diff options
Diffstat (limited to 'sms/tables.c')
| -rw-r--r-- | sms/tables.c | 135 |
1 files changed, 72 insertions, 63 deletions
diff --git a/sms/tables.c b/sms/tables.c index 1802952..85d21cb 100644 --- a/sms/tables.c +++ b/sms/tables.c @@ -40,57 +40,61 @@ static sfloat *sms_tab_sinc; * \param nTableSize size of table * \return error code \see SMS_MALLOC in SMS_ERRORS */ -int sms_prepSine (int nTableSize) +int sms_prepSine(int nTableSize) { - register int i; - sfloat fTheta; - - if((sms_tab_sine = (sfloat *)malloc(nTableSize*sizeof(sfloat))) == 0) - return (SMS_MALLOC); - fSineScale = (sfloat)(TWO_PI) / (sfloat)(nTableSize - 1); - fSineIncr = 1.0 / fSineScale; - fTheta = 0.0; - for(i = 0; i < nTableSize; i++) - { - fTheta = fSineScale * (sfloat)i; - sms_tab_sine[i] = sin(fTheta); - } - return (SMS_OK); + register int i; + sfloat fTheta; + + sms_tab_sine = (sfloat *)malloc(nTableSize * sizeof(sfloat)); + if(sms_tab_sine == NULL) + { + sms_error("Could not allocate memory for sine table"); + return SMS_MALLOC; + } + fSineScale = (sfloat)(TWO_PI) / (sfloat)(nTableSize - 1); + fSineIncr = 1.0 / fSineScale; + fTheta = 0.0; + for(i = 0; i < nTableSize; i++) + { + fTheta = fSineScale * (sfloat)i; + sms_tab_sine[i] = sin(fTheta); + } + return SMS_OK; } /*! \brief clear sine table */ void sms_clearSine() { - if(sms_tab_sine) - free(sms_tab_sine); - sms_tab_sine = 0; + if(sms_tab_sine) + free(sms_tab_sine); + sms_tab_sine = NULL; } /*! \brief table-lookup sine method * \param fTheta angle in radians * \return approximately sin(fTheta) */ -sfloat sms_sine (sfloat fTheta) +sfloat sms_sine(sfloat fTheta) { - int i; - fTheta = fTheta - floor(fTheta * INV_TWO_PI) * TWO_PI; - - if(fTheta < 0) - { - i = .5 - (fTheta * fSineIncr); - return(-(sms_tab_sine[i])); - } - else - { - i = fTheta * fSineIncr + .5; - return(sms_tab_sine[i]); - } + int i; + fTheta = fTheta - floor(fTheta * INV_TWO_PI) * TWO_PI; + + if(fTheta < 0) + { + i = .5 - (fTheta * fSineIncr); + return -(sms_tab_sine[i]); + } + else + { + i = fTheta * fSineIncr + .5; + return sms_tab_sine[i]; + } } /*! \brief Sinc method to generate the lookup table */ -static sfloat Sinc (sfloat x, sfloat N) +static sfloat Sinc(sfloat x, sfloat N) { - return (sinf ((N/2) * x) / sinf (x/2)); + return sinf((N/2) * x) / sinf(x/2); } /*! \brief prepare the Sinc table @@ -101,41 +105,45 @@ static sfloat Sinc (sfloat x, sfloat N) * \param nTableSize size of table * \return error code \see SMS_MALLOC in SMS_ERRORS */ -int sms_prepSinc (int nTableSize) +int sms_prepSinc(int nTableSize) { - int i, m; + int i, m; sfloat N = 512.0; sfloat fA[4] = {.35875, .48829, .14128, .01168}; - sfloat fMax = 0; - sfloat fTheta = -4.0 * TWO_PI / N; - sfloat fThetaIncr = (8.0 * TWO_PI / N) / (nTableSize); + sfloat fMax = 0; + sfloat fTheta = -4.0 * TWO_PI / N; + sfloat fThetaIncr = (8.0 * TWO_PI / N) / (nTableSize); + + sms_tab_sinc = (sfloat *)calloc(nTableSize, sizeof(sfloat)); + if(sms_tab_sinc == NULL) + { + sms_error("Could not allocate memory for sinc table"); + return (SMS_MALLOC); + } + + for(i = 0; i < nTableSize; i++) + { + for (m = 0; m < 4; m++) + sms_tab_sinc[i] += -1 * (fA[m]/2) * + (Sinc (fTheta - m * TWO_PI/N, N) + + Sinc (fTheta + m * TWO_PI/N, N)); + fTheta += fThetaIncr; + } - if((sms_tab_sinc = (sfloat *) calloc (nTableSize, sizeof(sfloat))) == 0) - return (SMS_MALLOC); - - for(i = 0; i < nTableSize; i++) - { - for (m = 0; m < 4; m++) - sms_tab_sinc[i] += -1 * (fA[m]/2) * - (Sinc (fTheta - m * TWO_PI/N, N) + - Sinc (fTheta + m * TWO_PI/N, N)); - fTheta += fThetaIncr; - } - fMax = sms_tab_sinc[(int) nTableSize / 2]; - for (i = 0; i < nTableSize; i++) - sms_tab_sinc[i] = sms_tab_sinc[i] / fMax; - - fSincScale = (sfloat) nTableSize / 8.0; - - return (SMS_OK); + fMax = sms_tab_sinc[(int) nTableSize / 2]; + for (i = 0; i < nTableSize; i++) + sms_tab_sinc[i] = sms_tab_sinc[i] / fMax; + + fSincScale = (sfloat) nTableSize / 8.0; + return SMS_OK; } /*! \brief clear sine table */ void sms_clearSinc() { - if(sms_tab_sinc) - free(sms_tab_sinc); - sms_tab_sinc = 0; + if(sms_tab_sinc) + free(sms_tab_sinc); + sms_tab_sinc = 0; } /*! \brief global sinc table-lookup method @@ -145,9 +153,10 @@ void sms_clearSinc() * \param fTheta angle in radians * \return approximately sinc(fTheta) */ -sfloat sms_sinc (sfloat fTheta) +sfloat sms_sinc(sfloat fTheta) { int index = (int) (.5 + fSincScale * fTheta); - - return (sms_tab_sinc[index]); + return sms_tab_sinc[index]; } + + |