diff options
Diffstat (limited to 'converter/other/fitstopnm.c')
| -rw-r--r-- | converter/other/fitstopnm.c | 212 |
1 files changed, 127 insertions, 85 deletions
diff --git a/converter/other/fitstopnm.c b/converter/other/fitstopnm.c index b41e0960..0d8753e5 100644 --- a/converter/other/fitstopnm.c +++ b/converter/other/fitstopnm.c @@ -39,11 +39,12 @@ #include <string.h> #include <float.h> +#include "pm_config.h" #include "pm_c_util.h" #include "mallocvar.h" +#include "floatcode.h" #include "shhopt.h" #include "pnm.h" -#include "pm_config.h" @@ -156,109 +157,150 @@ struct FITS_Header { }; +/* This code deals properly with integers, no matter what the byte order + or integer size of the host machine. We handle sign extension manually to + prevent problems with signed/unsigned characters. We read floating point + values properly only when the host architecture conforms to IEEE-754. If + you need to tweak this code for other machines, you might want to get a + copy of the FITS documentation from nssdca.gsfc.nasa.gov +*/ + static void -swapbytes(void * const p, - unsigned int const nbytes) { -#if BYTE_ORDER == LITTLE_ENDIAN - unsigned char * const c = p; - unsigned int i; - for (i = 0; i < nbytes/2; ++i) { - unsigned char const orig = c[i]; - c[i] = c[nbytes-(i+1)]; - c[nbytes-(i+1)] = orig; - } -#endif +readFitsChar(FILE * const ifP, + double * const vP) { + + /* 8 bit FITS integers are unsigned */ + + int const ich = getc(ifP); + + if (ich == EOF) + pm_error("EOF / read error"); + else + *vP = ich; } -/* - ** This code will deal properly with integers, no matter what the byte order - ** or integer size of the host machine. Sign extension is handled manually - ** to prevent problems with signed/unsigned characters. Floating point - ** values will only be read properly when the host architecture is IEEE-754 - ** conformant. If you need to tweak this code for other machines, you might - ** want to snag a copy of the FITS documentation from nssdca.gsfc.nasa.gov - */ static void -readVal(FILE * const ifP, - int const bitpix, - double * const vP) { +readFitsShort(FILE * const ifP, + double * const vP) { - switch (bitpix) { - /* 8 bit FITS integers are unsigned */ - case 8: { + int ich; + int ival; + unsigned char c[8]; + + ich = getc(ifP); + + if (ich == EOF) + pm_error("EOF / read error"); + + c[0] = ich; + + ich = getc(ifP); + + if (ich == EOF) + pm_error("EOF / read error"); + + c[1] = ich; + + if (c[0] & 0x80) + ival = ~0xFFFF | c[0] << 8 | c[1]; + else + ival = c[0] << 8 | c[1]; + + *vP = ival; +} + + + +static void +readFitsLong(FILE * const ifP, + double * const vP) { + + unsigned int i; + long int lval; + unsigned char c[4]; + + for (i = 0; i < 4; ++i) { int const ich = getc(ifP); if (ich == EOF) pm_error("EOF / read error"); - *vP = ich; - } break; + c[i] = ich; + } + + if (c[0] & 0x80) + lval = ~0xFFFFFFFF | c[0] << 24 | c[1] << 16 | c[2] << 8 | c[3]; + else + lval = c[0] << 24 | c[1] << 16 | c[2] << 8 | c[3] << 0; + + *vP = lval; +} + + + +static void +readFitsFloat(FILE * const ifP, + double * const vP) { - case 16: { - int ich; - int ival; - unsigned char c[8]; + unsigned int i; + pm_bigendFloat bigend; - ich = getc(ifP); + for (i = 0; i < 4; ++i) { + int const ich = getc(ifP); if (ich == EOF) pm_error("EOF / read error"); - c[0] = ich; - ich = getc(ifP); + bigend.bytes[i] = ich; + } + + *vP = pm_floatFromBigendFloat(bigend); +} + + + +static void +readFitsDouble(FILE * const ifP, + double * const vP) { + + unsigned int i; + pm_bigendDouble bigend; + + for (i = 0; i < 8; ++i) { + int const ich = getc(ifP); if (ich == EOF) pm_error("EOF / read error"); - c[1] = ich; - if (c[0] & 0x80) - ival = ~0xFFFF | c[0] << 8 | c[1]; - else - ival = c[0] << 8 | c[1]; - *vP = ival; - } break; + bigend.bytes[i] = ich; + } + + *vP = pm_doubleFromBigendDouble(bigend); +} + + + +static void +readVal(FILE * const ifP, + int const bitpix, + double * const vP) { + + switch (bitpix) { + case 8: + readFitsChar(ifP, vP); + break; + + case 16: + readFitsShort(ifP, vP); + break; - case 32: { - unsigned int i; - long int lval; - unsigned char c[4]; - - for (i = 0; i < 4; ++i) { - int const ich = getc(ifP); - if (ich == EOF) - pm_error("EOF / read error"); - c[i] = ich; - } - if (c[0] & 0x80) - lval = ~0xFFFFFFFF | c[0] << 24 | c[1] << 16 | c[2] << 8 | c[3]; - else - lval = c[0] << 24 | c[1] << 16 | c[2] << 8 | c[3] << 0; - *vP = lval; - } break; + case 32: + readFitsLong(ifP, vP); + break; - case -32: { - unsigned int i; - unsigned char c[4]; - - for (i = 0; i < 4; ++i) { - int const ich = getc(ifP); - if (ich == EOF) - pm_error("EOF / read error"); - c[i] = ich; - } - swapbytes(c, 4); - *vP = *((float *)c); - } break; + case -32: + readFitsFloat(ifP, vP); + break; - case -64: { - unsigned int i; - unsigned char c[8]; - - for (i = 0; i < 8; ++i) { - int const ich = getc(ifP); - if (ich == EOF) - pm_error("EOF / read error"); - c[i] = ich; - } - swapbytes(c, 8); - *vP = *((double *)c); - } break; + case -64: + readFitsDouble(ifP, vP); + break; default: pm_error("Strange bitpix value %d in readVal()", bitpix); |