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std.compress.zstandard: clean up integer casts

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This commit is contained in:
dweiller 2023-01-23 23:46:15 +11:00
parent fc64c279a4
commit 082acd7f17
1 changed files with 12 additions and 9 deletions
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21
lib/std/compress/zstandard/decompress.zig
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@ -168,8 +168,11 @@ pub const DecodeState = struct {
const data = table[@field(self, @tagName(choice)).state];
const T = @TypeOf(@field(self, @tagName(choice))).State;
const bits_summand = try bit_reader.readBitsNoEof(T, data.bits);
const next_state = data.baseline + bits_summand;
@field(self, @tagName(choice)).state = @intCast(@TypeOf(@field(self, @tagName(choice))).State, next_state);
const next_state = std.math.cast(
@TypeOf(@field(self, @tagName(choice))).State,
data.baseline + bits_summand,
) orelse return error.MalformedFseBits;
@field(self, @tagName(choice)).state = next_state;
},
}
}
@ -1045,10 +1048,10 @@ fn decodeHuffmanTree(src: []const u8, consumed_count: *usize) !LiteralsSection.H
const even_data = entries[even_state];
var read_bits: usize = 0;
const even_bits = try huff_bits.readBits(u32, even_data.bits, &read_bits);
weights[i] = @intCast(u4, even_data.symbol);
weights[i] = std.math.cast(u4, even_data.symbol) orelse return error.MalformedHuffmanTree;
i += 1;
if (read_bits < even_data.bits) {
weights[i] = @intCast(u4, entries[odd_state].symbol);
weights[i] = std.math.cast(u4, entries[odd_state].symbol) orelse return error.MalformedHuffmanTree;
log.debug("overflow condition: setting weights[{d}] = {d}", .{ i, weights[i] });
i += 1;
break;
@ -1058,11 +1061,11 @@ fn decodeHuffmanTree(src: []const u8, consumed_count: *usize) !LiteralsSection.H
read_bits = 0;
const odd_data = entries[odd_state];
const odd_bits = try huff_bits.readBits(u32, odd_data.bits, &read_bits);
weights[i] = @intCast(u4, odd_data.symbol);
weights[i] = std.math.cast(u4, odd_data.symbol) orelse return error.MalformedHuffmanTree;
i += 1;
if (read_bits < odd_data.bits) {
if (i == 256) return error.MalformedHuffmanTree;
weights[i] = @intCast(u4, entries[even_state].symbol);
weights[i] = std.math.cast(u4, entries[even_state].symbol) orelse return error.MalformedHuffmanTree;
log.debug("overflow condition: setting weights[{d}] = {d}", .{ i, weights[i] });
i += 1;
break;
@ -1100,9 +1103,9 @@ fn decodeHuffmanTree(src: []const u8, consumed_count: *usize) !LiteralsSection.H
log.debug("weight power sum = {d}", .{weight_power_sum});
// advance to next power of two (even if weight_power_sum is a power of 2)
max_number_of_bits = @intCast(u4, std.math.log2_int(u16, weight_power_sum) + 1);
max_number_of_bits = std.math.log2_int(u16, weight_power_sum) + 1;
const next_power_of_two = @as(u16, 1) << max_number_of_bits;
weights[symbol_count - 1] = @intCast(u4, std.math.log2_int(u16, next_power_of_two - weight_power_sum) + 1);
weights[symbol_count - 1] = std.math.log2_int(u16, next_power_of_two - weight_power_sum) + 1;
log.debug("weights[{d}] = {d}", .{ symbol_count - 1, weights[symbol_count - 1] });
var weight_sorted_prefixed_symbols: [256]LiteralsSection.HuffmanTree.PrefixedSymbol = undefined;
@ -1367,7 +1370,7 @@ fn decodeFseTable(
while (accumulated_probability < total_probability) {
// WARNING: The RFC in poorly worded, and would suggest std.math.log2_int_ceil is correct here,
// but power of two (remaining probabilities + 1) need max bits set to 1 more.
const max_bits = @intCast(u4, std.math.log2_int(u16, total_probability - accumulated_probability + 1)) + 1;
const max_bits = std.math.log2_int(u16, total_probability - accumulated_probability + 1) + 1;
const small = try bit_reader.readBitsNoEof(u16, max_bits - 1);
const cutoff = (@as(u16, 1) << max_bits) - 1 - (total_probability - accumulated_probability + 1);