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/**
* @file relocation.c
*/
#include "relocation.h"
#include "str.h"
/**
* Replace all occurrences of `target` with `replacement` in `original`
*
* ~~~{.c}
* char *str = calloc(100, sizeof(char));
* strcpy(str, "This are a test.");
* if (replace_text(str, "are", "is")) {
* fprintf(stderr, "string replacement failed\n");
* exit(1);
* }
* // str is: "This is a test."
* free(str);
* ~~~
*
* @param original string to modify
* @param target string value to replace
* @param replacement string value
* @param flags REPLACE_TRUNCATE_AFTER_MATCH
* @return 0 on success, -1 on error
*/
int replace_text(char *original, const char *target, const char *replacement, unsigned flags) {
char buffer[STASIS_BUFSIZ] = {0};
char *pos = original;
char *match = NULL;
size_t original_len = strlen(original);
size_t target_len = strlen(target);
size_t rep_len = strlen(replacement);
size_t buffer_len = 0;
if (original_len > sizeof(buffer)) {
errno = EINVAL;
SYSERROR("The original string is larger than buffer: %zu > %zu\n", original_len, sizeof(buffer));
return -1;
}
memset(buffer, 0, sizeof(buffer));
if ((match = strstr(pos, target))) {
while (*pos != '\0') {
// append to buffer the bytes leading up to the match
strncat(buffer, pos, match - pos);
// position in the string jump ahead to the beginning of the match
pos = match;
// replacement is shorter than the target
if (rep_len < target_len) {
// shrink the string
strcat(buffer, replacement);
memmove(pos, pos + target_len, strlen(pos) - target_len);
memset(pos + (strlen(pos) - target_len), 0, target_len);
} else { // replacement is longer than the target
// write the replacement value to the buffer
strcat(buffer, replacement);
// target consumed. jump to the end of the substring.
pos += target_len;
}
if (flags & REPLACE_TRUNCATE_AFTER_MATCH) {
if (strstr(pos, LINE_SEP)) {
strcat(buffer, LINE_SEP);
}
break;
}
// find more matches
if (!((match = strstr(pos, target)))) {
// no more matches
// append whatever remains to the buffer
strcat(buffer, pos);
// stop
break;
}
}
} else {
return 0;
}
buffer_len = strlen(buffer);
if (buffer_len < original_len) {
// truncate whatever remains of the original buffer
memset(original + buffer_len, 0, original_len - buffer_len);
}
// replace original with contents of buffer
strcpy(original, buffer);
return 0;
}
/**
* Replace `target` with `replacement` in `filename`
*
* ~~~{.c}
* if (file_replace_text("/path/to/file.txt", "are", "is")) {
* fprintf(stderr, "failed to replace strings in file\n");
* exit(1);
* }
* ~~~
*
* @param filename path to file
* @param target string value to replace
* @param replacement string
* @param flags REPLACE_TRUNCATE_AFTER_MATCH
* @return 0 on success, -1 on error
*/
int file_replace_text(const char* filename, const char* target, const char* replacement, unsigned flags) {
char buffer[STASIS_BUFSIZ];
char tempfilename[] = "tempfileXXXXXX";
FILE *fp = fopen(filename, "r");
if (!fp) {
fprintf(stderr, "unable to open for reading: %s\n", filename);
return -1;
}
FILE *tfp = fopen(tempfilename, "w+");
if (!tfp) {
SYSERROR("unable to open temporary fp for writing: %s", tempfilename);
fclose(fp);
return -1;
}
// Write modified strings to temporary file
int result = 0;
while (fgets(buffer, sizeof(buffer), fp) != NULL) {
if (strstr(buffer, target)) {
if (replace_text(buffer, target, replacement, flags)) {
result = -1;
}
}
fputs(buffer, tfp);
}
fflush(tfp);
// Replace original with modified copy
fclose(fp);
fp = fopen(filename, "w+");
if (!fp) {
SYSERROR("unable to reopen %s for writing", filename);
return -1;
}
// Update original file
rewind(tfp);
while (fgets(buffer, sizeof(buffer), tfp) != NULL) {
fputs(buffer, fp);
}
fclose(fp);
fclose(tfp);
remove(tempfilename);
return result;
}
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