From db44f4ed712b558166072348ac96fb26a6ccfbfd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=D0=9B=D0=B5=D0=BE=D0=BD=D0=B8=D0=B4=20=D0=AE=D1=80=D1=8C?=
 =?UTF-8?q?=D0=B5=D0=B2=20=28Leonid=20Yuriev=29?= <leo@yuriev.ru>
Date: Sun, 16 Mar 2025 20:02:26 +0300
Subject: [PATCH] =?UTF-8?q?mdbx-tools:=20=D0=B4=D0=BE=D0=B1=D0=B0=D0=B2?=
 =?UTF-8?q?=D0=BB=D0=B5=D0=BD=D0=B8=D0=B5=20=D0=BE=D0=BF=D1=86=D0=B8=D0=B8?=
 =?UTF-8?q?=20`-c`=20(concise)=20=D0=B2=20`mdbx=5Fdump`.?=
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---
 src/man1/mdbx_dump.1 |  5 ++++
 src/tools/dump.c     | 69 ++++++++++++++++++++------------------------
 src/tools/load.c     | 13 +++++++--
 3 files changed, 48 insertions(+), 39 deletions(-)

diff --git a/src/man1/mdbx_dump.1 b/src/man1/mdbx_dump.1
index 6b04c0af..39e917ce 100644
--- a/src/man1/mdbx_dump.1
+++ b/src/man1/mdbx_dump.1
@@ -12,6 +12,8 @@ mdbx_dump \- MDBX environment export tool
 [\c
 .BR \-q ]
 [\c
+.BR \-c ]
+[\c
 .BI \-f \ file\fR]
 [\c
 .BR \-l ]
@@ -41,6 +43,9 @@ Write the library version number to the standard output, and exit.
 .BR \-q
 Be quiet.
 .TP
+.BR \-c
+Concise mode without repeating keys in a dump, but incompatible with Berkeley DB and LMDB.
+.TP
 .BR \-f \ file
 Write to the specified file instead of to the standard output.
 .TP
diff --git a/src/tools/dump.c b/src/tools/dump.c
index c09b2b17..95d9c72b 100644
--- a/src/tools/dump.c
+++ b/src/tools/dump.c
@@ -20,6 +20,7 @@
 
 #define PRINT 1
 #define GLOBAL 2
+#define CONCISE 4
 static int mode = GLOBAL;
 
 typedef struct flagbit {
@@ -55,42 +56,23 @@ static void signal_handler(int sig) {
 
 #endif /* !WINDOWS */
 
-static const char hexc[] = "0123456789abcdef";
-
-static void dumpbyte(unsigned char c) {
-  putchar(hexc[c >> 4]);
-  putchar(hexc[c & 15]);
-}
-
-static void text(MDBX_val *v) {
-  unsigned char *c, *end;
-
+static void dumpval(const MDBX_val *v) {
+  static const char digits[] = "0123456789abcdef";
   putchar(' ');
-  c = v->iov_base;
-  end = c + v->iov_len;
-  while (c < end) {
-    if (isprint(*c) && *c != '\\') {
-      putchar(*c);
-    } else {
-      putchar('\\');
-      dumpbyte(*c);
+  for (const unsigned char *c = v->iov_base, *end = c + v->iov_len; c < end; ++c) {
+    if (mode & PRINT) {
+      if (isprint(*c) && *c != '\\') {
+        putchar(*c);
+        continue;
+      } else
+        putchar('\\');
     }
-    c++;
+    putchar(digits[*c >> 4]);
+    putchar(digits[*c & 15]);
   }
   putchar('\n');
 }
 
-static void dumpval(MDBX_val *v) {
-  unsigned char *c, *end;
-
-  putchar(' ');
-  c = v->iov_base;
-  end = c + v->iov_len;
-  while (c < end)
-    dumpbyte(*c++);
-  putchar('\n');
-}
-
 bool quiet = false, rescue = false;
 const char *prog;
 static void error(const char *func, int rc) {
@@ -185,12 +167,19 @@ static int dump_tbl(MDBX_txn *txn, MDBX_dbi dbi, char *name) {
       rc = MDBX_EINTR;
       break;
     }
-    if (mode & PRINT) {
-      text(&key);
-      text(&data);
-    } else {
-      dumpval(&key);
-      dumpval(&data);
+    dumpval(&key);
+    dumpval(&data);
+    if ((flags & MDBX_DUPSORT) && (mode & CONCISE)) {
+      while ((rc = mdbx_cursor_get(cursor, &key, &data, MDBX_NEXT_DUP)) == MDBX_SUCCESS) {
+        if (user_break) {
+          rc = MDBX_EINTR;
+          break;
+        }
+        putchar(' ');
+        dumpval(&data);
+      }
+      if (rc != MDBX_NOTFOUND)
+        break;
     }
   }
   printf("DATA=END\n");
@@ -206,10 +195,12 @@ static int dump_tbl(MDBX_txn *txn, MDBX_dbi dbi, char *name) {
 static void usage(void) {
   fprintf(stderr,
           "usage: %s "
-          "[-V] [-q] [-f file] [-l] [-p] [-r] [-a|-s table] [-u|U] "
+          "[-V] [-q] [-c] [-f file] [-l] [-p] [-r] [-a|-s table] [-u|U] "
           "dbpath\n"
           "  -V\t\tprint version and exit\n"
           "  -q\t\tbe quiet\n"
+          "  -c\t\tconcise mode without repeating keys,\n"
+          "  \t\tbut incompatible with Berkeley DB and LMDB\n"
           "  -f\t\twrite to file instead of stdout\n"
           "  -l\t\tlist tables and exit\n"
           "  -p\t\tuse printable characters\n"
@@ -268,6 +259,7 @@ int main(int argc, char *argv[]) {
                      "s:"
                      "V"
                      "r"
+                     "c"
                      "q")) != EOF) {
     switch (i) {
     case 'V':
@@ -298,6 +290,9 @@ int main(int argc, char *argv[]) {
       break;
     case 'n':
       break;
+    case 'c':
+      mode |= CONCISE;
+      break;
     case 'p':
       mode |= PRINT;
       break;
diff --git a/src/tools/load.c b/src/tools/load.c
index 0220ce22..6cb35c60 100644
--- a/src/tools/load.c
+++ b/src/tools/load.c
@@ -380,7 +380,16 @@ __hot static int readline(MDBX_val *out, MDBX_val *buf) {
       return badend();
     }
   }
-  if (fgets(buf->iov_base, (int)buf->iov_len, stdin) == nullptr)
+
+  /* modern concise mode, where space in second position mean the same (previously) value */
+  c = fgetc(stdin);
+  if (c == EOF)
+    return errno ? errno : EOF;
+  if (c == ' ')
+    return (ungetc(c, stdin) == c) ? MDBX_SUCCESS : (errno ? errno : EOF);
+
+  *(char *)buf->iov_base = c;
+  if (fgets((char *)buf->iov_base + 1, (int)buf->iov_len - 1, stdin) == nullptr)
     return errno ? errno : EOF;
   lineno++;
 
@@ -721,8 +730,8 @@ int main(int argc, char *argv[]) {
     }
 
     int batch = 0;
+    MDBX_val key = {.iov_base = nullptr, .iov_len = 0}, data = {.iov_base = nullptr, .iov_len = 0};
     while (err == MDBX_SUCCESS) {
-      MDBX_val key, data;
       err = readline(&key, &kbuf);
       if (err == EOF)
         break;