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Unified Diff: third_party/sqlite/src/ext/misc/compress.c

Issue 949043002: Add //third_party/sqlite to dirs_to_snapshot, remove net_sql.patch (Closed) Base URL: git@github.com:domokit/mojo.git@master
Patch Set: Created 5 years, 10 months ago
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Index: third_party/sqlite/src/ext/misc/compress.c
diff --git a/third_party/sqlite/src/ext/misc/compress.c b/third_party/sqlite/src/ext/misc/compress.c
new file mode 100644
index 0000000000000000000000000000000000000000..a4059116c9e4c981b1345fca9bb9c0edf35dcb4b
--- /dev/null
+++ b/third_party/sqlite/src/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;
+}
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