diff options
| -rw-r--r-- | renderfloat/renderfloat.go | 284 |
1 files changed, 142 insertions, 142 deletions
diff --git a/renderfloat/renderfloat.go b/renderfloat/renderfloat.go index 042a36d..e66209b 100644 --- a/renderfloat/renderfloat.go +++ b/renderfloat/renderfloat.go @@ -37,158 +37,158 @@ of code, hence the snippet. Feel free to reuse as you wish. package renderfloat import ( -"math" -"strconv" + "math" + "strconv" ) var renderFloatPrecisionMultipliers = [10]float64{ -1, -10, -100, -1000, -10000, -100000, -1000000, -10000000, -100000000, -1000000000, + 1, + 10, + 100, + 1000, + 10000, + 100000, + 1000000, + 10000000, + 100000000, + 1000000000, } var renderFloatPrecisionRounders = [10]float64{ -0.5, -0.05, -0.005, -0.0005, -0.00005, -0.000005, -0.0000005, -0.00000005, -0.000000005, -0.0000000005, + 0.5, + 0.05, + 0.005, + 0.0005, + 0.00005, + 0.000005, + 0.0000005, + 0.00000005, + 0.000000005, + 0.0000000005, } func RenderFloat(format string, n float64) string { -// Special cases: -// NaN = "NaN" -// +Inf = "+Infinity" -// -Inf = "-Infinity" -if math.IsNaN(n) { -return "NaN" -} -if n > math.MaxFloat64 { -return "Infinity" -} -if n < -math.MaxFloat64 { -return "-Infinity" -} - -// default format -precision := 2 -decimalStr := "." -thousandStr := "," -positiveStr := "" -negativeStr := "-" - -if len(format) > 0 { -// If there is an explicit format directive, -// then default values are these: -precision = 9 -thousandStr = "" - -// collect indices of meaningful formatting directives -formatDirectiveChars := []rune(format) -formatDirectiveIndices := make([]int, 0) -for i, char := range formatDirectiveChars { -if char != '#' && char != '0' { -formatDirectiveIndices = append(formatDirectiveIndices, i) -} -} - -if len(formatDirectiveIndices) > 0 { -// Directive at index 0: -// Must be a '+' -// Raise an error if not the case -// index: 0123456789 -// +0.000,000 -// +000,000.0 -// +0000.00 -// +0000 -if formatDirectiveIndices[0] == 0 { -if formatDirectiveChars[formatDirectiveIndices[0]] != '+' { -panic("RenderFloat(): invalid positive sign directive") -} -positiveStr = "+" -formatDirectiveIndices = formatDirectiveIndices[1:] -} - -// Two directives: -// First is thousands separator -// Raise an error if not followed by 3-digit -// 0123456789 -// 0.000,000 -// 000,000.00 -if len(formatDirectiveIndices) == 2 { -if (formatDirectiveIndices[1] - formatDirectiveIndices[0]) != 4 { -panic("RenderFloat(): thousands separator directive must be followed by 3 digit-specifiers") -} -thousandStr = string(formatDirectiveChars[formatDirectiveIndices[0]]) -formatDirectiveIndices = formatDirectiveIndices[1:] -} - -// One directive: -// Directive is decimal separator -// The number of digit-specifier following the separator indicates wanted precision -// 0123456789 -// 0.00 -// 000,0000 -if len(formatDirectiveIndices) == 1 { -decimalStr = string(formatDirectiveChars[formatDirectiveIndices[0]]) -precision = len(formatDirectiveChars) - formatDirectiveIndices[0] - 1 -} -} -} - -// generate sign part -var signStr string -if n >= 0.000000001 { -signStr = positiveStr -} else if n <= -0.000000001 { -signStr = negativeStr -n = -n -} else { -signStr = "" -n = 0.0 -} - -// split number into integer and fractional parts -intf, fracf := math.Modf(n + renderFloatPrecisionRounders[precision]) - -// generate integer part string -intStr := strconv.Itoa(int(intf)) - -// add thousand separator if required -if len(thousandStr) > 0 { -for i := len(intStr); i > 3; { -i -= 3 -intStr = intStr[:i] + thousandStr + intStr[i:] -} -} - -// no fractional part, we can leave now -if precision == 0 { -return signStr + intStr -} - -// generate fractional part -fracStr := strconv.Itoa(int(fracf * renderFloatPrecisionMultipliers[precision])) -// may need padding -if len(fracStr) < precision { -fracStr = "000000000000000"[:precision-len(fracStr)] + fracStr -} - -return signStr + intStr + decimalStr + fracStr + // Special cases: + // NaN = "NaN" + // +Inf = "+Infinity" + // -Inf = "-Infinity" + if math.IsNaN(n) { + return "NaN" + } + if n > math.MaxFloat64 { + return "Infinity" + } + if n < -math.MaxFloat64 { + return "-Infinity" + } + + // default format + precision := 2 + decimalStr := "." + thousandStr := "," + positiveStr := "" + negativeStr := "-" + + if len(format) > 0 { + // If there is an explicit format directive, + // then default values are these: + precision = 9 + thousandStr = "" + + // collect indices of meaningful formatting directives + formatDirectiveChars := []rune(format) + formatDirectiveIndices := make([]int, 0) + for i, char := range formatDirectiveChars { + if char != '#' && char != '0' { + formatDirectiveIndices = append(formatDirectiveIndices, i) + } + } + + if len(formatDirectiveIndices) > 0 { + // Directive at index 0: + // Must be a '+' + // Raise an error if not the case + // index: 0123456789 + // +0.000,000 + // +000,000.0 + // +0000.00 + // +0000 + if formatDirectiveIndices[0] == 0 { + if formatDirectiveChars[formatDirectiveIndices[0]] != '+' { + panic("RenderFloat(): invalid positive sign directive") + } + positiveStr = "+" + formatDirectiveIndices = formatDirectiveIndices[1:] + } + + // Two directives: + // First is thousands separator + // Raise an error if not followed by 3-digit + // 0123456789 + // 0.000,000 + // 000,000.00 + if len(formatDirectiveIndices) == 2 { + if (formatDirectiveIndices[1] - formatDirectiveIndices[0]) != 4 { + panic("RenderFloat(): thousands separator directive must be followed by 3 digit-specifiers") + } + thousandStr = string(formatDirectiveChars[formatDirectiveIndices[0]]) + formatDirectiveIndices = formatDirectiveIndices[1:] + } + + // One directive: + // Directive is decimal separator + // The number of digit-specifier following the separator indicates wanted precision + // 0123456789 + // 0.00 + // 000,0000 + if len(formatDirectiveIndices) == 1 { + decimalStr = string(formatDirectiveChars[formatDirectiveIndices[0]]) + precision = len(formatDirectiveChars) - formatDirectiveIndices[0] - 1 + } + } + } + + // generate sign part + var signStr string + if n >= 0.000000001 { + signStr = positiveStr + } else if n <= -0.000000001 { + signStr = negativeStr + n = -n + } else { + signStr = "" + n = 0.0 + } + + // split number into integer and fractional parts + intf, fracf := math.Modf(n + renderFloatPrecisionRounders[precision]) + + // generate integer part string + intStr := strconv.Itoa(int(intf)) + + // add thousand separator if required + if len(thousandStr) > 0 { + for i := len(intStr); i > 3; { + i -= 3 + intStr = intStr[:i] + thousandStr + intStr[i:] + } + } + + // no fractional part, we can leave now + if precision == 0 { + return signStr + intStr + } + + // generate fractional part + fracStr := strconv.Itoa(int(fracf * renderFloatPrecisionMultipliers[precision])) + // may need padding + if len(fracStr) < precision { + fracStr = "000000000000000"[:precision-len(fracStr)] + fracStr + } + + return signStr + intStr + decimalStr + fracStr } func RenderInteger(format string, n int) string { -return RenderFloat(format, float64(n)) + return RenderFloat(format, float64(n)) } |