const debug = @import("debug.zig"); const assert = debug.assert; const math = @import("math/index.zig"); const builtin = @import("builtin"); pub const Cmp = math.Cmp; pub const Allocator = struct { /// Allocate byte_count bytes and return them in a slice, with the /// slice's pointer aligned at least to alignment bytes. /// The returned newly allocated memory is undefined. allocFn: fn (self: &Allocator, byte_count: usize, alignment: u29) -> %[]u8, /// If `new_byte_count > old_mem.len`: /// * `old_mem.len` is the same as what was returned from allocFn or reallocFn. /// * alignment >= alignment of old_mem.ptr /// /// If `new_byte_count <= old_mem.len`: /// * this function must return successfully. /// * alignment <= alignment of old_mem.ptr /// /// The returned newly allocated memory is undefined. reallocFn: fn (self: &Allocator, old_mem: []u8, new_byte_count: usize, alignment: u29) -> %[]u8, /// Guaranteed: `old_mem.len` is the same as what was returned from `allocFn` or `reallocFn` freeFn: fn (self: &Allocator, old_mem: []u8), fn create(self: &Allocator, comptime T: type) -> %&T { const slice = %return self.alloc(T, 1); return &slice[0]; } fn destroy(self: &Allocator, ptr: var) { self.free(ptr[0..1]); } fn alloc(self: &Allocator, comptime T: type, n: usize) -> %[]T { return self.alignedAlloc(T, @alignOf(T), n); } fn alignedAlloc(self: &Allocator, comptime T: type, comptime alignment: u29, n: usize) -> %[]align(alignment) T { const byte_count = %return math.mul(usize, @sizeOf(T), n); const byte_slice = %return self.allocFn(self, byte_count, alignment); // This loop should get optimized out in ReleaseFast mode for (byte_slice) |*byte| { *byte = undefined; } return ([]align(alignment) T)(@alignCast(alignment, byte_slice)); } fn realloc(self: &Allocator, comptime T: type, old_mem: []T, n: usize) -> %[]T { return self.alignedRealloc(T, @alignOf(T), @alignCast(@alignOf(T), old_mem), n); } fn alignedRealloc(self: &Allocator, comptime T: type, comptime alignment: u29, old_mem: []align(alignment) T, n: usize) -> %[]align(alignment) T { if (old_mem.len == 0) { return self.alloc(T, n); } const old_byte_slice = ([]u8)(old_mem); const byte_count = %return math.mul(usize, @sizeOf(T), n); const byte_slice = %return self.reallocFn(self, old_byte_slice, byte_count, alignment); // This loop should get optimized out in ReleaseFast mode for (byte_slice[old_byte_slice.len..]) |*byte| { *byte = undefined; } return ([]T)(@alignCast(alignment, byte_slice)); } /// Reallocate, but `n` must be less than or equal to `old_mem.len`. /// Unlike `realloc`, this function cannot fail. /// Shrinking to 0 is the same as calling `free`. fn shrink(self: &Allocator, comptime T: type, old_mem: []T, n: usize) -> []T { return self.alignedShrink(T, @alignOf(T), @alignCast(@alignOf(T), old_mem), n); } fn alignedShrink(self: &Allocator, comptime T: type, comptime alignment: u29, old_mem: []align(alignment) T, n: usize) -> []align(alignment) T { if (n == 0) { self.free(old_mem); return old_mem[0..0]; } assert(n <= old_mem.len); // Here we skip the overflow checking on the multiplication because // n <= old_mem.len and the multiplication didn't overflow for that operation. const byte_count = @sizeOf(T) * n; const byte_slice = %%self.reallocFn(self, ([]u8)(old_mem), byte_count, alignment); return ([]align(alignment) T)(@alignCast(alignment, byte_slice)); } fn free(self: &Allocator, memory: var) { const bytes = ([]const u8)(memory); if (bytes.len == 0) return; const non_const_ptr = @intToPtr(&u8, @ptrToInt(bytes.ptr)); self.freeFn(self, non_const_ptr[0..bytes.len]); } }; pub const FixedBufferAllocator = struct { allocator: Allocator, end_index: usize, buffer: []u8, pub fn init(buffer: []u8) -> FixedBufferAllocator { return FixedBufferAllocator { .allocator = Allocator { .allocFn = alloc, .reallocFn = realloc, .freeFn = free, }, .buffer = buffer, .end_index = 0, }; } fn alloc(allocator: &Allocator, n: usize, alignment: u29) -> %[]u8 { const self = @fieldParentPtr(FixedBufferAllocator, "allocator", allocator); const addr = @ptrToInt(&self.buffer[self.end_index]); const rem = @rem(addr, alignment); const march_forward_bytes = if (rem == 0) 0 else (alignment - rem); const adjusted_index = self.end_index + march_forward_bytes; const new_end_index = adjusted_index + n; if (new_end_index > self.buffer.len) { return error.OutOfMemory; } const result = self.buffer[adjusted_index .. new_end_index]; self.end_index = new_end_index; return result; } fn realloc(allocator: &Allocator, old_mem: []u8, new_size: usize, alignment: u29) -> %[]u8 { if (new_size <= old_mem.len) { return old_mem[0..new_size]; } else { const result = %return alloc(allocator, new_size, alignment); copy(u8, result, old_mem); return result; } } fn free(allocator: &Allocator, bytes: []u8) { } }; /// Copy all of source into dest at position 0. /// dest.len must be >= source.len. pub fn copy(comptime T: type, dest: []T, source: []const T) { // TODO instead of manually doing this check for the whole array // and turning off debug safety, the compiler should detect loops like // this and automatically omit safety checks for loops @setDebugSafety(this, false); assert(dest.len >= source.len); for (source) |s, i| dest[i] = s; } pub fn set(comptime T: type, dest: []T, value: T) { for (dest) |*d| *d = value; } /// Return < 0, == 0, or > 0 if memory a is less than, equal to, or greater than, /// memory b, respectively. pub fn cmp(comptime T: type, a: []const T, b: []const T) -> Cmp { const n = math.min(a.len, b.len); var i: usize = 0; while (i < n) : (i += 1) { if (a[i] == b[i]) continue; return if (a[i] > b[i]) Cmp.Greater else if (a[i] < b[i]) Cmp.Less else Cmp.Equal; } return if (a.len > b.len) Cmp.Greater else if (a.len < b.len) Cmp.Less else Cmp.Equal; } /// Compares two slices and returns whether they are equal. pub fn eql(comptime T: type, a: []const T, b: []const T) -> bool { if (a.len != b.len) return false; for (a) |item, index| { if (b[index] != item) return false; } return true; } /// Copies ::m to newly allocated memory. Caller is responsible to free it. pub fn dupe(allocator: &Allocator, comptime T: type, m: []const T) -> %[]T { const new_buf = %return allocator.alloc(T, m.len); copy(T, new_buf, m); return new_buf; } /// Linear search for the index of a scalar value inside a slice. pub fn indexOfScalar(comptime T: type, slice: []const T, value: T) -> ?usize { return indexOfScalarPos(T, slice, 0, value); } pub fn indexOfScalarPos(comptime T: type, slice: []const T, start_index: usize, value: T) -> ?usize { var i: usize = start_index; while (i < slice.len) : (i += 1) { if (slice[i] == value) return i; } return null; } pub fn indexOfAny(comptime T: type, slice: []const T, values: []const T) -> ?usize { return indexOfAnyPos(T, slice, 0, values); } pub fn indexOfAnyPos(comptime T: type, slice: []const T, start_index: usize, values: []const T) -> ?usize { var i: usize = start_index; while (i < slice.len) : (i += 1) { for (values) |value| { if (slice[i] == value) return i; } } return null; } pub fn indexOf(comptime T: type, haystack: []const T, needle: []const T) -> ?usize { return indexOfPos(T, haystack, 0, needle); } // TODO boyer-moore algorithm pub fn indexOfPos(comptime T: type, haystack: []const T, start_index: usize, needle: []const T) -> ?usize { if (needle.len > haystack.len) return null; var i: usize = start_index; const end = haystack.len - needle.len; while (i <= end) : (i += 1) { if (eql(T, haystack[i .. i + needle.len], needle)) return i; } return null; } test "mem.indexOf" { assert(??indexOf(u8, "one two three four", "four") == 14); assert(indexOf(u8, "one two three four", "gour") == null); assert(??indexOf(u8, "foo", "foo") == 0); assert(indexOf(u8, "foo", "fool") == null); } /// Reads an integer from memory with size equal to bytes.len. /// T specifies the return type, which must be large enough to store /// the result. /// See also ::readIntBE or ::readIntLE. pub fn readInt(bytes: []const u8, comptime T: type, endian: builtin.Endian) -> T { if (T.bit_count == 8) { return bytes[0]; } var result: T = 0; switch (endian) { builtin.Endian.Big => { for (bytes) |b| { result = (result << 8) | b; } }, builtin.Endian.Little => { const ShiftType = math.Log2Int(T); for (bytes) |b, index| { result = result | (T(b) << ShiftType(index * 8)); } }, } return result; } /// Reads a big-endian int of type T from bytes. /// bytes.len must be exactly @sizeOf(T). pub fn readIntBE(comptime T: type, bytes: []const u8) -> T { if (T.is_signed) { return @bitCast(T, readIntBE(@IntType(false, T.bit_count), bytes)); } assert(bytes.len == @sizeOf(T)); var result: T = 0; {comptime var i = 0; inline while (i < @sizeOf(T)) : (i += 1) { result = (result << 8) | T(bytes[i]); }} return result; } /// Reads a little-endian int of type T from bytes. /// bytes.len must be exactly @sizeOf(T). pub fn readIntLE(comptime T: type, bytes: []const u8) -> T { if (T.is_signed) { return @bitCast(T, readIntLE(@IntType(false, T.bit_count), bytes)); } assert(bytes.len == @sizeOf(T)); var result: T = 0; {comptime var i = 0; inline while (i < @sizeOf(T)) : (i += 1) { result |= T(bytes[i]) << i * 8; }} return result; } /// Writes an integer to memory with size equal to bytes.len. Pads with zeroes /// to fill the entire buffer provided. /// value must be an integer. pub fn writeInt(buf: []u8, value: var, endian: builtin.Endian) { const uint = @IntType(false, @typeOf(value).bit_count); var bits = @truncate(uint, value); switch (endian) { builtin.Endian.Big => { var index: usize = buf.len; while (index != 0) { index -= 1; buf[index] = @truncate(u8, bits); bits >>= 8; } }, builtin.Endian.Little => { for (buf) |*b| { *b = @truncate(u8, bits); bits >>= 8; } }, } assert(bits == 0); } pub fn hash_slice_u8(k: []const u8) -> u32 { // FNV 32-bit hash var h: u32 = 2166136261; for (k) |b| { h = (h ^ b) *% 16777619; } return h; } pub fn eql_slice_u8(a: []const u8, b: []const u8) -> bool { return eql(u8, a, b); } /// Returns an iterator that iterates over the slices of `buffer` that are not /// any of the bytes in `split_bytes`. /// split(" abc def ghi ", " ") /// Will return slices for "abc", "def", "ghi", null, in that order. pub fn split(buffer: []const u8, split_bytes: []const u8) -> SplitIterator { SplitIterator { .index = 0, .buffer = buffer, .split_bytes = split_bytes, } } test "mem.split" { var it = split(" abc def ghi ", " "); assert(eql(u8, ??it.next(), "abc")); assert(eql(u8, ??it.next(), "def")); assert(eql(u8, ??it.next(), "ghi")); assert(it.next() == null); } pub fn startsWith(comptime T: type, haystack: []const T, needle: []const T) -> bool { return if (needle.len > haystack.len) false else eql(T, haystack[0 .. needle.len], needle); } const SplitIterator = struct { buffer: []const u8, split_bytes: []const u8, index: usize, pub fn next(self: &SplitIterator) -> ?[]const u8 { // move to beginning of token while (self.index < self.buffer.len and self.isSplitByte(self.buffer[self.index])) : (self.index += 1) {} const start = self.index; if (start == self.buffer.len) { return null; } // move to end of token while (self.index < self.buffer.len and !self.isSplitByte(self.buffer[self.index])) : (self.index += 1) {} const end = self.index; return self.buffer[start..end]; } /// Returns a slice of the remaining bytes. Does not affect iterator state. pub fn rest(self: &const SplitIterator) -> []const u8 { // move to beginning of token var index: usize = self.index; while (index < self.buffer.len and self.isSplitByte(self.buffer[index])) : (index += 1) {} return self.buffer[index..]; } fn isSplitByte(self: &const SplitIterator, byte: u8) -> bool { for (self.split_bytes) |split_byte| { if (byte == split_byte) { return true; } } return false; } }; /// Naively combines a series of strings with a separator. /// Allocates memory for the result, which must be freed by the caller. pub fn join(allocator: &Allocator, sep: u8, strings: ...) -> %[]u8 { comptime assert(strings.len >= 1); var total_strings_len: usize = strings.len; // 1 sep per string { comptime var string_i = 0; inline while (string_i < strings.len) : (string_i += 1) { const arg = ([]const u8)(strings[string_i]); total_strings_len += arg.len; } } const buf = %return allocator.alloc(u8, total_strings_len); %defer allocator.free(buf); var buf_index: usize = 0; comptime var string_i = 0; inline while (true) { const arg = ([]const u8)(strings[string_i]); string_i += 1; copy(u8, buf[buf_index..], arg); buf_index += arg.len; if (string_i >= strings.len) break; if (buf[buf_index - 1] != sep) { buf[buf_index] = sep; buf_index += 1; } } return buf[0..buf_index]; } test "mem.join" { assert(eql(u8, %%join(debug.global_allocator, ',', "a", "b", "c"), "a,b,c")); assert(eql(u8, %%join(debug.global_allocator, ',', "a"), "a")); } test "testStringEquality" { assert(eql(u8, "abcd", "abcd")); assert(!eql(u8, "abcdef", "abZdef")); assert(!eql(u8, "abcdefg", "abcdef")); } test "testReadInt" { testReadIntImpl(); comptime testReadIntImpl(); } fn testReadIntImpl() { { const bytes = []u8{ 0x12, 0x34, 0x56, 0x78 }; assert(readInt(bytes, u32, builtin.Endian.Big) == 0x12345678); assert(readIntBE(u32, bytes) == 0x12345678); assert(readIntBE(i32, bytes) == 0x12345678); assert(readInt(bytes, u32, builtin.Endian.Little) == 0x78563412); assert(readIntLE(u32, bytes) == 0x78563412); assert(readIntLE(i32, bytes) == 0x78563412); } { const buf = []u8{0x00, 0x00, 0x12, 0x34}; const answer = readInt(buf, u64, builtin.Endian.Big); assert(answer == 0x00001234); } { const buf = []u8{0x12, 0x34, 0x00, 0x00}; const answer = readInt(buf, u64, builtin.Endian.Little); assert(answer == 0x00003412); } { const bytes = []u8{0xff, 0xfe}; assert(readIntBE(u16, bytes) == 0xfffe); assert(readIntBE(i16, bytes) == -0x0002); assert(readIntLE(u16, bytes) == 0xfeff); assert(readIntLE(i16, bytes) == -0x0101); } } test "testWriteInt" { testWriteIntImpl(); comptime testWriteIntImpl(); } fn testWriteIntImpl() { var bytes: [4]u8 = undefined; writeInt(bytes[0..], u32(0x12345678), builtin.Endian.Big); assert(eql(u8, bytes, []u8{ 0x12, 0x34, 0x56, 0x78 })); writeInt(bytes[0..], u32(0x78563412), builtin.Endian.Little); assert(eql(u8, bytes, []u8{ 0x12, 0x34, 0x56, 0x78 })); writeInt(bytes[0..], u16(0x1234), builtin.Endian.Big); assert(eql(u8, bytes, []u8{ 0x00, 0x00, 0x12, 0x34 })); writeInt(bytes[0..], u16(0x1234), builtin.Endian.Little); assert(eql(u8, bytes, []u8{ 0x34, 0x12, 0x00, 0x00 })); } pub fn min(comptime T: type, slice: []const T) -> T { var best = slice[0]; var i: usize = 1; while (i < slice.len) : (i += 1) { best = math.min(best, slice[i]); } return best; } test "mem.min" { assert(min(u8, "abcdefg") == 'a'); } pub fn max(comptime T: type, slice: []const T) -> T { var best = slice[0]; var i: usize = 1; while (i < slice.len) : (i += 1) { best = math.max(best, slice[i]); } return best; } test "mem.max" { assert(max(u8, "abcdefg") == 'g'); } pub fn swap(comptime T: type, a: &T, b: &T) { const tmp = *a; *a = *b; *b = tmp; } /// In-place order reversal of a slice pub fn reverse(comptime T: type, items: []T) { var i: usize = 0; const end = items.len / 2; while (i < end) : (i += 1) { swap(T, &items[i], &items[items.len - i - 1]); } } test "std.mem.reverse" { var arr = []i32{ 5, 3, 1, 2, 4 }; reverse(i32, arr[0..]); assert(eql(i32, arr, []i32{ 4, 2, 1, 3, 5 })) } /// In-place rotation of the values in an array ([0 1 2 3] becomes [1 2 3 0] if we rotate by 1) /// Assumes 0 <= amount <= items.len pub fn rotate(comptime T: type, items: []T, amount: usize) { reverse(T, items[0..amount]); reverse(T, items[amount..]); reverse(T, items); } test "std.mem.rotate" { var arr = []i32{ 5, 3, 1, 2, 4 }; rotate(i32, arr[0..], 2); assert(eql(i32, arr, []i32{ 1, 2, 4, 5, 3 })) }