// Part of JoeyLib, Copyright (c) 2026 Scott Duensing, under the MIT License.
// See LICENSE.md for license information.
// SPDX-License-Identifier: MIT
//
// toolBuf.c - a growing byte buffer for the JoeyLib host tools (toolBuf.h).

#include <stdbool.h>
#include <stdlib.h>
#include <string.h>

#include "toolBuf.h"
#include "toolFile.h"

#define BUF_FIRST_CAP 256u
#define BYTE_BITS     8u
#define BYTE_MASK     0xFFu

static uint8_t *bufGrow(ToolBufT *buf, size_t len);
static void     bufNumber(ToolBufT *buf, uint32_t value, uint32_t bytes, bool bigEndian);


// Room for len more bytes at the end, counted in: where they go.
static uint8_t *bufGrow(ToolBufT *buf, size_t len) {
    uint8_t *data;
    size_t   cap;

    if (buf->len + len > buf->cap) {
        cap = buf->cap == 0u ? BUF_FIRST_CAP : buf->cap;
        while (cap < buf->len + len) {
            cap *= 2u;
        }
        data = (uint8_t *)realloc(buf->data, cap);
        if (data == NULL) {
            toolFail("out of memory");
        }
        buf->data = data;
        buf->cap  = cap;
    }
    data      = buf->data + buf->len;
    buf->len += len;
    return data;
}


static void bufNumber(ToolBufT *buf, uint32_t value, uint32_t bytes, bool bigEndian) {
    uint8_t *out;
    uint32_t i;
    uint32_t shift;

    out = bufGrow(buf, bytes);
    for (i = 0; i < bytes; i++) {
        shift  = (bigEndian ? bytes - 1u - i : i) * BYTE_BITS;
        out[i] = (uint8_t)((value >> shift) & BYTE_MASK);
    }
}


void toolBufAdd(ToolBufT *buf, const void *data, size_t len) {
    if (len > 0u) {
        memcpy(bufGrow(buf, len), data, len);
    }
}


void toolBufBe16(ToolBufT *buf, uint32_t value) {
    bufNumber(buf, value, 2u, true);
}


void toolBufBe32(ToolBufT *buf, uint32_t value) {
    bufNumber(buf, value, 4u, true);
}


void toolBufByte(ToolBufT *buf, uint32_t value) {
    *bufGrow(buf, 1u) = (uint8_t)value;
}


void toolBufFree(ToolBufT *buf) {
    free(buf->data);
    buf->data = NULL;
    buf->len  = 0u;
    buf->cap  = 0u;
}


void toolBufLe16(ToolBufT *buf, uint32_t value) {
    bufNumber(buf, value, 2u, false);
}


void toolBufLe32(ToolBufT *buf, uint32_t value) {
    bufNumber(buf, value, 4u, false);
}


void toolBufZeros(ToolBufT *buf, size_t count) {
    if (count > 0u) {
        memset(bufGrow(buf, count), 0, count);
    }
}