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/*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
size_t
getfilelength(FILE *fp)
{
/*
* return the number of bytes in file fp
* value of 0 returned is empty or error
* it doesn't matter for our purpose
*/
size_t retval;
if (!fp)
retval = 0;
else
{
fseek(fp, 0, SEEK_END);
retval = ftell(fp);
fseek(fp, 0, SEEK_SET);
}
return retval;
}
void
replaceappendchar(char *dest, char ch)
{
int len = strlen(dest);
dest[len] = ch;
dest[len+1] = '\0';
}
int
replaceinfile(char *originalfile, char *destinationfile, char *placeholder, char *replacement)
{
/*
* write originalfile into destinationfile replacing every instance
* of placeholder with replacement
*/
/* open files */
FILE *template = fopen(originalfile, "r");
FILE *destination = fopen(destinationfile, "w");
if (!template)
{
fclose(destination);
return 0;
}
int ch;
char *substr;
size_t filesize = getfilelength(template);
char *filebuffer = malloc(filesize+1);
if (!filebuffer)
return 0;
fread(filebuffer, 1, filesize, template);
substr = strstr(filebuffer, placeholder);
for (size_t i = 0; i < strlen(filebuffer); i++)
{
if (i == (substr-filebuffer))
{
i += strlen(placeholder);
substr++;
substr = strstr(substr, placeholder);
fprintf(destination, "%s", replacement);
}
ch = filebuffer[i];
fputc(ch, destination);
}
fclose(template);
fclose(destination);
free(filebuffer);
return 1;
}
char *
replaceinmemory(char *src, char *placeholder, char *replacement)
{
/*
* replace every placeholder with replacement in source src
* return pointer to string, NULL if no placement found
* user must free the returned memory
*/
char *dest = NULL;
size_t destsize;
char *substr = strstr(src, placeholder);
if (!substr)
return NULL;
/* initial dest size if only one placeholder exists */
destsize = (strlen(src)-strlen(placeholder))+strlen(replacement+1);
dest = malloc(destsize);
if (!dest)
return NULL;
dest[0] = '\0'; /* junk in memory, we need [0] to be null for strlen() later */
for (size_t i = 0; i < strlen(src); i++)
{
if (i == (substr-src))
{
i += strlen(placeholder);
substr++;
substr = strstr(substr, placeholder);
if (substr)
{
destsize = (destsize-strlen(placeholder))+strlen(replacement)+1;
dest = realloc(dest, destsize);
}
strcat(dest, replacement);
}
replaceappendchar(dest, src[i]);
}
return dest;
}
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