diff options
author | Hal Canary <halcanary@google.com> | 2018-01-02 16:25:53 -0500 |
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committer | Skia Commit-Bot <skia-commit-bot@chromium.org> | 2018-01-03 19:59:31 +0000 |
commit | 3c36ef6be93400368fee3ea2e0dca6cff4972bb0 (patch) | |
tree | 69ce7be26f6771d4fcb3d1da3bc979fc0120285f /src/pdf | |
parent | 0d825666f79f4d9baea489b21506da3163f73aa9 (diff) |
SkFloatToDecimal moved to src/utils
This change stages SkFloatToDecimal() for possible re-use by pdfium.
Change-Id: Iedc0c78c8a633f0b0973365d2d8b540b5443590d
Reviewed-on: https://skia-review.googlesource.com/90400
Commit-Queue: Hal Canary <halcanary@google.com>
Reviewed-by: Cary Clark <caryclark@google.com>
Diffstat (limited to 'src/pdf')
-rw-r--r-- | src/pdf/SkPDFUtils.cpp | 159 | ||||
-rw-r--r-- | src/pdf/SkPDFUtils.h | 16 |
2 files changed, 8 insertions, 167 deletions
diff --git a/src/pdf/SkPDFUtils.cpp b/src/pdf/SkPDFUtils.cpp index c9f5806211..c225fbda7a 100644 --- a/src/pdf/SkPDFUtils.cpp +++ b/src/pdf/SkPDFUtils.cpp @@ -287,165 +287,6 @@ size_t SkPDFUtils::ColorToDecimal(uint8_t value, char result[5]) { return j + 1; } -void SkPDFUtils::AppendScalar(SkScalar value, SkWStream* stream) { - char result[kMaximumFloatDecimalLength]; - size_t len = SkPDFUtils::FloatToDecimal(SkScalarToFloat(value), result); - SkASSERT(len < kMaximumFloatDecimalLength); - stream->write(result, len); -} - -// Return pow(10.0, e), optimized for common cases. -inline double pow10(int e) { - switch (e) { - case 0: return 1.0; // common cases - case 1: return 10.0; - case 2: return 100.0; - case 3: return 1e+03; - case 4: return 1e+04; - case 5: return 1e+05; - case 6: return 1e+06; - case 7: return 1e+07; - case 8: return 1e+08; - case 9: return 1e+09; - case 10: return 1e+10; - case 11: return 1e+11; - case 12: return 1e+12; - case 13: return 1e+13; - case 14: return 1e+14; - case 15: return 1e+15; - default: - if (e > 15) { - double value = 1e+15; - while (e-- > 15) { value *= 10.0; } - return value; - } else { - SkASSERT(e < 0); - double value = 1.0; - while (e++ < 0) { value /= 10.0; } - return value; - } - } -} - -/** Write a string into result, includeing a terminating '\0' (for - unit testing). Return strlen(result) (for SkWStream::write) The - resulting string will be in the form /[-]?([0-9]*.)?[0-9]+/ and - sscanf(result, "%f", &x) will return the original value iff the - value is finite. This function accepts all possible input values. - - Motivation: "PDF does not support [numbers] in exponential format - (such as 6.02e23)." Otherwise, this function would rely on a - sprintf-type function from the standard library. */ -size_t SkPDFUtils::FloatToDecimal(float value, - char result[kMaximumFloatDecimalLength]) { - /* The longest result is -FLT_MIN. - We serialize it as "-.0000000000000000000000000000000000000117549435" - which has 48 characters plus a terminating '\0'. */ - - /* section C.1 of the PDF1.4 spec (http://goo.gl/0SCswJ) says that - most PDF rasterizers will use fixed-point scalars that lack the - dynamic range of floats. Even if this is the case, I want to - serialize these (uncommon) very small and very large scalar - values with enough precision to allow a floating-point - rasterizer to read them in with perfect accuracy. - Experimentally, rasterizers such as pdfium do seem to benefit - from this. Rasterizers that rely on fixed-point scalars should - gracefully ignore these values that they can not parse. */ - char* output = &result[0]; - const char* const end = &result[kMaximumFloatDecimalLength - 1]; - // subtract one to leave space for '\0'. - - /* This function is written to accept any possible input value, - including non-finite values such as INF and NAN. In that case, - we ignore value-correctness and and output a syntacticly-valid - number. */ - if (value == SK_FloatInfinity) { - value = FLT_MAX; // nearest finite float. - } - if (value == SK_FloatNegativeInfinity) { - value = -FLT_MAX; // nearest finite float. - } - if (!std::isfinite(value) || value == 0.0f) { - // NAN is unsupported in PDF. Always output a valid number. - // Also catch zero here, as a special case. - *output++ = '0'; - *output = '\0'; - return output - result; - } - if (value < 0.0) { - *output++ = '-'; - value = -value; - } - SkASSERT(value >= 0.0f); - - int binaryExponent; - (void)std::frexp(value, &binaryExponent); - static const double kLog2 = 0.3010299956639812; // log10(2.0); - int decimalExponent = static_cast<int>(std::floor(kLog2 * binaryExponent)); - int decimalShift = decimalExponent - 8; - double power = pow10(-decimalShift); - int32_t d = static_cast<int32_t>(value * power + 0.5); - // SkASSERT(value == (float)(d * pow(10.0, decimalShift))); - SkASSERT(d <= 999999999); - if (d > 167772159) { // floor(pow(10,1+log10(1<<24))) - // need one fewer decimal digits for 24-bit precision. - decimalShift = decimalExponent - 7; - // SkASSERT(power * 0.1 = pow10(-decimalShift)); - // recalculate to get rounding right. - d = static_cast<int32_t>(value * (power * 0.1) + 0.5); - SkASSERT(d <= 99999999); - } - while (d % 10 == 0) { - d /= 10; - ++decimalShift; - } - SkASSERT(d > 0); - // SkASSERT(value == (float)(d * pow(10.0, decimalShift))); - uint8_t buffer[9]; // decimal value buffer. - int bufferIndex = 0; - do { - buffer[bufferIndex++] = d % 10; - d /= 10; - } while (d != 0); - SkASSERT(bufferIndex <= (int)sizeof(buffer) && bufferIndex > 0); - if (decimalShift >= 0) { - do { - --bufferIndex; - *output++ = '0' + buffer[bufferIndex]; - } while (bufferIndex); - for (int i = 0; i < decimalShift; ++i) { - *output++ = '0'; - } - } else { - int placesBeforeDecimal = bufferIndex + decimalShift; - if (placesBeforeDecimal > 0) { - while (placesBeforeDecimal-- > 0) { - --bufferIndex; - *output++ = '0' + buffer[bufferIndex]; - } - *output++ = '.'; - } else { - *output++ = '.'; - int placesAfterDecimal = -placesBeforeDecimal; - while (placesAfterDecimal-- > 0) { - *output++ = '0'; - } - } - while (bufferIndex > 0) { - --bufferIndex; - *output++ = '0' + buffer[bufferIndex]; - if (output == end) { - break; // denormalized: don't need extra precision. - // Note: denormalized numbers will not have the same number of - // significantDigits, but do not need them to round-trip. - } - } - } - SkASSERT(output <= end); - *output = '\0'; - return output - result; -} - void SkPDFUtils::WriteString(SkWStream* wStream, const char* cin, size_t len) { SkDEBUGCODE(static const size_t kMaxLen = 65535;) SkASSERT(len <= kMaxLen); diff --git a/src/pdf/SkPDFUtils.h b/src/pdf/SkPDFUtils.h index 27d0a3adbe..a291914a5a 100644 --- a/src/pdf/SkPDFUtils.h +++ b/src/pdf/SkPDFUtils.h @@ -7,6 +7,7 @@ #ifndef SkPDFUtils_DEFINED #define SkPDFUtils_DEFINED +#include "SkFloatToDecimal.h" #include "SkPDFTypes.h" #include "SkPaint.h" #include "SkPath.h" @@ -76,14 +77,13 @@ inline void AppendColorComponent(uint8_t value, SkWStream* wStream) { wStream->write(buffer, len); } -// 3 = '-', '.', and '\0' characters. -// 9 = number of significant digits -// abs(FLT_MIN_10_EXP) = number of zeros in FLT_MIN -const size_t kMaximumFloatDecimalLength = 3 + 9 - FLT_MIN_10_EXP; -// FloatToDecimal is exposed for unit tests. -size_t FloatToDecimal(float value, - char output[kMaximumFloatDecimalLength]); -void AppendScalar(SkScalar value, SkWStream* stream); +inline void AppendScalar(SkScalar value, SkWStream* stream) { + char result[kMaximumSkFloatToDecimalLength]; + size_t len = SkFloatToDecimal(SkScalarToFloat(value), result); + SkASSERT(len < kMaximumSkFloatToDecimalLength); + stream->write(result, len); +} + void WriteString(SkWStream* wStream, const char* input, size_t len); inline void WriteUInt16BE(SkDynamicMemoryWStream* wStream, uint16_t value) { |