Rename "External Matchfinder" to "Block-Level Sequence Producer" (#3484)

* change "external matchfinder" to "external sequence producer"

* migrate contrib/ to new naming convention

* fix contrib build

* fix error message

* update debug strings

* fix def of invalid sequences in zstd.h

* nit

* update CHANGELOG

* fix .gitignore

contrib/externalMatchfinder/.gitignore

@@ -1,2 +0,0 @@
-# build artifacts
-externalMatchfinder

contrib/externalMatchfinder/README.md

@@ -1,14 +0,0 @@
-externalMatchfinder
-=====================
-
-`externalMatchfinder` is a test tool for the external matchfinder API.
-It demonstrates how to use the API to perform a simple round-trip test.
-
-A sample matchfinder is provided in matchfinder.c, but the user can swap
-this out with a different one if desired. The sample matchfinder implements
-LZ compression with a 1KB hashtable. Dictionary compression is not currently supported.
-
-Command line :
-```
-externalMatchfinder filename
-```

contrib/externalSequenceProducer/.gitignore

@@ -0,0 +1,2 @@
+# build artifacts
+externalSequenceProducer

contrib/externalSequenceProducer/Makefile

@@ -23,11 +23,11 @@ DEBUGFLAGS= -Wall -Wextra -Wcast-qual -Wcast-align -Wshadow \
             -Wredundant-decls
 CFLAGS  += $(DEBUGFLAGS) $(MOREFLAGS)
 
-default: externalMatchfinder
+default: externalSequenceProducer
 
-all: externalMatchfinder
+all: externalSequenceProducer
 
-externalMatchfinder: matchfinder.c main.c $(LIBZSTD)
+externalSequenceProducer: sequence_producer.c main.c $(LIBZSTD)
 	$(CC) $(CPPFLAGS) $(CFLAGS) $^ $(LDFLAGS) -o $@
 
 .PHONY: $(LIBZSTD)
@@ -37,4 +37,4 @@ $(LIBZSTD):
 clean:
 	$(RM) *.o
 	$(MAKE) -C $(LIBDIR) clean > /dev/null
-	$(RM) externalMatchfinder
+	$(RM) externalSequenceProducer

contrib/externalSequenceProducer/README.md

@@ -0,0 +1,14 @@
+externalSequenceProducer
+=====================
+
+`externalSequenceProducer` is a test tool for the Block-Level Sequence Producer API.
+It demonstrates how to use the API to perform a simple round-trip test.
+
+A sample sequence producer is provided in sequence_producer.c, but the user can swap
+this out with a different one if desired. The sample sequence producer implements
+LZ parsing with a 1KB hashtable. Dictionary-based parsing is not currently supported.
+
+Command line :
+```
+externalSequenceProducer filename
+```

contrib/externalSequenceProducer/main.c

@@ -16,7 +16,7 @@
 #define ZSTD_STATIC_LINKING_ONLY
 #include "zstd.h"
 #include "zstd_errors.h"
-#include "matchfinder.h" // simpleExternalMatchFinder
+#include "sequence_producer.h" // simpleSequenceProducer
 
 #define CHECK(res)                                      \
 do {                                                    \
@@ -28,23 +28,23 @@ do {                                                    \
 
 int main(int argc, char *argv[]) {
     if (argc != 2) {
-        printf("Usage: exampleMatchfinder <file>\n");
+        printf("Usage: externalSequenceProducer <file>\n");
         return 1;
     }
 
     ZSTD_CCtx* const zc = ZSTD_createCCtx();
 
-    int simpleExternalMatchState = 0xdeadbeef;
+    int simpleSequenceProducerState = 0xdeadbeef;
 
     // Here is the crucial bit of code!
-    ZSTD_registerExternalMatchFinder(
+    ZSTD_registerSequenceProducer(
         zc,
-        &simpleExternalMatchState,
-        simpleExternalMatchFinder
+        &simpleSequenceProducerState,
+        simpleSequenceProducer
     );
 
     {
-        size_t const res = ZSTD_CCtx_setParameter(zc, ZSTD_c_enableMatchFinderFallback, 1);
+        size_t const res = ZSTD_CCtx_setParameter(zc, ZSTD_c_enableSeqProducerFallback, 1);
         CHECK(res);
     }
 

contrib/externalSequenceProducer/sequence_producer.c

@@ -9,15 +9,15 @@
  */
 
 #include "zstd_compress_internal.h"
-#include "matchfinder.h"
+#include "sequence_producer.h"
 
 #define HSIZE 1024
 static U32 const HLOG = 10;
 static U32 const MLS = 4;
 static U32 const BADIDX = 0xffffffff;
 
-size_t simpleExternalMatchFinder(
-  void* externalMatchState,
+size_t simpleSequenceProducer(
+  void* sequenceProducerState,
   ZSTD_Sequence* outSeqs, size_t outSeqsCapacity,
   const void* src, size_t srcSize,
   const void* dict, size_t dictSize,
@@ -31,7 +31,7 @@ size_t simpleExternalMatchFinder(
     size_t seqCount = 0;
     U32 hashTable[HSIZE];
 
-    (void)externalMatchState;
+    (void)sequenceProducerState;
     (void)dict;
     (void)dictSize;
     (void)outSeqsCapacity;

contrib/externalSequenceProducer/sequence_producer.h

@@ -14,8 +14,8 @@
 #define ZSTD_STATIC_LINKING_ONLY
 #include "zstd.h"
 
-size_t simpleExternalMatchFinder(
-  void* externalMatchState,
+size_t simpleSequenceProducer(
+  void* sequenceProducerState,
   ZSTD_Sequence* outSeqs, size_t outSeqsCapacity,
   const void* src, size_t srcSize,
   const void* dict, size_t dictSize,