US/UM AC container unpacker

/*
*   UnpackAC.c
*       by Reisyukaku
*
*   Unpacks files from AC/AS container (quick and dirty).
*/

#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <malloc.h>

#if defined(_WIN32)
    #include <direct.h>
#else
    #include <sys/stat.h>
#endif

typedef uint8_t u8;
typedef uint16_t u16;
typedef uint32_t u32;

typedef struct{
    u32 startAddr;
} Entry;

typedef struct{
    u16 magic;
    u16 entryCnt;
} Header;

void makeDir(const char* name) {
   #if defined(_WIN32)
        _mkdir(name);
    #else
        mkdir(name, 777);
   #endif
}

char *magicToExt(u32 magic){
    if(magic == 0x4D43) return ".cm";
    return ".bin";
}

int main(int argc, char **argv){
    u32 currPos = 0;
    char currFolder[8];
    char fullPath[0x20];
    u8 *fileBuffer;

    if(argc != 2){
        printf("Usage: %s <AS Package>\n", argv[0]);
        return -1;
    }

    //Open
    FILE *fpIn, *fpOut;
    fpIn = fopen(argv[1], "rb");
    if(!fpIn){printf("File not found!\n"); return -1;}

    //Read AC header
    Header acHead;
    fread(&acHead, sizeof(Header), 1, fpIn);
    Entry entries[acHead.entryCnt];
    fread(&entries, sizeof(Entry) * (acHead.entryCnt+1), 1, fpIn);
    if(acHead.magic != 0x4341 && acHead.magic != 0x5341){printf("Not and AC or AS container!\n"); goto final;}

    printf("Entries: %d\n\n", acHead.entryCnt);

    u32 i; for(i = 0; i < acHead.entryCnt; i++){
        currPos = entries[i].startAddr;
        fseek(fpIn, currPos, SEEK_SET);
        printf("Start: %08X\n\n", currPos);

        //Read CP headers
        Header cp;
        fread(&cp, sizeof(Header), 1, fpIn);
        Entry cpEntries[cp.entryCnt];
        fread(cpEntries, sizeof(Entry) * (cp.entryCnt+1), 1, fpIn);
        if(cp.magic != 0x5043 && cp.magic != 0x4D53){printf("Not CP or SM header!\n"); goto final;}
        snprintf(currFolder, 8, "%08X", currPos);
        makeDir(currFolder);

        printf("\tEntries: %d\n\n", cp.entryCnt);
        u32 j; for(j = 0; j < cp.entryCnt; j++){
            currPos = entries[i].startAddr + cpEntries[j].startAddr;
            u32 endPos = entries[i].startAddr + cpEntries[j+1].startAddr;
            fseek(fpIn, currPos, SEEK_SET);
            printf("\tStart: %08X\n", currPos);

            //Obtain info about file
            size_t size = endPos - currPos;
            fileBuffer = malloc(size);
            u32 fileMagic = 0;
            fread(&fileMagic, 2, 1, fpIn);
            fseek(fpIn, currPos, SEEK_SET);
            memset(fullPath, 0, 22);
            snprintf(fullPath, 0x20, "%s/%08X%s", currFolder, cpEntries[j].startAddr, magicToExt(fileMagic));
            printf("\tSize: %08X\n\tPath: %s\n\n", size, fullPath);

            //Write out file
            fpOut = fopen(fullPath, "wb");
            fread(fileBuffer, size, 1, fpIn);
            fwrite(fileBuffer, size, 1, fpOut);
            fclose(fpOut);
            free(fileBuffer);
        }
    }

    final:;
    fclose(fpIn);

    return 0;
}