| t2ex/bsd_source/lib/libc/src_bsd/stdio/setvbuf.c | bare source | permlink (0.01 seconds) |
1: /* $OpenBSD: setvbuf.c,v 1.11 2009/11/09 00:18:27 kurt Exp $ */ 2: /*- 3: * Copyright (c) 1990, 1993 4: * The Regents of the University of California. All rights reserved. 5: * 6: * This code is derived from software contributed to Berkeley by 7: * Chris Torek. 8: * 9: * Redistribution and use in source and binary forms, with or without 10: * modification, are permitted provided that the following conditions 11: * are met: 12: * 1. Redistributions of source code must retain the above copyright 13: * notice, this list of conditions and the following disclaimer. 14: * 2. Redistributions in binary form must reproduce the above copyright 15: * notice, this list of conditions and the following disclaimer in the 16: * documentation and/or other materials provided with the distribution. 17: * 3. Neither the name of the University nor the names of its contributors 18: * may be used to endorse or promote products derived from this software 19: * without specific prior written permission. 20: * 21: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31: * SUCH DAMAGE. 32: */ 33: 34: #include <stdio.h> 35: #include <stdlib.h> 36: #include "local.h" 37: 38: /* 39: * Set one of the three kinds of buffering, optionally including 40: * a buffer. 41: */ 42: int 43: setvbuf(FILE *fp, char *buf, int mode, size_t size) 44: { 45: int ret, flags; 46: size_t iosize; 47: int ttyflag; 48: 49: /* 50: * Verify arguments. The `int' limit on `size' is due to this 51: * particular implementation. Note, buf and size are ignored 52: * when setting _IONBF. 53: */ 54: if (mode != _IONBF) 55: if ((mode != _IOFBF && mode != _IOLBF) || (int)size < 0) 56: return (EOF); 57: 58: /* 59: * Write current buffer, if any. Discard unread input (including 60: * ungetc data), cancel line buffering, and free old buffer if 61: * malloc()ed. We also clear any eof condition, as if this were 62: * a seek. 63: */ 64: FLOCKFILE(fp); 65: ret = 0; 66: (void)__sflush(fp); 67: if (HASUB(fp)) 68: FREEUB(fp); 69: WCIO_FREE(fp); 70: fp->_r = fp->_lbfsize = 0; 71: flags = fp->_flags; 72: if (flags & __SMBF) 73: free((void *)fp->_bf._base); 74: flags &= ~(__SLBF | __SNBF | __SMBF | __SOPT | __SNPT | __SEOF); 75: 76: /* If setting unbuffered mode, skip all the hard work. */ 77: if (mode == _IONBF) 78: goto nbf; 79: 80: /* 81: * Find optimal I/O size for seek optimization. This also returns 82: * a `tty flag' to suggest that we check isatty(fd), but we do not 83: * care since our caller told us how to buffer. 84: */ 85: flags |= __swhatbuf(fp, &iosize, &ttyflag); 86: if (size == 0) { 87: buf = NULL; /* force local allocation */ 88: size = iosize; 89: } 90: 91: /* Allocate buffer if needed. */ 92: if (buf == NULL) { 93: if ((buf = malloc(size)) == NULL) { 94: /* 95: * Unable to honor user's request. We will return 96: * failure, but try again with file system size. 97: */ 98: ret = EOF; 99: if (size != iosize) { 100: size = iosize; 101: buf = malloc(size); 102: } 103: } 104: if (buf == NULL) { 105: /* No luck; switch to unbuffered I/O. */ 106: nbf: 107: fp->_flags = flags | __SNBF; 108: fp->_w = 0; 109: fp->_bf._base = fp->_p = fp->_nbuf; 110: fp->_bf._size = 1; 111: FUNLOCKFILE(fp); 112: return (ret); 113: } 114: flags |= __SMBF; 115: } 116: 117: /* 118: * Kill any seek optimization if the buffer is not the 119: * right size. 120: * 121: * SHOULD WE ALLOW MULTIPLES HERE (i.e., ok iff (size % iosize) == 0)? 122: */ 123: if (size != iosize) 124: flags |= __SNPT; 125: 126: /* 127: * Fix up the FILE fields, and set __cleanup for output flush on 128: * exit (since we are buffered in some way). 129: */ 130: if (mode == _IOLBF) 131: flags |= __SLBF; 132: fp->_flags = flags; 133: fp->_bf._base = fp->_p = (unsigned char *)buf; 134: fp->_bf._size = size; 135: /* fp->_lbfsize is still 0 */ 136: if (flags & __SWR) { 137: /* 138: * Begin or continue writing: see __swsetup(). Note 139: * that __SNBF is impossible (it was handled earlier). 140: */ 141: if (flags & __SLBF) { 142: fp->_w = 0; 143: fp->_lbfsize = -fp->_bf._size; 144: } else 145: fp->_w = size; 146: } else { 147: /* begin/continue reading, or stay in intermediate state */ 148: fp->_w = 0; 149: } 150: FUNLOCKFILE(fp); 151: __atexit_register_cleanup(_cleanup); 152: 153: return (ret); 154: }