file

file.c

/*
file.c
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>

#define FEED "\r\n" /* windows */

/*
get file size (byte)
@name: read file name
*/
unsigned long file_size (const char *name) {
    FILE *fp;
    struct stat statbuf;
    
    fp = fopen(name, "rb");
    if (!fp)
        return 0;
    if (fstat(fileno(fp), &statbuf) == -1) {
        fclose(fp);
        return 0;
    }
    fclose(fp);
    return (unsigned long) statbuf.st_size;
}

/*
count char length in file
length is not include EOF
@name: read file name
*/
unsigned long file_length (const char *name) {
    FILE *fp;
    unsigned long i = 0;

    fp = fopen(name, "rb");
    if (!fp)
        return 0;
    while (fgetc(fp) != EOF)
        i++;
    fclose(fp);
    return i;
}

/*
read all string in file
result string not include EOF
@name: read file name
Note: return string need free(res)
    char *p = file_read("aaa");
    free(p);
*/
char *file_read (const char *name) {
    FILE *fp;
    char *res;
    char *tmp;

    /* file_size() faster than file_length() */
    tmp = res = malloc((file_size(name) + 1) * sizeof(char));
    if (!res)
        return NULL;
    fp = fopen(name, "rb");
    if (!fp) {
        free(res);
        return NULL;
    }
    while ((*tmp++ = fgetc(fp)) != EOF)
        /* nothig */;
    *--tmp = '\0';
    fclose(fp);
    return res;
}

/*
count max line number in file
@name: read file name
*/
long file_lines (const char *name) {
    long lines = 0;
    char *read = file_read(name);
    char *p = read;

    if (!read)
        return 0;
    while (p = strstr(p, FEED)) {
        p++;
        lines++;
    }
    lines++;
    free(read);
    return lines;
}

/*
make new array from file
@name: read file name
example:
    // fp => example.txt //
    foo\r\n
    bar\r\n
    baz(EOF)
return: res = {
    res[0] = "foo",
    res[1] = "bar",
    res[2] = "baz"
    res[3] = NULL (end of array)
    (*res = "foo\0\0bar\0\0baz")
}
Note: need free(*res) && free(res)
    char **pp = file_make_array("aaa");
    free(*pp);
    free(pp);
*/
char **file_make_array (const char *name) {
    char **res;
    char *p;
    size_t i = 0;
    int j = 0;
    const int feed_len = strlen(FEED);

    /* 32bit PC: address is 4 byte, 64bit PC: address is 8 byte */
    res = malloc((file_lines(name) + 1) * sizeof(res));
    if (!res)
        return NULL;
    p = file_read(name);
    if (!p) {
        free(res);
        return NULL;
    }

    while (*p) {
        res[i++] = p;
        res[i] = NULL;
        p = strstr(p, FEED);
        if (!p)
            break;
        for (j = 0; j < feed_len; j++)
            *p++ = '\0';
    }
    return res;
}

file.h

/*
file.h
*/

#ifndef FILE_H
#define FILE_H 1

#if defined(__cplusplus)
extern "C" {
#endif

extern unsigned long file_size (const char *);
extern unsigned long file_length (const char *);
extern char *file_read (const char *);
extern long file_lines (const char *);
extern char **file_make_array (const char *);

#if defined(__cplusplus)
}  /* extern "C" { */
#endif

#endif /* FILE_H */