Add utilities to read header values.
Bug: 7540132
Change-Id: I19d85481135e79d8782f711da5cbb3a5a7bc06f8
diff --git a/native/jni/src/binary_format.h b/native/jni/src/binary_format.h
index 9a8c315..1c211e4 100644
--- a/native/jni/src/binary_format.h
+++ b/native/jni/src/binary_format.h
@@ -17,6 +17,7 @@
#ifndef LATINIME_BINARY_FORMAT_H
#define LATINIME_BINARY_FORMAT_H
+#include <cctype>
#include <limits>
#include <map>
#include "bloom_filter.h"
@@ -64,6 +65,9 @@
static int detectFormat(const uint8_t *const dict);
static unsigned int getHeaderSize(const uint8_t *const dict);
static unsigned int getFlags(const uint8_t *const dict);
+ static void readHeaderValue(const uint8_t *const dict, const char *const key,
+ int *outValue, const int outValueSize);
+ static int readHeaderValueInt(const uint8_t *const dict, const char *const key);
static int getGroupCountAndForwardPointer(const uint8_t *const dict, int *pos);
static uint8_t getFlagsAndForwardPointer(const uint8_t *const dict, int *pos);
static int getCodePointAndForwardPointer(const uint8_t *const dict, int *pos);
@@ -167,6 +171,70 @@
}
}
+inline void BinaryFormat::readHeaderValue(const uint8_t *const dict, const char *const key,
+ int *outValue, const int outValueSize) {
+ int outValueIndex = 0;
+ // Only format 2 and above have header attributes as {key,value} string pairs. For prior
+ // formats, we just return an empty string, as if the key wasn't found.
+ if (2 <= detectFormat(dict)) {
+ const int headerOptionsOffset = 4 /* magic number */
+ + 2 /* dictionary version */ + 2 /* flags */;
+ const int headerSize =
+ (dict[headerOptionsOffset] << 24) + (dict[headerOptionsOffset + 1] << 16)
+ + (dict[headerOptionsOffset + 2] << 8) + dict[headerOptionsOffset + 3];
+ const int headerEnd = headerOptionsOffset + 4 + headerSize;
+ int index = headerOptionsOffset + 4;
+ while (index < headerEnd) {
+ int keyIndex = 0;
+ int codePoint = getCodePointAndForwardPointer(dict, &index);
+ while (codePoint != NOT_A_CODE_POINT) {
+ if (codePoint != key[keyIndex++]) {
+ break;
+ }
+ codePoint = getCodePointAndForwardPointer(dict, &index);
+ }
+ if (codePoint == NOT_A_CODE_POINT && key[keyIndex] == 0) {
+ // We found the key! Copy and return the value.
+ codePoint = getCodePointAndForwardPointer(dict, &index);
+ while (codePoint != NOT_A_CODE_POINT
+ && outValueIndex < outValueSize) {
+ outValue[outValueIndex++] = codePoint;
+ codePoint = getCodePointAndForwardPointer(dict, &index);
+ }
+ if (outValueIndex < outValueIndex) outValue[outValueIndex] = 0;
+ // Finished copying. Break to go to the termination code.
+ break;
+ }
+ // We didn't find the key, skip the remainder of it and its value
+ while (codePoint != NOT_A_CODE_POINT) {
+ codePoint = getCodePointAndForwardPointer(dict, &index);
+ }
+ codePoint = getCodePointAndForwardPointer(dict, &index);
+ while (codePoint != NOT_A_CODE_POINT) {
+ codePoint = getCodePointAndForwardPointer(dict, &index);
+ }
+ }
+ // We couldn't find it - fall through and return an empty value.
+ }
+ // Put a terminator 0 if possible at all (always unless outValueSize is <= 0)
+ if (outValueIndex >= outValueSize) outValueIndex = outValueSize - 1;
+ if (outValueIndex >= 0) outValue[outValueIndex] = 0;
+ return;
+}
+
+inline int BinaryFormat::readHeaderValueInt(const uint8_t *const dict, const char *const key) {
+ const int bufferSize = LARGEST_INT_DIGIT_COUNT;
+ int intBuffer[bufferSize];
+ char charBuffer[bufferSize];
+ BinaryFormat::readHeaderValue(dict, key, intBuffer, bufferSize);
+ for (int i = 0; i < bufferSize; ++i) {
+ charBuffer[i] = intBuffer[i];
+ }
+ // If not a number, return S_INT_MIN
+ if (!isdigit(charBuffer[0])) return S_INT_MIN;
+ return atoi(charBuffer);
+}
+
AK_FORCE_INLINE int BinaryFormat::getGroupCountAndForwardPointer(const uint8_t *const dict,
int *pos) {
const int msb = dict[(*pos)++];
diff --git a/native/jni/src/defines.h b/native/jni/src/defines.h
index 894e5f1..ebdff7f 100644
--- a/native/jni/src/defines.h
+++ b/native/jni/src/defines.h
@@ -251,6 +251,12 @@
// GCC warns about this.
#define S_INT_MIN (-2147483647 - 1) // -(1 << 31)
#endif
+// Number of base-10 digits in the largest integer + 1 to leave room for a zero terminator.
+// As such, this is the maximum number of characters will be needed to represent an int as a
+// string, including the terminator; this is used as the size of a string buffer large enough to
+// hold any value that is intended to fit in an integer, e.g. in the code that reads the header
+// of the binary dictionary where a {key,value} string pair scheme is used.
+#define LARGEST_INT_DIGIT_COUNT 11
// Define this to use mmap() for dictionary loading. Undefine to use malloc() instead of mmap().
// We measured and compared performance of both, and found mmap() is fairly good in terms of