Asterisk.org: Developer Documentation (28 Oct 2009)

Wed Oct 28 15:47:47 2009

## Asterisk developer's documentation

# alaw.h

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    00001 /*
    00002  * Asterisk -- An open source telephony toolkit.
    00003  *
    00004  * Copyright (C) 1999 - 2005, Digium, Inc.
    00005  *
    00006  * Mark Spencer <markster@digium.com>
    00007  *
    00008  * See http://www.asterisk.org for more information about
    00009  * the Asterisk project. Please do not directly contact
    00010  * any of the maintainers of this project for assistance;
    00011  * the project provides a web site, mailing lists and IRC
    00012  * channels for your use.
    00013  *
    00014  * This program is free software, distributed under the terms of
    00015  * the GNU General Public License Version 2. See the LICENSE file
    00016  * at the top of the source tree.
    00017  */
    00018
    00019 /*! \file
    00020  * \brief A-Law to Signed linear conversion
    00021  */
    00022
    00023 #ifndef _ASTERISK_ALAW_H
    00024 #define _ASTERISK_ALAW_H
    00025
    00026 /*! Init the ulaw conversion stuff */
    00027 /*!
    00028  * To init the ulaw to slinear conversion stuff, this needs to be run.
    00029  */
    00030 extern void ast_alaw_init(void);
    00031
    00032 /*! converts signed linear to mulaw */
    00033 /*!
    00034   */
    00035 extern unsigned char __ast_lin2a[8192];
    00036
    00037 /*! help */
    00038 extern short __ast_alaw[256];
    00039
    00040 #define AST_LIN2A(a) (__ast_lin2a[((unsigned short)(a)) >> 3])
    00041 #define AST_ALAW(a) (__ast_alaw[(int)(a)])
    00042
    00043 #endif /* _ASTERISK_ALAW_H */