Added character skill parsing

Imanol-Mikel Barba Sabariego
1 parent f8fab420
Showing 2 changed files with 100 additions and 13 deletions
d2skills.c
d2skills.h
 #include "d2skills.h"
+#include "d2stat.h"
 #include <stdio.h>
 #include <stdlib.h>
@@ -11,36 +12,118 @@ const char* getSkillName(D2S_SKILL skillID) {
     return skillNames[skillID];
 }
-D2S_SKILL getSkillIDFromCharOffset(D2S_CHARCLASS class, unsigned int offset) {
-    if(offset < 0 || offset > D2S_SKILL_MAXSKILLS_PER_CHAR) {
-        fprintf(stderr,"libd2char error: Invalid character skill offset: %d\n",offset);
-        return D2S_SKILL_UNKNOWN;
-    }
+const D2S_SKILL* _getCharSkillTree(D2S_CHARCLASS class) {
     switch(class) {
         case D2S_CHARCLASS_AMAZON:
-            return amazonSkills[offset];
+            return amazonSkills;
         break;
         case D2S_CHARCLASS_SORCERESS:
-            return sorceressSkills[offset];
+            return sorceressSkills;
         break;
         case D2S_CHARCLASS_NECROMANCER:
-            return necromancerSkills[offset];
+            return necromancerSkills;
         break;
         case D2S_CHARCLASS_PALADIN:
-            return paladinSkills[offset];
+            return paladinSkills;
         break;
         case D2S_CHARCLASS_BARBARIAN:
-            return barbarianSkills[offset];
+            return barbarianSkills;
         break;
         case D2S_CHARCLASS_DRUID:
-            return druidSkills[offset];
+            return druidSkills;
         break;
         case D2S_CHARCLASS_ASSASSIN:
-            return assassinSkills[offset];
+            return assassinSkills;
         break;
         case D2S_CHARCLASS_UNKNOWN:
         default:
-            return D2S_SKILL_UNKNOWN;
+            return NULL;
         break;
     }
+}
+
+D2S_SKILL getSkillIDFromCharOffset(D2S_CHARCLASS class, unsigned int offset) {
+    if(offset < 0 || offset > D2S_SKILL_MAXSKILLS_PER_CHAR) {
+        fprintf(stderr,"libd2char error: Invalid character skill offset: %d\n",offset);
+        return D2S_SKILL_UNKNOWN;
+    }
+    const D2S_SKILL* skillTree = _getCharSkillTree(class);
+    if(!skillTree) {
+        fprintf(stderr,"libd2char error: Invalid character class: %d\n",class);
+        return D2S_SKILL_UNKNOWN;
+    }
+    return skillTree[offset];
+}
+
+void* _getCharSkillsOffset(void* charData, size_t dataLen) {
+    // Find skill header and look for previous 2 bytes
+    // possible good candidates:
+    //
+    // 0b0000000111111111
+    // 0b000000111111111x
+    // 0b00000111111111xx
+    // 0b0000111111111xxx
+    // 0b000111111111xxxx
+    // 0b00111111111xxxxx
+    // 0b0111111111xxxxxx
+    // 0b111111111xxxxxxx
+    unsigned int offset = 0;
+    while(offset < dataLen) {
+        void* offsetAddr = charData + (offset++);
+        if(!memcmp(offsetAddr, D2S_SKILL_HEADER, D2S_SKILL_HEADER_LENGTH)) {
+            uint16_t prevBytes = 0;
+            memcpy(&prevBytes, offsetAddr, sizeof(prevBytes));
+            // Shift a maximum of 7 positions, and check if at some point the candidate
+            // turns into the 9 bit D2S_STAT_FOOTER value
+            for(int i = 0; i < 7; ++i) {
+                if(prevBytes == D2S_STAT_FOOTER) {
+                    return offsetAddr;
+                }
+                prevBytes >>= 1;
+            }
+            // If we reach here, candidate was not viable, let's find a new candidate
+        }
+    }
+    return NULL;
+}
+
+int getSkillLevel(D2CharHeader* c, D2S_SKILL skillID, void* charData, size_t dataLen) {
+    const D2S_SKILL* skillTree = _getCharSkillTree(c->charClass);
+    if(!skillTree) {
+        fprintf(stderr,"libd2char error: Invalid character class: %d\n",c->charClass);
+        return D2S_SKILL_UNKNOWN;
+    }
+    for(int i = 0; i < D2S_SKILL_MAXSKILLS_PER_CHAR; ++i) {
+        if(skillTree[i] == skillID) {
+            void* skillOffset = _getCharSkillsOffset(charData, dataLen);
+            if(!skillOffset) {
+                fprintf(stderr,"libd2char error: Unable to find skill data offset in charData\n");
+                return -1;
+            }
+            return ((uint8_t*)skillOffset)[i + D2S_SKILL_HEADER_LENGTH];
+        }
+    }
+    fprintf(stderr,"libd2char error: The specified skillID is not in your class's skill tree\n");
+    return -1;
+}
+
+int setSkillLevel(D2CharHeader* c, D2S_SKILL skillID, unsigned int level, void* charData, size_t dataLen) {
+    const D2S_SKILL* skillTree = _getCharSkillTree(c->charClass);
+    if(!skillTree) {
+        fprintf(stderr,"libd2char error: Invalid character class: %d\n",c->charClass);
+        return D2S_SKILL_UNKNOWN;
+    }
+    for(int i = 0; i < D2S_SKILL_MAXSKILLS_PER_CHAR; ++i) {
+        if(skillTree[i] == skillID) {
+            void* skillOffset = _getCharSkillsOffset(charData, dataLen);
+            if(!skillOffset) {
+                fprintf(stderr,"libd2char error: Unable to find skill data offset in charData\n");
+                return -1;
+            }
+            ((uint8_t*)skillOffset)[i + D2S_SKILL_HEADER_LENGTH] = (uint8_t)level;
+            return 0;
+        }
+    }
+    fprintf(stderr,"libd2char error: The specified skillID is not in your class's skill tree\n");
+    return -1;
 }
 \ No newline at end of file
@@ -8,6 +8,8 @@
 #define D2S_SKILL_NUMSKILLS 357
 #define D2S_SKILL_MAXSKILLS_PER_CHAR 30
+#define D2S_SKILL_HEADER "if"
+#define D2S_SKILL_HEADER_LENGTH 2
 typedef enum D2S_SKILL {
     D2S_SKILL_UNKNOWN = -1,
@@ -964,5 +966,7 @@ const char* const skillNames[] = {
 // Returns static string from library memory, no need to free
 const char* getSkillName(D2S_SKILL skillID);
 D2S_SKILL getSkillIDFromCharOffset(D2S_CHARCLASS class, unsigned int offset);
+int getSkillLevel(D2CharHeader* c, D2S_SKILL skillID, void* charData, size_t dataLen);
+int setSkillLevel(D2CharHeader* c, D2S_SKILL skillID, unsigned int level, void* charData, size_t dataLen);
 #endif
 \ No newline at end of file