cog/Libraries/WavPack/Files/float.c

////////////////////////////////////////////////////////////////////////////
//			     **** WAVPACK ****				  //
//		    Hybrid Lossless Wavefile Compressor			  //
//		Copyright (c) 1998 - 2005 Conifer Software.		  //
//			    All Rights Reserved.			  //
//      Distributed under the BSD Software License (see license.txt)      //
////////////////////////////////////////////////////////////////////////////

// float.c

#include "wavpack.h"

#include <stdlib.h>

#ifdef DEBUG_ALLOC
#define malloc malloc_db
#define realloc realloc_db
#define free free_db
void *malloc_db (uint32_t size);
void *realloc_db (void *ptr, uint32_t size);
void free_db (void *ptr);
int32_t dump_alloc (void);
#endif

#ifdef PACK

void write_float_info (WavpackStream *wps, WavpackMetadata *wpmd)
{
    char *byteptr;

    byteptr = wpmd->data = malloc (4);
    wpmd->id = ID_FLOAT_INFO;
    *byteptr++ = wps->float_flags;
    *byteptr++ = wps->float_shift;
    *byteptr++ = wps->float_max_exp;
    *byteptr++ = wps->float_norm_exp;
    wpmd->byte_length = byteptr - (char *) wpmd->data;
}

int scan_float_data (WavpackStream *wps, f32 *values, int32_t num_values)
{
    int32_t shifted_ones = 0, shifted_zeros = 0, shifted_both = 0;
    int32_t false_zeros = 0, neg_zeros = 0;
    uint32_t ordata = 0, crc = 0xffffffff;
    int max_exp = 0, shift_count;
    int32_t count, value;
    f32 *dp;

    wps->float_shift = wps->float_flags = 0;

    for (dp = values, count = num_values; count--; dp++) {
	crc = crc * 27 + dp->mantissa * 9 + dp->exponent * 3 + dp->sign;

	if (dp->exponent > max_exp && dp->exponent < 255)
	    max_exp = dp->exponent;
    }

    wps->crc_x = crc;

    for (dp = values, count = num_values; count--; dp++) {
	if (dp->exponent == 255) {
	    wps->float_flags |= FLOAT_EXCEPTIONS;
	    value = 0x1000000;
	    shift_count = 0;
	}
	else if (dp->exponent) {
	    shift_count = max_exp - dp->exponent;
	    value = 0x800000 + dp->mantissa;
	}
	else {
	    shift_count = max_exp ? max_exp - 1 : 0;
	    value = dp->mantissa;

//	    if (dp->mantissa)
//		denormals++;
	}

	if (shift_count < 25)
	    value >>= shift_count;
	else
	    value = 0;

	if (!value) {
	    if (dp->exponent || dp->mantissa)
		++false_zeros;
	    else if (dp->sign)
		++neg_zeros;
	}
	else if (shift_count) {
	    int32_t mask = (1 << shift_count) - 1;

	    if (!(dp->mantissa & mask))
		shifted_zeros++;
	    else if ((dp->mantissa & mask) == mask)
		shifted_ones++;
	    else
		shifted_both++;
	}

	ordata |= value;
	* (int32_t *) dp = (dp->sign) ? -value : value;
    }

    wps->float_max_exp = max_exp;

    if (shifted_both)
	wps->float_flags |= FLOAT_SHIFT_SENT;
    else if (shifted_ones && !shifted_zeros)
	wps->float_flags |= FLOAT_SHIFT_ONES;
    else if (shifted_ones && shifted_zeros)
	wps->float_flags |= FLOAT_SHIFT_SAME;
    else if (ordata && !(ordata & 1)) {
	while (!(ordata & 1)) {
	    wps->float_shift++;
	    ordata >>= 1;
	}

	for (dp = values, count = num_values; count--; dp++)
	    * (int32_t *) dp >>= wps->float_shift;
    }

    wps->wphdr.flags &= ~MAG_MASK;

    while (ordata) {
	wps->wphdr.flags += 1 << MAG_LSB;
	ordata >>= 1;
    }

    if (false_zeros || neg_zeros)
	wps->float_flags |= FLOAT_ZEROS_SENT;

    if (neg_zeros)
	wps->float_flags |= FLOAT_NEG_ZEROS;

//  error_line ("samples = %d, max exp = %d, pre-shift = %d, denormals = %d",
//	num_values, max_exp, wps->float_shift, denormals);
//  if (wps->float_flags & FLOAT_EXCEPTIONS)
//	error_line ("exceptions!");
//  error_line ("shifted ones/zeros/both = %d/%d/%d, true/neg/false zeros = %d/%d/%d",
//	shifted_ones, shifted_zeros, shifted_both, true_zeros, neg_zeros, false_zeros);

    return wps->float_flags & (FLOAT_EXCEPTIONS | FLOAT_ZEROS_SENT | FLOAT_SHIFT_SENT | FLOAT_SHIFT_SAME);
}

void send_float_data (WavpackStream *wps, f32 *values, int32_t num_values)
{
    int max_exp = wps->float_max_exp;
    int32_t count, value, shift_count;
    f32 *dp;

    for (dp = values, count = num_values; count--; dp++) {
	if (dp->exponent == 255) {
	    if (dp->mantissa) {
		putbit_1 (&wps->wvxbits);
		putbits (dp->mantissa, 23, &wps->wvxbits);
	    }
	    else {
		putbit_0 (&wps->wvxbits);
	    }

	    value = 0x1000000;
	    shift_count = 0;
	}
	else if (dp->exponent) {
	    shift_count = max_exp - dp->exponent;
	    value = 0x800000 + dp->mantissa;
	}
	else {
	    shift_count = max_exp ? max_exp - 1 : 0;
	    value = dp->mantissa;
	}

	if (shift_count < 25)
	    value >>= shift_count;
	else
	    value = 0;

	if (!value) {
	    if (wps->float_flags & FLOAT_ZEROS_SENT) {
		if (dp->exponent || dp->mantissa) {
		    putbit_1 (&wps->wvxbits);
		    putbits (dp->mantissa, 23, &wps->wvxbits);

		    if (max_exp >= 25) {
			putbits (dp->exponent, 8, &wps->wvxbits);
		    }

		    putbit (dp->sign, &wps->wvxbits);
		}
		else {
		    putbit_0 (&wps->wvxbits);

		    if (wps->float_flags & FLOAT_NEG_ZEROS)
			putbit (dp->sign, &wps->wvxbits);
		}
	    }
	}
	else if (shift_count) {
	    if (wps->float_flags & FLOAT_SHIFT_SENT) {
		int32_t data = dp->mantissa & ((1 << shift_count) - 1);
		putbits (data, shift_count, &wps->wvxbits);
	    }
	    else if (wps->float_flags & FLOAT_SHIFT_SAME) {
		putbit (dp->mantissa & 1, &wps->wvxbits);
	    }
	}
    }
}

#endif

#if defined(UNPACK) || defined(INFO_ONLY)

int read_float_info (WavpackStream *wps, WavpackMetadata *wpmd)
{
    int bytecnt = wpmd->byte_length;
    char *byteptr = wpmd->data;

    if (bytecnt != 4)
	return FALSE;

    wps->float_flags = *byteptr++;
    wps->float_shift = *byteptr++;
    wps->float_max_exp = *byteptr++;
    wps->float_norm_exp = *byteptr;
    return TRUE;
}

#endif

#ifdef UNPACK

static void float_values_nowvx (WavpackStream *wps, int32_t *values, int32_t num_values);

void float_values (WavpackStream *wps, int32_t *values, int32_t num_values)
{
    uint32_t crc = wps->crc_x;

    if (!bs_is_open (&wps->wvxbits)) {
	float_values_nowvx (wps, values, num_values);
	return;
    }

    while (num_values--) {
	int shift_count = 0, exp = wps->float_max_exp;
	f32 outval = { 0, 0, 0 };
	uint32_t temp;

	if (*values == 0) {
	    if (wps->float_flags & FLOAT_ZEROS_SENT) {
		if (getbit (&wps->wvxbits)) {
		    getbits (&temp, 23, &wps->wvxbits);
		    outval.mantissa = temp;

		    if (exp >= 25) {
			getbits (&temp, 8, &wps->wvxbits);
			outval.exponent = temp;
		    }

		    outval.sign = getbit (&wps->wvxbits);
		}
		else if (wps->float_flags & FLOAT_NEG_ZEROS)
		    outval.sign = getbit (&wps->wvxbits);
	    }
	}
	else {
	    *values <<= wps->float_shift;

	    if (*values < 0) {
		*values = -*values;
		outval.sign = 1;
	    }

	    if (*values == 0x1000000) {
		if (getbit (&wps->wvxbits)) {
		    getbits (&temp, 23, &wps->wvxbits);
		    outval.mantissa = temp;
		}

		outval.exponent = 255;
	    }
	    else {
		if (exp)
		    while (!(*values & 0x800000) && --exp) {
			shift_count++;
			*values <<= 1;
		    }

		if (shift_count) {
		    if ((wps->float_flags & FLOAT_SHIFT_ONES) ||
			((wps->float_flags & FLOAT_SHIFT_SAME) && getbit (&wps->wvxbits)))
			    *values |= ((1 << shift_count) - 1);
		    else if (wps->float_flags & FLOAT_SHIFT_SENT) {
			getbits (&temp, shift_count, &wps->wvxbits);
			*values |= temp & ((1 << shift_count) - 1);
		    }
		}

		outval.mantissa = *values;
		outval.exponent = exp;
	    }
	}

	crc = crc * 27 + outval.mantissa * 9 + outval.exponent * 3 + outval.sign;
	* (f32 *) values++ = outval;
    }

    wps->crc_x = crc;
}

static void float_values_nowvx (WavpackStream *wps, int32_t *values, int32_t num_values)
{
    while (num_values--) {
	int shift_count = 0, exp = wps->float_max_exp;
	f32 outval = { 0, 0, 0 };

	if (*values) {
	    *values <<= wps->float_shift;

	    if (*values < 0) {
		*values = -*values;
		outval.sign = 1;
	    }

	    if (*values >= 0x1000000) {
		while (*values & 0xf000000) {
		    *values >>= 1;
		    ++exp;
		}
	    }
	    else if (exp) {
		while (!(*values & 0x800000) && --exp) {
		    shift_count++;
		    *values <<= 1;
		}

		if (shift_count && (wps->float_flags & FLOAT_SHIFT_ONES))
		    *values |= ((1 << shift_count) - 1);
	    }

	    outval.mantissa = *values;
	    outval.exponent = exp;
	}

	* (f32 *) values++ = outval;
    }
}

void float_normalize (int32_t *values, int32_t num_values, int delta_exp)
{
    f32 *fvalues = (f32 *) values, fzero = { 0, 0, 0 };
    int exp;

    if (!delta_exp)
	return;

    while (num_values--) {
	if ((exp = fvalues->exponent) == 0 || exp + delta_exp <= 0)
	    *fvalues = fzero;
	else if (exp == 255 || (exp += delta_exp) >= 255) {
	    fvalues->exponent = 255;
	    fvalues->mantissa = 0;
	}
	else
	    fvalues->exponent = exp;

	fvalues++;
    }
}

#endif