diff options
author | Joshua Haberman <joshua@reverberate.org> | 2011-02-13 12:59:54 -0800 |
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committer | Joshua Haberman <joshua@reverberate.org> | 2011-02-13 12:59:54 -0800 |
commit | 6bdbb45e88e7b88b294dfb6e4cb493cbc3c8cf74 (patch) | |
tree | 0e00246fb124ebdf6a2210c816704c1d840e2138 /src/upb_encoder.c | |
parent | ee84a7da167d2211066c4a663d41febdf9544438 (diff) |
Merged core/ and stream/ -> src/. The split wasn't worth it.
Diffstat (limited to 'src/upb_encoder.c')
-rw-r--r-- | src/upb_encoder.c | 420 |
1 files changed, 420 insertions, 0 deletions
diff --git a/src/upb_encoder.c b/src/upb_encoder.c new file mode 100644 index 0000000..304a423 --- /dev/null +++ b/src/upb_encoder.c @@ -0,0 +1,420 @@ +/* + * upb - a minimalist implementation of protocol buffers. + * + * Copyright (c) 2009 Joshua Haberman. See LICENSE for details. + */ + +#include "upb_encoder.h" + +#include <stdlib.h> +#include "descriptor.h" + +/* Functions for calculating sizes of wire values. ****************************/ + +static size_t upb_v_uint64_t_size(uint64_t val) { +#ifdef __GNUC__ + int high_bit = 63 - __builtin_clzll(val); // 0-based, undef if val == 0. +#else + int high_bit = 0; + uint64_t tmp = val; + while(tmp >>= 1) high_bit++; +#endif + return val == 0 ? 1 : high_bit / 7 + 1; +} + +static size_t upb_v_int32_t_size(int32_t val) { + // v_uint32's are sign-extended to maintain wire compatibility with int64s. + return upb_v_uint64_t_size((int64_t)val); +} +static size_t upb_v_uint32_t_size(uint32_t val) { + return upb_v_uint64_t_size(val); +} +static size_t upb_f_uint64_t_size(uint64_t val) { + (void)val; // Length is independent of value. + return sizeof(uint64_t); +} +static size_t upb_f_uint32_t_size(uint32_t val) { + (void)val; // Length is independent of value. + return sizeof(uint32_t); +} + + +/* Functions to write wire values. ********************************************/ + +// Since we know in advance the longest that the value could be, we always make +// sure that our buffer is long enough. This saves us from having to perform +// bounds checks. + +// Puts a varint (wire type: UPB_WIRE_TYPE_VARINT). +static uint8_t *upb_put_v_uint64_t(uint8_t *buf, uint64_t val) +{ + do { + uint8_t byte = val & 0x7f; + val >>= 7; + if(val) byte |= 0x80; + *buf++ = byte; + } while(val); + return buf; +} + +// Puts an unsigned 32-bit varint, verbatim. Never uses the high 64 bits. +static uint8_t *upb_put_v_uint32_t(uint8_t *buf, uint32_t val) +{ + return upb_put_v_uint64_t(buf, val); +} + +// Puts a signed 32-bit varint, first sign-extending to 64-bits. We do this to +// maintain wire-compatibility with 64-bit signed integers. +static uint8_t *upb_put_v_int32_t(uint8_t *buf, int32_t val) +{ + return upb_put_v_uint64_t(buf, (int64_t)val); +} + +static void upb_put32(uint8_t *buf, uint32_t val) { + buf[0] = val & 0xff; + buf[1] = (val >> 8) & 0xff; + buf[2] = (val >> 16) & 0xff; + buf[3] = (val >> 24); +} + +// Puts a fixed-length 32-bit integer (wire type: UPB_WIRE_TYPE_32BIT). +static uint8_t *upb_put_f_uint32_t(uint8_t *buf, uint32_t val) +{ + uint8_t *uint32_end = buf + sizeof(uint32_t); +#if UPB_UNALIGNED_READS_OK + *(uint32_t*)buf = val; +#else + upb_put32(buf, val); +#endif + return uint32_end; +} + +// Puts a fixed-length 64-bit integer (wire type: UPB_WIRE_TYPE_64BIT). +static uint8_t *upb_put_f_uint64_t(uint8_t *buf, uint64_t val) +{ + uint8_t *uint64_end = buf + sizeof(uint64_t); +#if UPB_UNALIGNED_READS_OK + *(uint64_t*)buf = val; +#else + upb_put32(buf, (uint32_t)val); + upb_put32(buf, (uint32_t)(val >> 32)); +#endif + return uint64_end; +} + +/* Functions to write and calculate sizes for .proto values. ******************/ + +// Performs zig-zag encoding, which is used by sint32 and sint64. +static uint32_t upb_zzenc_32(int32_t n) { return (n << 1) ^ (n >> 31); } +static uint64_t upb_zzenc_64(int64_t n) { return (n << 1) ^ (n >> 63); } + +/* Use macros to define a set of two functions for each .proto type: + * + * // Converts and writes a .proto value into buf. "end" indicates the end + * // of the current available buffer (if the buffer does not contain enough + * // space UPB_STATUS_NEED_MORE_DATA is returned). On success, *outbuf will + * // point one past the data that was written. + * uint8_t *upb_put_INT32(uint8_t *buf, int32_t val); + * + * // Returns the number of bytes required to encode val. + * size_t upb_get_INT32_size(int32_t val); + * + * // Given a .proto value s (source) convert it to a wire value. + * uint32_t upb_vtowv_INT32(int32_t s); + */ + +#define VTOWV(type, wire_t, val_t) \ + static wire_t upb_vtowv_ ## type(val_t s) + +#define PUT(type, v_or_f, wire_t, val_t, member_name) \ + static uint8_t *upb_put_ ## type(uint8_t *buf, val_t val) { \ + wire_t tmp = upb_vtowv_ ## type(val); \ + return upb_put_ ## v_or_f ## _ ## wire_t(buf, tmp); \ + } + +#define T(type, v_or_f, wire_t, val_t, member_name) \ + static size_t upb_get_ ## type ## _size(val_t val) { \ + return upb_ ## v_or_f ## _ ## wire_t ## _size(val); \ + } \ + VTOWV(type, wire_t, val_t); /* prototype for PUT below */ \ + PUT(type, v_or_f, wire_t, val_t, member_name) \ + VTOWV(type, wire_t, val_t) + +T(INT32, v, int32_t, int32_t, int32) { return (uint32_t)s; } +T(INT64, v, uint64_t, int64_t, int64) { return (uint64_t)s; } +T(UINT32, v, uint32_t, uint32_t, uint32) { return s; } +T(UINT64, v, uint64_t, uint64_t, uint64) { return s; } +T(SINT32, v, uint32_t, int32_t, int32) { return upb_zzenc_32(s); } +T(SINT64, v, uint64_t, int64_t, int64) { return upb_zzenc_64(s); } +T(FIXED32, f, uint32_t, uint32_t, uint32) { return s; } +T(FIXED64, f, uint64_t, uint64_t, uint64) { return s; } +T(SFIXED32, f, uint32_t, int32_t, int32) { return (uint32_t)s; } +T(SFIXED64, f, uint64_t, int64_t, int64) { return (uint64_t)s; } +T(BOOL, v, uint32_t, bool, _bool) { return (uint32_t)s; } +T(ENUM, v, uint32_t, int32_t, int32) { return (uint32_t)s; } +T(DOUBLE, f, uint64_t, double, _double) { + upb_value v; + v._double = s; + return v.uint64; +} +T(FLOAT, f, uint32_t, float, _float) { + upb_value v; + v._float = s; + return v.uint32; +} +#undef VTOWV +#undef PUT +#undef T + +static uint8_t *upb_encode_value(uint8_t *buf, upb_field_type_t ft, upb_value v) +{ +#define CASE(t, member_name) \ + case UPB_TYPE(t): return upb_put_ ## t(buf, v.member_name); + switch(ft) { + CASE(DOUBLE, _double) + CASE(FLOAT, _float) + CASE(INT32, int32) + CASE(INT64, int64) + CASE(UINT32, uint32) + CASE(UINT64, uint64) + CASE(SINT32, int32) + CASE(SINT64, int64) + CASE(FIXED32, uint32) + CASE(FIXED64, uint64) + CASE(SFIXED32, int32) + CASE(SFIXED64, int64) + CASE(BOOL, _bool) + CASE(ENUM, int32) + default: assert(false); return buf; + } +#undef CASE +} + +static uint32_t _upb_get_value_size(upb_field_type_t ft, upb_value v) +{ +#define CASE(t, member_name) \ + case UPB_TYPE(t): return upb_get_ ## t ## _size(v.member_name); + switch(ft) { + CASE(DOUBLE, _double) + CASE(FLOAT, _float) + CASE(INT32, int32) + CASE(INT64, int64) + CASE(UINT32, uint32) + CASE(UINT64, uint64) + CASE(SINT32, int32) + CASE(SINT64, int64) + CASE(FIXED32, uint32) + CASE(FIXED64, uint64) + CASE(SFIXED32, int32) + CASE(SFIXED64, int64) + CASE(BOOL, _bool) + CASE(ENUM, int32) + default: assert(false); return 0; + } +#undef CASE +} + +static uint8_t *_upb_put_tag(uint8_t *buf, upb_field_number_t num, + upb_wire_type_t wt) +{ + return upb_put_UINT32(buf, wt | (num << 3)); +} + +static uint32_t _upb_get_tag_size(upb_field_number_t num) +{ + return upb_get_UINT32_size(num << 3); +} + + +/* upb_sizebuilder ************************************************************/ + +struct upb_sizebuilder { + // Accumulating size for the current level. + uint32_t size; + + // Stack of sizes for our current nesting. + uint32_t stack[UPB_MAX_NESTING], *top; + + // Vector of sizes. + uint32_t *sizes; + int sizes_len; + int sizes_size; + + upb_status status; +}; + +// upb_sink callbacks. +static upb_sink_status _upb_sizebuilder_valuecb(upb_sink *sink, upb_fielddef *f, + upb_value val, + upb_status *status) +{ + (void)status; + upb_sizebuilder *sb = (upb_sizebuilder*)sink; + uint32_t size = 0; + size += _upb_get_tag_size(f->number); + size += _upb_get_value_size(f->type, val); + sb->size += size; + return UPB_SINK_CONTINUE; +} + +static upb_sink_status _upb_sizebuilder_strcb(upb_sink *sink, upb_fielddef *f, + upb_strptr str, + int32_t start, uint32_t end, + upb_status *status) +{ + (void)status; + (void)str; // String data itself is not used. + upb_sizebuilder *sb = (upb_sizebuilder*)sink; + if(start >= 0) { + uint32_t size = 0; + size += _upb_get_tag_size(f->number); + size += upb_get_UINT32_size(end - start); + sb->size += size; + } + return UPB_SINK_CONTINUE; +} + +static upb_sink_status _upb_sizebuilder_startcb(upb_sink *sink, upb_fielddef *f, + upb_status *status) +{ + (void)status; + (void)f; // Unused (we calculate tag size and delimiter in endcb). + upb_sizebuilder *sb = (upb_sizebuilder*)sink; + if(f->type == UPB_TYPE(MESSAGE)) { + *sb->top = sb->size; + sb->top++; + sb->size = 0; + } else { + assert(f->type == UPB_TYPE(GROUP)); + sb->size += _upb_get_tag_size(f->number); + } + return UPB_SINK_CONTINUE; +} + +static upb_sink_status _upb_sizebuilder_endcb(upb_sink *sink, upb_fielddef *f, + upb_status *status) +{ + (void)status; + upb_sizebuilder *sb = (upb_sizebuilder*)sink; + if(f->type == UPB_TYPE(MESSAGE)) { + sb->top--; + if(sb->sizes_len == sb->sizes_size) { + sb->sizes_size *= 2; + sb->sizes = realloc(sb->sizes, sb->sizes_size * sizeof(*sb->sizes)); + } + uint32_t child_size = sb->size; + uint32_t parent_size = *sb->top; + sb->sizes[sb->sizes_len++] = child_size; + // The size according to the parent includes the tag size and delimiter of + // the submessage. + parent_size += upb_get_UINT32_size(child_size); + parent_size += _upb_get_tag_size(f->number); + // Include size accumulated in parent before child began. + sb->size = child_size + parent_size; + } else { + assert(f->type == UPB_TYPE(GROUP)); + // As an optimization, we could just add this number twice in startcb, to + // avoid having to recalculate it. + sb->size += _upb_get_tag_size(f->number); + } + return UPB_SINK_CONTINUE; +} + +upb_sink_callbacks _upb_sizebuilder_sink_vtbl = { + _upb_sizebuilder_valuecb, + _upb_sizebuilder_strcb, + _upb_sizebuilder_startcb, + _upb_sizebuilder_endcb +}; + + +/* upb_sink callbacks *********************************************************/ + +struct upb_encoder { + upb_sink base; + //upb_bytesink *bytesink; + uint32_t *sizes; + int size_offset; +}; + + +// Within one callback we may need to encode up to two separate values. +#define UPB_ENCODER_BUFSIZE (UPB_MAX_ENCODED_SIZE * 2) + +static upb_sink_status _upb_encoder_push_buf(upb_encoder *s, const uint8_t *buf, + size_t len, upb_status *status) +{ + // TODO: conjure a upb_strptr that points to buf. + //upb_strptr ptr; + (void)s; + (void)buf; + (void)status; + size_t written = 5;// = upb_bytesink_onbytes(s->bytesink, ptr); + if(written < len) { + // TODO: mark to skip "written" bytes next time. + return UPB_SINK_STOP; + } else { + return UPB_SINK_CONTINUE; + } +} + +static upb_sink_status _upb_encoder_valuecb(upb_sink *sink, upb_fielddef *f, + upb_value val, upb_status *status) +{ + upb_encoder *s = (upb_encoder*)sink; + uint8_t buf[UPB_ENCODER_BUFSIZE], *ptr = buf; + upb_wire_type_t wt = upb_types[f->type].expected_wire_type; + // TODO: handle packed encoding. + ptr = _upb_put_tag(ptr, f->number, wt); + ptr = upb_encode_value(ptr, f->type, val); + return _upb_encoder_push_buf(s, buf, ptr - buf, status); +} + +static upb_sink_status _upb_encoder_strcb(upb_sink *sink, upb_fielddef *f, + upb_strptr str, + int32_t start, uint32_t end, + upb_status *status) +{ + upb_encoder *s = (upb_encoder*)sink; + uint8_t buf[UPB_ENCODER_BUFSIZE], *ptr = buf; + if(start >= 0) { + ptr = _upb_put_tag(ptr, f->number, UPB_WIRE_TYPE_DELIMITED); + ptr = upb_put_UINT32(ptr, end - start); + } + // TODO: properly handle partially consumed strings and partially supplied + // strings. + _upb_encoder_push_buf(s, buf, ptr - buf, status); + return _upb_encoder_push_buf(s, (uint8_t*)upb_string_getrobuf(str), end - start, status); +} + +static upb_sink_status _upb_encoder_startcb(upb_sink *sink, upb_fielddef *f, + upb_status *status) +{ + upb_encoder *s = (upb_encoder*)sink; + uint8_t buf[UPB_ENCODER_BUFSIZE], *ptr = buf; + if(f->type == UPB_TYPE(GROUP)) { + ptr = _upb_put_tag(ptr, f->number, UPB_WIRE_TYPE_START_GROUP); + } else { + ptr = _upb_put_tag(ptr, f->number, UPB_WIRE_TYPE_DELIMITED); + ptr = upb_put_UINT32(ptr, s->sizes[--s->size_offset]); + } + return _upb_encoder_push_buf(s, buf, ptr - buf, status); +} + +static upb_sink_status _upb_encoder_endcb(upb_sink *sink, upb_fielddef *f, + upb_status *status) +{ + upb_encoder *s = (upb_encoder*)sink; + uint8_t buf[UPB_ENCODER_BUFSIZE], *ptr = buf; + if(f->type != UPB_TYPE(GROUP)) return UPB_SINK_CONTINUE; + ptr = _upb_put_tag(ptr, f->number, UPB_WIRE_TYPE_END_GROUP); + return _upb_encoder_push_buf(s, buf, ptr - buf, status); +} + +upb_sink_callbacks _upb_encoder_sink_vtbl = { + _upb_encoder_valuecb, + _upb_encoder_strcb, + _upb_encoder_startcb, + _upb_encoder_endcb +}; + |