| 1 | /* |
| 2 | * Common Trace Format |
| 3 | * |
| 4 | * Floating point read/write functions. |
| 5 | * |
| 6 | * Copyright 2010-2011 EfficiOS Inc. and Linux Foundation |
| 7 | * |
| 8 | * Author: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 9 | * |
| 10 | * Permission is hereby granted, free of charge, to any person obtaining a copy |
| 11 | * of this software and associated documentation files (the "Software"), to deal |
| 12 | * in the Software without restriction, including without limitation the rights |
| 13 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
| 14 | * copies of the Software, and to permit persons to whom the Software is |
| 15 | * furnished to do so, subject to the following conditions: |
| 16 | * |
| 17 | * The above copyright notice and this permission notice shall be included in |
| 18 | * all copies or substantial portions of the Software. |
| 19 | * |
| 20 | * Reference: ISO C99 standard 5.2.4 |
| 21 | */ |
| 22 | |
| 23 | #include <babeltrace/ctf/types.h> |
| 24 | #include <glib.h> |
| 25 | #include <float.h> /* C99 floating point definitions */ |
| 26 | #include <limits.h> /* C99 limits */ |
| 27 | #include <babeltrace/endian.h> |
| 28 | |
| 29 | /* |
| 30 | * This library is limited to binary representation of floating point values. |
| 31 | * We use hardware support for conversion between 32 and 64-bit floating |
| 32 | * point values. |
| 33 | */ |
| 34 | |
| 35 | /* |
| 36 | * Aliasing float/double and unsigned long is not strictly permitted by strict |
| 37 | * aliasing, but in practice declaration prunning is well supported, and this permits |
| 38 | * us to use per-word read/writes rather than per-byte. |
| 39 | */ |
| 40 | |
| 41 | #if defined(__GNUC__) || defined(__MINGW32__) || defined(_MSC_VER) |
| 42 | #define HAS_TYPE_PRUNING |
| 43 | #endif |
| 44 | |
| 45 | #if (FLT_RADIX != 2) |
| 46 | |
| 47 | #error "Unsupported floating point radix" |
| 48 | |
| 49 | #endif |
| 50 | |
| 51 | union doubleIEEE754 { |
| 52 | double vd; |
| 53 | float vf; |
| 54 | #ifdef HAS_TYPE_PRUNING |
| 55 | unsigned long bits[(sizeof(double) + sizeof(unsigned long) - 1) / sizeof(unsigned long)]; |
| 56 | #else |
| 57 | unsigned char bits[sizeof(double)]; |
| 58 | #endif |
| 59 | }; |
| 60 | |
| 61 | static struct declaration_float *static_float_declaration, |
| 62 | *static_double_declaration; |
| 63 | |
| 64 | struct pos_len { |
| 65 | size_t sign_start, exp_start, mantissa_start, len; |
| 66 | }; |
| 67 | |
| 68 | int _ctf_float_copy(struct stream_pos *destp, |
| 69 | struct definition_float *dest_definition, |
| 70 | struct stream_pos *srcp, |
| 71 | const struct definition_float *src_definition) |
| 72 | { |
| 73 | int ret; |
| 74 | |
| 75 | /* We only support copy of same-size floats for now */ |
| 76 | assert(src_definition->declaration->sign->len == |
| 77 | dest_definition->declaration->sign->len); |
| 78 | assert(src_definition->declaration->exp->len == |
| 79 | dest_definition->declaration->exp->len); |
| 80 | assert(src_definition->declaration->mantissa->len == |
| 81 | dest_definition->declaration->mantissa->len); |
| 82 | /* Read */ |
| 83 | if (src_definition->declaration->byte_order == LITTLE_ENDIAN) { |
| 84 | ret = ctf_integer_read(srcp, &src_definition->mantissa->p); |
| 85 | if (ret) |
| 86 | return ret; |
| 87 | ret = ctf_integer_read(srcp, &src_definition->exp->p); |
| 88 | if (ret) |
| 89 | return ret; |
| 90 | ret = ctf_integer_read(srcp, &src_definition->sign->p); |
| 91 | if (ret) |
| 92 | return ret; |
| 93 | } else { |
| 94 | ret = ctf_integer_read(srcp, &src_definition->sign->p); |
| 95 | if (ret) |
| 96 | return ret; |
| 97 | ret = ctf_integer_read(srcp, &src_definition->exp->p); |
| 98 | if (ret) |
| 99 | return ret; |
| 100 | ret = ctf_integer_read(srcp, &src_definition->mantissa->p); |
| 101 | if (ret) |
| 102 | return ret; |
| 103 | } |
| 104 | |
| 105 | dest_definition->mantissa->value._unsigned = |
| 106 | src_definition->mantissa->value._unsigned; |
| 107 | dest_definition->exp->value._signed = |
| 108 | src_definition->exp->value._signed; |
| 109 | dest_definition->sign->value._unsigned = |
| 110 | src_definition->sign->value._unsigned; |
| 111 | |
| 112 | /* Write */ |
| 113 | if (dest_definition->declaration->byte_order == LITTLE_ENDIAN) { |
| 114 | ret = ctf_integer_write(destp, &dest_definition->mantissa->p); |
| 115 | if (ret) |
| 116 | return ret; |
| 117 | ret = ctf_integer_write(destp, &dest_definition->exp->p); |
| 118 | if (ret) |
| 119 | return ret; |
| 120 | ret = ctf_integer_write(destp, &dest_definition->sign->p); |
| 121 | if (ret) |
| 122 | return ret; |
| 123 | } else { |
| 124 | ret = ctf_integer_write(destp, &dest_definition->sign->p); |
| 125 | if (ret) |
| 126 | return ret; |
| 127 | ret = ctf_integer_write(destp, &dest_definition->exp->p); |
| 128 | if (ret) |
| 129 | return ret; |
| 130 | ret = ctf_integer_write(destp, &dest_definition->mantissa->p); |
| 131 | if (ret) |
| 132 | return ret; |
| 133 | } |
| 134 | return 0; |
| 135 | } |
| 136 | |
| 137 | int ctf_float_read(struct stream_pos *ppos, struct definition *definition) |
| 138 | { |
| 139 | struct definition_float *float_definition = |
| 140 | container_of(definition, struct definition_float, p); |
| 141 | const struct declaration_float *float_declaration = |
| 142 | float_definition->declaration; |
| 143 | struct ctf_stream_pos *pos = ctf_pos(ppos); |
| 144 | union doubleIEEE754 u; |
| 145 | struct definition *tmpdef; |
| 146 | struct definition_float *tmpfloat; |
| 147 | struct ctf_stream_pos destp; |
| 148 | struct mmap_align mma; |
| 149 | int ret; |
| 150 | |
| 151 | switch (float_declaration->mantissa->len + 1) { |
| 152 | case FLT_MANT_DIG: |
| 153 | tmpdef = static_float_declaration->p.definition_new( |
| 154 | &static_float_declaration->p, |
| 155 | NULL, 0, 0, "__tmpfloat"); |
| 156 | break; |
| 157 | case DBL_MANT_DIG: |
| 158 | tmpdef = static_double_declaration->p.definition_new( |
| 159 | &static_double_declaration->p, |
| 160 | NULL, 0, 0, "__tmpfloat"); |
| 161 | break; |
| 162 | default: |
| 163 | return -EINVAL; |
| 164 | } |
| 165 | tmpfloat = container_of(tmpdef, struct definition_float, p); |
| 166 | memset(&destp, 0, sizeof(destp)); |
| 167 | ctf_init_pos(&destp, -1, O_RDWR); |
| 168 | mmap_align_set_addr(&mma, (char *) u.bits); |
| 169 | destp.base_mma = &mma; |
| 170 | destp.packet_size = sizeof(u) * CHAR_BIT; |
| 171 | ctf_align_pos(pos, float_declaration->p.alignment); |
| 172 | ret = _ctf_float_copy(&destp.parent, tmpfloat, ppos, float_definition); |
| 173 | switch (float_declaration->mantissa->len + 1) { |
| 174 | case FLT_MANT_DIG: |
| 175 | float_definition->value = u.vf; |
| 176 | break; |
| 177 | case DBL_MANT_DIG: |
| 178 | float_definition->value = u.vd; |
| 179 | break; |
| 180 | default: |
| 181 | return -EINVAL; |
| 182 | } |
| 183 | definition_unref(tmpdef); |
| 184 | return ret; |
| 185 | } |
| 186 | |
| 187 | int ctf_float_write(struct stream_pos *ppos, struct definition *definition) |
| 188 | { |
| 189 | struct definition_float *float_definition = |
| 190 | container_of(definition, struct definition_float, p); |
| 191 | const struct declaration_float *float_declaration = |
| 192 | float_definition->declaration; |
| 193 | struct ctf_stream_pos *pos = ctf_pos(ppos); |
| 194 | union doubleIEEE754 u; |
| 195 | struct definition *tmpdef; |
| 196 | struct definition_float *tmpfloat; |
| 197 | struct ctf_stream_pos srcp; |
| 198 | struct mmap_align mma; |
| 199 | int ret; |
| 200 | |
| 201 | switch (float_declaration->mantissa->len + 1) { |
| 202 | case FLT_MANT_DIG: |
| 203 | tmpdef = static_float_declaration->p.definition_new( |
| 204 | &static_float_declaration->p, |
| 205 | NULL, 0, 0, "__tmpfloat"); |
| 206 | break; |
| 207 | case DBL_MANT_DIG: |
| 208 | tmpdef = static_double_declaration->p.definition_new( |
| 209 | &static_double_declaration->p, |
| 210 | NULL, 0, 0, "__tmpfloat"); |
| 211 | break; |
| 212 | default: |
| 213 | return -EINVAL; |
| 214 | } |
| 215 | tmpfloat = container_of(tmpdef, struct definition_float, p); |
| 216 | ctf_init_pos(&srcp, -1, O_RDONLY); |
| 217 | mmap_align_set_addr(&mma, (char *) u.bits); |
| 218 | srcp.base_mma = &mma; |
| 219 | srcp.packet_size = sizeof(u) * CHAR_BIT; |
| 220 | switch (float_declaration->mantissa->len + 1) { |
| 221 | case FLT_MANT_DIG: |
| 222 | u.vf = float_definition->value; |
| 223 | break; |
| 224 | case DBL_MANT_DIG: |
| 225 | u.vd = float_definition->value; |
| 226 | break; |
| 227 | default: |
| 228 | return -EINVAL; |
| 229 | } |
| 230 | ctf_align_pos(pos, float_declaration->p.alignment); |
| 231 | ret = _ctf_float_copy(ppos, float_definition, &srcp.parent, tmpfloat); |
| 232 | definition_unref(tmpdef); |
| 233 | return ret; |
| 234 | } |
| 235 | |
| 236 | void __attribute__((constructor)) ctf_float_init(void) |
| 237 | { |
| 238 | static_float_declaration = |
| 239 | float_declaration_new(FLT_MANT_DIG, |
| 240 | sizeof(float) * CHAR_BIT - FLT_MANT_DIG, |
| 241 | BYTE_ORDER, |
| 242 | __alignof__(float)); |
| 243 | static_double_declaration = |
| 244 | float_declaration_new(DBL_MANT_DIG, |
| 245 | sizeof(double) * CHAR_BIT - DBL_MANT_DIG, |
| 246 | BYTE_ORDER, |
| 247 | __alignof__(double)); |
| 248 | } |
| 249 | |
| 250 | void __attribute__((destructor)) ctf_float_fini(void) |
| 251 | { |
| 252 | declaration_unref(&static_float_declaration->p); |
| 253 | declaration_unref(&static_double_declaration->p); |
| 254 | } |