/* * a s c r 5 0 . c */ /*)LIBRARY */ #ifdef DOCUMENTATION title ascr50 Ascii to Radix 50 index Ascii to radix 50 synopsis .s.nf ascr50(count, input, output) int count; int *output; char *input; description Convert 'count' characters from Ascii to Radix 50. If there aren't a multiple of 3 characters, blanks are padded on the end. The Ascii string is moved to the output when finished. The input and output areas may be the same since three input characters are read for every two bytes of output. bugs #endif #ifdef pdp11 #define SHORT unsigned #else #define SHORT unsigned short #endif #ifdef OLD_CODE struct table { char low, high; int magic; }; static struct table r50tab[] = { { 'a', 'z', -0140 }, { 'A', 'Z', -0100 }, { '0', '9', -0022 }, { ' ', ' ', -0040 }, { '$', '$', -0011 }, { '.', '.', -0022 }, { 0, 0, 0 }, }; ascr50(count, input, output) int count; /* Characters to convert */ char *input; /* Input string (ascii) */ SHORT int *output; /* Output vector (rad50) */ { register char *wp; /* Work area pointer */ register int byte; /* Working byte */ register struct table *rp; /* Rad50 table pointer */ int result; /* Rad50 work -- gets value */ char work[3+1]; /* Gets next three bytes */ for (;;) { work[0] = work[1] = work[2] = ' '; for (wp = work; --count >= 0;) { *wp++ = *input++; /* Get one input byte */ if (wp >= &work[3]) break; } if (wp == work) return; /* Nothing left to do */ /* * Convert 3 bytes (in word) to rad50 */ result = 0; for (wp = work; wp < &work[3];) { byte = *wp++ & 0377; for (rp = r50tab; rp->low > 0; rp++) { if (byte >= rp->low && byte <= rp->high) break; } if (rp->low == 0) byte == 0; byte += rp->magic; result <<= 3; byte += result; result <<= 2; result += byte; } *output++ = result; } } #else /* * Dave Conroy's algorithm */ ascr50(count, input, output) int count; /* Characters to convert */ register char *input; /* Input string (ascii) */ register SHORT int *output; /* Output vector (rad50) */ { register int r50; while (--count >= 0) { r50 = 050 * 050 * r50char(*input++); r50 += 050 * r50char(*input++); r50 += r50char(*input++); *output++ = r50; } } static int r50char(c) register int c; { if (c == ' ') return (0); if (c >= 'A' && c <= 'Z') return (c - 'A' + 01); if (c >= 'a' && c <= 'z') return (c - 'a' + 01); if (c == '$') return (033); if (c == '.') return (034); if (c >= '0' && c <= '9') return (c - '0' + 036); return (035); } #endif