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https://github.com/Z3Prover/z3
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671faf8f1c
* Initial plan * Update z3 codebase to use std::string_view (except z3++.h) - Updated params.cpp/h to use string_view internally for parameter descriptions - Updated trace.h/cpp to accept string_view for trace tag functions - Updated hash.h/cpp to use string_view for string_hash function - Updated all callers of string_hash to use string_view - Properly handled nullptr to empty string_view conversions - All tests passing Co-authored-by: NikolajBjorner <3085284+NikolajBjorner@users.noreply.github.com> * Add missing string_view includes to headers Co-authored-by: NikolajBjorner <3085284+NikolajBjorner@users.noreply.github.com> --------- Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com> Co-authored-by: NikolajBjorner <3085284+NikolajBjorner@users.noreply.github.com>
95 lines
2.2 KiB
C++
95 lines
2.2 KiB
C++
/*++
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Copyright (c) 2006 Microsoft Corporation
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Module Name:
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hash.cpp
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Abstract:
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Basic hash computation support.
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Author:
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Leonardo de Moura (leonardo) 2006-09-11.
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Revision History:
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--*/
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#include "util/debug.h"
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#include "util/hash.h"
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#include <string.h>
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static unsigned read_unsigned(const char *s) {
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unsigned n;
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memcpy(&n, s, sizeof(unsigned));
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return n;
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}
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// I'm using Bob Jenkin's hash function.
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// http://burtleburtle.net/bob/hash/doobs.html
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unsigned string_hash(std::string_view str, unsigned init_value) {
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unsigned a, b, c, len;
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const char * data = str.data();
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unsigned length = static_cast<unsigned>(str.length());
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/* Set up the internal state */
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len = length;
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a = b = 0x9e3779b9; /* the golden ratio; an arbitrary value */
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c = init_value; /* the previous hash value */
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/*---------------------------------------- handle most of the key */
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SASSERT(sizeof(unsigned) == 4);
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while (len >= 12) {
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a += read_unsigned(data);
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b += read_unsigned(data+4);
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c += read_unsigned(data+8);
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mix(a,b,c);
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data += 12; len -= 12;
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}
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/*------------------------------------- handle the last 11 bytes */
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c += length;
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switch(len) { /* all the case statements fall through */
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case 11:
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c+=((unsigned)data[10]<<24);
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Z3_fallthrough;
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case 10:
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c+=((unsigned)data[9]<<16);
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Z3_fallthrough;
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case 9 :
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c+=((unsigned)data[8]<<8);
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Z3_fallthrough;
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/* the first byte of c is reserved for the length */
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case 8 :
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b+=((unsigned)data[7]<<24);
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Z3_fallthrough;
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case 7 :
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b+=((unsigned)data[6]<<16);
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Z3_fallthrough;
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case 6 :
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b+=((unsigned)data[5]<<8);
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Z3_fallthrough;
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case 5 :
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b+=data[4];
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Z3_fallthrough;
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case 4 :
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a+=((unsigned)data[3]<<24);
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Z3_fallthrough;
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case 3 :
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a+=((unsigned)data[2]<<16);
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Z3_fallthrough;
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case 2 :
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a+=((unsigned)data[1]<<8);
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Z3_fallthrough;
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case 1 :
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a+=data[0];
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/* case 0: nothing left to add */
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break;
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}
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mix(a,b,c);
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/*-------------------------------------------- report the result */
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return c;
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}
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