140 lines
3.1 KiB
C
140 lines
3.1 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* Utility routines.
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*
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* Copyright (C) 2005, 2006 Rob Landley <rob@landley.net>
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* Copyright (C) 2004 Erik Andersen <andersen@codepoet.org>
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* Copyright (C) 2001 Matt Krai
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*
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* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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*/
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#include "libbb.h"
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/* This function reads an entire line from a text file, up to a newline
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* or NUL byte, inclusive. It returns a malloc'ed char * which
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* must be free'ed by the caller. If end is NULL '\n' isn't considered
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* end of line. If end isn't NULL, length of the chunk read is stored in it.
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* Return NULL if EOF/error */
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char* FAST_FUNC bb_get_chunk_from_file(FILE *file, int *end)
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{
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int ch;
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int idx = 0;
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char *linebuf = NULL;
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int linebufsz = 0;
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while ((ch = getc(file)) != EOF) {
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/* grow the line buffer as necessary */
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if (idx >= linebufsz) {
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linebufsz += 80;
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linebuf = xrealloc(linebuf, linebufsz);
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}
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linebuf[idx++] = (char) ch;
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if (!ch || (end && ch == '\n'))
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break;
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}
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if (end)
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*end = idx;
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if (linebuf) {
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// huh, does fgets discard prior data on error like this?
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// I don't think so....
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//if (ferror(file)) {
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// free(linebuf);
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// return NULL;
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//}
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linebuf = xrealloc(linebuf, idx + 1);
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linebuf[idx] = '\0';
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}
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return linebuf;
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}
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/* Get line, including trailing \n if any */
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char* FAST_FUNC xmalloc_fgets(FILE *file)
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{
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int i;
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return bb_get_chunk_from_file(file, &i);
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}
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/* Get line. Remove trailing \n */
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char* FAST_FUNC xmalloc_fgetline(FILE *file)
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{
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int i;
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char *c = bb_get_chunk_from_file(file, &i);
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if (i && c[--i] == '\n')
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c[i] = '\0';
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return c;
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}
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/* Faster routines (~twice as fast). +170 bytes. Unused as of 2008-07.
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*
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* NB: they stop at NUL byte too.
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* Performance is important here. Think "grep 50gigabyte_file"...
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* Iironically, grep can't use it because of NUL issue.
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* We sorely need C lib to provide fgets which reports size!
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*/
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static char* xmalloc_fgets_internal(FILE *file, int *sizep)
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{
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int len;
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int idx = 0;
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char *linebuf = NULL;
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while (1) {
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char *r;
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linebuf = xrealloc(linebuf, idx + 0x100);
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r = fgets(&linebuf[idx], 0x100, file);
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if (!r) {
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/* need to terminate in case this is error
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* (EOF puts NUL itself) */
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linebuf[idx] = '\0';
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break;
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}
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/* stupid. fgets knows the len, it should report it somehow */
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len = strlen(&linebuf[idx]);
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idx += len;
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if (len != 0xff || linebuf[idx - 1] == '\n')
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break;
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}
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*sizep = idx;
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if (idx) {
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/* xrealloc(linebuf, idx + 1) is up to caller */
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return linebuf;
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}
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free(linebuf);
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return NULL;
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}
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/* Get line, remove trailing \n */
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char* FAST_FUNC xmalloc_fgetline_fast(FILE *file)
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{
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int sz;
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char *r = xmalloc_fgets_internal(file, &sz);
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if (r && r[sz - 1] == '\n')
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r[--sz] = '\0';
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return r; /* not xrealloc(r, sz + 1)! */
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}
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#if 0
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char* FAST_FUNC xmalloc_fgets(FILE *file)
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{
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int sz;
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return xmalloc_fgets_internal(file, &sz);
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}
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/* Get line, remove trailing \n */
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char* FAST_FUNC xmalloc_fgetline(FILE *file)
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{
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int sz;
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char *r = xmalloc_fgets_internal(file, &sz);
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if (!r)
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return r;
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if (r[sz - 1] == '\n')
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r[--sz] = '\0';
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return xrealloc(r, sz + 1);
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}
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#endif
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