/* getndelim2 - Read a line from a stream, stopping at one of 2 delimiters,
with bounded memory allocation.
- Copyright (C) 1993, 1996, 1997, 1998, 2000, 2003, 2004, 2006 Free
+ Copyright (C) 1993, 1996-1998, 2000, 2003-2004, 2006, 2008-2014 Free
Software Foundation, Inc.
This program is free software: you can redistribute it and/or modify
#include "getndelim2.h"
-#include <stdlib.h>
+#include <stdbool.h>
#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
#if USE_UNLOCKED_IO
# include "unlocked-io.h"
#endif
+#if !HAVE_FLOCKFILE
+# undef flockfile
+# define flockfile(x) ((void) 0)
+#endif
+#if !HAVE_FUNLOCKFILE
+# undef funlockfile
+# define funlockfile(x) ((void) 0)
+#endif
#include <limits.h>
#include <stdint.h>
+#include "freadptr.h"
+#include "freadseek.h"
+#include "memchr2.h"
+
#ifndef SSIZE_MAX
# define SSIZE_MAX ((ssize_t) (SIZE_MAX / 2))
#endif
+/* Use this to suppress gcc's "...may be used before initialized" warnings. */
+#ifdef lint
+# define IF_LINT(Code) Code
+#else
+# define IF_LINT(Code) /* empty */
+#endif
+
/* The maximum value that getndelim2 can return without suffering from
overflow problems, either internally (because of pointer
subtraction overflow) or due to the API (because of ssize_t). */
getndelim2 (char **lineptr, size_t *linesize, size_t offset, size_t nmax,
int delim1, int delim2, FILE *stream)
{
- size_t nbytes_avail; /* Allocated but unused bytes in *LINEPTR. */
- char *read_pos; /* Where we're reading into *LINEPTR. */
+ size_t nbytes_avail; /* Allocated but unused bytes in *LINEPTR. */
+ char *read_pos; /* Where we're reading into *LINEPTR. */
ssize_t bytes_stored = -1;
char *ptr = *lineptr;
size_t size = *linesize;
+ bool found_delimiter;
if (!ptr)
{
size = nmax < MIN_CHUNK ? nmax : MIN_CHUNK;
ptr = malloc (size);
if (!ptr)
- return -1;
+ return -1;
}
if (size < offset)
if (nbytes_avail == 0 && nmax <= size)
goto done;
- for (;;)
- {
- /* Here always ptr + size == read_pos + nbytes_avail. */
+ /* Normalize delimiters, since memchr2 doesn't handle EOF. */
+ if (delim1 == EOF)
+ delim1 = delim2;
+ else if (delim2 == EOF)
+ delim2 = delim1;
- int c;
+ flockfile (stream);
+
+ found_delimiter = false;
+ do
+ {
+ /* Here always ptr + size == read_pos + nbytes_avail.
+ Also nbytes_avail > 0 || size < nmax. */
+
+ int c IF_LINT (= 0);
+ const char *buffer;
+ size_t buffer_len;
+
+ buffer = freadptr (stream, &buffer_len);
+ if (buffer)
+ {
+ if (delim1 != EOF)
+ {
+ const char *end = memchr2 (buffer, delim1, delim2, buffer_len);
+ if (end)
+ {
+ buffer_len = end - buffer + 1;
+ found_delimiter = true;
+ }
+ }
+ }
+ else
+ {
+ c = getc (stream);
+ if (c == EOF)
+ {
+ /* Return partial line, if any. */
+ if (read_pos == ptr)
+ goto unlock_done;
+ else
+ break;
+ }
+ if (c == delim1 || c == delim2)
+ found_delimiter = true;
+ buffer_len = 1;
+ }
/* We always want at least one byte left in the buffer, since we
- always (unless we get an error while reading the first byte)
- NUL-terminate the line buffer. */
-
- if (nbytes_avail < 2 && size < nmax)
- {
- size_t newsize = size < MIN_CHUNK ? size + MIN_CHUNK : 2 * size;
- char *newptr;
-
- if (! (size < newsize && newsize <= nmax))
- newsize = nmax;
-
- if (GETNDELIM2_MAXIMUM < newsize - offset)
- {
- size_t newsizemax = offset + GETNDELIM2_MAXIMUM + 1;
- if (size == newsizemax)
- goto done;
- newsize = newsizemax;
- }
-
- nbytes_avail = newsize - (read_pos - ptr);
- newptr = realloc (ptr, newsize);
- if (!newptr)
- goto done;
- ptr = newptr;
- size = newsize;
- read_pos = size - nbytes_avail + ptr;
- }
-
- c = getc (stream);
- if (c == EOF)
- {
- /* Return partial line, if any. */
- if (read_pos == ptr)
- goto done;
- else
- break;
- }
-
- if (nbytes_avail >= 2)
- {
- *read_pos++ = c;
- nbytes_avail--;
- }
-
- if (c == delim1 || c == delim2)
- /* Return the line. */
- break;
+ always (unless we get an error while reading the first byte)
+ NUL-terminate the line buffer. */
+
+ if (nbytes_avail < buffer_len + 1 && size < nmax)
+ {
+ /* Grow size proportionally, not linearly, to avoid O(n^2)
+ running time. */
+ size_t newsize = size < MIN_CHUNK ? size + MIN_CHUNK : 2 * size;
+ char *newptr;
+
+ /* Increase newsize so that it becomes
+ >= (read_pos - ptr) + buffer_len. */
+ if (newsize - (read_pos - ptr) < buffer_len + 1)
+ newsize = (read_pos - ptr) + buffer_len + 1;
+ /* Respect nmax. This handles possible integer overflow. */
+ if (! (size < newsize && newsize <= nmax))
+ newsize = nmax;
+
+ if (GETNDELIM2_MAXIMUM < newsize - offset)
+ {
+ size_t newsizemax = offset + GETNDELIM2_MAXIMUM + 1;
+ if (size == newsizemax)
+ goto unlock_done;
+ newsize = newsizemax;
+ }
+
+ nbytes_avail = newsize - (read_pos - ptr);
+ newptr = realloc (ptr, newsize);
+ if (!newptr)
+ goto unlock_done;
+ ptr = newptr;
+ size = newsize;
+ read_pos = size - nbytes_avail + ptr;
+ }
+
+ /* Here, if size < nmax, nbytes_avail >= buffer_len + 1.
+ If size == nmax, nbytes_avail > 0. */
+
+ if (1 < nbytes_avail)
+ {
+ size_t copy_len = nbytes_avail - 1;
+ if (buffer_len < copy_len)
+ copy_len = buffer_len;
+ if (buffer)
+ memcpy (read_pos, buffer, copy_len);
+ else
+ *read_pos = c;
+ read_pos += copy_len;
+ nbytes_avail -= copy_len;
+ }
+
+ /* Here still nbytes_avail > 0. */
+
+ if (buffer && freadseek (stream, buffer_len))
+ goto unlock_done;
}
+ while (!found_delimiter);
/* Done - NUL terminate and return the number of bytes read.
At this point we know that nbytes_avail >= 1. */
bytes_stored = read_pos - (ptr + offset);
+ unlock_done:
+ funlockfile (stream);
+
done:
*lineptr = ptr;
*linesize = size;
- return bytes_stored;
+ return bytes_stored ? bytes_stored : -1;
}
projects / gnulib.git / blobdiff