From 6583fa3f0ab8b7ab7c34888a07b20af852a2ef3c Mon Sep 17 00:00:00 2001
From: Binh Vo <binhvo@fb.com>
Date: Wed, 9 Jun 2021 14:00:29 -0400
Subject: [PATCH] Add support for --long-param flag

---
 programs/zstdcli.c | 73 +++++++++++++++++++++++++++++++++++-----------
 tests/playTests.sh |  7 +++++
 2 files changed, 63 insertions(+), 17 deletions(-)

diff --git a/programs/zstdcli.c b/programs/zstdcli.c
index 9e2133c4f..28fc980a2 100644
--- a/programs/zstdcli.c
+++ b/programs/zstdcli.c
@@ -206,6 +206,7 @@ static void usage_advanced(const char* programName)
     DISPLAYOUT( "--ultra : enable levels beyond %i, up to %i (requires more memory) \n", ZSTDCLI_CLEVEL_MAX, ZSTD_maxCLevel());
     DISPLAYOUT( "--long[=#]: enable long distance matching with given window log (default: %u) \n", g_defaultMaxWindowLog);
     DISPLAYOUT( "--fast[=#]: switch to very fast compression levels (default: %u) \n", 1);
+    DISPLAYOUT( "--long-param=#: specify compression level, accepts negative values as fast compression levels \n");
     DISPLAYOUT( "--adapt : dynamically adapt compression level to I/O conditions \n");
     DISPLAYOUT( "--[no-]row-match-finder : force enable/disable usage of fast row-based matchfinder for greedy, lazy, and lazy2 strategies \n");
     DISPLAYOUT( "--patch-from=FILE : specify the file to be used as a reference point for zstd's diff engine. \n");
@@ -354,6 +355,25 @@ static unsigned readU32FromChar(const char** stringPtr) {
     return result;
 }
 
+#ifndef ZSTD_NOCOMPRESS
+/*! readIntFromChar() :
+ * @return : signed integer value read from input in `char` format.
+ *  allows and interprets K, KB, KiB, M, MB and MiB suffix.
+ *  Will also modify `*stringPtr`, advancing it to position where it stopped reading.
+ *  Note : function will exit() program if digit sequence overflows */
+static int readIntFromChar(const char** stringPtr) {
+    static const char errorMsg[] = "error: numeric value overflows 32-bit int";
+    int sign = 1;
+    unsigned result;
+    if (**stringPtr=='-') {
+        (*stringPtr)++;
+        sign = -1;
+    }
+    if (readU32FromCharChecked(stringPtr, &result)) { errorOut(errorMsg); }
+    return (int) result * sign;
+}
+#endif
+
 /*! readSizeTFromCharChecked() :
  * @return 0 if success, and store the result in *value.
  *  allows and interprets K, KB, KiB, M, MB and MiB suffix.
@@ -940,23 +960,6 @@ int main(int const argCount, const char* argv[])
                 if (longCommandWArg(&argument, "--trace")) { char const* traceFile; NEXT_FIELD(traceFile); TRACE_enable(traceFile); continue; }
 #endif
                 if (longCommandWArg(&argument, "--patch-from")) { NEXT_FIELD(patchFromDictFileName); continue; }
-                if (longCommandWArg(&argument, "--long")) {
-                    unsigned ldmWindowLog = 0;
-                    ldmFlag = 1;
-                    /* Parse optional window log */
-                    if (*argument == '=') {
-                        ++argument;
-                        ldmWindowLog = readU32FromChar(&argument);
-                    } else if (*argument != 0) {
-                        /* Invalid character following --long */
-                        badusage(programName);
-                        CLEAN_RETURN(1);
-                    }
-                    /* Only set windowLog if not already set by --zstd */
-                    if (compressionParams.windowLog == 0)
-                        compressionParams.windowLog = ldmWindowLog;
-                    continue;
-                }
 #ifndef ZSTD_NOCOMPRESS   /* linking ZSTD_minCLevel() requires compression support */
                 if (longCommandWArg(&argument, "--fast")) {
                     /* Parse optional acceleration factor */
@@ -981,8 +984,44 @@ int main(int const argCount, const char* argv[])
                     }
                     continue;
                 }
+
+                if (longCommandWArg(&argument, "--long-param")) {
+                    if (*argument == '=') {
+                        int maxLevel = ZSTD_maxCLevel();
+                        int minLevel = ZSTD_minCLevel();
+                        int readLevel;
+                        ++argument;
+                        readLevel = readIntFromChar(&argument);
+                        if (readLevel > maxLevel) readLevel = maxLevel;
+                        if (readLevel < minLevel) readLevel = minLevel;
+                        cLevel = readLevel;
+                    } else {
+                        /* --long-param requires an argument */
+                        badusage(programName);
+                        CLEAN_RETURN(1);
+                    }
+                    continue;
+                }
 #endif
 
+                if (longCommandWArg(&argument, "--long")) {
+                    unsigned ldmWindowLog = 0;
+                    ldmFlag = 1;
+                    /* Parse optional window log */
+                    if (*argument == '=') {
+                        ++argument;
+                        ldmWindowLog = readU32FromChar(&argument);
+                    } else if (*argument != 0) {
+                        /* Invalid character following --long */
+                        badusage(programName);
+                        CLEAN_RETURN(1);
+                    }
+                    /* Only set windowLog if not already set by --zstd */
+                    if (compressionParams.windowLog == 0)
+                        compressionParams.windowLog = ldmWindowLog;
+                    continue;
+                }
+
                 if (longCommandWArg(&argument, "--filelist")) {
                     const char* listName;
                     NEXT_FIELD(listName);
diff --git a/tests/playTests.sh b/tests/playTests.sh
index 252939006..09dae1a29 100755
--- a/tests/playTests.sh
+++ b/tests/playTests.sh
@@ -191,6 +191,13 @@ zstd --fast=3 -f tmp  # == -3
 zstd --fast=200000 -f tmp  # too low compression level, automatic fixed
 zstd --fast=5000000000 -f tmp && die "too large numeric value : must fail"
 zstd -c --fast=0 tmp > $INTOVOID && die "--fast must not accept value 0"
+println "test : --long-param compression levels"
+zstd --long-param=1 -f tmp
+zstd --long-param=0 -f tmp
+zstd --long-param=-1 -f tmp
+zstd --long-param=-10000 -f tmp # too low, automatic fixed
+zstd --long-param=10000 -f tmp # too high, automatic fixed
+zstd --long-param -f tmp > $INTOVOID && die "--long-param must be given a value"
 println "test : too large numeric argument"
 zstd --fast=9999999999 -f tmp  && die "should have refused numeric value"
 println "test : set compression level with environment variable ZSTD_CLEVEL"