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bigcat.cpp
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bigcat.cpp
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#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <unistd.h>
int BUFLEN=0x10000;
FILE* FOUT;
void cat(const char* fn, void* buf)
{
FILE *fp = fopen(fn, "r");
int nread;
if (fp == 0){
fprintf(stderr, "ERROR, failed to open \"%s\"\n", fn);
exit(1);
}
while((nread = fread(buf, 1, BUFLEN, fp)) > 0){
fwrite(buf, 1, nread, FOUT);
}
}
void mapcat(const char* fn, void* buf_notused)
{
FILE *fp = fopen(fn, "r");
void *pv;
if (fp == 0){
fprintf(stderr, "ERROR, failed to open \"%s\"\n", fn);
exit(1);
}
pv = mmap(0, BUFLEN, PROT_READ, MAP_PRIVATE, fileno(fp), 0);
write(fileno(FOUT), pv, BUFLEN);
}
int main(int argc, char* argv[]){
void* buf;
int ii;
void (*mycat)(const char*, void*) = cat;
if (getenv("BUFLEN")){
BUFLEN = strtoul(getenv("BUFLEN"),0,0);
}
if (getenv("MAPCAT")){
mycat = mapcat;
}
if (getenv("FOUT")){
FOUT = fopen(getenv("FOUT"), "w");
if (FOUT == 0){
fprintf(stderr, "ERROR failed to open \"%s\"\n",
getenv("FOUT"));
exit(1);
}
}else{
FOUT = stdout;
}
buf = malloc(BUFLEN);
for (ii = 1; ii < argc; ++ii){
mycat(argv[ii], buf);
}
return 0;
}