common.c

xmms-1.2.10.tar.gz学习使用的就下吧

#include <ctype.h>
#include <stdlib.h>
#include <signal.h>

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#include "config.h"

#include "mpg123.h"
#include "id3.h"
#include "id3_header.h"

/* max = 1728 */
#define MAXFRAMESIZE 1792

const int tabsel_123[2][3][16] = {
{{0, 32, 64, 96, 128, 160, 192, 224, 256, 288, 320, 352, 384, 416, 448,},
 {0, 32, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 384,},
 {0, 32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320,}},
{{0, 32, 48, 56, 64, 80, 96, 112, 128, 144, 160, 176, 192, 224, 256,},
 {0, 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160,},
 {0, 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160,}}
};

const int mpg123_freqs[9] =
{44100, 48000, 32000, 22050, 24000, 16000, 11025, 12000, 8000};

struct bitstream_info bsi;

extern gint mpg123_bitrate, mpg123_frequency, mpg123_length;
extern gchar *mpg123_title, *mpg123_filename;
extern gboolean mpg123_stereo;

static int fsizeold = 0, ssize;
static unsigned char bsspace[2][MAXFRAMESIZE + 512];	/* MAXFRAMESIZE */
static unsigned char *bsbuf = bsspace[1], *bsbufold;
static int bsnum = 0;

unsigned char *mpg123_pcm_sample;
int mpg123_pcm_point = 0;

static FILE *filept;
static int filept_opened;

static int get_fileinfo(void);

static int fullread(FILE * fd, unsigned char *buf, int count)
{
	int ret, cnt = 0;

	while (cnt < count)
	{
		if (fd)
			ret = fread(buf + cnt, 1, count - cnt, fd);
		else
			ret = mpg123_http_read(buf + cnt, count - cnt);
		if (ret < 0)
			return ret;
		if (ret == 0)
			break;
		cnt += ret;
	}
	return cnt;
}

static int stream_init(void)
{
	if (get_fileinfo() < 0)
		return -1;
	return 0;
}

void mpg123_stream_close(void)
{
	if (filept)
		fclose(filept);
	else if (mpg123_info->network_stream)
		mpg123_http_close();
}

#if 0
/**************************************** 
 * HACK,HACK,HACK: step back <num> frames 
 * can only work if the 'stream' isn't a real stream but a file
 */
static int stream_back_bytes(int bytes)
{
	if (fseek(filept, -bytes, SEEK_CUR) < 0)
		return -1;
	return 0;
}
#endif

static int stream_head_read(unsigned long *newhead)
{
	unsigned char hbuf[4];

	if (fullread(filept, hbuf, 4) != 4)
		return FALSE;

	*newhead = ((unsigned long) hbuf[0] << 24) |
		((unsigned long) hbuf[1] << 16) |
		((unsigned long) hbuf[2] << 8) |
		(unsigned long) hbuf[3];

	return TRUE;
}

static int stream_head_shift(unsigned long *head)
{
	unsigned char hbuf;

	if (fullread(filept, &hbuf, 1) != 1)
		return 0;
	*head <<= 8;
	*head |= hbuf;
	*head &= 0xffffffff;
	return 1;
}

static int stream_mpg123_read_frame_body(unsigned char *buf, int size)
{
	long l;

	if ((l = fullread(filept, buf, size)) != size)
	{
		if (l <= 0)
			return 0;
		memset(buf + l, 0, size - l);
	}
	return 1;
}

static long stream_tell(void)
{
	return ftell(filept);
}

#if 0
static void stream_rewind(void)
{
	fseek(filept, 0, SEEK_SET);
}
#endif

int mpg123_stream_jump_to_frame(struct frame *fr, int frame)
{
	if (!filept)
		return -1;
	mpg123_read_frame_init();
	fseek(filept, frame * (fr->framesize + 4), SEEK_SET);
	mpg123_read_frame(fr);
	return 0;
}

int mpg123_stream_jump_to_byte(struct frame *fr, int byte)
{
	if (!filept)
		return -1;
	fseek(filept, byte, SEEK_SET);
	mpg123_read_frame(fr);
	return 0;
}

int mpg123_stream_check_for_xing_header(struct frame *fr, xing_header_t * xhead)
{
	unsigned char *head_data;
	int ret;

	fseek(filept, -(fr->framesize + 4), SEEK_CUR);
	head_data = g_malloc(fr->framesize + 4);
	fread(head_data, 1, fr->framesize + 4, filept);
	ret = mpg123_get_xing_header(xhead, head_data);
	g_free(head_data);
	return ret;
}

static int get_fileinfo(void)
{
	guchar buf[3];

	if (filept == NULL)
		return -1;
	if (fseek(filept, 0, SEEK_END) < 0)
		return -1;

	mpg123_info->filesize = ftell(filept);
	if (fseek(filept, -128, SEEK_END) < 0)
		return -1;
	if (fullread(filept, buf, 3) != 3)
		return -1;
	if (!strncmp(buf, "TAG", 3))
		mpg123_info->filesize -=128;
	if (fseek(filept, 0, SEEK_SET) < 0)
		return -1;

	if (mpg123_info->filesize <= 0)
		return -1;

	return mpg123_info->filesize;
}

void mpg123_read_frame_init(void)
{
	memset(bsspace[0],0,MAXFRAMESIZE + 512);
	memset(bsspace[1],0,MAXFRAMESIZE + 512);
	mpg123_info->output_audio = FALSE;
}

/*
 * Function read_id3v2_tag (head)
 *
 *    Read ID3v2 tag from stream.  Return TRUE upon success, or FALSE if
 *    an error occurred.
 *
 */
static gboolean read_id3v2_tag(unsigned long head)
{
	char *id3buf;
	int hdrsize;
	struct id3_tag *id3d;
	struct id3tag_t tag;
	char buf[7];

	buf[0] = head & 0xff;
	/*
	 * Read ID3tag header.
	 */
	if (fullread(filept, buf + 1, 6) != 6)
		return FALSE;

	hdrsize = ID3_GET_SIZE28(buf[3], buf[4], buf[5], buf[6]);

	/*
	 * A invalid header could fool us into requesting insane
	 * amounts of memory.  Make sure the header size is
	 * reasonable.
	 */
	if ((mpg123_info->filesize && hdrsize > mpg123_info->filesize) ||
	    (!mpg123_info->filesize && hdrsize > 1000000))
		return FALSE;

	if (mpg123_cfg.disable_id3v2)
	{
		guint8 *tmp = g_malloc(hdrsize);
		gboolean ret;
		ret = (fullread(filept, tmp, hdrsize) == hdrsize);
		g_free(tmp);
		return ret;
	}

	id3buf = g_malloc(hdrsize + ID3_TAGHDR_SIZE + 3);
	memcpy(id3buf, "ID3", 3);
	memcpy(id3buf + 3, buf, ID3_TAGHDR_SIZE);

	/*
	 * Read ID3tag body.
	 */
	if (fullread(filept, id3buf + ID3_TAGHDR_SIZE + 3, hdrsize) != hdrsize)
	{
		g_free(id3buf);
		return FALSE;
	}

	/*
	 * Get info from tag.
	 */
	if ((id3d = id3_open_mem(id3buf, 0)) != NULL)
	{
		mpg123_get_id3v2(id3d, &tag);
		if (!mpg123_info->first_frame)
		{
			char *songname = mpg123_title;
			mpg123_title =
				mpg123_format_song_title(&tag, mpg123_filename);
			mpg123_ip.set_info(mpg123_title, mpg123_length,
					   mpg123_bitrate * 1000,
					   mpg123_frequency, mpg123_stereo);
			if (songname)
				g_free(songname);
		}
		else
		{			
			mpg123_title = mpg123_format_song_title(&tag,
								mpg123_filename);
		}
		id3_close(id3d);
	}
	g_free(id3buf);

	return TRUE;
}

int mpg123_head_check(unsigned long head)
{
	if ((head & 0xffe00000) != 0xffe00000)
		return FALSE;
	if (!((head >> 17) & 3))
		return FALSE;
	if (((head >> 12) & 0xf) == 0xf)
		return FALSE;
	if (!((head >> 12) & 0xf))
		return FALSE;
	if (((head >> 10) & 0x3) == 0x3)
		return FALSE;
	if (((head >> 19) & 1) == 1 &&
	    ((head >> 17) & 3) == 3 &&
	    ((head >> 16) & 1) == 1)
		return FALSE;
	if ((head & 0xffff0000) == 0xfffe0000)
		return FALSE;
	
	return TRUE;
}

/*****************************************************************
 * read next frame
 */
int mpg123_read_frame(struct frame *fr)
{
	unsigned long newhead;

	fsizeold = fr->framesize;	/* for Layer3 */

	if (!stream_head_read(&newhead))
		return FALSE;

	if (!mpg123_head_check(newhead) || !mpg123_decode_header(fr, newhead))
	{
		int try = 0;

		do
		{
			try++;
			if ((newhead & 0xffffff00) == ('I' << 24) + ('D' << 16) + ('3' << 8))
			{
				read_id3v2_tag(newhead);
				if (!stream_head_read(&newhead))
					return FALSE;
			}
			else if (!stream_head_shift(&newhead))
				return 0;
			
		}
		while ((!mpg123_head_check(newhead) ||
			!mpg123_decode_header(fr,newhead)) &&
		       try < (256 * 1024));
		if(try >= (256 * 1024))
			return FALSE;
		
		mpg123_info->filesize -= try;
	}
	/* flip/init buffer for Layer 3 */
	bsbufold = bsbuf;
	bsbuf = bsspace[bsnum] + 512;
	bsnum = (bsnum + 1) & 1;

	if (!stream_mpg123_read_frame_body(bsbuf, fr->framesize))
		return 0;

	bsi.bitindex = 0;
	bsi.wordpointer = (unsigned char *) bsbuf;


	return 1;

}

/*
 * the code a header and write the information
 * into the frame structure
 */
int mpg123_decode_header(struct frame *fr, unsigned long newhead)
{
	if (newhead & (1 << 20))
	{
		fr->lsf = (newhead & (1 << 19)) ? 0x0 : 0x1;
		fr->mpeg25 = 0;
	}
	else
	{
		fr->lsf = 1;
		fr->mpeg25 = 1;
	}
	fr->lay = 4 - ((newhead >> 17) & 3);
	if (fr->mpeg25)
	{
		fr->sampling_frequency = 6 + ((newhead >> 10) & 0x3);
	}
	else
		fr->sampling_frequency = ((newhead >> 10) & 0x3) + (fr->lsf * 3);
	fr->error_protection = ((newhead >> 16) & 0x1) ^ 0x1;

	fr->bitrate_index = ((newhead >> 12) & 0xf);
	fr->padding = ((newhead >> 9) & 0x1);
	fr->extension = ((newhead >> 8) & 0x1);
	fr->mode = ((newhead >> 6) & 0x3);
	fr->mode_ext = ((newhead >> 4) & 0x3);
	fr->copyright = ((newhead >> 3) & 0x1);
	fr->original = ((newhead >> 2) & 0x1);
	fr->emphasis = newhead & 0x3;

	fr->stereo = (fr->mode == MPG_MD_MONO) ? 1 : 2;

	ssize = 0;

	if (!fr->bitrate_index)
		return (0);

	switch (fr->lay)
	{
		case 1:
			fr->do_layer = mpg123_do_layer1;
			/* inits also shared tables with layer1 */
			mpg123_init_layer2(fr->synth_type == SYNTH_MMX);
			fr->framesize = (long) tabsel_123[fr->lsf][0][fr->bitrate_index] * 12000;
			fr->framesize /= mpg123_freqs[fr->sampling_frequency];
			fr->framesize = ((fr->framesize + fr->padding) << 2) - 4;
			break;
		case 2:
			fr->do_layer = mpg123_do_layer2;
			/* inits also shared tables with layer1 */
			mpg123_init_layer2(fr->synth_type == SYNTH_MMX);
			fr->framesize = (long) tabsel_123[fr->lsf][1][fr->bitrate_index] * 144000;
			fr->framesize /= mpg123_freqs[fr->sampling_frequency];
			fr->framesize += fr->padding - 4;
			break;
		case 3:
			fr->do_layer = mpg123_do_layer3;
			if (fr->lsf)
				ssize = (fr->stereo == 1) ? 9 : 17;
			else
				ssize = (fr->stereo == 1) ? 17 : 32;
			if (fr->error_protection)
				ssize += 2;
			fr->framesize = (long) tabsel_123[fr->lsf][2][fr->bitrate_index] * 144000;
			fr->framesize /= mpg123_freqs[fr->sampling_frequency] << (fr->lsf);
			fr->framesize = fr->framesize + fr->padding - 4;
			break;
		default:
			return (0);
	}
	if(fr->framesize > MAXFRAMESIZE)
		return 0;
	return 1;
}

void mpg123_open_stream(char *bs_filenam, int fd)
{
	filept_opened = 1;
	if (!strncasecmp(bs_filenam, "http://", 7))
	{
		filept = NULL;
		mpg123_http_open(bs_filenam);
		mpg123_info->filesize = 0;
		mpg123_info->network_stream = TRUE;
	}
	else
	{
		if ((filept = fopen(bs_filenam, "rb")) == NULL ||
		    stream_init() == -1)
			mpg123_info->eof = TRUE;
	}

}

void mpg123_set_pointer(long backstep)
{
	bsi.wordpointer = bsbuf + ssize - backstep;
	if (backstep)
		memcpy(bsi.wordpointer, bsbufold + fsizeold - backstep, backstep);
	bsi.bitindex = 0;
}

double mpg123_compute_bpf(struct frame *fr)
{
	double bpf;

	switch (fr->lay)
	{
		case 1:
			bpf = tabsel_123[fr->lsf][0][fr->bitrate_index];
			bpf *= 12000.0 * 4.0;
			bpf /= mpg123_freqs[fr->sampling_frequency] << (fr->lsf);
			break;
		case 2:
		case 3:
			bpf = tabsel_123[fr->lsf][fr->lay - 1][fr->bitrate_index];
			bpf *= 144000;
			bpf /= mpg123_freqs[fr->sampling_frequency] << (fr->lsf);
			break;
		default:
			bpf = 1.0;
	}

	return bpf;
}

int mpg123_calc_numframes(struct frame *fr)
{
	return (int) (mpg123_info->filesize / mpg123_compute_bpf(fr));
}

double mpg123_relative_pos(void)
{
	if (!filept || !mpg123_info->filesize)
		return 0;
	return ((double) stream_tell()) / mpg123_info->filesize;
}