move NBT_LIST case into its own function

This commit is contained in:
2025-08-22 09:52:55 +02:00
parent 3eb92541db
commit 949cac5bfe

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@@ -11,6 +11,32 @@
#define MAX_DEPTH 512 #define MAX_DEPTH 512
/* handles incrementing to the next tag in the case of `NBT_LIST`. This function shan't return `NULL`.
* `ptr` is assumed to be the start of the `NBT_LIST` data, e.i. The list's ID, followed by the list's length.
* If `ID` is `NBT_I8`, `NBT_I16`, `NBT_I32`, `NBT_I64`, `NBT_F32`, or `NBT_F64`, the entire list length is computed and returned.
* For other types this won't be possible, and thus will add `1` to `dpt`, and write the list data to `lens` and `tags` at this new `dpt`. */
static const u8 *nexttag_list(const u8 *restrict ptr, uint *restrict const dpt, i32 *restrict const lens, u8 *restrict const tags) {
const u8 *tag = ptr;
ptr++;
switch (*tag) {
case NBT_END: break;
case NBT_I8: ptr += (i32)be32toh(*(u32 *)ptr) * 1; break;
case NBT_I16: ptr += (i32)be32toh(*(u32 *)ptr) * 2; break;
case NBT_I32: // fall through
case NBT_F32: ptr += (i32)be32toh(*(u32 *)ptr) * 4; break;
case NBT_I64: // fall through
case NBT_F64: ptr += (i32)be32toh(*(u32 *)ptr) * 8; break;
default:
// TODO: handle out of bounds... Might not be required if we use flexible array member
(*dpt)++;
tags[*dpt] = *tag;
lens[*dpt] = (i32)be32toh(*(u32 *)ptr);
break;
}
ptr += 4;
return ptr;
}
/* TODO: write test cases for this function: /* TODO: write test cases for this function:
* - list:compound... * - list:compound...
* - non-existent type * - non-existent type
@@ -52,28 +78,7 @@ const u8 *nbt_nexttag(const u8 *restrict buf) {
case NBT_END: dpt--; break; case NBT_END: dpt--; break;
case NBT_COMPOUND: dpt++; break; case NBT_COMPOUND: dpt++; break;
// TODO: move this into it's own function for readability. case NBT_LIST: ptr = nexttag_list(ptr, &dpt, lens, tags); break;
case NBT_LIST: {
tag = ptr;
ptr++;
switch (*tag) {
case NBT_END: break;
case NBT_I8: ptr += (i32)be32toh(*(u32 *)ptr) * 1; break;
case NBT_I16: ptr += (i32)be32toh(*(u32 *)ptr) * 2; break;
case NBT_I32: // fall through
case NBT_F32: ptr += (i32)be32toh(*(u32 *)ptr) * 4; break;
case NBT_I64: // fall through
case NBT_F64: ptr += (i32)be32toh(*(u32 *)ptr) * 8; break;
default:
// TODO: handle out of bounds... Might not be required if we use flexible array member
dpt++;
tags[dpt] = *tag;
lens[dpt] = (i32)be32toh(*(u32 *)ptr);
break;
}
ptr += 4;
break;
}
default: return NULL; // unexpected value; buffer is likely corrupt default: return NULL; // unexpected value; buffer is likely corrupt
} }