lparse.c

   1 #define _GNU_SOURCE 1
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4 #include <unistd.h>
   5 #include <string.h>
   6 #include <errno.h>
   7 #include <sys/types.h>
   8 #include <sys/stat.h>
   9 #include <fcntl.h>
  10 #include "lparse.h"
  11
  12 static char *buf;
  13 #define MAX_BUF ((512 * 1024) - 1)
  14
  15 int lparse_fd(int fd, size_t size, int (*parse)(char *, size_t))
  16 {
  17         size_t tot_rd = 0, parsed = 0;
  18
  19         if (!buf && !(buf = calloc(1, MAX_BUF + 1)))
  20                 return -1;
  21
  22         while (tot_rd < size) {
  23                 char *next, *cur;
  24                 int bytes_rd;
  25                 size_t blkparsed;
  26
  27                 bytes_rd = read(fd, buf, MAX_BUF < size ? MAX_BUF : size);
  28                 if (bytes_rd < 0)
  29                         return -1;
  30
  31                 if (tot_rd + bytes_rd < size) {
  32                         /* rewind the file to the last found newline */
  33                         while (buf[bytes_rd - 1] != '\n')
  34                                 bytes_rd--;
  35                         lseek(fd, tot_rd + bytes_rd, SEEK_SET);
  36                 }
  37                 tot_rd += bytes_rd;
  38
  39                 /* set a sentinel for memchr() */
  40                 buf[bytes_rd] = '\n';
  41
  42                 cur = buf;
  43                 for (blkparsed = 0; blkparsed < bytes_rd; cur = next + 1) {
  44                         size_t len;
  45                         next = memchr(cur, '\n', bytes_rd + 1 - blkparsed);
  46                         len = next - cur;
  47                         blkparsed += len + 1;
  48
  49                         cur[len] = '\0';
  50                         parse(cur, len);
  51                 }
  52                 parsed += cur - buf;
  53         }
  54
  55         return 0;
  56 }
  57
  58 int lparse_path(const char *path, size_t size, int (*parse)(char *, size_t))
  59 {
  60         int fd, result;
  61
  62         /* zero size files are never interesting */
  63         if (!size)
  64                 return 0;
  65
  66         if ((fd = open(path, O_RDONLY)) < 0)
  67                 return -1;
  68
  69         result = lparse_fd(fd, size, parse);
  70
  71         close(fd);
  72
  73         return result;
  74 }