#include "replaceString.h"
size_t replaceStringLength(const char* from, const char* replace, const char* replacement){
size_t fromLength = strlen(from);
size_t replaceLength = strlen(replace);
size_t replacementLength = strlen(replacement);
size_t fromEndIt = 0;
size_t toLength = 0;
while(fromEndIt < fromLength){
int replaceIt = 0;
while(replaceIt < replaceLength && (fromEndIt+replaceIt) < fromLength && from[fromEndIt + replaceIt] == replace[replaceIt]){
++replaceIt;
}
if(replaceIt == replaceLength){
toLength += (fromEndIt + replacementLength);
from += (fromEndIt + replaceLength);
fromEndIt = 0;
continue;
}
++fromEndIt;
}
toLength += fromEndIt;
return toLength;
}
void replaceString(char* to, const char* from, const char* replace, const char* replacement){
size_t fromLength = strlen(from);
size_t replaceLength = strlen(replace);
size_t replacementLength = strlen(replacement);
size_t fromEndIt = 0;
while(fromEndIt < fromLength){
int replaceIt = 0;
while(replaceIt < replaceLength && (fromEndIt+replaceIt) < fromLength && from[fromEndIt + replaceIt] == replace[replaceIt]){
++replaceIt;
}
if(replaceIt == replaceLength){
memcpyToAndShiftPointers(to, from, fromEndIt);
memcpyToAndShiftPointer(to, replacement, replacementLength);
from += replaceLength;
fromEndIt = 0;
continue;
}
++fromEndIt;
}
memcpyToAndShiftPointer(to, from, fromEndIt);
to[0] = '\0';
}
#ifndef REPLACE_STRING_H
#define REPLACE_STRING_H
#include <string.h>
#define memcpyToAndShiftPointer(to,from,n); memcpy((to),(from),(n)); (to) += (n);
#define memcpyToAndShiftPointers(to,from,n); memcpy((to),(from),(n)); (to) += (n); (from) += n;
size_t replaceStringLength(const char* from, const char* replace, const char* replacement);
void replaceString(char* to, const char* from, const char* replace, const char* replacement);
#endif
#include <stdio.h>
#include <stdlib.h>
#include "replaceString.h"
#define BUFFER_SIZE (1<<21)
int main(int argc, char** argv){
char* buffer1 = (char*) malloc(BUFFER_SIZE);
char* buffer2 = (char*) malloc(BUFFER_SIZE);
if(buffer1 == NULL || buffer2 == NULL){
perror("You need a couple MBs of ram my boy");
return 1;
}
while(!feof(stdin)){
fread(buffer1, BUFFER_SIZE, 1, stdin);
char* activeBuffer = buffer1;
char* inactiveBuffer = buffer2;
char* tmp;
for(size_t i = 1; (i + 1) < argc; i += 2){
replaceString(inactiveBuffer, activeBuffer, argv[i], argv[i+1]);
tmp = activeBuffer;
activeBuffer = inactiveBuffer;
inactiveBuffer = tmp;
}
fputs(activeBuffer, stdout);
}
free(buffer1);
free(buffer2);
return 0;
}