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diff --git a/lib/lwres/man/lwres_buffer.html b/lib/lwres/man/lwres_buffer.html new file mode 100644 index 0000000..deb5262 --- /dev/null +++ b/lib/lwres/man/lwres_buffer.html @@ -0,0 +1,455 @@ +<!-- + - Copyright (C) 2004, 2005, 2007 Internet Systems Consortium, Inc. ("ISC") + - Copyright (C) 2000, 2001 Internet Software Consortium. + - + - Permission to use, copy, modify, and distribute this software for any + - purpose with or without fee is hereby granted, provided that the above + - copyright notice and this permission notice appear in all copies. + - + - THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH + - REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY + - AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, + - INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM + - LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE + - OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR + - PERFORMANCE OF THIS SOFTWARE. +--> +<!-- $Id: lwres_buffer.html,v 1.21 2007/01/30 00:24:59 marka Exp $ --> +<html> +<head> +<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> +<title>lwres_buffer</title> +<meta name="generator" content="DocBook XSL Stylesheets V1.71.1"> +</head> +<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="refentry" lang="en"> +<a name="id2476275"></a><div class="titlepage"></div> +<div class="refnamediv"> +<h2>Name</h2> +<p>lwres_buffer_init, lwres_buffer_invalidate, lwres_buffer_add, lwres_buffer_subtract, lwres_buffer_clear, lwres_buffer_first, lwres_buffer_forward, lwres_buffer_back, lwres_buffer_getuint8, lwres_buffer_putuint8, lwres_buffer_getuint16, lwres_buffer_putuint16, lwres_buffer_getuint32, lwres_buffer_putuint32, lwres_buffer_putmem, lwres_buffer_getmem — lightweight resolver buffer management</p> +</div> +<div class="refsynopsisdiv"> +<h2>Synopsis</h2> +<div class="funcsynopsis"> +<pre class="funcsynopsisinfo"> +#include <lwres/lwbuffer.h> +</pre> +<table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" style="padding-bottom: 1em"> +<tr> +<td><code class="funcdef"> +void +<b class="fsfunc">lwres_buffer_init</b>(</code></td> +<td>lwres_buffer_t * </td> +<td> +<var class="pdparam">b</var>, </td> +</tr> +<tr> +<td> </td> +<td>void * </td> +<td> +<var class="pdparam">base</var>, </td> +</tr> +<tr> +<td> </td> +<td>unsigned int </td> +<td> +<var class="pdparam">length</var><code>)</code>;</td> +</tr> +</table> +<table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" style="padding-bottom: 1em"><tr> +<td><code class="funcdef"> +void +<b class="fsfunc">lwres_buffer_invalidate</b>(</code></td> +<td>lwres_buffer_t * </td> +<td> +<var class="pdparam">b</var><code>)</code>;</td> +</tr></table> +<table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" style="padding-bottom: 1em"> +<tr> +<td><code class="funcdef"> +void +<b class="fsfunc">lwres_buffer_add</b>(</code></td> +<td>lwres_buffer_t * </td> +<td> +<var class="pdparam">b</var>, </td> +</tr> +<tr> +<td> </td> +<td>unsigned int </td> +<td> +<var class="pdparam">n</var><code>)</code>;</td> +</tr> +</table> +<table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" style="padding-bottom: 1em"> +<tr> +<td><code class="funcdef"> +void +<b class="fsfunc">lwres_buffer_subtract</b>(</code></td> +<td>lwres_buffer_t * </td> +<td> +<var class="pdparam">b</var>, </td> +</tr> +<tr> +<td> </td> +<td>unsigned int </td> +<td> +<var class="pdparam">n</var><code>)</code>;</td> +</tr> +</table> +<table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" style="padding-bottom: 1em"><tr> +<td><code class="funcdef"> +void +<b class="fsfunc">lwres_buffer_clear</b>(</code></td> +<td>lwres_buffer_t * </td> +<td> +<var class="pdparam">b</var><code>)</code>;</td> +</tr></table> +<table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" style="padding-bottom: 1em"><tr> +<td><code class="funcdef"> +void +<b class="fsfunc">lwres_buffer_first</b>(</code></td> +<td>lwres_buffer_t * </td> +<td> +<var class="pdparam">b</var><code>)</code>;</td> +</tr></table> +<table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" style="padding-bottom: 1em"> +<tr> +<td><code class="funcdef"> +void +<b class="fsfunc">lwres_buffer_forward</b>(</code></td> +<td>lwres_buffer_t * </td> +<td> +<var class="pdparam">b</var>, </td> +</tr> +<tr> +<td> </td> +<td>unsigned int </td> +<td> +<var class="pdparam">n</var><code>)</code>;</td> +</tr> +</table> +<table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" style="padding-bottom: 1em"> +<tr> +<td><code class="funcdef"> +void +<b class="fsfunc">lwres_buffer_back</b>(</code></td> +<td>lwres_buffer_t * </td> +<td> +<var class="pdparam">b</var>, </td> +</tr> +<tr> +<td> </td> +<td>unsigned int </td> +<td> +<var class="pdparam">n</var><code>)</code>;</td> +</tr> +</table> +<table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" style="padding-bottom: 1em"><tr> +<td><code class="funcdef"> +lwres_uint8_t +<b class="fsfunc">lwres_buffer_getuint8</b>(</code></td> +<td>lwres_buffer_t * </td> +<td> +<var class="pdparam">b</var><code>)</code>;</td> +</tr></table> +<table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" style="padding-bottom: 1em"> +<tr> +<td><code class="funcdef"> +void +<b class="fsfunc">lwres_buffer_putuint8</b>(</code></td> +<td>lwres_buffer_t * </td> +<td> +<var class="pdparam">b</var>, </td> +</tr> +<tr> +<td> </td> +<td>lwres_uint8_t </td> +<td> +<var class="pdparam">val</var><code>)</code>;</td> +</tr> +</table> +<table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" style="padding-bottom: 1em"><tr> +<td><code class="funcdef"> +lwres_uint16_t +<b class="fsfunc">lwres_buffer_getuint16</b>(</code></td> +<td>lwres_buffer_t * </td> +<td> +<var class="pdparam">b</var><code>)</code>;</td> +</tr></table> +<table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" style="padding-bottom: 1em"> +<tr> +<td><code class="funcdef"> +void +<b class="fsfunc">lwres_buffer_putuint16</b>(</code></td> +<td>lwres_buffer_t * </td> +<td> +<var class="pdparam">b</var>, </td> +</tr> +<tr> +<td> </td> +<td>lwres_uint16_t </td> +<td> +<var class="pdparam">val</var><code>)</code>;</td> +</tr> +</table> +<table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" style="padding-bottom: 1em"><tr> +<td><code class="funcdef"> +lwres_uint32_t +<b class="fsfunc">lwres_buffer_getuint32</b>(</code></td> +<td>lwres_buffer_t * </td> +<td> +<var class="pdparam">b</var><code>)</code>;</td> +</tr></table> +<table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" style="padding-bottom: 1em"> +<tr> +<td><code class="funcdef"> +void +<b class="fsfunc">lwres_buffer_putuint32</b>(</code></td> +<td>lwres_buffer_t * </td> +<td> +<var class="pdparam">b</var>, </td> +</tr> +<tr> +<td> </td> +<td>lwres_uint32_t </td> +<td> +<var class="pdparam">val</var><code>)</code>;</td> +</tr> +</table> +<table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" style="padding-bottom: 1em"> +<tr> +<td><code class="funcdef"> +void +<b class="fsfunc">lwres_buffer_putmem</b>(</code></td> +<td>lwres_buffer_t * </td> +<td> +<var class="pdparam">b</var>, </td> +</tr> +<tr> +<td> </td> +<td>const unsigned char * </td> +<td> +<var class="pdparam">base</var>, </td> +</tr> +<tr> +<td> </td> +<td>unsigned int </td> +<td> +<var class="pdparam">length</var><code>)</code>;</td> +</tr> +</table> +<table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"> +<tr> +<td><code class="funcdef"> +void +<b class="fsfunc">lwres_buffer_getmem</b>(</code></td> +<td>lwres_buffer_t * </td> +<td> +<var class="pdparam">b</var>, </td> +</tr> +<tr> +<td> </td> +<td>unsigned char * </td> +<td> +<var class="pdparam">base</var>, </td> +</tr> +<tr> +<td> </td> +<td>unsigned int </td> +<td> +<var class="pdparam">length</var><code>)</code>;</td> +</tr> +</table> +</div> +</div> +<div class="refsect1" lang="en"> +<a name="id2543892"></a><h2>DESCRIPTION</h2> +<p> + These functions provide bounds checked access to a region of memory + where data is being read or written. + They are based on, and similar to, the + <code class="literal">isc_buffer_</code> + functions in the ISC library. + </p> +<p> + A buffer is a region of memory, together with a set of related + subregions. + The <span class="emphasis"><em>used region</em></span> and the + <span class="emphasis"><em>available</em></span> region are disjoint, and + their union is the buffer's region. + The used region extends from the beginning of the buffer region to the + last used byte. + The available region extends from one byte greater than the last used + byte to the end of the buffer's region. + The size of the used region can be changed using various + buffer commands. + Initially, the used region is empty. + </p> +<p> + The used region is further subdivided into two disjoint regions: the + <span class="emphasis"><em>consumed region</em></span> and the <span class="emphasis"><em>remaining region</em></span>. + The union of these two regions is the used region. + The consumed region extends from the beginning of the used region to + the byte before the <span class="emphasis"><em>current</em></span> offset (if any). + The <span class="emphasis"><em>remaining</em></span> region the current pointer to the end + of the used + region. + The size of the consumed region can be changed using various + buffer commands. + Initially, the consumed region is empty. + </p> +<p> + The <span class="emphasis"><em>active region</em></span> is an (optional) subregion of the + remaining + region. + It extends from the current offset to an offset in the + remaining region. + Initially, the active region is empty. + If the current offset advances beyond the chosen offset, + the active region will also be empty. + </p> +<pre class="programlisting"> + /------------entire length---------------\\ + /----- used region -----\\/-- available --\\ + +----------------------------------------+ + | consumed | remaining | | + +----------------------------------------+ + a b c d e + </pre> +<p> + </p> +<pre class="programlisting"> + a == base of buffer. + b == current pointer. Can be anywhere between a and d. + c == active pointer. Meaningful between b and d. + d == used pointer. + e == length of buffer. + </pre> +<p> + </p> +<pre class="programlisting"> + a-e == entire length of buffer. + a-d == used region. + a-b == consumed region. + b-d == remaining region. + b-c == optional active region. +</pre> +<p> + </p> +<p><code class="function">lwres_buffer_init()</code> + initializes the + <span class="type">lwres_buffer_t</span> + <em class="parameter"><code>*b</code></em> + and assocates it with the memory region of size + <em class="parameter"><code>length</code></em> + bytes starting at location + <em class="parameter"><code>base.</code></em> + </p> +<p><code class="function">lwres_buffer_invalidate()</code> + marks the buffer <em class="parameter"><code>*b</code></em> + as invalid. Invalidating a buffer after use is not required, + but makes it possible to catch its possible accidental use. + </p> +<p> + The functions + <code class="function">lwres_buffer_add()</code> + and + <code class="function">lwres_buffer_subtract()</code> + respectively increase and decrease the used space in + buffer + <em class="parameter"><code>*b</code></em> + by + <em class="parameter"><code>n</code></em> + bytes. + <code class="function">lwres_buffer_add()</code> + checks for buffer overflow and + <code class="function">lwres_buffer_subtract()</code> + checks for underflow. + These functions do not allocate or deallocate memory. + They just change the value of + <em class="structfield"><code>used</code></em>. + </p> +<p> + A buffer is re-initialised by + <code class="function">lwres_buffer_clear()</code>. + The function sets + <em class="structfield"><code>used</code></em>, + <em class="structfield"><code>current</code></em> + and + <em class="structfield"><code>active</code></em> + to zero. + </p> +<p><code class="function">lwres_buffer_first</code> + makes the consumed region of buffer + <em class="parameter"><code>*p</code></em> + empty by setting + <em class="structfield"><code>current</code></em> + to zero (the start of the buffer). + </p> +<p><code class="function">lwres_buffer_forward()</code> + increases the consumed region of buffer + <em class="parameter"><code>*b</code></em> + by + <em class="parameter"><code>n</code></em> + bytes, checking for overflow. + Similarly, + <code class="function">lwres_buffer_back()</code> + decreases buffer + <em class="parameter"><code>b</code></em>'s + consumed region by + <em class="parameter"><code>n</code></em> + bytes and checks for underflow. + </p> +<p><code class="function">lwres_buffer_getuint8()</code> + reads an unsigned 8-bit integer from + <em class="parameter"><code>*b</code></em> + and returns it. + <code class="function">lwres_buffer_putuint8()</code> + writes the unsigned 8-bit integer + <em class="parameter"><code>val</code></em> + to buffer + <em class="parameter"><code>*b</code></em>. + </p> +<p><code class="function">lwres_buffer_getuint16()</code> + and + <code class="function">lwres_buffer_getuint32()</code> + are identical to + <code class="function">lwres_buffer_putuint8()</code> + except that they respectively read an unsigned 16-bit or 32-bit integer + in network byte order from + <em class="parameter"><code>b</code></em>. + Similarly, + <code class="function">lwres_buffer_putuint16()</code> + and + <code class="function">lwres_buffer_putuint32()</code> + writes the unsigned 16-bit or 32-bit integer + <em class="parameter"><code>val</code></em> + to buffer + <em class="parameter"><code>b</code></em>, + in network byte order. + </p> +<p> + Arbitrary amounts of data are read or written from a lightweight + resolver buffer with + <code class="function">lwres_buffer_getmem()</code> + and + <code class="function">lwres_buffer_putmem()</code> + respectively. + <code class="function">lwres_buffer_putmem()</code> + copies + <em class="parameter"><code>length</code></em> + bytes of memory at + <em class="parameter"><code>base</code></em> + to + <em class="parameter"><code>b</code></em>. + Conversely, + <code class="function">lwres_buffer_getmem()</code> + copies + <em class="parameter"><code>length</code></em> + bytes of memory from + <em class="parameter"><code>b</code></em> + to + <em class="parameter"><code>base</code></em>. + </p> +</div> +</div></body> +</html> |