From 892311dcd0ce23126307b5471a895a098dc0f985 Mon Sep 17 00:00:00 2001
From: qishenonly <1050026498@qq.com>
Date: Wed, 5 Jul 2023 18:23:36 +0800
Subject: [PATCH] feat: new method--HIncrBy(#136)

---
 structure/hash.go      | 62 ++++++++++++++++++++++++++++++++++++++++++
 structure/hash_test.go | 33 ++++++++++++++++++++++
 2 files changed, 95 insertions(+)

diff --git a/structure/hash.go b/structure/hash.go
index 94a54e99..698b3895 100644
--- a/structure/hash.go
+++ b/structure/hash.go
@@ -5,6 +5,7 @@ import (
 	"github.com/ByteStorage/FlyDB/config"
 	"github.com/ByteStorage/FlyDB/engine"
 	_const "github.com/ByteStorage/FlyDB/lib/const"
+	"strconv"
 	"time"
 )
 
@@ -432,3 +433,64 @@ func (hs *HashStructure) HUpdate(key, field, value []byte) (bool, error) {
 
 	return true, nil
 }
+
+// HIncrBy increments the integer value of a hash field by the given number.
+func (hs *HashStructure) HIncrBy(key, field []byte, increment int64) (int64, error) {
+	// Check the parameters
+	if len(key) == 0 || len(field) == 0 {
+		return 0, _const.ErrKeyIsEmpty
+	}
+
+	// Find the hash metadata by the given key
+	hashMeta, err := hs.findHashMeta(key, Hash)
+	if err != nil {
+		return 0, err
+	}
+
+	// If the counter is 0, return 0
+	if hashMeta.counter == 0 {
+		return 0, nil
+	}
+
+	// Create a new HashField
+	hf := &HashField{
+		field:   field,
+		key:     key,
+		version: hashMeta.version,
+	}
+
+	// Encode the HashField
+	hfBuf := hf.encodeHashField()
+
+	// Get the field from the database
+	value, err := hs.db.Get(hfBuf)
+	if err != nil && err == _const.ErrKeyNotFound {
+		return 0, nil
+	}
+
+	// Convert the value to int64
+	val, err := strconv.ParseInt(string(value), 10, 64)
+	if err != nil {
+		return 0, err
+	}
+
+	// Add the increment to the value
+	val += increment
+
+	// Convert the value to string
+	value = []byte(strconv.FormatInt(val, 10))
+
+	// new a write batch
+	batch := hs.db.NewWriteBatch(config.DefaultWriteBatchOptions)
+
+	// Put the field to the database
+	_ = batch.Put(hfBuf, value)
+
+	// Commit the write batch
+	err = batch.Commit()
+	if err != nil {
+		return 0, err
+	}
+
+	return val, nil
+}
diff --git a/structure/hash_test.go b/structure/hash_test.go
index 2bc41dab..78051c94 100644
--- a/structure/hash_test.go
+++ b/structure/hash_test.go
@@ -142,3 +142,36 @@ func TestHashStructure_HUpdate(t *testing.T) {
 	assert.Nil(t, err)
 	assert.Equal(t, l, 3)
 }
+
+func TestHashStructure_HIncrBy(t *testing.T) {
+	hash := initHashDB()
+
+	ok1, err := hash.HSet(randkv.GetTestKey(1), []byte("field1"), []byte("10"))
+	assert.Nil(t, err)
+	assert.True(t, ok1)
+
+	ok2, err := hash.HSet(randkv.GetTestKey(1), []byte("field2"), []byte("10"))
+	assert.Nil(t, err)
+	assert.True(t, ok2)
+
+	ok3, err := hash.HSet(randkv.GetTestKey(1), []byte("field3"), []byte("10"))
+	assert.Nil(t, err)
+	assert.True(t, ok3)
+
+	v1, err := hash.HIncrBy(randkv.GetTestKey(1), []byte("field1"), 1)
+	assert.Nil(t, err)
+	assert.Equal(t, v1, int64(11))
+
+	v2, err := hash.HIncrBy(randkv.GetTestKey(1), []byte("field2"), -1)
+	assert.Nil(t, err)
+	assert.Equal(t, v2, int64(9))
+
+	v3, err := hash.HIncrBy(randkv.GetTestKey(1), []byte("field3"), 0)
+	assert.Nil(t, err)
+	assert.Equal(t, v3, int64(10))
+
+	v4, err := hash.HIncrBy(randkv.GetTestKey(1), []byte("field4"), 1)
+	assert.Nil(t, err)
+	assert.Equal(t, v4, int64(0))
+
+}