| 183 | } |
| 184 | |
| 185 | func formatDigits(dst EncodingBuffer, shortest bool, neg bool, digs decimalSlice, prec int, fmt byte) { |
| 186 | switch fmt { |
| 187 | case 'e', 'E': |
| 188 | fmtE(dst, neg, digs, prec, fmt) |
| 189 | return |
| 190 | case 'f': |
| 191 | fmtF(dst, neg, digs, prec) |
| 192 | return |
| 193 | case 'g', 'G': |
| 194 | // trailing fractional zeros in 'e' form will be trimmed. |
| 195 | eprec := prec |
| 196 | if eprec > digs.nd && digs.nd >= digs.dp { |
| 197 | eprec = digs.nd |
| 198 | } |
| 199 | // %e is used if the exponent from the conversion |
| 200 | // is less than -4 or greater than or equal to the precision. |
| 201 | // if precision was the shortest possible, use precision 6 for this decision. |
| 202 | if shortest { |
| 203 | eprec = 6 |
| 204 | } |
| 205 | exp := digs.dp - 1 |
| 206 | if exp < -4 || exp >= eprec { |
| 207 | if prec > digs.nd { |
| 208 | prec = digs.nd |
| 209 | } |
| 210 | fmtE(dst, neg, digs, prec-1, fmt+'e'-'g') |
| 211 | return |
| 212 | } |
| 213 | if prec > digs.dp { |
| 214 | prec = digs.nd |
| 215 | } |
| 216 | fmtF(dst, neg, digs, max(prec-digs.dp, 0)) |
| 217 | return |
| 218 | } |
| 219 | |
| 220 | // unknown format |
| 221 | dst.Write([]byte{'%', fmt}) |
| 222 | return |
| 223 | } |
| 224 | |
| 225 | // Round d (= mant * 2^exp) to the shortest number of digits |
| 226 | // that will let the original floating point value be precisely |