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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 | /* * Linear conversion Plug-In * Copyright (c) 1999 by Jaroslav Kysela <perex@perex.cz>, * Abramo Bagnara <abramo@alsa-project.org> * * * This library is free software; you can redistribute it and/or modify * it under the terms of the GNU Library General Public License as * published by the Free Software Foundation; either version 2 of * the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Library General Public License for more details. * * You should have received a copy of the GNU Library General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * */ #include <linux/time.h> #include <sound/core.h> #include <sound/pcm.h> #include "pcm_plugin.h" /* * Basic linear conversion plugin */ struct linear_priv { int cvt_endian; /* need endian conversion? */ unsigned int src_ofs; /* byte offset in source format */ unsigned int dst_ofs; /* byte soffset in destination format */ unsigned int copy_ofs; /* byte offset in temporary u32 data */ unsigned int dst_bytes; /* byte size of destination format */ unsigned int copy_bytes; /* bytes to copy per conversion */ unsigned int flip; /* MSB flip for signeness, done after endian conv */ }; static inline void do_convert(struct linear_priv *data, unsigned char *dst, unsigned char *src) { unsigned int tmp = 0; unsigned char *p = (unsigned char *)&tmp; memcpy(p + data->copy_ofs, src + data->src_ofs, data->copy_bytes); if (data->cvt_endian) tmp = swab32(tmp); tmp ^= data->flip; memcpy(dst, p + data->dst_ofs, data->dst_bytes); } static void convert(struct snd_pcm_plugin *plugin, const struct snd_pcm_plugin_channel *src_channels, struct snd_pcm_plugin_channel *dst_channels, snd_pcm_uframes_t frames) { struct linear_priv *data = (struct linear_priv *)plugin->extra_data; int channel; int nchannels = plugin->src_format.channels; for (channel = 0; channel < nchannels; ++channel) { char *src; char *dst; int src_step, dst_step; snd_pcm_uframes_t frames1; if (!src_channels[channel].enabled) { if (dst_channels[channel].wanted) snd_pcm_area_silence(&dst_channels[channel].area, 0, frames, plugin->dst_format.format); dst_channels[channel].enabled = 0; continue; } dst_channels[channel].enabled = 1; src = src_channels[channel].area.addr + src_channels[channel].area.first / 8; dst = dst_channels[channel].area.addr + dst_channels[channel].area.first / 8; src_step = src_channels[channel].area.step / 8; dst_step = dst_channels[channel].area.step / 8; frames1 = frames; while (frames1-- > 0) { do_convert(data, dst, src); src += src_step; dst += dst_step; } } } static snd_pcm_sframes_t linear_transfer(struct snd_pcm_plugin *plugin, const struct snd_pcm_plugin_channel *src_channels, struct snd_pcm_plugin_channel *dst_channels, snd_pcm_uframes_t frames) { if (snd_BUG_ON(!plugin || !src_channels || !dst_channels)) return -ENXIO; if (frames == 0) return 0; #ifdef CONFIG_SND_DEBUG { unsigned int channel; for (channel = 0; channel < plugin->src_format.channels; channel++) { if (snd_BUG_ON(src_channels[channel].area.first % 8 || src_channels[channel].area.step % 8)) return -ENXIO; if (snd_BUG_ON(dst_channels[channel].area.first % 8 || dst_channels[channel].area.step % 8)) return -ENXIO; } } #endif if (frames > dst_channels[0].frames) frames = dst_channels[0].frames; convert(plugin, src_channels, dst_channels, frames); return frames; } static void init_data(struct linear_priv *data, snd_pcm_format_t src_format, snd_pcm_format_t dst_format) { int src_le, dst_le, src_bytes, dst_bytes; src_bytes = snd_pcm_format_width(src_format) / 8; dst_bytes = snd_pcm_format_width(dst_format) / 8; src_le = snd_pcm_format_little_endian(src_format) > 0; dst_le = snd_pcm_format_little_endian(dst_format) > 0; data->dst_bytes = dst_bytes; data->cvt_endian = src_le != dst_le; data->copy_bytes = src_bytes < dst_bytes ? src_bytes : dst_bytes; if (src_le) { data->copy_ofs = 4 - data->copy_bytes; data->src_ofs = src_bytes - data->copy_bytes; } else data->src_ofs = snd_pcm_format_physical_width(src_format) / 8 - src_bytes; if (dst_le) data->dst_ofs = 4 - data->dst_bytes; else data->dst_ofs = snd_pcm_format_physical_width(dst_format) / 8 - dst_bytes; if (snd_pcm_format_signed(src_format) != snd_pcm_format_signed(dst_format)) { if (dst_le) data->flip = (__force u32)cpu_to_le32(0x80000000); else data->flip = (__force u32)cpu_to_be32(0x80000000); } } int snd_pcm_plugin_build_linear(struct snd_pcm_substream *plug, struct snd_pcm_plugin_format *src_format, struct snd_pcm_plugin_format *dst_format, struct snd_pcm_plugin **r_plugin) { int err; struct linear_priv *data; struct snd_pcm_plugin *plugin; if (snd_BUG_ON(!r_plugin)) return -ENXIO; *r_plugin = NULL; if (snd_BUG_ON(src_format->rate != dst_format->rate)) return -ENXIO; if (snd_BUG_ON(src_format->channels != dst_format->channels)) return -ENXIO; if (snd_BUG_ON(!snd_pcm_format_linear(src_format->format) || !snd_pcm_format_linear(dst_format->format))) return -ENXIO; err = snd_pcm_plugin_build(plug, "linear format conversion", src_format, dst_format, sizeof(struct linear_priv), &plugin); if (err < 0) return err; data = (struct linear_priv *)plugin->extra_data; init_data(data, src_format->format, dst_format->format); plugin->transfer = linear_transfer; *r_plugin = plugin; return 0; } |