gno/usr.bin/sort/loadarray.c

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1996-01-28 00:52:48 +00:00
#ifdef __CCFRONT__
#include <14:pragma.h>
#endif
#include "common.h"
#include <errno.h>
#include <stdlib.h>
#include <string.h>
/*
* char **loadarray (unsigned long n, char *filename, size_t maxlinelen);
*
* Pre: <filename> is the name of a file containing <n> lines of text,
* the number of lines. The file <filename> must be closed.
* <maxlinelen> is the length of the longest line in <filename>
*
* Post: Returns a pointer to an array of pointers to malloc'd strings,
* where the strings are successive lines from the file <filename>.
* On return <filename> will be closed. If loadarray() fails for
* any reason, it will return NULL.
*
* Warning: The use of realloc() with a NULL pointer for the initial
* allocation may not be portable. If this is not valid for your
* current libraries, then #define BROKEN_REALLOC.
*
* Uses Globals:
* v_flag
*/
char **loadarray (unsigned long n, char *filename, size_t maxlinelen) {
char **result;
unsigned long i,j;
FILE *in_fp;
static char *inbuf=NULL;
static size_t previous_size = 0;
char *p;
#ifndef BROKEN_REALLOC /* realloc() is ANSI-compliant with NULL first arg */
/* reallocate the input buffer if necessary */
if (maxlinelen > previous_size) {
if ((p = realloc(inbuf,maxlinelen+1)) == NULL) {
if (v_flag) perror("loadarray: couldn't (re)allocate input buffer");
return NULL;
}
previous_size = maxlinelen;
inbuf = p;
}
#else /* BROKEN_REALLOC */
/* reallocate the input buffer if necessary */
if (maxlinelen > previous_size) {
if (previous_size == 0) {
if ((p = malloc(maxlinelen+1)) == NULL) {
if (v_flag) perror("loadarray: couldn't allocate input buffer");
return NULL;
}
} else {
if ((p = realloc(inbuf,maxlinelen+1)) == NULL) {
if (v_flag) perror("loadarray: couldn't reallocate input buffer");
return NULL;
}
}
previous_size = maxlinelen;
inbuf = p;
}
#endif /* BROKEN_REALLOC */
/* allocate the array */
if ((result = malloc (n * sizeof(char *)))==NULL) {
if (v_flag) perror("loadarray: couldn't allocate base array");
return NULL;
}
/* set up the input stream */
in_fp = fopen(filename,"r");
if (in_fp == NULL) { /* open failed */
free(result);
if (v_flag) perror("loadarray: couldn't open input file");
return NULL;
}
/* allocate and copy elements */
for (i=0; i<n; i++) {
/* read into the buffer */
if(fgets(inbuf,maxlinelen+1,in_fp)==NULL) {
/* read failed; clean up and exit */
if (v_flag) {
if (ferror(in_fp)) perror("loadarray: read error on input file");
else perror ("loadarray: premature EOF on input file");
}
for (j=0; j<i; j++) free(result[j]);
free(result);
fclose(in_fp);
return NULL;
}
/* copy the buffer to the array */
result[i] = malloc(strlen(inbuf)+1);
if (result[i]==NULL) {
/* malloc failed; clean up and exit */
if (v_flag) perror("loadarray: couldn't duplicate buffer");
for (j=0; j<i; j++) free(result[j]);
free(result);
fclose(in_fp);
return NULL;
}
strcpy(result[i],inbuf);
}
fclose(in_fp);
return result;
}