Edit: printbuf.h
/* * $Id: printbuf.h,v 1.4 2006/01/26 02:16:28 mclark Exp $ * * Copyright (c) 2004, 2005 Metaparadigm Pte. Ltd. * Michael Clark <michael@metaparadigm.com> * * This library is free software; you can redistribute it and/or modify * it under the terms of the MIT license. See COPYING for details. * * * Copyright (c) 2008-2009 Yahoo! Inc. All rights reserved. * The copyrights to the contents of this file are licensed under the MIT License * (http://www.opensource.org/licenses/mit-license.php) */ /** * @file * @brief Internal string buffer handing. Unless you're writing a * json_object_to_json_string_fn implementation for use with * json_object_set_serializer() direct use of this is not * recommended. */ #ifndef _printbuf_h_ #define _printbuf_h_ #ifdef __cplusplus extern "C" { #endif struct printbuf { char *buf; int bpos; int size; }; typedef struct printbuf printbuf; extern struct printbuf* printbuf_new(void); /* As an optimization, printbuf_memappend_fast() is defined as a macro * that handles copying data if the buffer is large enough; otherwise * it invokes printbuf_memappend() which performs the heavy * lifting of realloc()ing the buffer and copying data. * * Your code should not use printbuf_memappend() directly unless it * checks the return code. Use printbuf_memappend_fast() instead. */ extern int printbuf_memappend(struct printbuf *p, const char *buf, int size); #define printbuf_memappend_fast(p, bufptr, bufsize) \ do { \ if ((p->size - p->bpos) > bufsize) { \ memcpy(p->buf + p->bpos, (bufptr), bufsize); \ p->bpos += bufsize; \ p->buf[p->bpos]= '\0'; \ } else { printbuf_memappend(p, (bufptr), bufsize); } \ } while (0) #define printbuf_length(p) ((p)->bpos) /** * Results in a compile error if the argument is not a string literal. */ #define _printbuf_check_literal(mystr) ("" mystr) /** * This is an optimization wrapper around printbuf_memappend() that is useful * for appending string literals. Since the size of string constants is known * at compile time, using this macro can avoid a costly strlen() call. This is * especially helpful when a constant string must be appended many times. If * you got here because of a compilation error caused by passing something * other than a string literal, use printbuf_memappend_fast() in conjunction * with strlen(). * * See also: * printbuf_memappend_fast() * printbuf_memappend() * sprintbuf() */ #define printbuf_strappend(pb, str) \ printbuf_memappend ((pb), _printbuf_check_literal(str), sizeof(str) - 1) /** * Set len bytes of the buffer to charvalue, starting at offset offset. * Similar to calling memset(x, charvalue, len); * * The memory allocated for the buffer is extended as necessary. * * If offset is -1, this starts at the end of the current data in the buffer. */ extern int printbuf_memset(struct printbuf *pb, int offset, int charvalue, int len); /** * Formatted print to printbuf. * * This function is the most expensive of the available functions for appending * string data to a printbuf and should be used only where convenience is more * important than speed. Avoid using this function in high performance code or * tight loops; in these scenarios, consider using snprintf() with a static * buffer in conjunction with one of the printbuf_*append() functions. * * See also: * printbuf_memappend_fast() * printbuf_memappend() * printbuf_strappend() */ extern int sprintbuf(struct printbuf *p, const char *msg, ...); extern void printbuf_reset(struct printbuf *p); extern void printbuf_free(struct printbuf *p); #ifdef __cplusplus } #endif #endif
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