columnt.c

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#include <unistd.h>
#include "alloc.h"
#include "logmsg.h"
#include "buffer.h"
#include "stralloc.h"
#include "exit.h"
#include "readclose.h"
 
#define WHO "columnt"
 
#define BSIZE 4096
 
char outbuf[BSIZE];
buffer bo = BUFFER_INIT(write,1,outbuf,sizeof(outbuf));
 
void nomem() { logmsg(WHO,111,FATAL,"out of memory"); }
void die_read() { logmsg(WHO,110,ERROR,"unable to read input: "); }
void die_write() { logmsg(WHO,110,ERROR,"unable to write output: "); }
 
stralloc file = {0};
int *width;
int maxfield = 0;
 
void nothing()
{
  ;
}
 
void printline()
{
  if (buffer_put(&bo,"\n",1) == -1) die_write();
}
 
void maxfield_check(int fieldnum,char *buf,int len)
{
  if (fieldnum > maxfield) maxfield = fieldnum;
}
 
void width_check(int fieldnum,char *buf,int len)
{
  if (len > width[fieldnum]) width[fieldnum] = len;
}
 
void width_init()
{
  int i;
 
  width = (int *) alloc((maxfield + 1) * sizeof(int));
  if (!width) nomem();
  for (i = 0; i <= maxfield; ++i) 
    width[i] = 0;
}
 
void printfield(int fieldnum,char *buf,int len)
{
  int i;
 
  if (fieldnum < maxfield)
    for (i = len; i < width[fieldnum]; ++i)
      if (buffer_put(&bo," ",1) == -1) die_write();
 
  if (buffer_put(&bo,buf,len) == -1) die_write();
 
  if (fieldnum < maxfield)
    if (buffer_put(&bo,"  ",2) == -1) die_write();
}
 
void split(void (*dofield)(), void (*doline)())
{
  int i;
  int j;
  int fieldpos;
  int fieldnum;
 
  for (j = i = 0; j < file.len; ++j)
    if (file.s[j] == '\n') {
      fieldnum = 0;
      for (;;) {
        while ((file.s[i] == ' ') || (file.s[i] == '\t')) ++i;
        if (i == j) break;
        fieldpos = i;
        while ((file.s[i] != ' ') && (file.s[i] != '\t') && (file.s[i] != '\n')) ++i;
        dofield(fieldnum++,file.s + fieldpos,i - fieldpos);
      }
      doline();
      i = j + 1;
    }
}
 
int main()
{
  if (readclose_append(0,&file,BSIZE) == -1) die_read();
  if (!file.len) _exit(0);
  if (file.s[file.len - 1] != '\n')
    if (!stralloc_append(&file,"\n")) nomem();
 
  split(maxfield_check,nothing);
  width_init();
  split(width_check,nothing);
  split(printfield,printline);
 
  if (buffer_flush(&bo) == -1) die_write();
  _exit(0);
}