Index: third_party/sqlite/sqlite-src-3080704/ext/misc/compress.c |
diff --git a/third_party/sqlite/sqlite-src-3080704/ext/misc/compress.c b/third_party/sqlite/sqlite-src-3080704/ext/misc/compress.c |
new file mode 100644 |
index 0000000000000000000000000000000000000000..a4059116c9e4c981b1345fca9bb9c0edf35dcb4b |
--- /dev/null |
+++ b/third_party/sqlite/sqlite-src-3080704/ext/misc/compress.c |
@@ -0,0 +1,107 @@ |
+/* |
+** 2014-06-13 |
+** |
+** The author disclaims copyright to this source code. In place of |
+** a legal notice, here is a blessing: |
+** |
+** May you do good and not evil. |
+** May you find forgiveness for yourself and forgive others. |
+** May you share freely, never taking more than you give. |
+** |
+****************************************************************************** |
+** |
+** This SQLite extension implements SQL compression functions |
+** compress() and uncompress() using ZLIB. |
+*/ |
+#include "sqlite3ext.h" |
+SQLITE_EXTENSION_INIT1 |
+#include <zlib.h> |
+ |
+/* |
+** Implementation of the "compress(X)" SQL function. The input X is |
+** compressed using zLib and the output is returned. |
+** |
+** The output is a BLOB that begins with a variable-length integer that |
+** is the input size in bytes (the size of X before compression). The |
+** variable-length integer is implemented as 1 to 5 bytes. There are |
+** seven bits per integer stored in the lower seven bits of each byte. |
+** More significant bits occur first. The most significant bit (0x80) |
+** is a flag to indicate the end of the integer. |
+*/ |
+static void compressFunc( |
+ sqlite3_context *context, |
+ int argc, |
+ sqlite3_value **argv |
+){ |
+ const unsigned char *pIn; |
+ unsigned char *pOut; |
+ unsigned int nIn; |
+ unsigned long int nOut; |
+ unsigned char x[8]; |
+ int i, j; |
+ |
+ pIn = sqlite3_value_blob(argv[0]); |
+ nIn = sqlite3_value_bytes(argv[0]); |
+ nOut = 13 + nIn + (nIn+999)/1000; |
+ pOut = sqlite3_malloc( nOut+5 ); |
+ for(i=4; i>=0; i--){ |
+ x[i] = (nIn >> (7*(4-i)))&0x7f; |
+ } |
+ for(i=0; i<4 && x[i]==0; i++){} |
+ for(j=0; i<=4; i++, j++) pOut[j] = x[i]; |
+ pOut[j-1] |= 0x80; |
+ compress(&pOut[j], &nOut, pIn, nIn); |
+ sqlite3_result_blob(context, pOut, nOut+j, sqlite3_free); |
+} |
+ |
+/* |
+** Implementation of the "uncompress(X)" SQL function. The argument X |
+** is a blob which was obtained from compress(Y). The output will be |
+** the value Y. |
+*/ |
+static void uncompressFunc( |
+ sqlite3_context *context, |
+ int argc, |
+ sqlite3_value **argv |
+){ |
+ const unsigned char *pIn; |
+ unsigned char *pOut; |
+ unsigned int nIn; |
+ unsigned long int nOut; |
+ int rc; |
+ int i; |
+ |
+ pIn = sqlite3_value_blob(argv[0]); |
+ nIn = sqlite3_value_bytes(argv[0]); |
+ nOut = 0; |
+ for(i=0; i<nIn && i<5; i++){ |
+ nOut = (nOut<<7) | (pIn[i]&0x7f); |
+ if( (pIn[i]&0x80)!=0 ){ i++; break; } |
+ } |
+ pOut = sqlite3_malloc( nOut+1 ); |
+ rc = uncompress(pOut, &nOut, &pIn[i], nIn-i); |
+ if( rc==Z_OK ){ |
+ sqlite3_result_blob(context, pOut, nOut, sqlite3_free); |
+ } |
+} |
+ |
+ |
+#ifdef _WIN32 |
+__declspec(dllexport) |
+#endif |
+int sqlite3_compress_init( |
+ sqlite3 *db, |
+ char **pzErrMsg, |
+ const sqlite3_api_routines *pApi |
+){ |
+ int rc = SQLITE_OK; |
+ SQLITE_EXTENSION_INIT2(pApi); |
+ (void)pzErrMsg; /* Unused parameter */ |
+ rc = sqlite3_create_function(db, "compress", 1, SQLITE_UTF8, 0, |
+ compressFunc, 0, 0); |
+ if( rc==SQLITE_OK ){ |
+ rc = sqlite3_create_function(db, "uncompress", 1, SQLITE_UTF8, 0, |
+ uncompressFunc, 0, 0); |
+ } |
+ return rc; |
+} |