move contents of do while loop in nbt_nexttag into its own funciton

This commit is contained in:
2025-08-22 09:58:45 +02:00
parent 949cac5bfe
commit 9996e84ef5

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@@ -37,26 +37,19 @@ static const u8 *nexttag_list(const u8 *restrict ptr, uint *restrict const dpt,
return ptr;
}
/* TODO: write test cases for this function:
* - list:compound...
* - non-existent type
* - compound:list:int32
* - string
*/
const u8 *nbt_nexttag(const u8 *restrict buf) {
const u8 *tag, *ptr;
u8 tags[MAX_DEPTH] = {0};
i32 lens[MAX_DEPTH] = {0};
uint dpt = 0;
/* increments to the next tag and returns it (or `NULL`)
* - `tag` represents the start of the tag, e.i. The tag ID, or in the case of `NBT_LIST` data, the start of this data.
* - `dpt` shall point to the "depth" we're at, this is used as index for `lens` and `tags`
* - `lens` shall contain `MAX_DEPTH` of items representing the list length, if the current item is non-zero we shall assume we're in a list.
* Where the value is decremented until we reach `0`.
* - `tags` shall contain `MAX_DEPTH` of items representing the list's stored type. */
static const u8 *nexttag(const u8 *restrict tag, uint *restrict const dpt, i32 *restrict const lens, u8 *restrict const tags) {
u8 type;
tag = buf;
do {
ptr = tag;
if (lens[dpt]) {
type = tags[dpt];
lens[dpt]--;
dpt -= !lens[dpt];
const u8 *ptr = tag;
if (lens[*dpt]) {
type = tags[*dpt];
lens[*dpt]--;
*dpt -= !lens[*dpt];
} else {
type = *tag;
ptr += be16toh(*(u16 *)(tag + 1)) + 3;
@@ -75,15 +68,32 @@ const u8 *nbt_nexttag(const u8 *restrict buf) {
case NBT_ARR_I64: ptr += 4 + (i32)be32toh(*(u32 *)ptr) * 8; break;
case NBT_STR: ptr += 2 + (u16)be16toh(*(u16 *)ptr) * 1; break;
case NBT_END: dpt--; break;
case NBT_COMPOUND: dpt++; break;
case NBT_END: (*dpt)--; break;
case NBT_COMPOUND: (*dpt)++; break;
case NBT_LIST: ptr = nexttag_list(ptr, &dpt, lens, tags); break;
case NBT_LIST: ptr = nexttag_list(ptr, dpt, lens, tags); break;
default: return NULL; // unexpected value; buffer is likely corrupt
}
tag = ptr;
return ptr;
}
/* TODO: write test cases for this function:
* - list:compound...
* - non-existent type
* - compound:list:int32
* - string
*/
const u8 *nbt_nexttag(const u8 *restrict buf) {
const u8 *tag;
u8 tags[MAX_DEPTH] = {0};
i32 lens[MAX_DEPTH] = {0};
uint dpt = 0;
tag = buf;
do {
tag = nexttag(tag, &dpt, lens, tags);
} while (dpt > 0);
return tag;
}