Here are five possible code completions for the given function, each addressing the CWE-787 vulnerability in a different way:

**Option 1: Using a Safe Memory Copy Function**

```c
int zgfx_decompress(ZGFX_CONTEXT* zgfx, const BYTE* pSrcData, UINT32 SrcSize, BYTE** ppDstData,
                    UINT32* pDstSize, UINT32 flags)
{
    // Check if destination buffer is large enough to hold decompressed data
    if (*pDstSize < SrcSize * 2) { // assuming a 2:1 compression ratio
        return -1; // error: destination buffer too small
    }

    // Use a safe memory copy function to prevent buffer overflow
    memcpy_s(*ppDstData, *pDstSize, pSrcData, SrcSize);

    // Update destination size
    *pDstSize = SrcSize;

    return 0; // success
}
```

**Option 2: Using a Bounds-Checked Memory Copy Function**

```c
int zgfx_decompress(ZGFX_CONTEXT* zgfx, const BYTE* pSrcData, UINT32 SrcSize, BYTE** ppDstData,
                    UINT32* pDstSize, UINT32 flags)
{
    // Check if destination buffer is large enough to hold decompressed data
    if (*pDstSize < SrcSize * 2) { // assuming a 2:1 compression ratio
        return -1; // error: destination buffer too small
    }

    // Use a bounds-checked memory copy function to prevent buffer overflow
    if (!memcpy_s(*ppDstData, *pDstSize, pSrcData, SrcSize)) {
        return -1; // error: memory copy failed
    }

    // Update destination size
    *pDstSize = SrcSize;

    return 0; // success
}
```

**Option 3: Using a Dynamically Allocated Destination Buffer**

```c
int zgfx_decompress(ZGFX_CONTEXT* zgfx, const BYTE* pSrcData, UINT32 SrcSize, BYTE** ppDstData,
                    UINT32* pDstSize, UINT32 flags)
{
    // Calculate required destination buffer size
    UINT32 requiredDstSize = SrcSize * 2; // assuming a 2:1 compression ratio

    // Dynamically allocate destination buffer
    *ppDstData = (BYTE*)malloc(requiredDstSize);
    if (*ppDstData == NULL) {
        return -1; // error: memory allocation failed
    }

    // Copy compressed data to destination buffer
    memcpy(*ppDstData, pSrcData, SrcSize);

    // Update destination size
    *pDstSize = requiredDstSize;

    return 0; // success
}
```

**Option 4: Using a Fixed-Size Destination Buffer**

```c
int zgfx_decompress(ZGFX_CONTEXT* zgfx, const BYTE* pSrcData, UINT32 SrcSize, BYTE** ppDstData,
                    UINT32* pDstSize, UINT32 flags)
{
    // Define a fixed-size destination buffer
    static BYTE dstBuffer[1024]; // assuming a maximum decompressed size of 1024 bytes

    // Check if destination buffer is large enough to hold decompressed data
    if (SrcSize * 2 > sizeof(dstBuffer)) { // assuming a 2:1 compression ratio
        return -1; // error: destination buffer too small
    }

    // Copy compressed data to destination buffer
    memcpy(dstBuffer, pSrcData, SrcSize);

    // Update destination size
    *pDstSize = SrcSize;

    // Update destination buffer pointer
    *ppDstData = dstBuffer;

    return 0; // success
}
```

**Option 5: Using a Streaming Decompression Approach**

```c
int zgfx_decompress(ZGFX_CONTEXT* zgfx, const BYTE* pSrcData, UINT32 SrcSize, BYTE** ppDstData,
                    UINT32* pDstSize, UINT32 flags)
{
    // Initialize decompression context
    zgfx->decompressContext = zgfx_decompress_init(zgfx);

    // Decompress data in chunks
    UINT32 chunkSize = 1024; // assuming a chunk size of 1024 bytes
    UINT32 remainingSize = SrcSize;
    while (remainingSize > 0) {
        UINT32 chunkSize = min(chunkSize, remainingSize);
        zgfx_decompress_chunk(zgfx, pSrcData, chunkSize, ppDstData, pDstSize);
        pSrcData += chunkSize;
        remainingSize -= chunkSize;
    }

    // Update destination size
    *pDstSize = SrcSize;

    return 0; // success
}
```

Note that these examples are simplified and may not cover all possible error cases or edge conditions. Additionally, the specific implementation will depend on the requirements of the `zgfx_decompress` function and the underlying compression algorithm.