1 files changed, 383 insertions, 0 deletions
diff --git a/git2d/bare.c b/git2d/bare.c
new file mode 100644
index 0000000..23c0352
--- /dev/null
+++ b/git2d/bare.c
@@ -0,0 +1,383 @@
+/*-
+ * SPDX-License-Identifier: MIT
+ * SPDX-FileCopyrightText: Copyright (c) 2022 Frank Smit <https://61924.nl/>
+ */
+
+#include <string.h>
+#include <stdbool.h>
+
+#include "bare.h"
+#include "utf8.h"
+
+#define UNUSED(x) (void)(x)
+
+enum {
+	U8SZ = 1,
+	U16SZ = 2,
+	U32SZ = 4,
+	U64SZ = 8,
+	MAXVARINTSZ = 10,
+};
+
+static bool
+checkstr(const char *x, uint64_t sz)
+{
+	if (x == NULL || sz == 0) {
+		return true;
+	}
+
+	int err = 0;
+	uint32_t cp = 0;
+	char *buf = (void *)x;
+	uint64_t chunk = 4;
+	char *pad = (char *)(char[4]){0, 0, 0, 0};
+
+#define _utf8_decode(buf) \
+	do { \
+		buf = utf8_decode(buf, &cp, &err); \
+		if (err > 0) { \
+			return false; \
+		} \
+	} while (0)
+
+	for (; sz >= chunk; sz -= chunk) {
+		_utf8_decode(buf);
+	}
+
+	if (sz > 0) {
+		memcpy(pad, buf, sz);
+		_utf8_decode(pad);
+	}
+
+#undef _utf8_decode
+
+	return true;
+}
+
+bare_error
+bare_put_uint(struct bare_writer *ctx, uint64_t x)
+{
+	uint64_t i = 0;
+	uint8_t b[MAXVARINTSZ];
+
+	while (x >= 0x80) {
+		b[i] = (uint8_t)x | 0x80;
+		x >>= 7;
+		i++;
+	}
+
+	b[i] = (uint8_t)x;
+	i++;
+
+	return ctx->write(ctx->buffer, b, i);
+}
+
+bare_error
+bare_get_uint(struct bare_reader *ctx, uint64_t *x)
+{
+	bare_error err = BARE_ERROR_NONE;
+
+	uint8_t shift = 0;
+	uint64_t result = 0;
+
+	for (uint8_t i = 0;i < 10;i++) {
+		uint8_t b;
+
+		err = ctx->read(ctx->buffer, &b, U8SZ);
+		if (err != BARE_ERROR_NONE) {
+			break;
+		}
+
+		if (b < 0x80) {
+			result |= (uint64_t)b << shift;
+			break;
+		} else {
+			result |= ((uint64_t)b & 0x7f) << shift;
+			shift += 7;
+		}
+	}
+
+	*x = result;
+
+	return err;
+}
+
+bare_error
+bare_put_int(struct bare_writer *ctx, int64_t x)
+{
+	uint64_t ux = (uint64_t)x << 1;
+
+	if (x < 0) {
+		ux = ~ux;
+	}
+
+	return bare_put_uint(ctx, ux);
+}
+
+bare_error
+bare_get_int(struct bare_reader *ctx, int64_t *x)
+{
+	uint64_t ux;
+
+	bare_error err = bare_get_uint(ctx, &ux);
+
+	if (err == BARE_ERROR_NONE) {
+		*x = (int64_t)(ux >> 1);
+
+		if ((ux & 1) != 0) {
+			*x = ~(*x);
+		}
+	}
+
+	return err;
+}
+
+bare_error
+bare_put_u8(struct bare_writer *ctx, uint8_t x)
+{
+	return ctx->write(ctx->buffer, &x, U8SZ);
+}
+
+bare_error
+bare_get_u8(struct bare_reader *ctx, uint8_t *x)
+{
+	return ctx->read(ctx->buffer, x, U8SZ);
+}
+
+bare_error
+bare_put_u16(struct bare_writer *ctx, uint16_t x)
+{
+	return ctx->write(ctx->buffer, (uint8_t[U16SZ]){x, x >> 8}, U16SZ);
+}
+
+bare_error
+bare_get_u16(struct bare_reader *ctx, uint16_t *x)
+{
+	bare_error err = ctx->read(ctx->buffer, x, U16SZ);
+
+	if (err == BARE_ERROR_NONE) {
+		*x = (uint16_t)((uint8_t *)x)[0]
+		   | (uint16_t)((uint8_t *)x)[1] << 8;
+	}
+
+	return err;
+}
+
+bare_error
+bare_put_u32(struct bare_writer *ctx, uint32_t x)
+{
+	uint8_t buf[U32SZ];
+
+	buf[0] = (uint8_t)(x);
+	buf[1] = (uint8_t)(x >> 8);
+	buf[2] = (uint8_t)(x >> 16);
+	buf[3] = (uint8_t)(x >> 24);
+
+	return ctx->write(ctx->buffer, buf, U32SZ);
+}
+
+bare_error
+bare_get_u32(struct bare_reader *ctx, uint32_t *x)
+{
+	bare_error err = ctx->read(ctx->buffer, x, U32SZ);
+
+	if (err == BARE_ERROR_NONE) {
+		*x = (uint32_t)(((uint8_t *)x)[0])
+		   | (uint32_t)(((uint8_t *)x)[1] << 8)
+		   | (uint32_t)(((uint8_t *)x)[2] << 16)
+		   | (uint32_t)(((uint8_t *)x)[3] << 24);
+	}
+
+	return err;
+}
+
+bare_error
+bare_put_u64(struct bare_writer *ctx, uint64_t x)
+{
+	uint8_t buf[U64SZ];
+
+	buf[0] = x;
+	buf[1] = x >> 8;
+	buf[2] = x >> 16;
+	buf[3] = x >> 24;
+	buf[4] = x >> 32;
+	buf[5] = x >> 40;
+	buf[6] = x >> 48;
+	buf[7] = x >> 56;
+
+	return ctx->write(ctx->buffer, buf, U64SZ);
+}
+
+bare_error
+bare_get_u64(struct bare_reader *ctx, uint64_t *x)
+{
+	bare_error err = ctx->read(ctx->buffer, x, U64SZ);
+
+	if (err == BARE_ERROR_NONE) {
+		*x = (uint64_t)((uint8_t *)x)[0]
+		   | (uint64_t)((uint8_t *)x)[1] << 8
+		   | (uint64_t)((uint8_t *)x)[2] << 16
+		   | (uint64_t)((uint8_t *)x)[3] << 24
+		   | (uint64_t)((uint8_t *)x)[4] << 32
+		   | (uint64_t)((uint8_t *)x)[5] << 40
+		   | (uint64_t)((uint8_t *)x)[6] << 48
+		   | (uint64_t)((uint8_t *)x)[7] << 56;
+	}
+
+	return err;
+}
+
+bare_error
+bare_put_i8(struct bare_writer *ctx, int8_t x)
+{
+	return bare_put_u8(ctx, x);
+}
+
+bare_error
+bare_get_i8(struct bare_reader *ctx, int8_t *x)
+{
+	return bare_get_u8(ctx, (uint8_t *)x);
+}
+
+bare_error
+bare_put_i16(struct bare_writer *ctx, int16_t x)
+{
+	return bare_put_u16(ctx, x);
+}
+
+bare_error
+bare_get_i16(struct bare_reader *ctx, int16_t *x)
+{
+	return bare_get_u16(ctx, (uint16_t *)x);
+}
+
+bare_error
+bare_put_i32(struct bare_writer *ctx, int32_t x)
+{
+	return bare_put_u32(ctx, x);
+}
+
+bare_error
+bare_get_i32(struct bare_reader *ctx, int32_t *x)
+{
+	return bare_get_u32(ctx, (uint32_t *)x);
+}
+
+bare_error
+bare_put_i64(struct bare_writer *ctx, int64_t x)
+{
+	return bare_put_u64(ctx, x);
+}
+
+bare_error
+bare_get_i64(struct bare_reader *ctx, int64_t *x)
+{
+	return bare_get_u64(ctx, (uint64_t *)x);
+}
+
+bare_error
+bare_put_f32(struct bare_writer *ctx, float x)
+{
+	uint32_t b;
+	memcpy(&b, &x, U32SZ);
+
+	return bare_put_u32(ctx, b);
+}
+
+bare_error
+bare_get_f32(struct bare_reader *ctx, float *x)
+{
+	return ctx->read(ctx->buffer, x, U32SZ);
+}
+
+bare_error
+bare_put_f64(struct bare_writer *ctx, double x)
+{
+	uint64_t b;
+	memcpy(&b, &x, U64SZ);
+
+	return bare_put_u64(ctx, b);
+}
+
+bare_error
+bare_get_f64(struct bare_reader *ctx, double *x)
+{
+	return ctx->read(ctx->buffer, x, U64SZ);
+}
+
+bare_error
+bare_put_bool(struct bare_writer *ctx, bool x)
+{
+	return bare_put_u8(ctx, (uint8_t)x);
+}
+
+bare_error
+bare_get_bool(struct bare_reader *ctx, bool *x)
+{
+	return bare_get_u8(ctx, (uint8_t *)x);
+}
+
+bare_error
+bare_put_fixed_data(struct bare_writer *ctx, uint8_t *src, uint64_t sz)
+{
+	return ctx->write(ctx->buffer, (void *)src, sz);
+}
+
+bare_error
+bare_get_fixed_data(struct bare_reader *ctx, uint8_t *dst, uint64_t sz)
+{
+	return ctx->read(ctx->buffer, dst, sz);
+}
+
+bare_error
+bare_put_data(struct bare_writer *ctx, uint8_t *src, uint64_t sz)
+{
+	bare_error err = BARE_ERROR_NONE;
+
+	err = bare_put_uint(ctx, sz);
+
+	if (err == BARE_ERROR_NONE) {
+		err = bare_put_fixed_data(ctx, src, sz);
+	}
+
+	return err;
+}
+
+bare_error
+bare_get_data(struct bare_reader *ctx, uint8_t *dst, uint64_t sz)
+{
+	bare_error err = BARE_ERROR_NONE;
+	uint64_t ssz = 0;
+
+	err = bare_get_uint(ctx, &ssz);
+
+	if (err == BARE_ERROR_NONE) {
+		err = ssz <= sz \
+			? bare_get_fixed_data(ctx, dst, ssz) \
+			: BARE_ERROR_BUFFER_TOO_SMALL;
+	}
+
+	return err;
+}
+
+bare_error
+bare_put_str(struct bare_writer *ctx, char *src, uint64_t sz)
+{
+	if (!checkstr(src, sz)) {
+		return BARE_ERROR_INVALID_UTF8;
+	}
+
+	return bare_put_data(ctx, (uint8_t *)src, sz);
+}
+
+bare_error
+bare_get_str(struct bare_reader *ctx, char *dst, uint64_t sz)
+{
+	bare_error err = bare_get_data(ctx, (uint8_t *)dst, sz);\
+
+	if (err == BARE_ERROR_NONE) {
+		err = !checkstr(dst, sz) ? BARE_ERROR_INVALID_UTF8 : err;
+	}
+
+	return err;
+}