/*
* Insert a jump offset at 'offset' to complete an instruction
* (the jump offset is always the last component of an instruction).
* The 'skip' argument must be computed relative to 'offset',
* -without- taking into account the skip field being inserted.
*
* ... A B C ins X Y Z ... (ins may be a JUMP, SPLIT1/SPLIT2, etc)
* => ... A B C ins SKIP X Y Z
*
* Computing the final (adjusted) skip value, which is relative to the
* first byte of the next instruction, is a bit tricky because of the
* variable length UTF-8 encoding. See doc/regexp.rst for discussion.
*/
DUK_LOCAL duk_uint32_t duk__insert_jump_offset(duk_re_compiler_ctx *re_ctx, duk_uint32_t offset, duk_int32_t skip) {
duk_small_int_t len;
/* XXX: solve into closed form (smaller code) */
if (skip < 0) {
/* two encoding attempts suffices */
len = duk_unicode_get_xutf8_length((duk_codepoint_t) duk__encode_i32(skip));
len = duk_unicode_get_xutf8_length((duk_codepoint_t) duk__encode_i32(skip - (duk_int32_t) len));
DUK_ASSERT(duk_unicode_get_xutf8_length(duk__encode_i32(skip - (duk_int32_t) len)) == len); /* no change */
skip -= (duk_int32_t) len;
}
return duk__insert_i32(re_ctx, offset, skip);
}
/* XXX: return type should probably be duk_size_t, or explicit checks are needed for
* maximum size.
*/
DUK_LOCAL duk_uint32_t duk__insert_u32(duk_re_compiler_ctx *re_ctx, duk_uint32_t offset, duk_uint32_t x) {
duk_uint8_t buf[DUK_UNICODE_MAX_XUTF8_LENGTH];
duk_small_int_t len;
len = duk_unicode_encode_xutf8((duk_ucodepoint_t) x, buf);
DUK_BW_INSERT_ENSURE_BYTES(re_ctx->thr, &re_ctx->bw, offset, buf, len);
return (duk_uint32_t) len;
}
DUK_LOCAL duk_uint32_t duk__append_u32(duk_re_compiler_ctx *re_ctx, duk_uint32_t x) {
duk_uint8_t buf[DUK_UNICODE_MAX_XUTF8_LENGTH];
duk_small_int_t len;
len = duk_unicode_encode_xutf8((duk_ucodepoint_t) x, buf);
DUK_BW_WRITE_ENSURE_BYTES(re_ctx->thr, &re_ctx->bw, buf, len);
return (duk_uint32_t) len;
}
DUK_LOCAL duk_uint32_t duk__insert_i32(duk_re_compiler_ctx *re_ctx, duk_uint32_t offset, duk_int32_t x) {
return duk__insert_u32(re_ctx, offset, duk__encode_i32(x));
}
#if 0 /* unused */
DUK_LOCAL duk_uint32_t duk__append_i32(duk_re_compiler_ctx *re_ctx, duk_int32_t x) {
return duk__append_u32(re_ctx, duk__encode_i32(x));
}
/*
* Insert a jump offset at 'offset' to complete an instruction
* (the jump offset is always the last component of an instruction).
* The 'skip' argument must be computed relative to 'offset',
* -without- taking into account the skip field being inserted.
*
* ... A B C ins X Y Z ... (ins may be a JUMP, SPLIT1/SPLIT2, etc)
* => ... A B C ins SKIP X Y Z
*
* Computing the final (adjusted) skip value, which is relative to the
* first byte of the next instruction, is a bit tricky because of the
* variable length UTF-8 encoding. See doc/regexp.rst for discussion.
*/
DUK_LOCAL duk_uint32_t duk__insert_jump_offset(duk_re_compiler_ctx *re_ctx, duk_uint32_t offset, duk_int32_t skip) {
#if 0
/* Iterative solution. */
if (skip < 0) {
duk_small_int_t len;
/* two encoding attempts suffices */
len = duk_unicode_get_xutf8_length((duk_codepoint_t) duk__encode_i32(skip));
len = duk_unicode_get_xutf8_length((duk_codepoint_t) duk__encode_i32(skip - (duk_int32_t) len));
DUK_ASSERT(duk_unicode_get_xutf8_length(duk__encode_i32(skip - (duk_int32_t) len)) == len); /* no change */
skip -= (duk_int32_t) len;
}
#endif
#if defined(DUK_USE_PREFER_SIZE)
/* Closed form solution, this produces smallest code.
* See re_neg_jump_offset (closed2).
*/
if (skip < 0) {
skip--;
if (skip < -0x3fL) {
skip--;
}
if (skip < -0x3ffL) {
skip--;
}
if (skip < -0x7fffL) {
skip--;
}
if (skip < -0xfffffL) {
skip--;
}
if (skip < -0x1ffffffL) {
skip--;
}
if (skip < -0x3fffffffL) {
skip--;
}
}
#else /* DUK_USE_PREFER_SIZE */
/* Closed form solution, this produces fastest code.
* See re_neg_jump_offset (closed1).
*/
if (skip < 0) {
if (skip >= -0x3eL) {
skip -= 1;
} else if (skip >= -0x3fdL) {
skip -= 2;
} else if (skip >= -0x7ffcL) {
skip -= 3;
} else if (skip >= -0xffffbL) {
skip -= 4;
} else if (skip >= -0x1fffffaL) {
skip -= 5;
} else if (skip >= -0x3ffffff9L) {
skip -= 6;
} else {
skip -= 7;
}
}
#endif /* DUK_USE_PREFER_SIZE */
return duk__insert_i32(re_ctx, offset, skip);
}
DUK_LOCAL duk_uint32_t duk__insert_i32(duk_re_compiler_ctx *re_ctx, duk_uint32_t offset, duk_int32_t x) {
return duk__insert_u32(re_ctx, offset, duk__encode_i32(x));
}
/* XXX: return type should probably be duk_size_t, or explicit checks are needed for
* maximum size.
*/
DUK_LOCAL duk_uint32_t duk__insert_u32(duk_re_compiler_ctx *re_ctx, duk_uint32_t offset, duk_uint32_t x) {
duk_uint8_t buf[DUK_UNICODE_MAX_XUTF8_LENGTH];
duk_small_int_t len;
len = duk_unicode_encode_xutf8((duk_ucodepoint_t) x, buf);
DUK_BW_INSERT_ENSURE_BYTES(re_ctx->thr, &re_ctx->bw, offset, buf, len);
return (duk_uint32_t) len;
}
DUK_LOCAL void duk__append_u32(duk_re_compiler_ctx *re_ctx, duk_uint32_t x) {
DUK_BW_WRITE_ENSURE_XUTF8(re_ctx->thr, &re_ctx->bw, x);
}
DUK_LOCAL void duk__append_7bit(duk_re_compiler_ctx *re_ctx, duk_uint32_t x) {
#if defined(DUK_USE_PREFER_SIZE)
duk__append_u32(re_ctx, x);
#else
DUK_ASSERT(x <= 0x7fU);
DUK_BW_WRITE_ENSURE_U8(re_ctx->thr, &re_ctx->bw, (duk_uint8_t) x);
#endif
}
#if 0
DUK_LOCAL void duk__append_2bytes(duk_re_compiler_ctx *re_ctx, duk_uint8_t x, duk_uint8_t y) {
DUK_BW_WRITE_ENSURE_U8_2(re_ctx->thr, &re_ctx->bw, x, y);
}
#endif
DUK_LOCAL duk_uint32_t duk__insert_i32(duk_re_compiler_ctx *re_ctx, duk_uint32_t offset, duk_int32_t x) {
return duk__insert_u32(re_ctx, offset, duk__encode_i32(x));
}
DUK_LOCAL void duk__append_reop(duk_re_compiler_ctx *re_ctx, duk_uint32_t reop) {
DUK_ASSERT(reop <= 0x7fU);
(void) duk__append_7bit(re_ctx, reop);
}
#if 0 /* unused */
DUK_LOCAL void duk__append_i32(duk_re_compiler_ctx *re_ctx, duk_int32_t x) {
duk__append_u32(re_ctx, duk__encode_i32(x));
}
