /* assign the converted value */ *pos = (c != 0 || d[0] == '0') ? c : *++chr; break; case '0': /* octal value (0 to 3 digits)(\0NNN) */ d[3] = '\0'; /* pre-terminate the string */ /* verify next three characters are octal */ d[0] = (isdigit(*(chr+1)) && *(chr+1) < '8') ? *++chr : '\0'; if (d[0] != '\0') d[1] = (isdigit(*(chr+1)) && *(chr+1) < '8') ? *++chr : '\0'; if (d[1] != '\0') d[2] = (isdigit(*(chr+1)) && *(chr+1) < '8') ? *++chr : '\0'; /* convert the characters to decimal */ c = (uint8_t)strtoul(d, 0, 8); /* assign the converted value */ *pos = c; break; default: /* single octal (\0..7) or unknown sequence */ if (isdigit(*chr) && *chr < '8') { d[0] = *chr; d[1] = '\0'; *pos = (uint8_t)strtoul(d, 0, 8); } else *pos = *chr; } /* Increment to next offset, possible next escape sequence */ pos++; chr++; } } /* * Expand only the escaped newlines in a buffer pointed to by `source'. This * function steps through each character, and converts the "\n" sequence into * a literal newline and the "\\n" sequence into "\n". * * You should not pass a string constant or literal to this function or the * program will likely segmentation fault when it tries to modify the data. * * The string length will either shorten or stay the same depending on whether * any escaped newlines were converted but the amount of memory allocated does * not change. */ void strexpandnl(char *source) { uint8_t backslash = 0; char *cp1; char *cp2; /* Replace '\n' with literal in dprompt */ cp1 = cp2 = source; while (*cp2 != '\0') { *cp1 = *cp2; if (*cp2 == '\\') backslash++; else if (*cp2 != 'n') backslash = 0; else if (backslash > 0) { *(--cp1) = (backslash & 1) == 1 ? '\n' : 'n'; backslash = 0; } cp1++; cp2++; } *cp1 = *cp2; } /* * Convert a string to lower case. You should not pass a string constant to * this function. Only pass pointers to allocated memory with null terminated * string data. */ void strtolower(char *source) { char *p = source; if (source == NULL) return; while (*p != '\0') { *p = tolower(*p); p++; /* would have just used `*p++' but gcc 3.x warns */ } }
