woof-CE-libre/woof-code/support/printcols.c

/*(c) Copyright Barry Kauler 2009*/
/*Invoke like this: printcols afilename 1 6 2 9
  ...columns with '|' delimiter character get printed, in order specified.
     handles up to 15 columns.
Designed for use in the Puppy Package Manager, puppylinux.com
Compile statically:
# diet gcc -nostdinc -O3 -fomit-frame-pointer -ffunction-sections -fdata-sections -fmerge-all-constants -Wl,--sort-common -Wl,-gc-sections -o printcols -o printcols printcols.c
* OR
* musl-gcc -static -O3 -fomit-frame-pointer -ffunction-sections -fdata-sections -fmerge-all-constants -Wl,--sort-common -Wl,-gc-sections -o printcols printcols.c
*
* then:
* strip --strip-all -R .note -R .comment
*/

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#define BUF_SIZE (1024 * 1024 * 1)
#define LINE_SIZE BUF_SIZE

int main (int argc, char ** argv) {
 int cntargs;
 char *buffer1;
 char *buffer2;
 FILE* fp;
 char *ptokens[15];
 int i;
 int cnt;
 int max=0;
	int nextarg;
	int args[15];

	for (cntargs=2;cntargs<argc;++cntargs) {
		args[cntargs]=atoi(argv[cntargs]);
		if (cntargs==2) max=args[cntargs]; else max=args[cntargs]>max ? args[cntargs] : max;
	}

 buffer1 = malloc(LINE_SIZE);
 buffer2 = malloc(BUF_SIZE);
 fp = fopen(argv[1],"r");
 setbuffer(fp, buffer2, BUF_SIZE);

 while( fgets(buffer1,LINE_SIZE,fp) != NULL ) {

  cnt=1;

  ptokens[0]=buffer1;
  i=0;
  while (buffer1[i]!='\0' && cnt<=max) {
	if (buffer1[i]=='|') {
	 buffer1[i]='\0';
     ptokens[cnt]=&buffer1[i+1];
     ++cnt;
    }
    ++i;
  }

		/*print the fields in requested order...*/
		for (cntargs=2;cntargs<argc;++cntargs) {

			nextarg=args[cntargs];

			if ( nextarg >= cnt ) { putc('|', stdout); continue; } /*in case of lines with less fields*/
			fputs(ptokens[nextarg - 1], stdout);
			putc('|', stdout);
	 }
		putc('\n', stdout);
 }


 fclose(fp);
 free(buffer2);
 free(buffer1);

 return 0;
}